Technical What are the 28IMB carb differences?

[smart51]

The 28IMB carb comes in 4 variants as far as I can tell. 28IMB, 28IMB1/100, 28IMB5/250 and 20IMB10. I can't find anything anywhere that explains the difference. Can anyone shed any light on this? And which would best suit a 594cc 500R?

 

[Toshi 975]

The 28IMB carb comes in 4 variants as far as I can tell. 28IMB, 28IMB1/100, 28IMB5/250 and 20IMB10. I can't find anything anywhere that explains the difference. Can anyone shed any light on this? And which would best suit a 594cc 500R?

Not sure where you got your carb codes from but the 500R was originally fitted with the restricted Weber 24IMB and the 126 at the time had a 28IMB 3 which was quite quickly superseded by the Weber 28IMB 1 which was used until 1977 when the 28IMB 5 was fitted on the 650 engine. Later the 28IMB 12/250 then along came the carbs with the solenoid fuel cut off incorporated.
They are all interchangeable and have small variations in jet sizes. Any would be worth a try and with new jets being available cheaply not had to make modifications if necessary.

 

[smart51]

Not sure where you got your carb codes from but the 500R was originally fitted with the restricted Weber 24IMB and the 126 at the time had a 28IMB 3 which was quite quickly superseded by the Weber 28IMB 1 which was used until 1977 when the 28IMB 5 was fitted on the 650 engine. Later the 28IMB 12/250 then along came the carbs with the solenoid fuel cut off incorporated.
They are all interchangeable and have small variations in jet sizes. Any would be worth a try and with new jets being available cheaply not had to make modifications if necessary.

I didn't say that the 500R came with a 28IMB, I know they had a 24IMB from the factory. I was asking which 28 would suit it. I'm going to look at a 500R next week and plan to replace the 24 with a 28, if it hasn't been done already. I'm trying to find out which are suitable.

I got my list of numbers by looking at the ones I've seen for sale. It may not be an exhaustive list, but it presents a practical limit.