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Cub Camshaft & Gearing Etc.


trialsrfun
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What is the performance difference between a std cam & an R cam when fitted to a 199cc Cub.

If the R cam is used do you need to fit stronger valve springs.

Also engine, gearbox & rear wheel sprockets, I thought of going with 17t engine, 13t gearbox & 60 or 62 rear wheel on 420 chain, does a wider size chain catch or rub around the gearbox sprocket area.

Which is the best Carb to use I am told the Del-Orto 22mm is very good is this correct.

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I use wide chain on my cub with no problems with rubbing etc. it was on when i bought the bike a year ago and its done maybe 30 trials this year. yes I should buy a new one but lubed with Tesco 'value' oil at 93p a litre its clean but 'stretched'

in strict compliance with p65 rules i have a fantastic english carb made near Whitby (well 5000 miles from Whitby) sadly no longer made and parts no longer available, even from the land of the free ( one of my jets has 3 amp fuse wire through it to fine tune it) but it does run fantastic.

a new del Orto is the easier way to go and has everything you'll need, its too late to remember my gearing but i'll drop a line mon. a.m. when i've had chance to have a look.

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Depends on which gearset you have, I have:

16T Engine Sprocket

14T Gearbox

54T Rear Sprocket

WR Gearset with Serco 2nd Gear

Makes bottom and 2nd quite useable. I also have an R cam fitted. Seems to be able to deal with most things, don't know about the springs being heavier. I think they are std but the tappet setting is tighter.

Dellorto works well to, but you might need to change this depending where you're riding.

Edited by Subira
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The sleeve gear is 29t which I believe is for trials, got the idea of 13/60-62 from the Sammy Miller catologue these ratios would seem to be very much lower than the ones you have Subira. Is the WR gearset the trials one with the 29t sleeve gear.

Know what you mean Totalshell about the Villiers gearing I too have tried every combination low 1st, high 1st, different 2nds & 3rds you name it.

Best set up for me is 20t engine with heavy duty endless chain from Simon Bateman/Nametab Eng. trials cluster with a 2 cog 2nd again fron Simon, 13t on gearbox & I think 62 on rear wheel. 2nd is useful and no big jump between 3 & 4 also the primary chain which compared to a Cub is minimal lasts ok without stretching.

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It seems that the 29t sleeve gear is for trials,

29t trials

28t road

27t close ratio

25t extra close reatio

Also both gears throughout the gearbox always add up to 45 teeth per pair, have to add I am not the anorak that worked this one out.

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Friend of mine rides a Cub and he too runs with a small Japanese carb about 18mm choke he picked it up from a Stafford Autojumble for little or nothing. The bike runs really well on it but we do not know what it came from and have not seen another like it so it looks like a Del-Orto is one way to go assuming that you can ride at most events with one.

Judging by the number of Cubs with a Del-Orto fitted they must be accepted by most clubs.

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