Commando in Jan ‘Classic Bike’
- Thread starter Fast Eddie
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Really good de$ision to that upgrade.
Schwany
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Realistically, they are horizontal (side draft) flat slide race carburetors with an accelerator pump. They can be made to work well on a street bike using the settings info provided by early adopters here, but they are performance toys.
That single Mikuni you have on there probably works pretty good. The FCRs are kind of a PITA to fit on a Commando, and you could buy a lot of tires with the same amount of money.
It was just a silly suggestion based on use. I am a late adopter and recently replaced a pair of Mikuni carburetors I had on a Norton 750 engine with the FCRs and have no complaints. I wasn't planning on selling my bike though. Nobody would want it.
NoLongerHere
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The owner/builder reckons the front wheel is the "worst wheel ever designed" due to the spokes being near vertical to get the right offset for the disc.
I've not heard of any wheels colllapsing?
And Roadholders? Just rubbish really!
LOL.
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Fast Eddie
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The author is a Rupert Paul. Widely regarded as a bit of a prick back in the day IIRC... probably took sensible words from the owner and edited them into nonsense !
NoLongerHere
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Is that the drag racer?
When I was a kid, there was a model of Triumph 650 which came out with an SU type carb. We replaced the SU carbs with ordinary Amals. On thinking about that these days, the SU was probably a good casrb. It automatically compensates for loss of vacuum as you open the throttle. In Mk2 Amals and Mikunis the compensation is achieved by the taper on the needles. If you swap carbs onto bikes with different port sizes and cams, the compensation is not automatic. You need to play with needle tapers to get the carburation really right.
There was a mad Irishman I knew. He used to work in the Triumph factory and got a 12th on the IOM in about 1948. He swore by SU carbs, but I always thought he was an idiot.
I don't like pumper carbs. If you are the slightest bit too rich, the motor will be sluggish. I would rather be required to feed the throttle on in a controlled fashion. Judging by a lot of those on-board videos on Youtube, a lot of guys don't know how to get a motorcycle really going. Have a listen to what they do with the throttle.
Schwany
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Always a good story. Thanks
I was still in the negative age numbers in 1948.
I certainly agree that there is very high potential for Keihin FCR carburetors to be problematic under load, especially if expecting them to work out of the box. The pair I got were too rich for my motor out of the box. Dropping the needle, and leaning out the low speed fuel and air mixture adjusters cleaned up the out of box settings a lot on my little 750. I still need some good weather to see how they work outside the garage. I may have to play with the pump shot duration, and go to a leaner main. Don't know yet.
Every multi cylinder Japanese bike I owned that was built without fuel injection had some form of SU type carburetion. In California needles could still make a difference on those, because they were shipped with California smog compliant tunes. They were usually too lean off idle and lean at tip-in from cruise. DynoJet and a company called Factory did alright selling needle and jet kits, and ignition advance rotors for the multi-cylinder bikes in the 80's.
That's enough going off topic out of me.
hi, Thought I was looking at my bike at first glance / Beautiful !here mine the last few weeks when having wine i have been thinking of selling it and getting RE Continental GT what ya'll think?
He said 'when you get racing, come and see me for a ride'. I never believed in him and I did not know about the two short stroke Manx Nortons in his back room, until many years later. About 20 nyears ago, he was living on the northern outskirts of Melbourne and he used to rat through the garbage bins of motorcycle shops. One of the dealers asked me about him. I replied he was the real dea - you would never have thought him capable of doing anything.Apparently when he worked at Triumph, he got out of the UK just ahead of the police.Any reports on what he thought about you??
These days I can still remember some of the things he said about road racing, They did not make sense back then, buy they do now. Have a look in the Motorcycling Year Book for 1948 - Baldo Meli.
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