Hello guys.

I have bought a factory restricted 96' KLE 500 (34HP). I want to remove this restriction, since I have a license that allows me to drive any motorbike.

The problem is, that I'm not 100% sure how this bike is restricted. So far I found it has different throttle (holes drilled through) and main jets. I already changed main jets to 112, and my mechanic put some sleeve into the throttle to block the holes, but though the bike is definitely more powerful than at the beginning, it sill looses power above 7500 rpm, and starts to shake badly. It's impossible to rev it higher than 9K at speed, though on neutral it revs fine beyond 10K.
It also struggles badly when I hit WOT at 3.000 rpm.

Does anybody have any idea what I missed and what could be the reason of this behavior? My last idea is wrong needle, but I'm totally lost on what to do. And since I already invested all my money into bike purchase, service, tires, insurance etc, I simply can't afford to buy whole new carburators

Any help greatly appreciated.

Hello, Mendelmax!

My first thought was the carbs, as in: are there any washer in the venturi, which is blocking the "airflow"? I know that's a common restriction for GPZ 500s, not sure if you've checked that already, but just a thought!

If you check this link - Kit 25 kw for Kawasaki KLE500, type LE500A, yr 1991-, ho. F670 einschl. N.05, orig. 35 / 37 (20) kw, EUR 179.40 --> ati-... - it says the following...

Hence why I suspect the venturi (yeah, same as inlet )

And just out of curiosity: what main jet sizes did you have before the change to 112 main jets?

Keep me/us updated!

Regards,
Mollrik

edit: About those vibrations/shakings. With a stock exhaust, the bike tends to vibrate a lot when you go WOT at 3000RPM, a new exhaust with equal headers will help with that. And just to fill in: the bike (with stock exhaust) loses a lot of HP in the higher RPM range, which I also verified in the "tuning" thread, but just in case; here's a graph that shows you how the KLE 500 performs in the higher RPM range!



I'm sure the needles are correct, what needles are you using? The standard ones are N96J for the older KLE 500, and N96L and N60D for the newer ones (yes, different sizes due to the header length difference).

Thanks for reply.


There were no venturis in the carb- I guess it's the way to restrict it on your own, but factory did it the other way. But I will double check that just in case.

I can't tell what were my main jets at the beginning, because my mechanic changed them before even letting me know.

So far I decided to buy used full-power carbs and simply swap them, or just interchange necessary parts if the "new" carbs will be in poor condition. They cost 50 euro, so I think it's not worth the hassle to try different configurations on my current carbs, since in the end it may appear even more expensive.

As for shaking at 3.000, I know it can be expected, but what worries me is that it continues throughout whole RPM range. Up to 8.500, cause beyond this point it's impossible to rev the bike higher even on 2nd gear. I can't try it on 1st, cause it shakes really violent then, and I wouldn't like to fall off this way

I performed a little test, accelerating WOT on hot engine and choke on, to check if it's not running too lean (should have smoothed out on choke, right?), but it was much worse then, so I bet it's running rich. The fuel economy and slight petrol smell from the exhaust would also tell that.

I know the torque curve drops dramatically beyond full power mark, but in my case it seems to drop a huge amount from less than 7K, where theoretically it should pull great. So something is definitely wrong.

When I will get my "new" carbs I will post what were the exact differences. So far the only thing to blame that I can find is this damn needle, cause everything else seems to be checked so far (blinded throttle holes, main jets changed).

Hey again!

Ahh, ok. I think it's very weird though that your bike is losing power before 8500 RPM, and the vibrations are also strange, not sure the reason for that! Have you checked the diaphram for cracks, and do you have any hole in your slide (thinking about a dynojet conversion)?

And yeah, if you can get a used carb for 50 euro, then get it! If it can save you a lot of time, then that extra money can be worth it, AND you'll have spare parts! I really hope it will help with your problems!

And yeah, you're right! If the bike runs worse when it's "warmed up", then that's usually an indication of a "too-rich" mixture, but I must ask you! Do you have a small or big snorkel? If you have a small one, then it will certainly run rich with 112 main jets, and you must modify that by either getting the big snorkel, or opening up the airbox ("drilling" holes).

Regards,
Mollrik

edit: About the choke. From what I've read, it doesn't really operate while you are giving throttle on CV carbs, so that's not a good way to check a lean/rich condition, but a cold/warm engine still applies! I've tried the choke method myself, and that seems to apply, since I tried to use it many times myself, without any changes!

Well, the diaphragms according to my mechanic are in perfect shape, but I must check it myself, cause your diagnose fits the symptoms- it acts like if the slider would fall down, block the air passage, then with huge vacuum, lift up, and act in the cycle this way.

There were holes in the slider, but they were blanked with the sleeve inserted in them. In first posts I used word "throttle" for this slider, since in Polish we usually call these two parts the same (throttle and vacuum throttle). Sorry for confusion.

As for the snorkel, I have to check it, but if I remember right, on 1996 there were only the large ones made. But that's a good point to check. If I'll be running rich on new carb (will dyno it) I will most likely open the airbox as you suggest.

Thanks a lot for a "food for thoughts"!

So I got my bike back from the workshop yesterday.

The problem appeared to be a job totally messed up by previous mechanic. It was a set of problems joining together to create this totally unpredictable behavior and mixed symptoms of both lean and rich mixture.

The sliders were sleeved properly, but the needles were not inserted deep enough and moved freely inside sliders. Therefore they randomly opened and closed fuel supply, which was the reason for huge hesitation.

The second thing is that though the jets were 112, the needles were N60D, left from the previous, restricted setup. Unfortunately I don't know what jets were in restricted version since I have never seen them.

The third problem was that mechanic inserted air filter the wrong way- it wasn't filtering at all, cause it was placed longitudinal instead of transversal.

Last problem was that the carburators were not screwed up properly, and air entered behind the throttle.

No I'm having newer setup, with 95 and 92 jets. Everything is tightened as supposed to and tuned properly. Geeez, what a difference! The bike now flies compared to what it has been before. It easily reaches 10.000rpm under acceleration (I know it's pointless, but wanted to check it).

So, I should kill my previous mechanic, but I'm so happy that my KLE is now running fine, that I will just ignore him.

Thanks for all thoughts in this thread!


Maciek