Hi,

Would like to know what modifiations should be made to a D14. 4 speed motor to make it competitive and reliable in Pre 65 trials ?

Expecting to use alloy barrell, modified Fantic head ?, electronic ignition, replacement carb, etc, etc.

Would be great to hear from someone who has done this recently and built a good engine ?

Thanks, Jon.

Firstly you need to establish if you will ever intend to ride the bike in the Scottish Pre65 2 day or at some point sell it to somebody who might aspire to. You havent said where you are from or intend to ride but the mods you suggest and more are the basis of the better Bantams around. Really you need to check what is acceptable at the clubs you intend to ride with. The bike you suggest would also have to enter at least as a "special" at Yorkshire Classic events to name but one club. Bantams are possibly the most highly modified of the "Pre65" LOL trials bikes and when done make very good trials bikes however as with all P65 machines double check the rules first with the clubs you will be riding with.

Good luck

Thanks for the reply,

I am aware of the eligibility issues, especially as my bike has no lower frame tube !!

Its the engine mods I am keen to explore further.

Thanks again

In theory no D14/4 speed gear box should be allowed in the Scottish as these were manufactured after 1965, late '66 I believe. Only 3 speed boxes were made prior to '65 in the D7 motor. Don't why later motors are allowed, probably like a whole host of other mods the blind eye has been turned from. So mod away. Blue printed barrel polished and ported, 185cc piston, George Todd ali head, modded clutch, smaller primary gear and probably much more.

Worth uprating the gearbox too as some have been experienceing problems due to the massively increased torque over what the engine, remember it was originally a gutless 125, was "designed" for. Also they are very sensitive, like all 2 strokes, to exhaust design and very worthwhile benifits can be gained there. Take a look at Wrightys and Mick Grants which are pretty highly developed and go nothing like what you would imagine a Bantam would. You could also ask them but i doubt they would tell you whats in there but what you can see and photo will give you a good start.. Last but not least though remember theres a LOT more to a sucessful trials bike than a greta motor. IMHO junk the frame and start again plus good suspension is worth more than a trick motor every day in the real world.

If it aint gripping and driving forward it's a five

Edited November 15, 201213 yr by old trials fanatic

Many thanks for the replies,

Has anyone got pictures of the above bikes they could forward ?

Cheers.

http://www.trialscentral.com/forums/topic/39832-new-bantam-project/page__st__15

Mons Trial last weekend.

Edited November 15, 201213 yr by b40rt

For some good advice on Bantam builds you could try Jim Pickering on 07850 836571 who builds the Drayton Bantams

He has a good number of years experience developing the Bantam trials and has turned out some very nice bikes. The engine in the rigid Bantam that Juan Knight won the Manx Classic on was one of jim's and he has done work for a few other 'names' as well. He can supply parts, build engines or complete bikes.

Definitely worth a call if you're looking to build a competitive Bantam.

Many thanks Woody,

I will certainly give him a call - my Bantam is very similar to a Drayton one !!!

Cheers, Jon.

Just spoken with Jim Pickering - (Drayton), cannot recommend him high enough !!

Sensible, down to earth advice on building a competitive Bantam. Many thanks,

Thanks to all who posted on this thread too.

Cheers, Jon

This is mine, frame modified by someone else, though Jim is on the ball and helpful .

Engine is a B175, mods inc a Suzuki TS 185 piston, Fahron porting, brass flywheel weight (from Jim) Electrex ignition, lower 2nd gear, clutch from Rex Caunt. Currently has Delorto carb but may go Amal if I can get a new slide. I have a modded Fantic head but not using it at present.

Edited November 16, 201213 yr by andy m

What oil in the clutch? Mine has new plates and heavy duty springs (from Rex Count) but still slips in 3rd and top....?

Mine slips when cold, not bad when warm, I used semi syn 10.40 Silkolene.

Thanks b40rt,

Mons will be in my travel plan for next year..

Peters packing/architecture of fuel tank, seat and muffler is one of the best Banters Ive seen. Have planned this height positioning of fuel tank, tunnel vs top tube like a speedway-ish fuel tank position..and sub frame height vs head, fun to see it executed

Edited November 21, 201213 yr by pat