My B Rapide carb's are very worn and I want to replace them. The bike is not matching numbers and while I would rather keep it more or less looking standard I am more interested in reliability and cost. What carb's and from where would be best for touring use? I will have the originals re-sleeved at some point.
Worn Carb replacement
- Thread starter Bob P
- Start date
Try Steve at Motocarb u.k. 28 mm. Mikunis are currently in stock, and he will jet them correctly for you.
actual choke size
Hi Bob, I just replaced mine with Amal Mk 11 from Hitchcocks They are 28mm choke. which is close to my original carbs. cost GBP 105.00 . They came with adaptors and jubilee clips . MPG went from 42 to 54 Power increased dramatically. I have since downsized the no.1 carb needle jet as it was running rich on the no.1 pot. I expect the power to stay and the MPG to get even better.I had to change the cables , and bend the choke lever on the no. 1 to fit . The chokes work well. I will have the original carbs rebuilt, .cheers Kevin Fowler
Hi Bob, I just replaced mine with Amal Mk 11 from Hitchcocks They are 28mm choke. which is close to my original carbs. cost GBP 105.00 . They came with adaptors and jubilee clips . MPG went from 42 to 54 Power increased dramatically. I have since downsized the no.1 carb needle jet as it was running rich on the no.1 pot. I expect the power to stay and the MPG to get even better.I had to change the cables , and bend the choke lever on the no. 1 to fit . The chokes work well. I will have the original carbs rebuilt, .cheers Kevin Fowler
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Just a note regarding Mikunis,
they have a cast in bell mouth so if you want to use airfilters they will get very big and stick out very much ( the various K&N i tried did).
I just saw an all foam airfilter that will fit perfectly.
please check out : www.ramair-filters.co.uk and then look for the MR range. For a 36 mm Mikuni the flange is 62 mm , so the MR-011 will fit perfect.
the good thing is that when you touch it with your knee it will bend away but still work ok without a problem unless you are a Gorilla type of guy.
if you do not know the size of your carb bellmouth, have a look for further information at www.mikuni-topham.de search for your carb and you will find all the measurements.
HTH
Bernd
they have a cast in bell mouth so if you want to use airfilters they will get very big and stick out very much ( the various K&N i tried did).
I just saw an all foam airfilter that will fit perfectly.
please check out : www.ramair-filters.co.uk and then look for the MR range. For a 36 mm Mikuni the flange is 62 mm , so the MR-011 will fit perfect.
the good thing is that when you touch it with your knee it will bend away but still work ok without a problem unless you are a Gorilla type of guy.
if you do not know the size of your carb bellmouth, have a look for further information at www.mikuni-topham.de search for your carb and you will find all the measurements.
HTH
Bernd
With regard to choke size: 28mm should be all you need if you have a standard motor and don't spend all your time on motorways at 80 odd mph. you really only need larger sizes if you ride it at or near full frottle aller time! sometimes a smaller choke size can actually give you better performance at lower speed because of higher gas speeds through the venturi on pick-up.
A very good point.
I have 28 mm Mikuni's on my Rapide, very close to the original Amal choke size fitted. It is more than adequate for general riding.
Another thing to consider is that the VM series uses a few base castings to cover their choke sizes. The 28 mm uses one of the smaller castings. The larger choke sizes use a larger casting and you may find installation under the petrol tank, etc more difficult.
I have 28 mm Mikuni's on my Rapide, very close to the original Amal choke size fitted. It is more than adequate for general riding.
Another thing to consider is that the VM series uses a few base castings to cover their choke sizes. The 28 mm uses one of the smaller castings. The larger choke sizes use a larger casting and you may find installation under the petrol tank, etc more difficult.