main jet - 162 vs. 165

[knobbyboy]

My 250R is running awesome. My only question is the main jet- I have a 295cc sleeved engine with a K&N and an FMF exhaust. I run 50:1 93 gas and premium brand oil. I am running a 162 main- stays clean on the low end, exhaust stays a little wet on the tip- but on a lot of hard, fast open field runs I can tell that the exhaust tip is not wet anymore. I was running a 165 before but it takes a bit to clean out coming out of a tight woods sections. Any opinions? 162 or 165 main jet? Its down to those 2 options for me- I have messed with it a lot and its like 99% there for me.

[86 Quad R]

have ya done a WOT plug chop with each of those jets? if so, what color was the plug?

[peeping TOM]

maybe u still on the needle when u coming out of tight corners .not the main.just a though.

[dunatic]

exactly.....drop the clip one notch

[knobbyboy]

you guys are right on, what was i thinking, I had changed needle in this whole jetting thing also. That was the change that cleaned it up, not the main. I think I just need to put the 165 main there. thanks

[peeping TOM]

id even try a170 172.ive allways had a theory that its better to run a bit rich then nip up and ruin u days ride .

[LONG-ROD]

What size carb are you running?? guessing the typical 38 or 39, I would try upwards of 175 to 188 main jet. If the electrics and everything are working right and the pipe is not choked up and the filter is clean there is no reason to be that lean on the top, someone correct me if I am wrong, that pump gas runs hot as it is, feed the machine, pull the plug cap off and make sure you can see some good wire, if not strip it, I see this over looked alot and people have to lean there bike out to make it run right. good luck

[knobbyboy]

My coil, plug wire, and cap are all new parts. I will have a 165, 170, 172, and 175 on hand this weekend for some test and tune.

:)

[LONG-ROD]

also check to make sure the carb slide opens completly at full throttle, there should be aperfect round hole, this very important for you to be able to tune this properly.

[knobbyboy]

Ran a 170 main this weekend- about 45 degrees, 93 pump gas, H1R at 50:1. She ran great.

It was lean on that 162/165- no doubt about it.

[LONG-ROD]

How did it run on the needle? and you should really concider runing 32:1 and ditch the Bell Ray, just my opion though. Oil helps seal up the rings, and lube everything in the crank case, and cylinder walls. I don't think 50:1 will give you any better power gains if tuned right.

[knobbyboy]

Originally posted by LONG-ROD
How did it run on the needle? and you should really concider runing 32:1 and ditch the Bell Ray, just my opion though. Oil helps seal up the rings, and lube everything in the crank case, and cylinder walls. I don't think 50:1 will give you any better power gains if tuned right.

Humm, I came from a bike background and we were all running 50:1 in our KTM bikes in most places. At one race that was more open than others we would drop back to 40:1. I guess I could drop back to 40:1 on the quad and try that. I know the Honda paper work on this machine says to 20:1! What oil(s) are folks running?

It ran great on the needle! No problems at all, very clean from bottom to top. When I first got this quad I had so much jetting trouble with it. Turns out it had some weird needle in it. In the process of making repairs I had gotten a carb rebuild kit for the bowl gasket. Upon checking all the parts I noticed the needle numbers from the kit - which was OEM specs - to the needle number in the quad were way different. I ditched the non OEM spec needle and all my problems were solved. I am running the clip in the middle.

[LONG-ROD]

Good to here it's running better. I ran beel ray for years when I raced mx bikes. switched to Maxum 927 and and had way more time between rebuilds, I now run klotz R 50. take 3-4 old pistons cover them in diffrent 2 stroke oil put them in the oven at 200 and decide for your self, as for 50:1 and 40:1 it's your machine not mine. Note: quads have much more load on them thaen a mx bike.