CR125 Running sluggish

[ysr89]

I'm having an issue with my 87 CR. I got it running, but it isn't riding well. It starts first or second kick, idles and revs perfectly. BUT, when I start riding, it's very sluggish. It feels like the clutch has a wicked slip, but the cable is adjusted for it to be as engaged as possible. When I start moving, it slowly gets to a slow speed (approx. 10 mph) and levels out. It can be wide open, but it stays at a constant speed and rpm. If you come off the clutch wide open, it bogs and will die unless you pull the clutch right back in. I adjusted the carb to the specs in my Clymer manual. Any ideas?

edit: Also, when I took it on it's first run after getting it running, it ran like this, then after it ran backwards (see thread "interesting...", it ran well. It ran out of gas, so I put a gallon in it and it ran badly again.

 

[ysr89]

CR125 help

Hey, I've made a little progress on the 125 being sluggish and so forth, What the bike is doing now is this. It starts off a little slow, and builds up some speed. When it gets close to the power band, it levels off. I can hear it starting to hit the powerband, but it won't go. It just levels off and stays at a constant speed. If it get RIGHT on the edge of the power band, and I feather the clutch, it explodes into top end. Gets moving quick, but it won't go unless I feather the clutch, and it's still pretty sluggish on the low to mid end. Does this sound like a powervalve issue? It revs and idles perfectly, just as good as my 2000 250. It only has issues moving. Any ideas?

 

[YZracer021]

How hard is it to start the bike? If its hard to start check your compression. or if your compression is fine check your reed vavles and make sure they're not curled.

 

[fatboyslim]

Compression test, clean air filter, check reeds.

 

[ysr89]

Starts first or second kick every time. New reeds and cage, New cylinder, head, piston, rings, stator and clutch.

 

[_JOE_]

Starts first or second kick every time. New reeds and cage, New cylinder, head, piston, rings, stator and clutch.

You answered your own question.

 

[ysr89]

How so?

 

[YZracer021]

pull your power valves see if there gummed up but if you just rebuilt the top end thats somthing you would have been able to see. If your power valves are fine then it could be a carb issue. let your bike idle for a while then hold it open for a second a see if it sounds too rich at the top. the bike could jsut be starvin for fuel so clean your carb out. i doubt theres an air leak anywere cus the motor would surge up and down.

 

[ysr89]

I went through the powervalve entirely, with a Clymer manual for reference. Everything was right, I took it all apart and put it all back together. The bike runs and idles perfectly. I tried the Idle to full throttle procedure already, revved like a champ, nice and crisp. It must be fighting something, almost like my brakes are sticking, but they aren't. If I adjust the clutch out enough so it slips, it runs through the RPM range fine, it just doesn't move fast, because the clutch is slipping.

 

[IndyMX]

Have you checked the gear box for bad bearings?

How are the wheel bearings?

 

[ysr89]

I haven't torn into the gearbox, but I know one of the front wheel bearings has a lot of play. I'm in the process of buying a new one, but I wasn't sure if that could cause something like this.

 

[YZracer021]

You said the clutch is new, what all did you replace? if you didnt change your clutch basket check the fingers for groves, the will cause your plates to hang up and float, and your clutch to slip. other wise check the torque on your clutch srings.

 

[ysr89]

All that is good, new basket. Not really sure what to look for. I don't think it's a motor issue, it seems like the bike is struggling to move at certain RPMs. To put it into perspective, it runs better downhill that up. This is on a low grade hill.

 

[YZracer021]

problems like this are hard to do without ridin the bike. But is sounds like the bike runs fine until you hit the top end. when your bike hits the higher rpms, does it bog out and sound fat or does it just wind out and not go anywhere? if its winding out then you definitly have a clutch problem. if it bogging down the you got a mixture problem. if you didnt already check your airfilter make sure its clean, sometimes its the easy stuff that gets over looked.

 

[ysr89]

I talked to Lee at OnThePipe Racing, I'm thinking it's a powervalve problem. I'll let you guys know if that's it.