Keihin FCRs

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Apr 6, 2005
I have posted this on the INOAList and thought I would also post it here as my first post.

Can those with Keihin FCR's on their Commandos comment on their experiences with them?

Are you happy with them?

How do you feel about the cost to benefit ratio?

Are they worthwhile on a generally stock engine (see below) or does the engine need to be modded for real benefits?

Did you get them out of Sudco or elsewhere? Prices?

How about the manifolds?

What did you do about air cleaners?

I have a '74 850 with an RH10 head. The head is stock but rebuilt. What is recommended for matching the 35mm carbs/manifolds to this head? Or would you recommend using another head to keep the RH10 original?

Thanks much.


I'm a fan of nice new stuff and have done much of the same research you're doing, but don't discount the competence of a set of well adjusted, resleeved Amals until you've gone that route.

Sudco *is* the US importer for Keihin, so all the dealers get them from there. If you buy direct from Sudco, however, you will pay full list price. Pro-Flo is a good on-line retailer that you should look in to.

FCR's are nice but pricey and BIG. Fit is a critical issue with a Commando frame. Space will determine what you can and cannot do with air filters.

If you're stuck on Keihin's, consider the CR Specials instead (a pair of 31's for a stock 750 or 33's for a modded 750/stock 850). The CRS's are the most tuneable, best running roundslides around - I have a pair and have used them in other applications with great results. Bonus, they're the same size as Mikuni VM's and fit the same spigot manifolds.

And, when you ask about 35mm's, you're talking about a single carb application, right? If not - you'll get nothing but a great big chunk of BOG through most of your power range. A single FCR will not fit under a Commando top tube - its too tall and will destroy itself as it vibrates against the frame.

Finally, stock sized carbs are right for a stock motor. To get any benefit from opening up the intake you need to open up the exhaust, then think about the head and camshaft then compression ratio - then you're into all sorts of expensive parts.
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