I can't figure out what is up with my 88 lt. It idles fine, but has no top end, it acts like its missing big time. I changed plugs, checked the power valve, and I have compression still. I just can't figure it out now. The motor isn't too worked over, just ported and polished, milled head, piped, and a hinson clutch. Any help would be appriciated.

Thanks Dink

 

It sound like you may have a dirty carb or jetting problem. Have you had this machine for a while, or did you just get it? Have you cleaned the airfilter regularly?

 

Make that plug gap smaller if it makes a difference in top end your problem is spark, but it is most likely a fuel problem of some sort. Make sure your wheels all turn freely {bearings or brake drag}

 

I would do a full throttle jetting check. Make sure you use a new spark plug when you do it. Use the kill switch and clutch after you've run it out so you get a good reading.

 

Had same problem. needs new reeds.

 

Also need to get ride of stock carb. Keihin 38MM is the way to go. My 92 250 had same trouble. Bought mine last year ran good but no topend. This machine was in ment cond but was just putted around on. I rebuilt it and done same stuff as you but mine still has factory bore. Also I put rad valve on it. I plan to change carbs to but it is wicked fastand has tones of over rev. YES IT SMOKES A RAPTOR.