So I rebuilt the 250r. Got it all back together. It ran fine but spuddered on topend. I went up to a 150 main jet from a 147.5 before I rebuilt it. So this one guy who works at the parts store said its running lean on the main jet and try to go up a few sizes. So I tried a 155 and a 160. Made no difference. The guy said it still has to be lean and that I should try to adjust the fuel/air mixture screw and check for an airleak by spraying wd40 on the motor while its running and see if it sucks it in anywhere. If it does, theres my air leak.

Well my dad tried adjusing my fuel/air mixutre screw and it ran worse then it did before he messed with it. It won't kick in to powerband at all now. He even said he supposeivly set it back to where it was and it still doesn't run right. I am so clueless right now as to what the problem is. We will check for an airleak but I have a feeling even if we do find one, we're still gonna have problems. Any help or suggestions would be really really helpful.

Thanks
Warrior68man

 

wait wait.. you were running a 147.5 main jet with stock sized carb and it was sputtering?? what mods are done to your bike, also.. have you pulled the sparkplug out and made sure it was gapped correctly?

 

Before I blew a topend, it ran fine. No problems at all. Then it blew, and while I was waiting for my piston, I went out and bought a 150 main jet. Then when I got it all back together. I put the old plug back in and ran it and it would studder in powerband. I never gapped the plug but I know that can't be it because before I blew my topend that day I had filed a plug and I just popped on in and it ran fine until it blew up.

But now its so bad it barely moves. Starts right up with no trouble at all though. Now it barely moves and I had to keep fethering the clutch to get it to stay running. Something is wrong and it seems like its only getting worse since my dad adjusted my fuel/air mixture. I have no idea what to do. I am clueless.

 

have you checked so that the jets are clear, and there is nothing blocking or disrupting the gasflow?

 

I have cleaned the carb about 5 times. I haven't checked the fuel lines. But it doesn't stall if you keep giving it gas.

 

You are jetting the main the wrong way. Try going down to 145 or so, with a new plug.

 

If your running lean why go up, is that the way your suppose to go.. I thought the bigger the number the leaner it gets??[img]i/expressions/face-icon-small-confused.gif[/img]

To get richer you would go down right??

 

nope.

If your lean that means your letting TOO much air into your motor compared to fuel, your motor should run HOT if its doing this. If its too rich, it ussually bogs down too much on the top end. It should idle find though, this means your main jet is TOO large, so you should drop a jet or two and see if its running better, also do plug checks, and do NOT blow it up!

 

hey, did you happen to disconnect the ign. coil when you did the top end if so you might want to revs. the two wires w/each other it happens alot.. it starts fine and runs w/ wires rev. but brakes up when you get on it.....p.s i would put the jets back to the way they were before u did the job..also on some old carbs you have to raze the clip up one notch on the slide for them to work correctly good luck...........

 

My buddy has a 250r and he had the exact same problem. We tried smaller and larger jets and never could get the sputter out of the top end. We even tried another carb we had sitting around. He then bought a new set of reeds and new coil. We put the coil in first and I was thinking this isn't going to do any good, but that is what it turned out to be. The coil was going bad... who would have thought??? I thought they worked or didnt work but not so!