1983 125xc

Thanks a lot. Topic still open if someone has a 34 on and can check the setting. To be exact, my bike is 1980-81 (with horizontal reed block, but not the 82-83 larger one).

aahhh...

Use the 38mm as that is what came with it stock or if needs replacing as its worn out, get another 38mm as they work MUCH better than the smaller carbs for all-round performance. Husky did their homework with that motor and it worked well.

Thanks Dmcoz, the stock one I have is the Bing 32 (Mikuni 38 is from '82 year) but I have also a Mikuni 35 (but it is a flat slide and is not possible to use in vintage races) and a normal Mikuni 34 that is like new and I think can give good performance but I have to set up. I think the 38mm is too big for enduro (need a good low-mid), may be is good for motocross, no?

(need a good low - mid) - get a 400! last thing you can find on a husky 125 is any of that!!

No, they did not do their homework, they just used the same carb they used on the 250 and 430. The 38mm is WAY too big, even the 36mm is too big, it is at least usable on a 175, but even the 175 runs better with a 34mm. Modern 125s did not go to a 38mm carb until the mid 2000s, in the early 80s nearly every other 125 had a 32mm, very few even had a 34mm carb and there is good reason for that. The 38 is so big the 125 engine can not create enough vacuum to draw enough fuel through even a 530 main jet.

Yes, for enduro you definitely want another 32 Bing or a 34 Mikuni. If you get a new universal 34mm Mikuni the jetting that is in it will be very close.

Thanks a lot Kart! In fact I was 'afraid' of that strange 530 main jet on the 38....
I will start standard with the mik 34

and dear Surprize, you say: (need a good low - mid) - get a 400! last thing you can find on a husky 125 is any of that!!) but husky 125 around 1980 have only good mid-low power (being 125 obviously) and what they need are some ponies!

best 125 i have seen was an 81 with some serious port work and all the fruit. it was fast and the rider was good. even in snotty rocky 1st and second gear climbs, he ran me down on the 400 and disappeared in a cloud of dust ... (i know im not very fast! )

wow!

Disagree, 125's are all about revs and top end power and have used either 36 or 38mm carbs on all my 125,s - 1974 -36 and 38 Bing and that ran like a scalded cat, 77 - 38 Bing and 81/82 - 38 mikuni and 38 Bing. It is rare to find a stock 125, it is even rarer to find one that is raced stock. Port it correctly, use the right pipe and ignition plus open up the air in and they have no trouble running this size carb. And why anyone would use a 530 main jet is beyond me- stock main on a 82 is 470.