What should the baseline jetting for a '87-up LT250 with a stock pipe, DG silencer ,and UNI filter/airbox lid removed be? Bike runs fine now, cranks easily and even idles good, but I need to clean the carb out good and just wanted to check while i was there. Oh yeah, sea level atlitude, 32:1 mixed Bel-Ray H1R/92 Octane.
Greg Coats
Petal, MS
'87 LT250R
'00 Rancher ES 2X4

 

I found that i had to jet up heaps when i uncorked the air box and added a decent muffler to my 92 LT

main went from a #260 to a #300, believe it !! this is still a fraction lean, i'll be rejetting with my RM 250 cylinder conversion and FMF pipe soon anyway.

needle raised one notch

idle jet went down to a # 27.5, to rich at idle and a bit prone to loadinhg up on the stock #30 idle jet once the muffler was added.

see my page at :

http://homepages.ihug.co.nz/~crainic/INDEX.htm

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Kiwi Craig

 

I rejetted from a 240 main to a 280 main, raised needle 1 clip (now in 2nd from bottom), and left pilot at 37.5, because I could'nt get a smaller pilot jet locally. Air screw 2 turns out. Now it wants to load up bad, leading me to think it's way rich. It might have slightly more top end (not enough to put up with the loading) Since it ran better before, I guess I'll go back to the 240 main (stock), 3rd from bottom needle, stock jetting. Would just putting the needle back in the 3rd groove solve the loading up at lower speeds?

 

Does it rev out strongly or not, if the loading up is at low revs then its the idle jet for sure, two turns out is about the limit on the air screw. I'd try dropping the needle back to stock and see if it helps first before going back to the stock main, it'll be to small for sure.

 

It might have revved out slightly better. It still acted kinda rich though, even at high revs. I rejetted it back stock (I almost fouled my last plug beyond repair playing with this!) I want to try leaving the needle where it is, a 260 main and a lower pilot (i'll have to order one) stock pilot is 37.5, maybe a 30 pilot? or lower? It wanted to foul the plug unless I kept it WIDE open, so that would mean both the needle and the pilot were rich? It fouled bad at idle, would only idle for a second before starting to load up..I'm gonna pick up a couple of plugs and a 260 main, and try to find some pilots (mine was a little short one, the only ones the dealer had were long) and try all this again
thanks-
Greg Coats
Petal, MS
'87 LT250R
'00 Rancher ES 2X4

 

I looked up my manual, stock jetting is:
Main 240
needle middle
pilot 37.5
air screw 1 1/2

I'd try the 260 main, needle stock. It definitely sounds like the idle jet is too rich I went down 2.5 on mine and it cleaned things up great, maybe a #35

Have you checked the float level, does it flood when sitting, I had that problem and had to replce the float needle cause it was always flooding when stopped = very rich and loading up when started.

Craig