Triumph Cub R Cam

[trialsrfun]

My 199 Cub is fitted with the R cam, it always has had this cam so I have no comparison but at a trial today I rode a 199cc Cub with similar engine set up to my bike but with the std Cub camshaft.

Now I realise that bike set up is subjective and it could have been the 'new broom' thing but the std cam seemed to provide as much power at the bottom end but possibly a more controllable and steadier pick up. The R cam really makes the motor go once off tick over but having ridden the alternative set up I now am thinking might this be the way to go?

In most trials you simply do not require loads of power, a smooth engine seems better so what cam is most widely used in the little Triumph Tiger.

Edited April 13, 2014 by trialsrfun

[gii]

Well, I have the standard cam in a 250 motor and it's very strong at the bottom end.

But if I try a mate's similar bike with the R cam, whilst it has a good bit less at the bottom end I really like the extended rev range.

It depends on the sort of trials you ride.

Plenty of R cams available and not a difficult swap, drain all the oil, loosen off the valve clearances and take the covers off then lay the bike flat on its side and you can pull one cam out and shove the new one in before the cam followers drop down.

[mattylad]

What compression piston are you using.

Best combinations seem to be R cam and low comp piston or std cam and high comp piston.

I use the former.

[trialsrfun]

The set up on my bike is low comp piston, late side points motor with PVL ignition and Del Orto carb.

I rode two other Cub's each low comp piston, electronic ign, one had the Del Orto carb the other a small Mikuni from a Honda.

Edited April 14, 2014 by trialsrfun

[naichuff]

I am building a 200 cub and have been adviced to use high comp piston and R cam If I am to build it bigger to use standard cam and low piston Not haven ridden a 4stroke(always 2t) offroad it will be trial and error but exhuast and inlet track length can also alter the power as can the type of carb fitted

[trialsrfun]

My trials bikes have always been two stroke, the Cub motor is certainly different being a lot punchier, still smooth but surprisingly powerful for 200cc with a great sound track.

I imagine R cam, high comp piston might be the Cub scrambles engine spec. I have only seen one Cub scrambler that was at the Red Marley Hill Climb and it certainly went very well against mostly bigger capacity bikes.

Edited April 15, 2014 by trialsrfun

[brucey]

I run R cam, Delorto Carb, PVL (type) ignition and std 200cc low compression piston.

I weigh 96kg and the bike runs sweetly! I have had the same (Iridium) plug fitted for the last year with no oiling or sooting up.

You want something that picks up from low down and pulls rather than something that has to rev to get going most of the time.

Hope this helps.

Bruce.