August 18, 20215 yr So finally got the Sherpa T 175 all back together and it struck up after a few kicks. The issue I have is when I acquired the bike it wasn't actually running and as such I have no idea whether the carb or the jets where making for optimum performance. I can obtain new jets of course but I don't have a bench mark to work from. The bike has good compression and has just been re-ringed and has new gaskets. It has an Amal Mk2 concentric 2625 carb on it at present and the symptoms are as follows. Lumpy running and not able to obtain full revs. Its very smoky and currently running using 95 ron and and Castrol semi syn oil at a ratio of 50:1. Its difficult to start especially when cold. Its fuel consumption seems to be excessive. Currently it has a Main Jet size 160, a Pilot Jet of 20 and a Needle Jet of 106. The needle position is at 2. Unfortunately my knowledge of 2 stroke carb tuning is limited as 4 stroke is more my thing. Any experience you guys my have or can suggest a different jetting that you know works well on your machine would be really appreciated.
August 18, 20215 yr I'd bin that carb and go for a mikuni. Give in motion a ring they'll be able to help
August 19, 20215 yr The usual thing with those carbies is that the needle jet wears alarmingly fast which makes it run rich just about everywhere. They also suffer from the jet needle wearing and the slide wearing and the body wearing. Have a look through the needle jet and I wouldn't be surprised if the hole is elongated rather than round. The jet sizes sound OK but you didn't mention the needle size. OKO. Keihin, Mikuni, Dell Orto all make great carbies for your bike. Bultaco with good carby and good ignition = fun times
August 19, 20215 yr Author 12 hours ago, feetupfun said: The usual thing with those carbies is that the needle jet wears alarmingly fast which makes it run rich just about everywhere. They also suffer from the jet needle wearing and the slide wearing and the body wearing. Have a look through the needle jet and I wouldn't be surprised if the hole is elongated rather than round. The jet sizes sound OK but you didn't mention the needle size. OKO. Keihin, Mikuni, Dell Orto all make great carbies for your bike. Bultaco with good carby and good ignition = fun times Going to have a chat with Allens performance and hopefully get something sorted, thanks for the suggestions
August 19, 20215 yr 36 minutes ago, cde050583 said: Allens performance Be persistent. They can be mega-slow by email, may be worth calling by phone and calling again.
August 19, 20215 yr A 150 main jet was stock on the 350`s, so a 160 is way too big. At least try a 150, but something even smaller would be best.
August 22, 20215 yr Author Allens performance have sorted the job, Mikuni on its way, fingers crossed for a transformed bike.
August 22, 20215 yr On 8/20/2021 at 12:43 AM, lineaway said: A 150 main jet was stock on the 350`s, so a 160 is way too big. At least try a 150, but something even smaller would be best. The 325 came with a Bing Carburettor, so totally different. Although the numbers might sound similar a Bing 150 will not correspond in anyway with that of a Amal 150. The best advice received, is dump the Amal and get a Mikuni. Edited August 22, 20215 yr by model80
August 23, 20215 yr Two best things I did to my M98 Sherpina was swap over to a Mikuni and dump the points for electronic ignition.
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.