Too much smoke!

[viclioce]

Got the idle adjusted. It idles nicely now, but I’m getting way more smoke than usual with a 32:1 pre-mix ratio. Does this mean the main jet is too big, or the pilot jet?

It’s a VM26 carb, with a 180 main jet & a 50 pilot jet, which is supposed to be stock for a VM26 on a Model 03. Only this is a Combat Wombat with reed valve.

Suggestions? Should I try a smaller pilot jet because of my elevation? Victor.

[Al Harpster]

If it runs "right" I'd do nothing.

If it's too rich it'll tell you when you get on the throttle.

Then proceed with caution.

You might consider dropping the jet needle a notch.

Go slowly.

[viclioce]

Al. The main jet was at 220. Dropped it to 180 and it smoked less and ran better at mid throttle. WOT drops off power. Going to wait until I get the correct needle in the mail from Terry. Then I can adjust some more without unknowns.

I really thought the reeded Combat Wombat motor would do more. Thought it would take a bigger carb with bigger main jets. But it looks like the 26mm carb is doing the job. Soon as I have the correct needle, I can fine tune the main jet. No sense in juggling things around until the needle gets here.

She is starting first kick with the choke on nearly every time u start it cold. And when warmed up a bit, she starts first kick with the choke off. So I’m almost there.

Idles great now. Pulls good taking off and beginning of each gear. Just need to continue to accelerate at WOT!

And I did a fine tune adjustment on my chain guide with a hammer! . Nothing like a little persuasion!!! Victor

[Bullfrog]

Smoke production is not a reliable indicator of jetting.

NUMBER ONE: Go to the Mikuni tuning procedures. Do the procedure for dialing in the pilot jet and pilot air screw. NO other jetting should be done until AFTER you do that.

Ed

[thrownchain]

too much smoke could point to a leaky right side crank seal also.

[taber hodaka]

WOT on a new engine without a break in?, Jet and adjust starting at the bottom working up. never WOT until you have the lower range dialed in and running time on the engine. Make sure you have a over sized main jet installed, drop one size at a time until the engine runs crisp with just a few blips. Tune riding, not on a engine stand. Don't look for performance until the engine is tuned. Everyone has their own system but some of us oldtimers have seen new engines melted down before the finish of the first race. -------- Clarence

[viclioce]

Clarence. I always tune from the bottom up. Had too big a main jet in this carb. It’s a 26mm and had a 220 main in it. Stock calls for a 180 main with a 2.0 slide. I currently have a 1.5 slide in it, and dropped the main to 170. She runs pretty good now!

When the correct jet needle arrives, I’ll change to the 2.0 slide, and go back up to a 180 main. The pilot is the stock 50. I’ll get there! Rode it around the subdivision a few laps. The front end is starting to float when I gas it now!!!

This is my first time setting up an unknown reeded motor. Everyone kept telling me go big or go home. Had a 30mm & a 28mm but settled in with the 26mm from the Model 03 Wombat. Almost there. Soon the carb will be configured at the factory settings. Just waiting on the needle. Victor

[viclioce]

Tabor. This is not a “brand new” engine. She is an existing .030 bore. I put it together & tested compression with the reeds & carb on & got 130 psi.

Measurements were within specs for piston & ring. So no fresh bore. Just fresh bottom end. Didn’t want to bore it to .040 unless I absolutely had to, which I did not! I didn’t see any sense in going to the last available piston size until it actually needs it.

The intake in the cylinder was cleaned with the vapor blasting. I dare say I’ll have her all dialed in with jetting, needle and needle clip when the correct needle arrives. I used the closest needle I had on hand, which isn’t the correct size for the needle jet in this carb.

I’ll also be changing from a 1.5 slide to a 2.0 slide when the needle arrives. This will set the carb back to stock for a VM26 for a Model 03. Victor