I just purchased a '97 KE100 for my son and when I bought it, it had no power on the low end. Once you get revs up, it seems to run good but until that time, you have to rev it really high to and slip the clutch to get it to even move. I took it to my local independent repair shop that I've used for 20 years. They said it needed a top end. After that was done, it was still the same. They have checked the exhaust for restrictions, adjusted the carburetor, sprayed WD40 on the crank seal from the stator end to see if it would rev differently but the symptoms are still the same! It has 160 lbs. compression. Starts on the first or second kick and idles fine. The plug has a nice tan color. They tried reversing the plate on the rotary valve and that just made it start in reverse and run worse. They said when the held their hand over the rotary valve and kicked the starter, they could feel it suck in as it should, then it seemed to blow out, like the valve timing was off but they couldn't find any info on how many degrees the valve was supposed to open. They're stumped and I'm now deep enough into it where I could have bought anything else. They don't know where to go with it and I have to much into it to turn it into yard art! It has about 2200 miles on it and looks good. I have no repair history on it. Does anyone have a direction we can go? We just want a nice trail bike for a 13 year old to start on. Thanks.

 

My bet is no one you've spoken to has a clue how a 100cc two stroke should perform or you're not believing them if they say it is normal.

A 100cc two stroke will not have power down low like a 100 four stroke. They won't really pull until 4000-5000 rpm. They need some rpm to get into their good power zone and some clutch slippage to get them started out. That is especially true since the bike is probably geared more for road riding than off road, being as the KE was a dual sport.

The one thing you can do to make it a decent trail ride for your 13 year old is to lower the final drive gearing by changing to either a smaller counter shaft sprocket (drop 1 to 2 teeth) or go to a larger rear sprocket (go up 4-6 teeth). That will make the bike get rolling easier and handle off road riding better. Counter shaft sprockets are only around $30, so it isn't big bucks.

Virtually every KLX250 rider that rides off road drops the counter shaft sprocket by 2 teeth from a 15 to a 13. The top speed and comfortable freeway speed is lowered, but that doesn't matter off road.

Gear it down, see what it does and let your kid have a blast.


I did some searching and one comment I found that is ringing true would be this...

well after looking online for info i found out why some say no power its because they are geard extremely high. and they only have 11 hp stock but its a good bike just to ride around like sorta wanted it for. its a classic so i gotta have it. But i have to have everything thats cheap. maybe that explains why I need a barn..... but I am going to look at it this saturday so I post how i come out.

Found it here

There used to be a bunch of guys that hopped them up for flat tracking. Low buck fun for them... like watching paint drying seeing them race on a half mile though!

 

Thanks for the suggestion and I probably will put a larger sprocket on the back, once I can get this to move. Back in the mid 70's I had a Hodaka 90 Dirt Squirt that would run circles around this bike in it's current condition. The mechanics acknowledge there is a definite problem. It has almost zero power and stumbles around until you get the RPMs up in the mid range. It seriously won't leave a starting line without being about halfway revved. Thanks again for the suggestion. If anyone knows of a site that has the degrees to open and close for the rotary valve, the mechanics say that would be helpful.