jjdalynh
XS650 Member
Hello! Total newb with XS650s, bought a bobber project for my wife and am in the process of tuning and identifying exactly what we have.
This is an '77 frame, totally irrelevant probably.
The motor is from an '81 XS-H Special II.
The carbs however appear to be early BS38s (nonadjustable pilot air bleed, obvious BS38 float chamber with brass floats and needle/seat assembly as described in carbguide.pdf)
The problem i'm having it trying to determine just what the jets should be on this bike with these carbs (supposedly 1 rebuild, i'm guessing .5 mm overbore).
The pilot jets i took out are BS30 type, 42.5 and main jet of 145. The pilot appears to be of the wrong type, the float bowl is the BS38 type with the non-drilled air passageway. Further disassembly shows that the needle jet is a Z-2 type. obvious plier marks indicates it's at least been removed before. I need to get some longer c-clip pliers to get the needle out to see what type it is though.
Based on this info, does anyone have any further suggestions for determining the exact carb year and what would be a good starting point for jetting this 81 motor (open foam air cleaners and drag pipes). The plugs are kinda oily looking, so i'm thinking it's pretty rich, but i do get deceleration popping..... Also, the thing kicks over on the first try with barely any need for the choke. (which i haven't disassembled yet, perhaps a leaky enrichment circuit is the cause of the richness....). Anyways, any pointers on what else to investigate (i will be figuring out the needle situation today)?
This is an '77 frame, totally irrelevant probably.
The motor is from an '81 XS-H Special II.
The carbs however appear to be early BS38s (nonadjustable pilot air bleed, obvious BS38 float chamber with brass floats and needle/seat assembly as described in carbguide.pdf)
The problem i'm having it trying to determine just what the jets should be on this bike with these carbs (supposedly 1 rebuild, i'm guessing .5 mm overbore).
The pilot jets i took out are BS30 type, 42.5 and main jet of 145. The pilot appears to be of the wrong type, the float bowl is the BS38 type with the non-drilled air passageway. Further disassembly shows that the needle jet is a Z-2 type. obvious plier marks indicates it's at least been removed before. I need to get some longer c-clip pliers to get the needle out to see what type it is though.
Based on this info, does anyone have any further suggestions for determining the exact carb year and what would be a good starting point for jetting this 81 motor (open foam air cleaners and drag pipes). The plugs are kinda oily looking, so i'm thinking it's pretty rich, but i do get deceleration popping..... Also, the thing kicks over on the first try with barely any need for the choke. (which i haven't disassembled yet, perhaps a leaky enrichment circuit is the cause of the richness....). Anyways, any pointers on what else to investigate (i will be figuring out the needle situation today)?