Tri-Z Jetting Experts

[Rider414]

I got this Tri-Z that runs like crap on the pilot/needle circuit.

Starts and idles until warm, then it wont idle even with the idle screw all the way in.
Loads up and blubbers right off idle.
I rebuilt the fuel pump already hoping that was the issue.

It's a 85 Tri Z with a what I believe is a 85 carb. Last owner said he put a different carb on it. I put a new 45 pilot jet in it because I couldn't read the number on the one in the carb. Runs like crap. I put a 35 pilot in it as recommended by another associate, no change at all. Air Screw doesn't make a difference. It has to be this carb. Worn needle jet? Etc;

Let me know your thoughts and what the next move should be.

[El Camexican]

The make, model and size of your carb would help get you some answers

[Rider414]

Its a stock Mikuni VM32 carb. The parts inside the carb lead it to be a 85 Model. Slide is 2.0 and Needle is a 6H3.

Today was cooler, I went 3 turns out on the air screw, needle was dropped to the leanest setting. It will barely idle now and seemed to improve and clear out. What is stumping me is why it wants such a lean pilot? I think if I go to a 25 pilot it will get better.

If I decide to bail on this carb, what replacement carb would work well with a stockish bike? What will retain the stock thumb throttle?

[jmax857]

Its a stock Mikuni VM32 carb. The parts inside the carb lead it to be a 85 Model. Slide is 2.0 and Needle is a 6H3.

Today was cooler, I went 3 turns out on the air screw, needle was dropped to the leanest setting. It will barely idle now and seemed to improve and clear out. What is stumping me is why it wants such a lean pilot? I think if I go to a 25 pilot it will get better.

If I decide to bail on this carb, what replacement carb would work well with a stockish bike? What will retain the stock thumb throttle?


Have you checked your Reed petals?

[Dirtcrasher]

Or maybe an air leak? or bad o-ring somewhere?

[El Camexican]

A stock carb with the factory jets and the needle clip set to the middle with the air screw out 1.5 turns should start and run well enough to begin tuning anywhere from -2000 to +8000 feet. Check your float height and the reeds as suggested and make 100% sure your fuel return line isn't obstructed then try it again. If you do buy another carb I'd recommend a 36mm Air Striker.

[Rider414]

Reeds are new, Return line was pulled and checked - looking for a replacement carb.

[redrider77x]

I know on my 86 carb there is a flat spot by the choke lever on the side that faces the reeds. 1RX is stamped in there very small, I dont know if the 85's have 38W stamped there or not?
Also 85 and 86 have completly different jetting setups not sure if you knew?

However i second El Camexican on the float height, it's a fine line between pouring fuel out your carb and running the pilot lean.
Good luck.