OzVMX Forum
Marque Remarks => Kawasaki => Topic started by: John Orchard on October 15, 2013, 11:44:08 am
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Well I finally got the KDX400A1/KX250A5 finished, now to test it out at The Farm this Friday. I have the '84 KX front end for the 'Pre 90' Thumpercross event in a couple of weeks, after that I'll put a sorted Evo front end in it for Open class Evo.
Mods ....
KDX400A1 '79 engine.
As new complete gearshafts replaced.
NOS shift drum.
NOS shift shaft.
NOS std bore KDX400 piston, rings, pin & small-end.
New main bearings and all crankcase seals.
Resleeve with sleeve thick enough to go to a 3mm bigger KX420 piston at a later date.
Ported barrel (opened tiny exhaust ports).
Increased reed-valve flow area 20% with full carbon reed petals.
New clutch plates.
Heavy duty EBC clutch springs.
New swingarm bearings & seals.
YSS rear shocks with adjustable compression & rebound damping.
New .46kg fork springs.
New headstem bearings.
KX250A6/420 triple-clamps have 10mm less offset, down from 35mm to 25mm, for more trail.
KX500 '84 lower chain guide.
New sealed chain rollers.
Std KDX400 pipe cut-up to fit.
Rear KDX400 engine hanger modified to fit 250A5 swingarm.
Hand-made front engine mounting plates.
Lower rear engine mounts cut-off and repositioned.
New folding gearlever.
Footpegs widened.
Still running KDX stator (external flywheel) with lighting coil.
New Nightmare plastics.
New Unifilter aircleaner.
KX250A5 38mm carb.
New clutch & throttle cables.
New kill-switch.
Ordered custom made KX400 decals (coming).
(http://i1093.photobucket.com/albums/i423/JohnnyRacer89/KX400RH_zpse21f0658.jpg) (http://s1093.photobucket.com/user/JohnnyRacer89/media/KX400RH_zpse21f0658.jpg.html)
(http://i1093.photobucket.com/albums/i423/JohnnyRacer89/KX400LH_zpse750f134.jpg) (http://s1093.photobucket.com/user/JohnnyRacer89/media/KX400LH_zpse750f134.jpg.html)
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Congrats John, my kind of Kawasaki!
Kt
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Awesome results JO, well done man 8).
I'm going to be in touch soon as I'm just about to start the exact same project myself. My KDX400 motor arrived from the USA yesterday.
So did the motor bolt straight into the frame as I've heard conflicting opinions on that?
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I'm going to be in touch soon as I'm just about to start the exact same project myself. My KDX400 motor arrived from the USA yesterday.
So did the motor bolt straight into the frame as I've heard conflicting opinions on that?
It took more work than I was expecting, not sure if I would have taken the job on had I known, maybe it just felt like a big job because I freshened-up the whole engine at the same time?
The rear 400A1 engine hanger had to be cut & shut to fit the narrower gap in the swing arm, the front engine plates needed to have the upper-rear bolt to be 5mm higher when compared to the stock 250 plates. The lower rear engine mounts had to be totally cut off and repositioned. Standard 400 head-stay bolted straight on, reed valve-carb-airbox joint lined-up perfect.
Had to turn the front sprocket around so the boss was facing out to line up the sprockets. Pipe clearance is a VERY tight squeeze, I spaced the tank up 4mm, would probably be ok if I was making a whole new pipe.
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It took more work than I was expecting, not sure if I would have taken the job on had I known, maybe it just felt like a big job because I freshened-up the whole engine at the same time?
The rear 400A1 engine hanger had to be cut & shut to fit the narrower gap in the swing arm, the front engine plates needed to have the upper-rear bolt to be 5mm higher when compared to the stock 250 plates. The lower rear engine mounts had to be totally cut off and repositioned. Standard 400 head-stay bolted straight on, reed valve-carb-airbox joint lined-up perfect.
Had to turn the front sprocket around so the boss was facing out to line up the sprockets. Pipe clearance is a VERY tight squeeze, I spaced the tank up 4mm, would probably be ok if I was making a whole new pipe.
Wow, a great effort there John, I have a big task ahead of me but all in good time. With my motor I also received the original KDX engine mounts, pipe, carby etc. I have a busy time for the rest of this year so it's a project for next year for me. Keep us up to date with your ride impressions after this weekend :)
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Great looking bike John, you must be happy with the result of all that work :D
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Nice work John, that looks bloody brilliant!
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Very nice John now you can mow the lawn
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Very nice John now you can mow the lawn
Ha ha ! Jodie only just said to me "you could have mowed the lawn before you took the pics", I said "it adds to the story for the bike, I haven't had time to mow it, been working on the bike" LOL
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Anyway, she did it only two weeks ago LOL
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Hey John is the throttle cable running over the top of the brake cable. I was told that is a big no no. I was told to always run them under the brake cable
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Hey John is the throttle cable running over the top of the brake cable. I was told that is a big no no. I was told to always run them under the brake cable
Good point, thanks Ted, I'll have a look at that. Don't want a 400 'coming-on' when I want to be slowing-down ;-)
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Nice Job, well worth the effort..hope it doesn't peg out at full throttle when you start it! :o
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Beautiful job John.
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Nice, im Green with envy....lol
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Looks like it came from the factory John. Very nice.
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Looks great John. Can't wait to hear what you think of how it rides.
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I forgot to say if you ever want to sell that complete front end.
I know a very good home for it.
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Sorry Shane, the '84 front normally lives on my 'Pre 85' KX250A5. I just put it on the 400 for the 'Pre 90' class at the Thumper-Cross meeting on Nov 2 & 3.
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That looks great John, a relatively easy fit ;) Inspiring me to get and do some work on my bikes ::)
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Sorry Shane, the '84 front normally lives on my 'Pre 85' KX250A5. I just put it on the 400 for the 'Pre 90' class at the Thumper-Cross meeting on Nov 2 & 3.
All good mate. If I pulled my finger out and had a look, I've probably got the bits.
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Tested at The Farm today .....
(http://i1093.photobucket.com/albums/i423/JohnnyRacer89/Bermbust1_zps546a7611.jpg) (http://s1093.photobucket.com/user/JohnnyRacer89/media/Bermbust1_zps546a7611.jpg.html)
(http://i1093.photobucket.com/albums/i423/JohnnyRacer89/Toplefthander_zps96a9bfaa.jpg) (http://s1093.photobucket.com/user/JohnnyRacer89/media/Toplefthander_zps96a9bfaa.jpg.html)
It sure was different to the 250, I went 'one up' on the front sprocket, not enough, have to find a much smaller rear now.
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John Titman in QLD can make sprockets for you John. I've dealt with him and can honestly say that his service is very old school (as in first rate) and his prices are very reasonable.
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I always wanted one of these and have been very tempted at times when Ive seen those KDX 400 going cheap.
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John Titman in QLD can make sprockets for you John. I've dealt with him and can honestly say that his service is very old school (as in first rate) and his prices are very reasonable.
i'll second that, Mr Titman isone of natures true gentlemen, old school for sure and does very good work, still on the tools too, good to see.
Kt.
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Well had my first outing at Lardner Park in Warragul on the weekend, it didn't go too bad,was running first in class until a crash in the last leg, ended-up third overall.
Our race was combined with the 'Pre 90' class, first race the KX was first home outright, beating a few water-cooled CR500's in the 'Pre 90' class! Took a second overall in the second race too, with many 'Pre 90' bikes behind.
Next on the list of things to improve~ The wide ratio gearbox (lower first & second) does not work on the mx track, now have a KX420 gearbox coming for it. I'll have to make a pipe for the bike; it had no top-end power, that combined with a wide-ratio box caused the bike to bog-down on the up-shifts if I didn't rev it into the gutless top-end. I'll try it with the noise-deadening mesh ripped-out to see if that helps, failing that it may be a trip to GMC is on the cards.
Below, getting the jump on the CR500 that won all but one race (which the KX won :-) )
(http://i1093.photobucket.com/albums/i423/JohnnyRacer89/LardnerParkHoleshot_zpsafa70f9c.jpg) (http://s1093.photobucket.com/user/JohnnyRacer89/media/LardnerParkHoleshot_zpsafa70f9c.jpg.html)
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PM sent re pipe.
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Ok now it's in 'Evo' form ready for 'Open class Evo'.
Fitted 250A5 front end with KDX400 triple-clamps with 10mm less offset and rubber mounted bar clamps. Forks have new .46kg springs, 4mm preload, 15wt oil at 170mm and original top-out springs cut & ground to 50mm long.
Pipe now has the mesh ripped out, will test this weekend.
Rear shocks now have straight-rate 15 N/mm springs fitted, feels good, I want to fit the same to my 250A5's.
(http://i1093.photobucket.com/albums/i423/JohnnyRacer89/KX400EvoLH_zps17690856.jpg) (http://s1093.photobucket.com/user/JohnnyRacer89/media/KX400EvoLH_zps17690856.jpg.html)
(http://i1093.photobucket.com/albums/i423/JohnnyRacer89/KX400EvoRH_zps5f8c2670.jpg) (http://s1093.photobucket.com/user/JohnnyRacer89/media/KX400EvoRH_zps5f8c2670.jpg.html)
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Look forward to seeing it on the grid evo all powers next year John, evo should be a bit more exciting in viper next year I have heard with the return of a few quick fellas. Looks better without the disc anyway!!
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Thanks Brendan :-) testing at the Farm this Sunday, coming?
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Let me know how those spring rates work out as I haven't ordered springs for the A5 yet. ;)
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John that looks great 8) 8) 8) IMHO it looked wrong with the disc front end ( although i could see your reasons for going that way )
In its current form it looks the dogs bollox ;D go out and enjoy it :)
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You best be sending me that one as well. I'll send it back so you go 1. 1 . next time ;D ;D
Looks great buddy.
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Thanks Guy's :-) I tested the bike today, even if I do say so myself, "bloody brilliant ride", aside from the front drum brake, this is possibly one of the best bikes I have ever ridden! With the pipe cleaned-out, the power is much broader, easy to control with the heavy flywheel. Probably not the most fire-breathing open-classer but so user friendly.
Much more comfortable with the rubber handlebar mounts over the rigid mounts of the '84 KX125 front-end that I just took off.
Just waiting on a smaller rear sprocket to land (which may mean I won't have to fit the KX420/500 gearbox) and I will be in heaven :-)
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I knew you would get it right mate.
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Tried the 48 tooth Talon sprocket (with 15 tooth front), it made 1st gear of the KDX400 box useable but the gap from first to second and second to third was too great. Now have all the parts from KX420 & KX500 to go in the gearbox.
(http://i1093.photobucket.com/albums/i423/JohnnyRacer89/KX400RRsprocket48t_zps6c86893b.jpg) (http://s1093.photobucket.com/user/JohnnyRacer89/media/KX400RRsprocket48t_zps6c86893b.jpg.html)
Had power loss from overheating, the vents in the front guard seem to have helped, I'll also try some higher octane fuel.
The rubber mounted bars tended to twist too easily, fitting a one-piece bar clamp cap from a later model (KX250F1) has fixed the issue.
(http://i1093.photobucket.com/albums/i423/JohnnyRacer89/KX400ventedguard_zpsff4d1c6b.jpg) (http://s1093.photobucket.com/user/JohnnyRacer89/media/KX400ventedguard_zpsff4d1c6b.jpg.html)
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Tried the 48 tooth Talon sprocket (with 15 tooth front), it made 1st gear of the KDX400 box useable but the gap from first to second and second to third was too great. Now have all the parts from KX420 & KX500 to go in the gearbox.
Run the ratios through Gearing Commander to check your rpm drop each gear change, if your still falling out of band you have to widen the engines effective rpm range.
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Have set-up a mixture of KX420 & 83 KX500 gears, with a taller first & second. A KX420 input shaft & gears drops straight in with an 83 KX500 output shaft & gears. KX500 kick idle gear is 1mm narrower, I will machine the KDX400 kick idle gear to work.
The two free-spinning gears on the ouput shaft of KDX400, KDX420 & KX420 have siezure issues, the KX500 runs same gears as KX420 but uses anti-sieze bushes in the above gears.
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Anyone with KX125/250A5's will know the problem of constantly breaking sidecover mounts, the vibration from the big-bore makes them break even quicker, I just braced the mount, should fix it.
(http://i1093.photobucket.com/albums/i423/JohnnyRacer89/CAM00064_zps66464be6.jpg) (http://s1093.photobucket.com/user/JohnnyRacer89/media/CAM00064_zps66464be6.jpg.html)
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The next mod to combat engine heat, the Pro-Flow scoop, this is a genuine Kawasaki SR380 works item, sourced from Ted's Emporium of rare vmx parts ;-)
(http://i1093.photobucket.com/albums/i423/JohnnyRacer89/CAM00080_zps131f2728.jpg) (http://s1093.photobucket.com/user/JohnnyRacer89/media/CAM00080_zps131f2728.jpg.html)
(http://i1093.photobucket.com/albums/i423/JohnnyRacer89/CAM00082_zps598f26f0.jpg) (http://s1093.photobucket.com/user/JohnnyRacer89/media/CAM00082_zps598f26f0.jpg.html)
(http://i1093.photobucket.com/albums/i423/JohnnyRacer89/CAM00083_zpsfa24dc62.jpg) (http://s1093.photobucket.com/user/JohnnyRacer89/media/CAM00083_zpsfa24dc62.jpg.html)
http://www.motocrossactionmag.com/Main/News/MXAS-GYRO-GEARLOOSE-INVENTION-OF-THE-DAY-TRYING-TO-10617.aspx
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OK Guy's, you can now score this baby, time for a new project, $5900 claims it.
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I rode it the other day and its a sweet ride, stunning engine and rides nicely.... pay me later John ;D
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That is nice John and a credit to you, I'd be all over this (saves me from having to do all the hard work ;D), but unfortunately I was made redundant a little while ago and am struggling to find something else :(
Did you end up changing the gearbox ratios?
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Yep, it runs a mixture of KX420 and KX500 gears, the KX420 for the good 1st & 2nd ratios and the KX500 output shaft for the anti-seize gears.
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Comes with good spare KDX400 gearbox. And still has the lighting coil fitted.
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I also have a kx250a5 but I put a kdx450 motor in it with a thicker liner to accept a 74 kx450 piston which makes it a 477,I also had overheating problems,the fuel was actually boiling in the fuel tank,run clear fuel line and in line fuel filter to view,have not come up with a fix yet,also the 1980 kdx400 had a different pipe with a longer straight section much better performance,
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ok next step in the project (yeh still got it), after riding one of the ex Gary Hacking's RM400T's, I was amazed at how much low rpm power it had, got me to thinking that I could get a bit more out of the KX, so I whipped the head off for a few measurements.
Squish clearance was 2.20mm, yes miles too much! Combustion volume was 49.8cc, so I'll whip 1.00mm off the head sealing surface, that will take squish clearance to 1.2mm and reduce chamber volume by 5.2cc to 44.6cc.
Squishband width is 11.00mm, while I'd like it be 12 to 13mm for an 80mm bore, we'll give it a try and see what it's like.
Stock chamber
(http://i1093.photobucket.com/albums/i423/JohnnyRacer89/KX400combustionchamber_zpsa1efe270.jpg) (http://s1093.photobucket.com/user/JohnnyRacer89/media/KX400combustionchamber_zpsa1efe270.jpg.html)
Measuring volume
(http://i1093.photobucket.com/albums/i423/JohnnyRacer89/ccKX400head_zpsbb6d7fc8.jpg) (http://s1093.photobucket.com/user/JohnnyRacer89/media/ccKX400head_zpsbb6d7fc8.jpg.html)
Stay tuned (no pun intended ;-) )
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I hope you don't have a domed piston?
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Perhaps making a vented front numberplate can help with a tiny bit of air flow to the engine
It's strange Kawasaki never made one of these.
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John, I hope that's FPV 49.8cc Not CCV.
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Just fitted a Yam TT600 top triple-clamp (thanks for the heads-up Brendan) as I wanted rubber bar clamps, bonus the bar clamps aren't angled back like the original Kawa item :-)
I've got the '83 KX125 disc front-end back in, a 400 is too fast to have poor brakes :-) They now have Honda CR480 fork springs.
(http://i1093.photobucket.com/albums/i423/JohnnyRacer89/TT600tripleclamp_zps6526015d.jpg) (http://s1093.photobucket.com/user/JohnnyRacer89/media/TT600tripleclamp_zps6526015d.jpg.html)
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Have decided to turn the KX400 into a Vinduro bike, just put a new custom-made seat cover on, a KX250A5 cover with KDX screen printed on, got it from 'Pit-Replica'.
Got a 'period' KDX headlight shroud coming from BigK and ordered a TY tailight. The bike still has the KDX400A1 lighting-coil, just gotta wire them in.
(http://i1093.photobucket.com/albums/i423/JohnnyRacer89/KDX400_zps7746b453.jpg) (http://s1093.photobucket.com/user/JohnnyRacer89/media/KDX400_zps7746b453.jpg.html)
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I have TY tail lamps in stock. They are great for vinduro bikes.
K
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the lights dont have to work unless your going for club reg.... ;D
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Thanks K, add it to the pile :-)
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Next step in broadening the power was a change to the header pipe, the stock KDX400 pipe came out of the cylinder and went straight down, making for a very short header, I cut a section out of a spare pipe I had laying around and extended the header by 45mm, it now runs out to the left before running back under to the right side.
Much more low-down power that hasn't seemed to have dulled the top-end. Next step is to increase the core size of the 250 muffler currently fitted.
(http://i1093.photobucket.com/albums/i423/JohnnyRacer89/CAM00270_zpse705f066.jpg) (http://s1093.photobucket.com/user/JohnnyRacer89/media/CAM00270_zpse705f066.jpg.html)
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Well I was a little sad having missed the VCM event this weekend, having put the disc brake front end in prevented me from being able to run the Evo class. So with a couple of new axle spacers and a small brake anchor-plate, I made the A5 drum brake fit into the 43mm forks ........ just a day too late :-)
So now in a couple of minutes I can swap back & forwards from a disc or drum :-D
(http://i1093.photobucket.com/albums/i423/JohnnyRacer89/KDX40043mmanddrum_zps1d628468.jpg) (http://s1093.photobucket.com/user/JohnnyRacer89/media/KDX40043mmanddrum_zps1d628468.jpg.html)
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....and queue evo fork eligibility argument ....;)
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should have strapped a headlight to it and ridden at Beaufort John, lovely bike for the ride....
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....and queue evo fork eligibility argument ....;)
Yeh I don't agree with the new rules that allow components from non-Evo bikes, but this is only for club events. It's an old SLS brake & the forks are stock early 43's so I think it's still 'in the spirit' of things.
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Hi John. I know you said it is only a club level bike but it can still be protested. The steward will just refer to the MoMS for clarification. The top triple clamp could also be protested with its vertical risers.Different meet. Different steward. Shit happens.
I don't give a toss. The bike looks great.
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Ahhh Ted, in NSW you can get fined if you don't hold your mouth right when you fart! Down here in friendly Vic we just want like-minded friends at the events.
When I was roadracing I always hated going to NSW; officials with bad attitudes & bedside manners. Everytime race friends came down to Vic to race, they'd say " wow everything is so easy & laid-back down here".
VICTORIA, RACING A STATE OF ECSTASY ;-)
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Really loving the bike right now, with the header pipe lengthened 45mm from the stock KDX400 pipe and the larger diameter muffler core, the bike has such a wide spread of power now, love it.
The muffler core (straight through perforated core) is now 34mm ID, not any louder than the small core that was on it (a 250 muffler with 25mm core).
There is a set length that a 2-stroke stinger should be, if you continue with a muffler core of the same diameter, you effectively are lengthening the stinger; moving power up the rev range AND causing higher combustion temperatures. Either making the muffler core markedly larger or running a mechanical-baffle with large chambers would negate this effects.
Well I did it to the KDX and I am satisfied with what I have done.
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There is a set length that a 2-stroke stinger should be, if you continue with a muffler core of the same diameter, you effectively are lengthening the stinger; moving power up the rev range AND causing higher combustion temperatures. Either making the muffler core markedly larger or running a mechanical-baffle with large chambers would negate this effects.
No set lengths for stinger length, diameter is the one that holds sway. Seen and used every length from 80mm to nearly 600mm on a NSR250. Though there is a limit to how long you can go.
The KDX pipe is good idea.
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There seems to be so much information around saying that a stinger that's too long/small can move power up the rev-range and produce more engine heat though, yeh?
The few things I have read, talks about a 400/500cc off-road bike (non roadrace) having a stinger approximately 400mm / 29mm ID, those dimensions seem to have worked for me.
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Diameter over rules everything, the stinger being 40 or 400mm will make no difference so long as the ID stayed at 29mm. Stinger ID's falls into very defined ranges, always with a lower limit. upper limit can vary 1-2mm
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Well why don't they make them all 40mm long? Would save weight & room.
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Packaging, wouldn't allow 40mm stinger on an up pipe
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Why didn't Roger DeCoster have 40mm stinger on his RN74 downpipe?
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have been following and enjoying the evalution of a great build, well done ;)
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A 2st pipe can be tuned at the stinger as well as any other section of the pipe.
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Diameter over rules everything, the stinger being 40 or 400mm will make no difference so long as the ID stayed at 29mm. Stinger ID's falls into very defined ranges, always with a lower limit. upper limit can vary 1-2mm
That's why 500's and most enduro's have very long mufflers, 125 short and why Eric Gorr and a host of other engine tuners other engine tuners recommended cutting mufflers on certain bikes , 93 RM 250 for eg, to get them to rev on a bit more. On and on and on....
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Diameter over rules everything, the stinger being 40 or 400mm will make no difference so long as the ID stayed at 29mm. Stinger ID's falls into very defined ranges, always with a lower limit. upper limit can vary 1-2mm
That's why 500's and most enduro's have very long mufflers, 125 short and why Eric Gorr and a host of other engine tuners other engine tuners recommended cutting mufflers on certain bikes , 93 RM 250 for eg, to get them to rev on a bit more. On and on and on....
I thought it was for noise....
Look at a standard mid 90's CR500 muffler and a pro circuit version, about 400mm shorter, makes more noise and not much else.
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John, what is the actual diameter size of the out let at the end of the reflector?
about 32mm should be close to being on the money..
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Stinger 29mm ID and 420mm long, muffler on the end is 34mm ID and 300mm long .... lovin it ;-)
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Great, and I'm betting it will help with engine heat as well. If the outlet is too restrictive, the pressure in the pipe will be higher on average than it should be. Leading to higher gas temperature in the pipe and the pipe will be resonant at a higher rpm and if it is excessively restrictive the exhaust gases will not be able to evacuate the cylinder completely by the time the transfers open and you will get hot gases traveling down the transfer feeder/ducts, mixing with and heating that mixture in the transfer ports and everything else along with it, piston cylinder and crankcase.
I have seen this more than a few times 83 KX500's was one bike that this was a problem.
And I've just recently seen it in a big bore Yamaha. In the Yamaha there was even carbon built up in the transfer ports.
This thing knocked it's head off. All good now..
Bla Bla Bla. I got on a roll then.lol.. Anyway I'd love to hear how your engine heat problem is now.
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That's why 500's and most enduro's have very long mufflers, 125 short and why Eric Gorr and a host of other engine tuners other engine tuners recommended cutting mufflers on certain bikes , 93 RM 250 for eg, to get them to rev on a bit more. On and on and on....
....(http://anotherschwab.files.wordpress.com/2013/09/miss-the-point.png)
talking about stingers not mufflers ...............
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Great, and I'm betting it will help with engine heat as well. If the outlet is too restrictive, the pressure in the pipe will be higher on average than it should be. Leading to higher gas temperature in the pipe and the pipe will be resonant at a higher rpm and if it is excessively restrictive the exhaust gases will not be able to evacuate the cylinder completely by the time the transfers open and you will get hot gases traveling down the transfer feeder/ducts, mixing with and heating that mixture in the transfer ports and everything else along with it, piston cylinder and crankcase.
I have seen this more than a few times 83 KX500's was one bike that this was a problem.
And I've just recently seen it in a big bore Yamaha. In the Yamaha there was even carbon built up in the transfer ports.
This thing knocked it's head off. All good now..
Bla Bla Bla. I got on a roll then.lol.. Anyway I'd love to hear how your engine heat problem is now.
A too small stinger will send an engine into pre-ignition in a very short time seconds even . Black soot in the transfers is a sign of insuffiecient blowdown angle/time area not a too small stinger. Most of the hottest exhaust gas leaves the cylinder just as the exhaust port opens(highest temp and pressure).
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Hi John. I know you said it is only a club level bike but it can still be protested. The steward will just refer to the MoMS for clarification. The top triple clamp could also be protested with its vertical risers.Different meet. Different steward. Shit happens.
I don't give a toss. The bike looks great.
These sort of rules just shit me. A not so rich dirt tracker who cannot afford to shorten the forks can just push them through say an inch to lower the bike. If the handle bars are in the way then use a riser or fit fat bars /converter which also rises the bars to allow the forks push through. IMO There is no possible performance gained when fitting handle bar risers.
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Great, and I'm betting it will help with engine heat as well. If the outlet is too restrictive, the pressure in the pipe will be higher on average than it should be. Leading to higher gas temperature in the pipe and the pipe will be resonant at a higher rpm and if it is excessively restrictive the exhaust gases will not be able to evacuate the cylinder completely by the time the transfers open and you will get hot gases traveling down the transfer feeder/ducts, mixing with and heating that mixture in the transfer ports and everything else along with it, piston cylinder and crankcase.
I have seen this more than a few times 83 KX500's was one bike that this was a problem.
And I've just recently seen it in a big bore Yamaha. In the Yamaha there was even carbon built up in the transfer ports.
This thing knocked it's head off. All good now..
Bla Bla Bla. I got on a roll then.lol.. Anyway I'd love to hear how your engine heat problem is now.
A too small stinger will send an engine into pre-ignition in a very short time seconds even . Black soot in the transfers is a sign of insuffiecient blowdown angle/time area not a too small stinger. Most of the hottest exhaust gas leaves the cylinder just as the exhaust port opens(highest temp and pressure).
Yep, agree. " A too small stinger will send an engine into pre-ignition in a very short time seconds even".
But do you disagree. That If the stinger and or muffler is excessively restrictive the exhaust gases will not be able to evacuate the cylinder completely by the time the transfers open and you will get hot gases traveling down the transfer feeder/ducts, mixing with and heating that mixture in the transfer ports and everything else along with it, piston cylinder and crankcase?
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Does this also mean too big of a diameter muffler ie 38mm id on say a 250 2 stroke could also cause detonation?
Brett
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Hi John. I know you said it is only a club level bike but it can still be protested. The steward will just refer to the MoMS for clarification. The top triple clamp could also be protested with its vertical risers.Different meet. Different steward. Shit happens.
I don't give a toss. The bike looks great.
These sort of rules just shit me. A not so rich dirt tracker who cannot afford to shorten the forks can just push them through say an inch to lower the bike. If the handle bars are in the way then use a riser or fit fat bars /converter which also rises the bars to allow the forks push through. IMO There is no possible performance gained when fitting handle bar risers.
The protest wouldn't come from raising the bars but from moving the bars further forward ( like a modern ) which these clamps enable you to do. Yes it is an enhancement. Yes they are off a model that we thought didn't comply with Evo. However if Dave Tanner gets his interpretation over the line they will be ok for Evo, along with a 84 KX 500 in it as well.
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Does this also mean too big of a diameter muffler ie 38mm id on say a 250 2 stroke could also cause detonation?
Brett
My guess is that it won't be causing detonation but you could be losing some top-end power.
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Hi John. I know you said it is only a club level bike but it can still be protested. The steward will just refer to the MoMS for clarification. The top triple clamp could also be protested with its vertical risers.Different meet. Different steward. Shit happens.
I don't give a toss. The bike looks great.
These sort of rules just shit me. A not so rich dirt tracker who cannot afford to shorten the forks can just push them through say an inch to lower the bike. If the handle bars are in the way then use a riser or fit fat bars /converter which also rises the bars to allow the forks push through. IMO There is no possible performance gained when fitting handle bar risers.
The protest wouldn't come from raising the bars but from moving the bars further forward ( like a modern ) which these clamps enable you to do. Yes it is an enhancement. Yes they are off a model that we thought didn't comply with Evo. However if Dave Tanner gets his interpretation over the line they will be ok for Evo, along with a 84 KX 500 in it as well.
How the hell does this get into a discussion about exhausts on a bike where the owner/builder doesn't give a toss about NATIONAL eligibility? He just wants to ride a very nice bike that he built with his own 2 hands....unlike some people who get others to build their bikes and then stick some young bloke on it at a national event to do what they can't..... If eligibility is what you want to discuss, use the administration of competition thread.
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I'm talking to the bloke that sold me said bike. Pull your head in.
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I'm talking to the bloke that sold me said bike. Pull your head in.
Head is pulled in...... ::)
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A business proposition has arisen, looking at moving-on the big KX/KDX, specs as follows ......
KX250A5 ('79) chassis.
KDX400A1 ('79) engine, mildly ported, head squish set.
KX500 ('83) gearbox.
KX125 ('83) front-end.
TT600 ('83) triple-clamps (rubber bar mounts).
Near new YSS shocks.
Fresh resleeve, new standard KDX400 piston & rings, sleeve with enough meat to fit KX420 piston.
Carbon reeds.
New wheel bearings front & rear.
New headstem bearings.
New swwingarm bearings, bushes & seals.
New brake shoes.
KX500 all-plastic chain-guide.
Wide stainless footpegs.
New Unifilter airfilter.
Fresh engine bearings & seals.
Heavy duty clutch springs.
New clutch plates.
New custom-made seat cover - KX250A5 with KDX screen-print.
SPARES
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KX250A5 front wheel.
KX250A5 forks, disassembled, one leg slightly bent.
KX250A5 triple clamps x 2.
KDX400 rear hub, painted with new bearings ready for lacing to a rim.
KDX400 gearbox.
KDX400 mag cover.
KX420 gearbox.
New fuel tank & sidecover decals.
New & used front & rear sprockets.
Reed cage.
Clutch plates.
KX250A5 seat cover (used).
New KDX175 'period' Maier headlight shroud.
New TY tail-light.
New KDX400 gasket kit.
Plus heaps more KX & KDX bits & bobs that I will not need anymore.
The bike is great to ride, the only thing I think it needs to complete it is a GMC pipe, the modified KDX400 pipe works ok but looks a little untidy.
$4500 can get you a VERY rare & admired bike, it breaks my heart to sell it, but of all the bikes I have for sale, this is probably the most sort-after.
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Leg End Ted told us all that he bought the bike ??? ??? ??? ??? ???
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Leg End Ted told us all that he bought the bike ??? ??? ??? ??? ???
Ted bought an RM125B off me a couple of years ago (the one with the alloy swingarm ;-) )
Getting to turn-1 first at Viper a couple of months ago....
(http://i1093.photobucket.com/albums/i423/JohnnyRacer89/KX400%20holeshot%20at%20Krusics_zpsbzdjxx6b.jpg) (http://s1093.photobucket.com/user/JohnnyRacer89/media/KX400%20holeshot%20at%20Krusics_zpsbzdjxx6b.jpg.html)
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Still avail for sale, selling due to the onset of my old-age.
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Your not coming to classic dirt by chance?
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Your not coming to classic dirt by chance?
Tooooo far :-)
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It is a bloody long way from Vic that's for sure. I would have thought you would have sold this quickly given what it is? Why not make the effort and bring it with you?
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John , Two things I have purchased 3 bikes from Bendigo in last 3 years and I'm sick of driving down there,
This a bista and there for a bit of unknown so I would not buy it with out a good test ride plus its not something that's cheap that you purchase on spec. Bring it to CD and if I like it I will buy it.
Cheers Mick
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John , Two things I have purchased 3 bikes from Bendigo in last 3 years and I'm sick of driving down there,
This a bista and there for a bit of unknown so I would not buy it with out a good test ride plus its not something that's cheap that you purchase on spec. Bring it to CD and if I like it I will buy it.
Cheers Mick
Forget it pal, I'm not taking the bike out of the state and I am not giving anyone test rides, I'm happy to keep it rather than be jerked-around !
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Yep still for sale (until I change my mind again lol), price drop, I'm selling it because I never ride it; hasn't even done 60 min's riding since building, it just sits in my front room, have too many other bikes in the way to get it out :-)
KX250A5 ('79) chassis.
KDX400A1 ('79) engine, mildly ported, head squish set.
KX500 ('83) gearbox.
KX125 ('83) front-end.
CR480 fork springs.
TT600 ('83) triple-clamps (rubber bar mounts).
Near new YSS shocks.
Fresh resleeve, new standard KDX400 piston & rings, sleeve with enough meat to fit KX420 piston.
Carbon reeds.
New wheel bearings front & rear.
New headstem bearings.
New swingarm bearings, bushes & seals.
New brake shoes.
KX500 all-plastic chain-guide.
Wide stainless footpegs.
New Unifilter airfilter.
Fresh engine bearings & seals.
Heavy duty clutch springs.
New clutch plates.
New custom-made seat cover - KX250A5 with KDX screen-print.
SPARES
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KX250A5 front wheel.
KX250A5 forks, disassembled, one leg slightly bent.
KX250A5 triple clamps x 2.
KDX400 rear hub, painted with new bearings ready for lacing to a rim.
KDX400 gearbox.
KDX400 mag cover.
KX420 gearbox.
New fuel tank & sidecover decals.
New & used front & rear sprockets.
Reed cage.
Clutch plates.
KX250A5 seat cover (used).
New KDX175 'period' Maier headlight shroud.
New TY tail-light.
New KDX400 gasket kit.
Plus heaps more KX & KDX bits & bobs that I will not need anymore.
The bike is great to ride, the only thing I think it needs to complete it is a GMC pipe, the modified KDX400 pipe works ok but looks a little untidy.
$4500 can get you a VERY rare & admired bike, it breaks my heart to sell it, but of all the bikes I have for sale, this is probably the most sort-after.
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Will accept a swap for a modern bike.