OzVMX Forum
Marque Remarks => Kawasaki => Topic started by: cloggy on April 29, 2011, 01:37:30 am
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I've just discovered my spare engine has a roller bearing head. Were these standard towards the end of the production run and is the power any different?
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Does it just have a roller bearing on the cam chain side, and a plain (in the alloy) one on t'other ?
If it does, then that will be the later C model if it is a KLX motor. Good old Kawasaki finally woke up the the shortcomings of the original set up.
As far as I am aware the cams are the same. Not sure if the head is from a KL or KLT.
If it has bearings both ends of the cam, it is possibly a Megacycle conversion.
Have you got your KLX up and running yet ?
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Thanks Grouty
It's a Kawasaki head, no klx markings on the cam sprocket, which is indented to line up with the cam and fastened with a central bolt.
I've raced the KLX three times, a welsh forest rally where the rear brake shoes disintegrated, the Hot Trod in Northumberland, where I discovered that the brake shoes had disintegrated, and the footrest half fell off; and the Doman Hill twinshock enduro where the sump guard came loose. I think I may have had a set of fork legs off you via ebay.
I found that although it would run happily, the jetting was way off. I have the needle on the top notch and am running a P-O needle jet. I later dropped the main 5 to 135 and now it takes 5 minutes to warm up so I probably should raise the needle one notch. I took the head off to fit new valve seals but it is still burning a lot of oil till it gets down to the last litre. Also the gear change misses a fair bit when racing so I took the spare out of it's frame this morning and that's when I realised. The head in the oil burner has an aftermarket cam and a phospor bronze bush and revs like crazy with it's bigger bore exhaust. I took the head off the spare to check the barrel with the intention of swapping the heads.
The spare motor seems to have a smoother gearchange [at rest] so we'll see......
I can see why these things never finished a Dakar. You have to be really on top of checking the fastenings, you don't have a spare sump guard clamp do you?
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Sounds like you're having more fun with yours than I am with mine at the mo. I took the engine out of the frame for the first time in 30 years at Christmas ! Oval bore because the big end had gone west ! So, frame, swingarm painted and motor being rebuilt. New 262 piston and fresh barrel.
Rear brake shoes seem to be a pain, mine wear out in a few months. Never had them break up though. Replace the springs on the shoes though. They have a habit of breaking and chewing things up. If you have a worn drum, there are oversize Yamaha shoes that fit.
I had an issue with gearchanges earlier last year. Turned out to be my change of boots from old soft classic ones to modern "no bend" things. I was convinced that there was a problem until I went back to the old classic boots. I had to re-teach myself how to change gear.
Exhausts with 1"1/2 dia are the best. As far as I am aware there were 3 primary pipes made by Technical Tubes in 1982 for the army ISDT team. One spare, and two fitted to bikes. The two bikes in question had 262cc kits fitted. BSA type rear silencers were fitted at the time but had to have inserts stuck up their rear end to pass the noise test. The may well have been other primary pipes made since then though. I am just about to have one made for mine.
Cloggy, see PM for info on spares. It was not me that sold the fork legs, but at a guess it was Paul.
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Thanks for the PM. I found the second engine to be sound. We did half a days trail riding an the KLX and the DR. One small oil leak was the only problem. I had the exhaust patched. It's a bigger diameter than standard. I got back, sorted the leak and left it running to check. It stopped. It reluctantly started only to stop again. No spark. I have spares of the electrical components but no spare time till the back end of june. Swapping plugs and coils did not elicite a spark. I'll check the old coil on one of the DRs. Does the exciter coil ever stop exciting?
On a brighter note there was another KLX at the last event. With a 262 conversion ,bigger pipe and mini SuperTrapp, and a non standard carb. The rider said I was pulling away in a few places but that's probably due to gearing and my weighing less.
I copied one the threads here and gave it to him the next day at Red Marley
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I think you will find the KLF 250 farm 4 wheeler head fits a KLX and the cam runs in bearings :) Google KLF 250
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I have never had ignition woes with the old KLX (touches wood !).
Have you checked the engine / frame / ignition earths ?
I have been running 262cc for a year or two now. Goes much better. Just need to do the 1"1/2 exhaust and 34mm Mikuni carb bits to go with the new Megacycle head.
The only part I cannot find at the moment is "time" :D
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Good to see the humble KLX has some dedicated followers - Can some one advise me what piston you use to punch the KLX out to 262 cc - and does it make much of a difference? Is 262 cc as far as you can go with the cylinder in stock form? Also does the Megacycle cam make a difference? Thanks guys.
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I just ran mine as standard setup, but with the 262 piston. I use an MTC piston from Joe Hooper in the USA. It does make a small difference though. Seems to pull better right through the range. The piston will need 1mm filing off the skirt to clear the crank webs. As standard the valves clear the piston crown happily. Not sure with the extra lift on the Megacycle though.
I have not put the Megacycle converted head on yet. The main difference with this is that it supports the cam on two needle roller bearings. You will need to convert your standard head to accept the inner bearing. Easy to do with a Dremel.
Full instructions come with the camshaft. The cam chain cap on the left side needs to be bored out to accept the outer needle roller. This is a bit more tricky as you have to make sure it runs concentric with the cam for obvious reasons.
I ended up making a large steel jig to clock off the machined area for the big o-ring as the mating part in the head would have been machined together with the cam housings. The joy of a large mill at work !
Usually Megacycle will do an exchange on this cap. Just that they didn't have any blanks a while ago. I now have three of them done and ready to go.
The liner is a bit thin with the 72mm bore, but seems quite happy. I think any more and it would require a new liner and some machining.
The man to talk to here is Derail. He is the guru on getting more power out of these things.
Trent, if you need details on the piston supplier just send me a PM.
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Thanks for that Grouty - I think Wiseco do pistons that may fit so will research those - will also contact Megacycle and order a cam from them. The old KLX's are great bikes. handle well, cheap for parts and look great too. Just got to find some more power but I know its in there.
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This is the MTC piston. Silicone free drag racing jobbie. Used in pre-78 KZ1000 motors.
(http://i470.photobucket.com/albums/rr61/grouty60/KLXpiston-1.jpg)
Note that it does not use circlips to hold the pin in. High quality teflon buttons are supplied instead. Makes removing and re-fitting the piston a doddle.
I have never been a fan of Wiseco pistons myself. Some swear by them though. If you do a search on here you should find a thread by Derail that gives you the Wiseco part number, along with a load of useful info.
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One of the kawasaki pistons for a KZ1100 is supposed to fit. I did research it a while back and they came in three compression ratios. Looking at your piston Grouty that looks nothing like the flat topped standard so is that a pretty high compression? If so does it run on standard pump petrol? From what I've gleaned the KLX was possibly overvalved and definately over carbed so what seems to happen is the engine produces far higher % increase in torque as against horsepower; ie it's more efficient per firing cycle across the mid range once it's been bored out. Still haven't had time to fix the spark. I'll check the exciter coil first. I have a Multimeter.
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From the info that Derail gave me, the piston eqates to the one I mentioned above. I think the later models of KZ1000 used a bigger piston pin. The KLX is (I think) a 17mm dia affair. I did look at the 1100 pistons but was not convinced they would fit. My piston is quoted as a 1050cc conversion for the KZ1000 that runs at 10.5:1 in the KZ. It may run at more in the KLX. Just make sure the piston is for the early KZ and not the later ones.
If I fill up at home I use my race mix I keep for the 73 CCM. That is 97 octane super unleaded with 20% mix of 114 octane leaded race fuel. If I am out green laning I have to top up with super unleaded. Use the normal 95 octane and it will "pink" it's way home !
Derail has mentioned that increasing the valve size would make them hit each other on the overlap. I am going to try the Megacycle head with standard valves and carb.
The cam I got from Megacycle is the one intended for mid/high rpm power. Maybe I should have chosen a different one, but I won't be able to tell until I have tried it. There is a choice of three on their web site.
I reckon you are right about the power/carb thing too. Mine was a much happier motor with the 72mm bore.
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I've no idea what cam I have but it has a bit more duration than the standard cam. The lift doesn't seem radically altered so I don't think it is extreme. I have no idea what the springs are either but am not too worried as it will do around 70 on a 44 and nothing has touched either then or on multiple missed shifts. Thanks for explaining the piston pin size change. At the moment I am getting more speed out of the bike by losing weight. It's the most cost effective option, and the only one I can presently justify in these straightened times.
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Changed all the ignition gubbins one by one, turned out to be the generator coils.
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wiseco piston kits 4052MO7200 KZ900/1000 10.25comp,17mm pin,i use them in a 57 MV250 roadrace bike,pretty good piston,although wouldn't mind looking at that MTC piston too!, :P
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I did some checking
Neither Bike Bandit nor csmnl list the C model KLX. Bike Bandit showed the three wheeler KLT to have the roller head then the KL followed suite in about 83.
My parts bike is a B1. It came with a bunch of spare engine parts, Supposedly someone at Williams F! had built the motor.
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KLX Update - thanks for all the info over the past few months, I have finally fitted the new Wiseco 262 piston mated to a specially made up 1.5 inch diameter pipe with a Supertrapp muffler, still using the standard carb and cam . I fitted new valves, and cleaned up the ports. The bike now runs really well, pulls strong and smooth all the way through the range - feels like a different bike. Handles, turns and has power to boot. Can anyone advise what difference a larger carb or the Megacycle cam will make and also does anyone have any recommendations with regards to optional rear shocks? Cheers.
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I can't see any point in a bigger carb. The carb is the same size as a DR370 already. The KLX carb is a whopping 4mm bigger than the KL. I think they put it on knowing folks would overbore the motor. I have a non standard cam, but never having used the standard one I don't know what difference it makes.
What compression are you running? If it is the above piston I understand that you'll have to add .25 to .5 on top of the stated compression. When both my engines have got really hot they've predetonated at low revs under load until they've cooled down, so I've bought octane booster and will try that
As for shocks Honda Red Rocket ones fit and don't lose you much height or travel. 17.5" and 5.5" as against 18.25 and 5.9. I bought a set of s/h Red Rocket Ohlins, backed off the preload and they're fine
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Have finally got a garage up ;D have mounted new rear muguard, fitted some original shocks - now to
put in vale stem seals, rings and tidy her up.
These threads tempt me, but I think I'll stay with a standard motor.
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Where did you get the shocks from?
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Hey Cloggy, what size is the KLX carby? I'm after a bigger one for my TT250 project. Is it pumper?
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It's a 32mm oval bore cranked slide mikuni. Superficially the same as a SP370's carb though it's lacking that carb's additional primary fuel jet at the base of the venturi. Neither have a pumper circuit. I don't know how they flow as compared to a round bore venturi carb, but it's probably significant that the DR370/400 use much the same notional sizes as the XT500 with similar piston sizes. Although these carbs look as if they interchange it's far from simple, they are very model specific. For instance the 370 carb works happily over a wide range of tuning options, including an altered airbox. the DR400 carb [in my experience] will not tolerate the airbox being derestricted. The obvious differences, bigger body, 1mm extra bore size and only a single taper needle. That last is the killer, and the SP needle is a suzuki unavailable part, not a mikuni standard size. The USA spec DR500 used a slightly bigger carb of I think the same design, 34 or 35mm. Guys tuning XT500s tend to use a round slide aftermarket mikuni for their lack of complication and ease of tuning, rather than any possible additional power. Going bigger may make sense in road racing where peak power is important but it's not always the right way to go in offroad where a bigger carb is likely to dig holes in your midrange.
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Where did you get the shocks from?
Egay in the US - good nick and seem to damp ok - won't know until I ride it obviously.
Now need to flog the MT350 shocks which didn't fit.
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I've got those Ohlins mt350 shocks on a standard swingarm DR400. Nice shocks but too short for a KLX. Bees Knees for a DR400 though at 16.5"
I checked the logbook on my KLX B1. It was sold late '82. So it may well have had the roller bearing cam as standard. Also the late KL has the same engine as the early KLX, just a year or so later, just different carb and exhaust. I picked up a low mileage KL engine on ebay. Parts Book has the wrong diagram for the cam but the numbers match up
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The only downside looking for parts in the U.S. is that they only think the KLX ran for the "A" series. The "B" models did not feature over there. The rest of the world got the "B". UK, Germany, and OZ. The "C" model as I understand it is very rare.
I bought an 83 KL parts bike just for the motor. Trouble is, the barrel is a different shape regarding the fins. Exactly the same internally though. The rest of the motor is good for parts.
I need to find a pair of old genuine KLX shocks and experiment on rebuilding them. It must be possible to do it.
Progress on my resto has ground to a halt until we press the crank back together with it's new rod and left side main bearing.
The thread on the KLX resto is http://devongtrf.activeboard.com/t40184062/1981-klx250-rebuild/ (http://devongtrf.activeboard.com/t40184062/1981-klx250-rebuild/)
My time has been spent getting the 390WR husky back on the road. Along with finishing the VMX season on the CCM.
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AND drinking wine ;D
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I've just checked my new KL barrel against the KLX and found that I have two types of KLX barrel; and that the KL barrel is identical to one of them. The only difference I could find was the finning just above the single barrel bolt.
I now have 3 spare heads
The roller head has a knackered cam lobe- cost to replace [inclusive of new rocker arms] £141 + post
The new engine has unstretched head bolts and good rubber head seals but the head is shot, both journals and lobes. [did a lot of short field jouneys]
and lastly a spare head that I already had, bog standard and perfect.
I'd like to keep it that way
I plan to use 0-40 Amsoil oil to get the cam lubed quickly, and I'd like to take out the tacho drive and plug the gap.
I've already done this once but the bike had already been modded with a phospor bronze bush head and an end cap in place of the tacho drive. All I did was grind off the cam tacho drive and insert plug as per instructions from this forum
All the other heads have the tacho driven worm in place. I can't work out how to remove the tacho drive or find what end cap was used to seal the chamber from the outside world
There appears to be no obvious way to unscrew it, a task made more problematic due to the one good head's tach drive cable threads being damaged and it not being shown in either the parts book or the workshop manual. Anyone know how it comes out?
I suppose if all else fails I could get it machined out
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Cloggy, from memory (read.... vague !) the tach drive comes out once you have removed the washer and seal. I think I used and old "easy out" with a left hand thread to grab it and twist it out. I have only ever had one head with this drive in place, and that was many moons ago. If you don't have a plug to measure for the thread, then let me know and I will dig one out and measure it.
Or give me a ring.
There must be someone on here that has a KL250 with tacho drive to speed the process.
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I am pretty sure the seal is what holds the drive in.
So all you need is to pull on the drive shaft and the whole kit and kaboodle should come out.
The tacho drive would only be in KL heads as KLX had speedo only.
There is a plug for the drive hole and you should be able to find it in the parts book.
If all else fails and you can't track one down cut the end off a tacho cable (the part that scews into the head) solder/weld the hole in the middle and you have a plug.
Personally I would leave the drive mechanism in the head. It fills the void and keeps the oil pressure up.
Thanks
DOK
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All my UK KLX and KL heads have tacho drive. Even the one that didn't have the driven worm had the worm drive on the end of the cam
As for the whole lot coming out with a tug, none have so far. I've taken the seal off the centre; it seems just to be a fibre spacer for the cable outer to abutt against. Derail talks of replacing the worm drive with a blank plug. I had assumed that this was due to the worm drive sucking/pumping the oil in the opposite direction, not that ultimately it could go anywhere or fill up much of an empty space. I'm wondering if all this is a bit of a myth, that perhaps plugging an empty chamber somehow got confused in countries/models that had tacho drive with removing the tacho drive and replacing with a static plug. I've rechecked my 1979 USA parts book and found the end plug; doh.
I've looked at parts fiches for the Z250 and the ally collar is quite complex as it is also a sleeve for the worm drive. I'll look at the running bike and try to see how far the threads go down, assuming I can get the plug out, but at present I'm not convinced there's much benefit replacing it.
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Trust me ..... I took Derail's advice a couple of years ago and made a plug to fit the chamber. It works perfectly. The plug stops the oil filling the chamber and re-directs it to where it's needed. Down the cam ! The only issue I had was a tapping noise when the engine was started. This was down to the pulsing from the oil pump causing the plug to move slightly back and forth. I cured this with a couple of o-rings under the plug to push the plug against it's stop. I only ground enough off the teeth on the cam worm to clear the plug.
I have thrashed the daylights out of the motor since doing this, and found no wear on the (outer) large cam journal. A good move !
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Yeh my other bike now has the plug but this has the tacho drive and there's very little space in there for the oil to pool since the tacho drive gubbins fills up the space. Since one has to cut off the end of the cam to make the plug work I'm not at all sure the available empty volume is very much different. Might check my running bike tomorrow and take a look at the cam drive.
I know that leaving the drive worm et all in there is not going to guarantee the safety of my journals as one of my heads is already knackered.
A local had a KLX back in the day and he had two heads under warranty in the first six months. I talked to Amsoil when I got oil for my DRs and they said go thinner if you have oiling issues on plain heads. The 0-40 they sell isn't far off water cold, perhaps that's what 0 signifies, anyway the oil is sold to be used for a lot of cold starts where normal oil gets too thick on morning start ups. They did say thicker oil has ultimately better antiseize characteristics but that's not much good if it doesn't get there in time.
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I used a heat gun for nearly an hour on a knackered head
It finally came out [been bonded in at the factory]
Looking at the design there is no earthly reason to replace it with the plug. There is a very small splash lubricated shaft that has a drain into the sump via a headbolt gallery but the amount of oil that can escape this way is infinitesimal. The amount of space taken up by the drive and driven components is greater than that with the aftermarket plug, combined with the cam worm drive removed of necessity. So I'm leaving it as is and concluding that the plug was originally intended to replace an empty chamber as my other bike. Unfortunately this means that I have no easy way to increase the oil capacity to the journals.
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I've built up the roller head with a new cam The roller head cam sprocket has a single long shaft 14mm bolt and a composite washer connecting it to the cam. Has anyone any idea what the torque setting is?
The head is common to the KLT three wheeler, the late KL, and the KZ road bike; and also more recently the quad.
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Out of interest, what does the composite washer do ?
Is the bolt 14mm A/F or 14mm dia thread. The general tightening torques given in the KLX manual would probably apply to the thread o.d. and pitch. Except if the composite washer is squeezed between !
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It appears to be a composite washer with a very thin rubber sandwich. However as it's bolted up to about 20ft lbs I'm not going to disassemble to check. I would imagine it's there to isolate the bolt head slightly from shock forces, but I know nothing. It takes a 14mm socket, though I would say the shaft is a larger diameter than the head studs which take the same socket
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Hi All
I'm really a two stroke fan but today, my mind's firing every 2nd revolution ;D
2 questions:
1] Is the cam journal bearing wear a weak point on the KLX?
2] Grouty, you mentioned a Megacycle roller bearing conversion. Are they worthwhile?
http://www.megacyclecams.com/catalog/Page41.pdf
Regards
David
Does it just have a roller bearing on the cam chain side, and a plain (in the alloy) one on t'other ?
If it does, then that will be the later C model if it is a KLX motor. Good old Kawasaki finally woke up the the shortcomings of the original set up.
As far as I am aware the cams are the same. Not sure if the head is from a KL or KLT.
If it has bearings both ends of the cam, it is possibly a Megacycle conversion.
Have you got your KLX up and running yet ?
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YES!
A local guy got through three heads in one summer, but then I've had old engines that are fine.
I guess it's how they are warmed up on starting
The oil goes in one end of the cam from the small journal and feeds two rocker pads and then the big load bearing plain journal on the cam chain side. The further it travels the less oil there seems to be.
Even Kawasaki seemed to know there was a problem. If you read their oil change intervals, very very short for a converted roadster engine.
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Cloggy is right !
The early heads were the worst for contact patch area on the cam chain side. They became bigger in 1980. This helped a little, but did not stop the mound of scrap heads piling up at the dealers.
Frequent oil changes as Cloggy said, plus the need to ensure there is plenty of oil in there to start with.
The head on mine went west in 1983. I had'nt done that many miles, but I guess maybe a low oil level and not warming it up properly did the trick.
The later genuine roller bearing heads from Kawasaki cured the problem. You can find these on the 82/83 KL250's and the "rare as hens teeth" KLX250 C1
The Megacycle cam is good. Has needle roller bearings both ends too.