??Tri Z jetting after mod??

[Tryzeedudeman]

What up, just got my cylinder ported and polished and the head shaved according to the yamaha wrench report. I have a 38 mm mikuni carb, boeysen power reeds, and full dg exhaust. I was wondering if anyone would be able to give me a good idea on jet sizes to start out at. Thanks a lot!!!!!!

[ATC-Eric]

I would start at 175 main, 55 pilot. Thats where I started with mine. Poilished, V-Force Reeds, 39 pwk, Dg full, lightened flywheel, milled dome, I eneded up at a 172 I think......... Does pretty good, I just got to adjust the clip again when I have the energy.

:beer

[Tryzeedudeman]

what do you mean "adjust the clip" what is the purpose of that?

[ATC-Eric]

what do you mean "adjust the clip" what is the purpose of that?

The clip position on the carb needle. Its a bit rich right now, I think I can tune it in right by raising the clip on the needle to lean it out.


So you have an 85.5?

Post some pics up!

[factoryX]

does the stock head pipe suck? i have a after market pipe in the back but a stock head pipe....

[Tryzeedudeman]

the pic in my avatar is my bike when its clean. When i get it back together and cleaned up a bit i'll get some pics posted. About the pipe, I dont know how big of a difference it will make because i bought mine with the DG and havnt ridden it with the stock pipe. I know the DG is like $200.00 so you would think it would make a noticable difference.

[Mosh]

Most mikunis run completely different jet sizes than a PWK carb.

I am not sure the Pwk jet sizes transpond to the Mikuni.

I would ditch the mikuni and snag up a Pwk 39 mil carb,then Go with Atc Erics suggestions.
Pwk is a better carb IMO.

[ceaserthethird]

DG for the Tri-Z's aren't bad - Good for Hi Rev

But if you want to ride trails go with the Stock Pipe ( Good Low End Torque )

[Tryzeedudeman]

it was jetted perfect with the main jet size of 290 before the port work. I'm gonna try a 310 and see what happens from there. This mikuni carb has been great for me. What do you not like about it and what do you like so much about the pwk?

[ColeTrickle]

Finally got my Z back together with the stage 2 port job and a Mikuni 38mm flat slide carb. I have been jetting this thing for days but I'm finally close to being spot on. I have a 350 main(will go up to a 370 as it gets colder), NAFF needle in the second richest position, a 40 pilot and a 3.0 slide. The report recomends a 6F45-3 needle but this one is the only one I had lean enough to run good. It's a stock needle out of my 01 kx250 I believe. I am very pleased with how she pulls all the way through the range. I can't believe the difference.

A few things I found while doing all this work;
rip in gasket for vacuum fuel pump, was letting gas by and following vacuum tube directly into bottom end. Not only was the gas flooding the bottom end while the bike sat but it was feeding the engine while it was running. I believe this has been going on for a while.
Also the 35 pilot that I kept going back to was drilled out bigger than the 45. So when I thought I was leaning out the low speed I was acually richening it up. This was really giving me fits. I used a small drill bit set to find a pilot between the 45 and 37.5.
I also had a slightly blown head gasket ( kept pushing a little antifreeze out the vent tube)

My plan is to order the needle size that is recomended but for now the Tri-Z is running strong:w00t:

I got to rip it up in the first snow fall of the year today:D

[Yamahondaman]

A 320 Mikuni Jet is the same as the 160 Keihin ...