Hi, I've just bought a 1977 Sherpa 350 with a mikuni carb. I've cleaned it thoroughly as it was leaking from the overflow pipe. Does anyone know the float height setting? I have it running but not easy to start and it dies like it's out of fuel after just a short run but starts again after. The air screw is only about 3/4 turn out and I've seen elsewhere it should be 2 turns out. Can anyone confirm this?

Cheers

Neil

Hi Netley welcome to the tc forum.

Probably best to strip the carb and clean with compressed air, check the condition of the float sometimes they can split if they are the hollow type, clean air filter, check ignition timing, check wiring contacts maybe a condenser as well then fit a new plug and try again.

On the Beta section there is info on Mikuni settings, best place for Mikuni spares if required is Motocarb.

Good luck

Edited July 9, 201610 yr by trialsrfun

Hi

 

My 199A runs quite well with the following jetting (26mm VM carb): Needle 5C23, throttle 2,  main jet 140, idle jet  30, needle jet O3, needle first groove from top. The problems with dribbling VM carbs are well known (see Beta forum). This is why I´m now testing a Dellorto PHBL.

/Carl

Welcome to the forum netley.

Here is a very well laid out fix you can read through http://www.motomerlin.co.uk/moto/betacarb.pdf

I also came across the following article as well, "Is your BETA drooling fuel? By Clark Pittman" on a Club newsletter from the States http://www.ntxtrials.com/web_newsletters/RCR0106.pdf scroll down to the 2nd page.

Hopefully this might sort your carb.

Edited July 9, 201610 yr by model80

Neil, my 340 runs with air screw at 1 1/2 turns out with a 35 pilot jet. Runs very well on the vm26. Also had a 250 on one, also very nice runner. Both needed a good flood for cold start (lean bike over) but 1st kick when warm.

Just fitted an OKO to a Montesa 348 and very impressed, if you don't percevier with the mikuni, an OKO might be a good option - eBay for about £65. Don't be tempted with the cheap ones which are likely copies.

Hi

 

My 199A runs quite well with the following jetting (26mm VM carb): Needle 5C23, throttle 2,  main jet 140, idle jet  30, needle jet O3, needle first groove from top. The problems with dribbling VM carbs are well known (see Beta forum). This is why I´m now testing a Dellorto PHBL.

/Carl

 

have you got dellorto settings at all yet?

Hi,

It runs OK at the moment but it is really not sorted out yet. If you like I post the settings later when I think I got something to share.

/Carl

Thanks people, Really appreciate the help. I've now had it running but there is still some fuel overflowing but I won't have time to reset the float height until next week.

Cheers.

Neil

This is the jetting for PHBL 26mm that I´m currently using:

Pilot 30

Needle jet K266

Needle D56 4th groove

Main 105

Throttle valve 60

 

Low and mid throttle is as good as it was with the Mikuni but I get some more revs from tne engine at top end and it feels sharper overall and there is no dribbling.

Both the Mikuni and Dellorto are way better than the original Bing

Adaptors for both carb inlet and outlet  must be made.

Do I have to say that I stay with the Dellorto

Edited July 15, 201610 yr by carl ekblom

Hi, Thanks for all the replies. I wondered if anyone could identify this carb?

That way I can make sure I have the correct settings and float height. I'll be adding the air filter Tuesday.

Cheers

I think I have answered my own question having taken some higher quality pics and googled the numbers on the carb.

 

https://yamahaclub.com/forums/topic/28494-dt-175-mx-main-jets/

see advice from Airhead.

 

Not really suitable for an engine nearly twice the capacity ?

 

Neil

A Yamaha 3U5 carby is a bit small for a 325. Marginally OK on a trials 250. I run that size Yamaha-Mikuni on my 210cc TY175 and it goes great

Do you want another

This should do the job. The Mikuni it should have fitted.

Edited July 19, 201610 yr by netley