Hi guys,
My friend and i are redoing an 87 lt250r and I feel its not up to where it should be at this point.
The guy that i purchased it off of had the powervalve cranked all the way down (low end setting im assuming)
now the quad ran strong but nowhere near where it should be. so far we have cleaned the carb, ran all the crap gas out of it, and replaced the reeds.
Now we adjusted the powervalve open and its running alot better. i think my friends 400ex is just a hair quicker (jetted, full curtis sparks exhaust, k and n)
Now from everything i hear the racer should be annihilating the 400 so im wondering a couple things.
1. is the stock hgead pipe super resrictive ?
2. i have heard that the powervalve is ultra tricky to dial in, almost like the quad wont fully open up unless its perfect.
can anyone shed anylight on this?
also could the powervalve be all gummed up ?
thanks,
mike

 

i have mine set by putting the pring in then cap and spinning cap 360 degrees counter clockwise. then tighten screws. and mine ripssssssssss

 

1) Yes, the stock pipe and silencer are super restrictive. Did you clean the air filter?

2) Look through the little window as you rev the bike to make sure that the powervalve is operating. If not, it's all gummed up.

 

yep airfilter cleaned.
the bike has the stock head pipe and an fmf silencer.
ill relay the powervalve stuff to my buddy thats helpn with the bike. (im on house arrest for a diu....whata dumb ***) so i can't really fool with the mechanical stuff.
i know that when we got the bike the guy said he hasd it all set up for low end. the powervalve ws as closed as u can make it.
should u be able to turn the valve without loosening the screws?
and if my basic understanding is correct, that valve regulates exhaust so if it was too closed that would restrict exhaust and severely limit the top end ?
and is that thing as tricky to dial in as i was told ?
thanks again,
mike

 

ok he is gonna check the powervalve to make sure its operating correctly tonight. he opened it up some more and says its running alot better now but the 400ex is still a bit quicker.
in you guys opinion would a 400ex with jet, kn, and curtis sparks full exhaust be a touch quicker that the lt250r? like i said all that it has done is bored 10 over, boyseen reeds and a uni filter ? is a head pipe where all this difference is at u think ?
thanks,
mike

 

hmm i would think it would still beat the 400...

 

thats what im thinking. i think that valve needs adjusted a little better and cleaned out perhaps.
what was the stock rear tire size on those also because it may be geared too low right now. i know it has the stock 12/42 gear ratio but im not sure if the rear tires are smaller than stock.
thanks,
mike

 

they were either 21's or 22's stock...

 

I had the gut's removed from my engine to the power valve,like the gear's that activate the valve and locked it closed.In slow speed's it is open,mid to top end it close's.With it being shut it does'nt mess with the low end at all in my set up,in top end it riiiiiiippp's!!