hi all ive put new mikuni carb on my 199B its the VM26 with 130 main jet and 35 pilot seems hard to get it tickin over quiet it runs great with the mikuni but just cant seem to set the air screw any body know how many turns out it is from bottom?

Edited June 12, 201313 yr by bondy

Set the screw 1.5 to 1.75 turns out. Warm the bike up well then set a slightly fast tick over this the slide stop screw. if any adjustment of the air screw slows the engine it is already correct. If adjusting the screw increases tickover adjust it to the fastest, if necessary unscrewing the slide stop so it is not too fast.

If with tickover fastest the screw is between 1 and 2.5 turns out jetting is near enough. At low speed these bikes run best with a thick oil like Silkoline classic 2T sae 40 at 30:1. These air cooled engines have quite a bit of piston clearance and a thick oil reduces blowby which at low revs can contaminate the fresh mixture in the crankcase and inlet tract making a steady idle virtually impossible to achieve. Persevere and these engines can be made to run really smoothly and pick up cleanly from near zero revs.

Cheers

cheers mate ill give that ago im runing it on putoline trials TT pro at 50 to 1 at the moment ill buy some thicker oil thanks.

hi all ive put new mikuni carb on my 199B its the VM26 with 130 main jet and 35 pilot seems hard to get it tickin over quiet it runs great with the mikuni but just cant seem to set the air screw any body know how many turns out it is from bottom?

Punctuation, it's not just a good idea, it's the law.

Edited June 20, 201313 yr by guys

punctuation, it's not just a good idea, it's the law.

What about capitals ?

What about capitals ?

Damn, you've got me there. Thank god for 'edit'.

And if I make an other mistake, I can always use the excuse that I'm from Belgium

Edited June 20, 201313 yr by guys

Mmmh 1:30 that is really quite rich, even with 1:50 the engine is spitting left over aka unburned oil out from the exhaust.

Back in the day's I used the Bultavo oil, (at least produced for them). This was the only oil which was recommend by Bultaco for use with 1:100 as a mix ratio.

Now I use 1:75 as premix no problems so far ...

And you really use SAE 30 as premix, here I am very curious...

Isn't the Sherpa spitting oil like hell or might I have misunderstood something ?

And as for a thick film of oil in the barrel: I used a modern semi synthetic two stroke oil at 80/1 in my Cota 315R and when I opend the engine there was a nice firm oil film on the inside of the barrel, so I don't see the advantage of a classic SAE 40 at oil at 30/1...

Edited June 22, 201313 yr by guys