H: Hubs, Wheels and Tyres Rim and tyre choices for the track

greg brillus

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Methanol fuels and castor based oils absorb water so as the engine cools it draws in moisture, it is quite possible this might have happened after I had my crash back in 2015 as was unable to service the bike as quickly as I normally would due to injury. Davidd helped out with the cams, they are not readily available, and certainly not a direct replacement in a road engine without significant rework of the engine, especially the valves and guide clearances...........lets just say you need at least a half inch of travel for safety. I had already made valves from Big Block Chevy valves where we moved the step on the stem further up by 0.080" this is almost mandatory for more valve travel in these engines.
 

vibrac

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One of the real limiters with the Avon's is that the rear chain on a twin is very close to the tyre wall but with the short races available in the UK it can be kept under control
 

Herman-Handlebars

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Firstly I have to apologise for such a late response! Thanks for all your comments and advise above
I've held off building my wheels, concentrating on getting my engine complete and mulling over the options, whilst squirrelling away parts as I buy them so the wife doesn't find out!
I'm planning on racing ( not too seriously ) with BHR in the UK, although its 7 years so far and counting. As the bike will be pretty standard in capacity and cycle part's, I think for now going with wm2-3 in 19 inch giving a choice of Roadriders or Avon Gp/ribbed front as a starting point.
Also ground clearance being a factor as well.

I've periodically been reading the racing related threads on here with great interest. A wealth of knowledge and technical experience has made great reading and many hours thinking what I should I do. Cheers
 

vibrac

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What year do you claim for the twin? because it could enter the up to 49 class you can and we did since Girdraulics were at the 49 Earls Court Show
we may see you in 21 at one BHR meeting but after 30 odd years of fun the last few years we have found the ignoring of class leaders in the mixed races with vastly differing speeds, the exclusion of girdraulics from the girder fork championship by the ACU championship and the prevelence of just 4 lap races mean we have lost a lot of enjoyment at their meetings and we are concentrating on Lansdowne events. (with 18" wheels!)
 

timetraveller

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If you wish to race as safely as possible then you need to read up about modifying the steering head, fitting a different damper and springs etc. If you also go for taper roller head races then you are looking at about £1k so it is not cheap but read up about it as and when you can.
 

Herman-Handlebars

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Hi Vibrac, yes its a shame the way BHR evolved. After watching the Landsdowne series over the past years, it certainly a well run competitive series and a challenge.
I'm not 100% on the year but the frame members are i think 51/2 series C comet with girdraulics that I've inherented from my Dad as a project. The engine is new as our original B engine is in such a poor state, i came to the conclusion that building a new one would be cheaper in many ways.

Hi Timetraveller, I purchased one of your fine steering head's, steering damper and Avo damper kits the other year. After following the thread, I thought I was definitely the way to go, and is clear to see from all its praise Although I haven't fitted it just yet due to many challenges getting the engine together, it is in the pipeline
 

timetraveller

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Great. When it comes time to fit and experiment then remember that I have a range of spring strengths available to get the handling suitable for your and the bikes weight. You probably need either 36 or 33 lbs/inch springs depending upon how stripped down the bike is. Good luck with it.
 

Herman-Handlebars

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Thanks Timetraveller, I think I have a pair of 36 lb springs as a starting point as I remember. Bike wise I'm looking towards the lightning style with few modifications at this stage as thats all the parts I have so far and being new to Vincent's.
 

timetraveller

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Hi Herman, were you using a different 'handle' when you bought the parts? If it is more than about three years ago then that would have been before I developed a hydraulic steering damper kit to fit to the new steering stems. For racing, or even normal road use, it increases the safety without much weight increase.
 

Herman-Handlebars

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Hi Timetraveller, I think it's been a few years gone since purchasing them from you. I understand the damper was from a kawasaki and the bracket bolted to the base of the steering stem. The only thing I've done since is offering up a bottom link to see about opening up the eyes for fitting the races. I think I used the same name, as it was part of my email address.
 
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