2003 LTZ Jetting Help
#1
2003 LTZ Jetting Help
Yes.. I've gone through the 13 pages of "jetting database"! But I could use a little help beyond that.
My 2003 LTZ400 is mostly stock, the only mods being air lid removed and slip on.
Using the jetting database as a guideline, I put a 25 pilot, 160 main and shimmed the needle (3mm washer). Fuel screw 2.5 turns. I am near sea level.
It starts and runs mostly well.. when the engine is cold/cool it will bog under heavy throttle. It will not take heavy throttle for 10-15 mins. Once there, it runs ok but just seems a little flat and "rich" in my opinion. On one hand, I know from experience that when engines run a little rough when cold that means they are lean. Yet to me it still seems rich.. like it doesn't pull hard.
Reading through the database it seems 160 would be the biggest I would want to go. In fact it seems most are a DJ160 which is supposedly somewhere near high 140's in dynojet terms. I have a 152.5 main. I'm thinking of trying that. I would like to try a dynojet needle versus the shimmed one but it appears nobody sells just the needle now, you have to buy the whole dynojet kit. $55 for a needle is a little painful.
Thoughts? I think the pilot is fine. 2.5 turns seems reasonable and there is no backfiring or popping on decal.
Thanks!
My 2003 LTZ400 is mostly stock, the only mods being air lid removed and slip on.
Using the jetting database as a guideline, I put a 25 pilot, 160 main and shimmed the needle (3mm washer). Fuel screw 2.5 turns. I am near sea level.
It starts and runs mostly well.. when the engine is cold/cool it will bog under heavy throttle. It will not take heavy throttle for 10-15 mins. Once there, it runs ok but just seems a little flat and "rich" in my opinion. On one hand, I know from experience that when engines run a little rough when cold that means they are lean. Yet to me it still seems rich.. like it doesn't pull hard.
Reading through the database it seems 160 would be the biggest I would want to go. In fact it seems most are a DJ160 which is supposedly somewhere near high 140's in dynojet terms. I have a 152.5 main. I'm thinking of trying that. I would like to try a dynojet needle versus the shimmed one but it appears nobody sells just the needle now, you have to buy the whole dynojet kit. $55 for a needle is a little painful.
Thoughts? I think the pilot is fine. 2.5 turns seems reasonable and there is no backfiring or popping on decal.
Thanks!
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Ckieffer29
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02-16-2016 12:46 PM
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