KLX's - a shared disease

[GMC]

My only concern with the barrel would be the wall thickness between the fins. If the casting is does not have enough meat then the boring will break through.
 

I can't remember what the bore size of mine was now, only that the piston was from a Kawasaki road bike of some sort. It was all part of a kit you could buy at the time.
I don't remember the liner came anywhere near breaking through.

[Paulsky]

Ok, I'm done polishing this turd of motor, I'm going to drop a xl350 engine into it, anyone have any experience of this?


Here is one that has by a guy in France

[grouty]

What's up with it Paul ?
I guess not enough power. At least with an old XL350 motor you can always go bigger. The new KSI Thumpers are 470 and 500.
I have just got my KLX back on the road this week. With the big exhaust and Megacycle cam, the original jetting is not far out. An annoying bog just off tickover. Open the throttle a little too quick and it will stall. I need to get the time to do some plug chops. Other than that I am happy with the motor.
The fork springs seem a little weak. Still well within spec, but too soft. I will have a look for a couple of old valve springs to stick in there.

[Graham]

There is a lighter option than a xl 350 Honda, I am currently building a KLX up with a XT 250 2 valve engine, fits in with very little mods, the motor will run a 85mm piston using a yamaha BW 350 barrel and head,the 250 crank is being stroked, should come out around the 450 mark.

With a dose of Methanol she should be a flyer

[grouty]

Had a rummage through my old valve springs. All too big in the diameter department 

Has anyone used or had experience of after market ones ? I was looking at "Progressive Suspension" part #11-1136
Are they any good ?
Mine has always been too soft, so now would be a good time to look at it. Maybe Walter does some sprigs that would work ...

[cloggy]

 Try www.rdvalvespring.com
 I rang them and got a set for a DR400. I knew what the Pro Tec spring rate was, and the length; so although they no longer had a spring kit for the model they were able to send a set that fitted: once I got the Pro Tec valve keepers machined to fit.
 Not being fond of knicker elastic I didn't want to use the NOS Pro Tec springs. If R & D have a kit I'd be interested in sharing shipping. I knackered my aftermarket cam using the standard springs it came with.
 I used to use ford crossflow aftermarket springs with Pro Tec keepers on my DR  but they are not made anymore.
 That's another possibility UK car springs. Some makers have charts with specs
 

[grouty]

As I rather like the springing on my 390 Husky, I thought maybe the same springs would give similar results in the Kawasaki forks.
The spare set I have in the workshop are good. With the two Husky springs together they are too long. Seems a shame to cut the smaller one down to maybe find it doesn't work 
I have a spare set of KLX springs too, but I don't want to cut them either.
What to do ........   

[cloggy]

 Ah, I thought you needed valve springs.
I cut mine down to up the spring rate. That worked, though I put in about 5lbs air pressure too. The mags specified somewhere over 20lbs, that's how bad the standard springs were!
 I also got Kamar motosport to send a set of YSS cartridge emulators. They sent the wrong ones and replaced them straightaway. The standard forks aren't as confused as my RM ones but the emulators still noticeably improved their action. I'm not a fan of preloading soft springs; especially not after watching one bike spit it's forks off with predictable damage to the rider, though  I suppose a lot of air does exactly the same thing.
As a matter of interest what valve springs did you fit?

[grouty]

I used the R&D valve springs in the engine. Well pleased with them. The standard jetting seems to work ok with the big pipe and Megacycle cam. But still work to do to get it right.
I fitted the two springs each side from my spare Husky forks. They were tw&ts to get back together and seem a little hard. Would be ok for motocross but not green leaning or Enduro's. I think I will sacrifice one of the shorter Husky springs and cut it down. At least Husky bits are easier to get than KLX stuff.
I will need to up the preload on the rear when the forks are done. It won't help too much, but stiffer springs for the rear don't exist.
Cloggy, have you looked at the ISDT centenary ride in Carlisle next August ?? I am planning on going as we have a team of 3. Should be a good laugh.

[cloggy]

 I want to do something for 2013. I had a load of work clashes this year, couldn't do the second Doman Hill enduro or the Hot Trod  or any of the rallies  or other twinshock enduros. I only did one scramble and Doman
 It sounds good but I also want to do the Auroux in 2013.
 Do you know  the R&D springs keepers etc code numbers were?
 Er don't bother with that last question , I've decided to go standard due to cost, unless of course the springs aren't available

[Bumper]

paulsky,what,s up with your motor that you have to lower yourself that you have to put a honda motor in it
2004 i got 2nd place in evo all powers on a 1981 klx 250 in the vic thumper cross
the last 2 round,s they wanted full grid,s so they put us in the 250cc morden class
still have in pride of place the 3rd place plate for overall, for one of the round,s on a grid of 35 for morden class  
last dyno run was 37.9 hp yes 37.9 .you can make big hp out of these puppy,s
5 gear box,s later ,to hold the hp ,heap,s o werd stuff ,klr600 valves ,cut 3.5 kg from the motor
no flywheel ,inside rotor,no sleep and no sleep and no sleep ,sw valve springs ,no sleep
no sleep and no beer make,s bumper, beer something beer ,bumper beer sleeeeeeeeeeeep

[grouty]

All seems to be good on the front fork problem. I used the spare set of springs from my 78 Husky 390WR. The long springs were used as is. The short top spring was cut in half and used with a 30mm spacer.
The pre-load on the rears was taken up (down) a notch. Now if feels more like the Husky suspension. Yet to be used in anger though.

Not seen my replacement air filter from Uni-Filter yet though !

[cloggy]

 Corby Kawasaki have about 30 original preoiled klx filters. All rotten apparently so they sell this for KLXs instead; Putoline pre oiled for kdx200 1989/kdx220 stock code 151352. They fit pretty well.

[Paulsky]

It's done, 412 cc, megacycle cam and a flatslide carb, gonna run it on Wed, let you guys know how it goes

[grouty]

That sounds good .... 412 
Please let us know how you did it, and how it goes.
I'm not sure I need to go that big for trail riding and maybe the odd enduro, so maybe (unless I get bored) will leave mine at 270.

I actually managed to get out on mine now it's finished. In between the rain  .  Did some plug chops to check the mixture, and all seems good on the standard jetting. I guess that using a larger bore header pipe will make it run leaner (like Cloggy's), but then having the megacycle cam with longer duration and higher lift will even things out.
My prowess with a camera does not seem to have improved though !




Not sure about the yellow side plates though  I guess they will have to do for the ISDT Centenary next August.