jetting thoughts

[spego]

Hi all.....first time poster here......hoping someone might be able to give me some advice.

First of all I'm mechanically savvy.......but this has been my first experience with jetting an ATV and had a hell of a time with it so far.

Let me start from the beginning.

The bike is a 2006 Raptor 350. It has a brand new carb on it when I got it (zoom zoom carb). It was totally stock except for that carb.....even stock tires still.

So I installed a K&N, intake bracket (no lid) and a HMF pipe.

I bought a jet kit and got to work. At first I had the main too high.....put a 165 in there and when running WOT it would load up. I went down to a 162.5 and better.....but just a little bit of a loadup or flat area on the top end. Now down to a 160 and this pulled all the way through......had power right until I ran out of throttle cable. So ok I found my main!!

Then I started messing with the pilot......because it would load up on tight trail riding.....almost acting like a 2 stroke......I would have to stop and rev it up to clear out the missing and farting it would do after chugging it through tight trails. I also had a sputter off the line from a stand still.

I have 2 pilots.....the stock and the one with the kit which is a 25. I tried both but the 25 was obviously worse. The stock pilot no matter where I set the air screw was still flooding out the low circuit.

Someone suggested adjusting the needle to lean it out......this kind of helped a little bit.....but the issue was still there. I put it back to stock/middle.

This all took place over about 2 months now.......so this has been an on going event.

My buddy said.....put a small main in it and it will stop. I said at this point I'll try anything as I'm one screw turn away from it going into a shop.

So I put a 157.5 main and the 25 pilot in there. Runs great......no missing.....no farting....idles and runs fine.

So what's the problem?

Well the 160 pulled hard through the mid to WOT......it still pulls but just not as it did before......the 160 really made the midrange and top end come alive. Now the top end to me feels "dry" and just doesn't have that power it did before. Thought about enriching the needle position with the 157.5 but i don't know that will do much.

So I was hoping maybe some carb guys might be on this forum that might be able to give some advice on this one.

Is the 160 just not the jet for this situation? Did I miss something I should have tried to make the low circuit work with the 160?

I thought about taking it to a shop and explaining it to them......maybe they could get it tuned out with the 160 some how.....or they might charge me for their time and give it back to me the way it is now.

Or maybe I should leave it alone and just be happy it runs correctly through the whole range at this point? lol

 

[alex456123]

Sounds really really rich. What does the spark plug look like?
You should be running a 155 or lower.

 

[geeessfore]

For a totally stock bike with little mods i cant see any reason to be jumping from 142.5 to a 160

 

[spego]

The plug currently looks tan/brown when I checked it last.

The jet kit recommended starting with a 165..... So that's how I ended up with the 160. Being it runs correctly through all ranges at this point I'll probably just leave it alone with the 157.5 in it then. I actually don't see any reason to go lower..... My thought was the fact it ran better on the upper range with the 160...... But sounds like it was just too damn big.

 

[Warrior1996]

What jet kit did you buy? the jets could be numbered differently than the mikuni jets most of us run...

 

[spego]

It's a Phoenix jet kit for a Raptor 350......purchased off Ebay.

 

[Warrior1996]

From what I found on google, that kit is numbered like the dynojet kits.

 

[spego]

Hmm ok.

Just doing some research on that then.....This chart shows the Dynojet vs. Mikuni jet sizes.

DYNOJET/MIKUNI
150 140
152 142.5
154 145
156
158 147.5
160 150
162 152.5
164
166 155
168 157.5
170 160

The area I was playing around with is highlighted. Something seems off there if you guys are saying I should be running a mikuni 155 because that would be equal to the Phoenix 165 I started with and that ran like a$$. I'm all the way down to a 157.5 Phoenix now and if thats right I'm down to a 146-147 mikuni then......which seems too lean.

Should I just buy mikuni jets.....a 150, 152.5 and 155 and try those instead?

 

[Warrior1996]

What size pilot do you have?

 

[spego]

The pilot that came with the kit is a 25. I also have the stock pilot that was in the carb here with the extra parts.

 

[Warrior1996]

is that the jet kit number or mikuni number?

 

[spego]

Sorry that is the phoenix jet number.....I should have said that.

 

[geeessfore]

I got a nice list of mods snd run 25/ 152.5

 

[spego]

Is that 25/152.5 in dynojet or mikuni jets?

 

[lbjamm]

Is that a Raptor 350 carb or a Warrior carb? Sorry, I'm getting confused by the numbers. Prolly should just get Mikuni jets. OEM usually work best.

 

[spego]

Raptor carb

 

[lbjamm]

I found this. Maybe will help...


http://www.raptorforum.com/forums/73-raptor-350-discussion/3848-jetting-questions.html

 

[spego]

Yeah I've read that and mostly all other posts online about jetting a raptor 350 with a pipe/open box. Most people don't say what jets they used.....so the Phoenix kits are higher numbered I guess (thanks to the info posted in this topic they are the same as Dynojets) which I never knew. So that makes some sense.

What doesn't make sense is why a Phoenix 157.5 (which is roughly equal to a Mikuni 148) runs better when everyone else is running Mikuni 155's.

I may be better off just buying a few Mikuni jets and trying those and see what happens I guess.

 

[lbjamm]

OEM are more accurate I believe. I had the same trouble with a Dynojet kit in my warrior.

 

[spego]

Doh.....ok good to know. I suppose I'll try that next.