T100r Carburetors

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KSP25

Member
I have here a 1972 T100R with two carburetors. Based upon the information I have, they look like Amal concentric. I have worked on 100's of Japanese carburetors and are very familiar with those products. I don't really understand these and hope somebody can put me on the right track. The bike acts like it has plugged pilot jets (idles poorly, erratically, up and down) but I don't even see pilot jets in the exploded view diagrams I have got? Somebody told me they are in there behind a (Welsh plug) and you have to dig them out or something like that? I have had these carbs apart and cleaned them completely including new float valves, screens, filters, gaskets etc. Any help is appreciated.
 
Bushmans Carb Tuning Secrets

Unless something else has been fitted over the years you have Concentric's.

Try the site above for help with your Concentric's. They are quite easy to tune as long as they're not worn out.
The pilot jets are fixed and not removable. They can be cleaned with a bit of wire taking great care not to remove any metal and enlarging the jet while doing it.
Amal carbs are well known to have excessive clearance between the slide and body after years of wear making tuning very difficult - and a reliable idle almost impossible.
This because both the slide and body are made of the same metal which wears easily, creating clearance, and allowing air in. Modern Concentric's have a coated slide.
The new Premier Concentric's have an improved fuel system and a removable pilot jet.
They aren't cheap, but are worth the money in the long run with much improved performance and running.
If you intend to keep the bike I recommend getting a pair.
 
Bushmans Carb Tuning Secrets

Unless something else has been fitted over the years you have Concentric's.

Try the site above for help with your Concentric's. They are quite easy to tune as long as they're not worn out.
The pilot jets are fixed and not removable. They can be cleaned with a bit of wire taking great care not to remove any metal and enlarging the jet while doing it.
Amal carbs are well known to have excessive clearance between the slide and body after years of wear making tuning very difficult - and a reliable idle almost impossible.
This because both the slide and body are made of the same metal which wears easily, creating clearance, and allowing air in. Modern Concentric's have a coated slide.
The new Premier Concentric's have an improved fuel system and a removable pilot jet.
They aren't cheap, but are worth the money in the long run with much improved performance and running.
If you intend to keep the bike I recommend getting a pair.
Thank you so much! I think I get it now. I did not know these carbs were set up this way. I will get to this and let you know how it worked out.
Thanks Again, Ken
 
Thanks again, that was all I needed. Once I saw the pic of the carb, I see exactly how the carbs work and was able to clean the pilot circuits. Idles perfect and runs good now!
 

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