Jet Size Suggestions Please !!!

[Hairyblackdude]

Hey all,

I just signed up w/ the forums yesterday, but I've been trolling for the past several weeks. Me & several of my friends got quads recently and mine is obviously a Blaster. Its a 96. I went through & overhauled the whole thing, it was crappy.

Anyway, I would like some suggestions on Jet sizes to use for my Blaster. Basically just looking for a good starting point so I can cut down on trial and error time.

Its bored .020 over w/ a wiseco piston. I have a Boyeson reed cage w/ Boyeson carbon reeds & a DG Muffler. The expansion pipe is stock. I usually keep the airbox lid ON.

My friend ruined my pilot jet trying to open it up a little bit w/ a dremel. I took the jet off a motorcycle & modified it to work w/ the blaster- but its not the greatest. When in neutral, the revs take a few seconds to drop back down & you can hear it firing by itself.

So, if someone would be so kind as to suggest a good size pilot & main jet size to start off with, I would much appreciate it !!!

Thanks !!!

 

[cyphertext69]

Here is a Jetting Guide, maybe it will help you understand what the jet is doing:
http://www.blasterforum.com/do-yourself/1625-jetting-101-everything-explained.html

There is a difference as to what you are doing with the airbox lid. If it is off, you need a bigger jet, if it is on, you need a smaller jet.

You don't have very many modifications to your quad so here are my suggestions:
240 with airbox lid on
250 with airbox lid off
260 while it's cold outside.

Keep in mind that elevation and temp can be a factor as well. These are only my suggestions and in my area, I am at sea level, I would use this setup with your mods.

The carb stock has a 230 main jet in it.

Do you have the stock carb on there? Have you changed the Pilot Jet or anything else on the quad?

*EDITED* for a pilot jet, I would use a stock pilot jet (32.5).

 

[crusty4365]

240 is perfect for you

 

[Hairyblackdude]

I have read the Jetting 101, very good information there... I was basically just looking for a good starting point to cut down on the time/effort it takes to tune it.

It is the stock carb, but I do not have a stock pilot jet in there, its some crazy one I made from a motorcycle.

I am going to install another stock pilot jet in there & see what happens, I thought the jet thats in there right now was larger than stock, so I was surprised when the revs take a few seconds to come down. I assumed this was because it was too lean.- but I'm not sure.

I just got a bunch of different sized jets in the mail yesterday so I'm good now. When I used the motorcycle pilot jet, I was in a real pinch because we were going riding the next day & I couldnt find one anywhere.

The main jet that is in the carb right now is a 290. I think its a bit rich because at WOT, the quad falls on its face. It accelerates faster at like 60% throttle. So I'm going to drop that jet down also..

Any ideas for the needle setting? I havn't taken that out yet to see where it is set, but mid range throttle response seems pretty good.

I appreciate your response. Any other suggestions or tips are more than welcome.

 

[blaster551]

with that bore i wouldent go lower then a 250 you will run it to lean and blow it up if you have been reading i have been having the same probelms but im running a 260

 

[cyphertext69]

I have read the Jetting 101, very good information there... I was basically just looking for a good starting point to cut down on the time/effort it takes to tune it.

It is the stock carb, but I do not have a stock pilot jet in there, its some crazy one I made from a motorcycle.

I am going to install another stock pilot jet in there & see what happens, I thought the jet thats in there right now was larger than stock, so I was surprised when the revs take a few seconds to come down. I assumed this was because it was too lean.- but I'm not sure.

I just got a bunch of different sized jets in the mail yesterday so I'm good now. When I used the motorcycle pilot jet, I was in a real pinch because we were going riding the next day & I couldnt find one anywhere.

The main jet that is in the carb right now is a 290. I think its a bit rich because at WOT, the quad falls on its face. It accelerates faster at like 60% throttle. So I'm going to drop that jet down also..

Any ideas for the needle setting? I havn't taken that out yet to see where it is set, but mid range throttle response seems pretty good.

I appreciate your response. Any other suggestions or tips are more than welcome.

I have the very same problem occasionally. I have a 290 in mine as well but I have full FMF Exhaust, Uni Filter (no airbox lid), 28mm carb, boysen reeds, vito's reed cage and vito's piston. I should be running a 280, maybe but I think my pilot jet is f-ed up.

 

[Hairyblackdude]

Alright guys,

I had some time last night to go through & play w/ my Blaster a little bit. I installed a #35 pilot jet & a 260 main jet. I wanted to go a little more on the richer side to be safe.

The quad is running soooo much better.. I surprised the hell out of myself last night pulling a pretty big wheelie starting out in first !! I wasn't pulling any wheelies before- but now the front end is popping up all over the place, even in second gear !!

I'm going to install the stock 32.5 pilot jet & probably throw in the 250 main jet & see if I can squeeze a little more juice out of it.

Thanks for the tips !! I:I

 

[Oldfart1stATV]

Check your plug!!

Check your plug and make dam skippy sure you aren't lean. It will run like a scalded dog and then die if it's lean.

A