10 replies to this topic

[daveg]

hi just bought a c15 engine distriputor type.thinking of putting it in oif b25 frame to do a few small club events.going to strip engine to check any usfull suggestions without braking bank.will fit elecronic ignition.cant find engine number.

[charlie prescott]

Hi Guy's.
Hi Dave.
Engine number should be on the crankcases on the left hand side just underneath the bottom of the barrel.

Dizzy motor could realy do with the timingside mainbearing conversion, If you strip the motor. But mainly oil pump needs checking, along with rings, bushes,bearings etc.and check for stripped threads. A lot of people think this motor is a lot softer than the later ones. You could also try to find a wide ratio gearset, I think there are some new ones about but they are expensive. Good luck with the build. PS. have you narrowed the frame?

Regards Charlie.

[Pierre66]

charlie prescott, on 10 November 2011 - 10:55 AM, said:

Dizzy motor could really do with the timingside mainbearing conversion, If you strip the motor.

Hi Dave,
Hi Charlie,
I`ve just started stripping my engine down, I`m heading for the bigend but I`m gonna see about upgrading the timing side bush whilst I`m in there. I spoke to a guy at Alpha Bearings and, if I understood him correctly, they do a bearing replacement for the timing side bush, no machining required, £128.
He also said if the timing side bush is worn it can lead to oil starvation of the bigend.

I`d be interested to know what anyone who has done this conversion thinks.

Back on topic. My hopefully, useful suggestion,
If you strip the engine right down make sure you prime the oil pump (a pump oil can on the feed line works) before you start it and check you have oil returning to the oil tank before you ride off, don`t ask how I found this out first time

Edited by Pierre66, 10 November 2011 - 08:31 PM.

[Woody]

Pierre66, on 10 November 2011 - 06:16 PM, said:

Hi Dave,
Hi Charlie,
I`ve just started stripping my engine down, I`m heading for the bigend but I`m gonna see about upgrade the timing side bush whilst I`m in there. I spoke to a guy at Alpha Bearings and, if I understood him correctly, they do a bearing replacement for the timing side bush, no machining required, £128.
He also said if the timing side bush is worn it can lead to oil starvation of the bigend.

I`d be interested to know what anyone who has done this conversion thinks.

If you strip the engine right down make sure you prime the oil pump (a pump oil can on the feed line works) before you start it and check you have oil returning to the oil tank before you ride off, don`t ask how I found this out first time

Yes, roller bigend and timinf bush conversion definitely worth doing. I had mine done by Alpha Bearings in 2007 and the bike took some real abuse with no problems at all.

For trials, a not essential, but worthwhile mod, is to fit a Triumph piston (assuming it will have a rebore during rebuild) Either a 70mm or bigger will give a bit more torque over standard. Just ensure it is a low compression piston (compare the crown to your original) and they sometimes need the skirt cutting back to clear the crank.

Standard road cam, head, valves are fine for trials. The road gearbox is ok too, just needs gearing down on the primary drive.

Mine had standard head, cam, Triumph piston and eventually a trials gearbox plus PVL ignition. It was a very good motor with plenty of power for classic events and many modern events.

If you do away with the distributor, you need to make sure that the skew gear remains engaged with the oil pump as the distributor is driven off it too and holds it in place. If it isn't you will have no oil circulation.

[Pierre66]

Hi Woody,
Thanks for that. Already got the later conecting rod with roller bigend. The bigend bearing and crank pin is £108 from Alpha, must admit being told a worn timing bush can wreck the bigend has spooked me into considering the conversion.

Just had the barrel re bored +40 so on the hunt for a piston,rings etc, ebay seems to be the cheapest.

I left my dizzy in place when I fitted electronic ignition, just removed the points and condensor. Like you said it keeps the skew gear engaged and if I`m honest I personally like the look of the standard engine.

[daveg]

hi guys.thanks for all that info.charlie what do you mean by narrowing frame.also no numbers in ussual place under barrell drive side and it dosnt look as though numbers ground off.im not sure about timing side bush conversion as i ran a 500 triumph for years with plain bush and gave it some welly but changed oil on time.and had no problems.cheers

Edited by daveg, 12 November 2011 - 12:54 AM.

[charlie prescott]

Hi Guy's
Hi Dave.
Looks like you have a set of replacment crankcases then?
To narrow the frame you pull in the two seat down tubes to a narrower section at the top, you have to cut the tubes, take a small amount out, heat the tubes to pull them back in and then reweld. I will take a picture of one done today for you.
Timing side bush is OK as long as it is tight and in good condition, if not you will loose oil presure and this does not help the big end to survive long. A single is a bit more vunerable than a twin!! for some reason, smoothness perhaps???
Good luck anyway.

Regards Charlie.

[charlie prescott]

Hi Guy's
Hi Dave.
Picture has promised.

Regards Charlie.

Attached Images

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[daveg]

charlie prescott, on 12 November 2011 - 11:18 PM, said:

Hi Guy's
Hi Dave.
Picture has promised.

Regards Charlie.

hi charlie thanks for that will let you know how i get on was thinking of putting it in oif.frame b25.cheers dave

[daveg]

thanks for all the info.going to use road gears for now any suggestions for gearing down.cheers dave

[Clerky]

Hi Charlie, New to this site. Can you help me, is the frame pictured legal for the Scottish Pre 65 Trial, thanks, Iain