'55 G80CS... Saga - Caburetter specs?!
Posted: Sat Sep 29, 2018 5:19 am
Hi all,
Thank you again so much for helping me through my ordeal.
I've sent my head off for new valve guides, valves and seats, and have the barrel at engineer getting a new +060" JP piston clearanced.
I've stripped the carb, and done some measuring.
1. It appears that it is a AMAL 389/203 for a T120 Triumph.
2. Bore is 1 1/8" - as opposed to the manual's 1 5/32" requirement. - Hence, undersized by around 0.031"
3. I've used anything from a 260 to the current 400 main jet.
4. I have now identified the slide as a #3 1/2. (the '.5' marking is very faint, but definitely a bigger cutout compared to a spare #3 I have.
My new piston, and most of the previous ones have been aparently, are 8.5:1 even though I was told they were 7.3:1.
Basically, I would have thought, that if the carb is too small, this would make velocity higher and also , make the jetting weaker? That said, with the bigger jet (400), one would think it wouldn't be too lean?
So, given all this information, Any ideas on how I should Jet my carb or, is it to small for my Matchy?
Thank you again so much for helping me through my ordeal.
I've sent my head off for new valve guides, valves and seats, and have the barrel at engineer getting a new +060" JP piston clearanced.
I've stripped the carb, and done some measuring.
1. It appears that it is a AMAL 389/203 for a T120 Triumph.
2. Bore is 1 1/8" - as opposed to the manual's 1 5/32" requirement. - Hence, undersized by around 0.031"
3. I've used anything from a 260 to the current 400 main jet.
4. I have now identified the slide as a #3 1/2. (the '.5' marking is very faint, but definitely a bigger cutout compared to a spare #3 I have.
My new piston, and most of the previous ones have been aparently, are 8.5:1 even though I was told they were 7.3:1.
Basically, I would have thought, that if the carb is too small, this would make velocity higher and also , make the jetting weaker? That said, with the bigger jet (400), one would think it wouldn't be too lean?
So, given all this information, Any ideas on how I should Jet my carb or, is it to small for my Matchy?