You may want to check that the carb is seated properly. If there are any air leaks in the system that can cause havoc. Check everything between the airbox and the intake.

 

Interesting using the lid as a diagnostic.. He knows that removing it lets the engine breath so much more better that it can be used to diagnose jetting ... lol

How bout if it runs better with it off, leave it off and tweak remaining issues...?

 

it was a tight fit... but the boot is on properly as far as i can tell, and the clamps are tight. I'll play with it when i get home...

 

Yeah, i'll have a go at that too.. Didn't want to touch anything til I spoke to Bill.

The air jet fuel on this mikuni is on the engine side of the carb. (If I'm looking at the right one ? ) the one with the handle right ? My understanding is turn the iidle down to low rpm. maybe 600 or so, then turn this in til the engine is about to die, then 1/2 turn out....

 

Not really.

Warm the bike up. Set you idle to normal. Turn the screw in till you hear the engine slow. Then turn slowly out (counterclockwise), the engine will pick up rpms. Keep turning it out until is starts slowing again. Then turn it back in, back and forth till you think your centered in the band with the highest possible rpm.
Then readjust your idle.

Your done.

 

Well i think i've found the problem... Pulled what was a new plug 100miles ago, and look how much soot there is. I'm currently on a main 142.5 Bill told me... I guess i should go down, but to what? 140 ? Never really changed jets before, but i'm sure i can work it out.. Remove the carb (great cos this was a pain to get in !!) then take the bowl off and unscrew ! But i'd like to get it right first time if possible and save the hour or so of frustration getting the carb in and out.

 

Your plug is not your problem, it is the symptom. You have been running it without tuning the carb, what do you expect?
I am running stock everything except 350 & 34 Mikun; 130main, 32.5 pilot, 3300-9,000 elevation. Everyone else here runs way too rich! That is my story and I'm sticking with it!!!!
I would suggest you get on the internet and get some carb info before changing anything. You have decided to modify your bike, so now finish the job.

Before your done, you'll be able to pull/install the carb in 20 min. Ha!

 

I'm going to try a 140 and see how that works out.

 

Did you run w/o the airbox lid?
I'd look at similar set ups on the jetting spread sheet we have floating around somewhere. Not a lot of TMs, but there are a few.

 

Here is a link to our forums' "Tuning Spreadsheet" - https://docs.google.com/spreadsheets...it?pli=1#gid=0