hey all, I have a 91'lt250r rebuilt crank,counterbalancer, and top end bored .80.When I bought it it had a fmf fatty and powercore pipe, and the guy said he thought it was jetted. I was just wondering what number main jet should it have? I live in the southern most part of maine and its pretty cold,was wondering cause it starts right up idles fine, but it sputers when u try to just putt on it, but when u give it a good amount of gas it gets up and goes fine, would that be the jetting??? any info would be appreciated. Thanks

 

It sputters when you putt around on it because it's a two-stroke and to an extent that is normal especially when cold, I would suggest running good two-cycle oil w/ 93 octane at 40:1 or 50:1.

As far as you main jet, assuming you have the stock 34mm Mikuni TM carb, it should be close to a 270 main. But jetting is dependant on so many factors that every quad is different and should be tuned individually.

 

Thanx ChewyR, Thats what people have been tellin me that it is normal for the most part,and have also said that u cant put on an after market pipe without re jetting it, and im not good with the whole carb tuning thing, just wanted to have everything perfect. And also, do u know what the stock jet is on it? I think I remember seeing a 220 on it when i cleaned it.And should I have it professionally tuned or just buy a bunch of jets and keep trying different ones until i get it? ohh ya, im using vp racing C2 oil 40:1, and 93 octane always, Thanks

 

I'm almost positive 200 main is stock. So at 220 you're only two sizes up, which isn't much especially in cold weather. My LT 250r is at a 230 main, needle raised 1 notch, & air screw in 1/2 turn. This is for 60* plus temps in Wisconsin. If you're planning on riding in the cold, I'd start at a 270 main like ChewyR said, & raise the needle 2 notches. Be sure it's getting plenty of fuel or else....... boom.[img]i/expressions/face-icon-small-frown.gif[/img]

 

Thanks Thecatman, Ok, ill try a 270 main and ill look at what notch the needle is at and see what happens , but basically i wanted to get opinions from people that had my same machine, i just put alot of $$$$ in it and i wanted everything right. Cause i havent found too many people that know alot about a quadracer, and the few I have found say there junk, but its faster then what they have so i think there jealous,lol im not cocky but i got to say it will keep up with any machine out there, any faster and u would be teleporting,lol, Its the fastest machine ive ever owned, just wanted to putt on it too sometimes.Any tips or anything would be appreciated. Thanks

 

My brother's is perfect with a 260 main and a rad valve. Probably need a little bigger with regular reeds. I believe after the 85/86 models a 240 mj is stock. I don't know about mine, it's been sitting needed to be tuned.

 

jmane, anyone who says the LT's are junk are just that...... JEALOUS!!! Yes it has it's shortcomings, but what quad doesn't. Even the mighty "ride red" boys know, but won't admit that the Lt 250r is faster that the Honda 250r. The honda handles a little better, otherwise the LT is just as good. I know that mine is an '86, but other than no powervalve & internal reeds, the engines are basicly the same. Remember, jet rich to start with & work your way down to the perfect setting. Jets & spark plugs are much cheaper than pistons, rings, & cylinder borings fees. Just keep spanking the new breeds of sport quads and enjoy your little piece of ATV history.

 

Actually, they're not. The early LT engines are completely different than the 87 and up. The 85-86 LT250 motor is a half-breed. Mostly piston port, but w/a sub intake/reed valve system. Plus, the lack of a sixth gear really hurts these motors. It was an enduro motor before quads came along. The 87 and up is a reed valve motor that came from 86 RM.

 

Sam 250 is right on about the differences in motors .
I had a 86 and have a92 now and the difference is real.
Got a 92 rebuilt motor complete with v force reeds and stock carb run a 110 pilot jet and 300 main,
but also switched to the k&n with prefilter lid on and think i FINALLY got the set up right,I run yamalube at 32 to 1. Have any of you guys run a bigger carb like even a 36 and dialed it in right?
if anything what set ups worked for you.
Im at sea level in jersey so thats my startin point.

 

Alright, I opened the carb up and found out it had a 200 main, so I put a 250 in it and it runs like a new bike,Dont know why I didnt spend the 3 bucks a while ago. I got the chance to line up with the new 700r and got to say he waisted his money, I only got about 3000 soon to be about 4500 in my lt and I had to let off to let him pull ahead then gunned it and slowly but surely passed him before we ran out of room, and he must have spent like 8000.