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jimstravlin
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VBMWMO #2339
Joined: 10/27/2006
Posts: 101

i have a 1967 R69S and really want to get rid of the bings. have done the conversion to mikuni on my /5 bikes and love them. i think what i need is the manifold flange, 26mm, to mount to the /2 heads with a collar to mount the rubber for the mikuni carb. does anyone have any info about this? who might have a pair of flanges ? i thought this might me a good place to start before i look into have a pair made..... thanks... jim

EuroIron
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VBMWMO #7266
Joined: 04/23/2007
Posts: 414
bing to mikuni carb conversion

all you need is a spigot adapter and spigot bodied mikunis set up for a four stroke

using flange mount mikunis would be a bit more work and ultimately require one off adapters

either 26 or 28mm will be fine

if I used 28's on one, I'd open the port to the 28mm and taper/blend it in about an inch, or a bit more, biased in respect to raising the port roof/top side...... outboard most and top most parts of the port

and in that order

EuroIron
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VBMWMO #7266
Joined: 04/23/2007
Posts: 414
bing to mikuni carb conversion

btw....... the spigot adapters for a brit bike

amal to mikuni spigot adapters

are close enough that only a small amount of opening up of the bolt holes will have them popping right on the bmw head

if you can find them for a 500 triumph 626 concentric to mikuni spigot

it will have an internal bore of 26mm

the 650 and larger will have 30mm and larger internal bores

perhaps you'll find this useful and it will save you some time/money

EuroIron
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VBMWMO #7266
Joined: 04/23/2007
Posts: 414
bing to mikuni carb conversion

I was digging thru some of this previously mentioned brit suff a couple days ago

I did run across several pieces that had internal bores right at 28mm

it's generally for early-mid 60's stuff ranging from 650-750cc's

and the all rubber adapters/confirmation fittings/intake flange whatevers can be had, readily and easily, in the amal concentric bolt pattern and accepting the spigot of common VM round slide mikuni's

I was fondling some the the other day as well and realized that would probably be the best solution with the added bonus of reducing heat transfer to the carb body as opposed to metal adapters

just requires a tiny bit of stud hole filing/modifying

the app for which Sudco, or whomever, would supply you with rubber adapters of 26mm internal bore would be say

1970 Triumph Daytona (twin carb)

28 mm would be 69 Triumph Tiger (single carb) or say 1964 BSA Royal Star

30 mm would be most anything else like 67-70+ Bonneville or Lightning Commando (although some of the commandos are 32mm)

good luck and you're welcome

jimstravlin
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VBMWMO #2339
Joined: 10/27/2006
Posts: 101
thanks

thanks so much. have been out of town and not able to than you proper for all your insight on this. time to go back to work and see if i can make this work....

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