There have been a lot of contributions of late about Cubs and the building and setting up thereof. Well for my sins i an in the final stages of building a B40 so what are the recommendations for a B40?

You know the usual stuff?

Carb size and type.

High Comp or Low comp piston.

Sports or road cam.

Gearing.

Michelin or IRC tyres. (While I'm at it I've been told that tubeless Michelins are slightly softer construction than tubed ones. Is this true?)

My bike has a Faber frame and Betor front forks and has a Ex WD GB B40 Engine at present with points on sidecover but has had them removed and a PVL ignition fitted. I was thinking of fitting a Amal Mk 1 Concentric 26mm NB Good idea?

I know we have a lot of Cub experts here but anybody know anything about B40's

As a bodger of cubs i dont have much experience of the B40

but i know of a nice one with a mk1 624 amal 170 main .105 needle and 3.5 slide needle at the middle slot (acording to the notes i took)

with the pvl you've nailed the ignition with either the mark 1 or 2 faber frame ( the later is steeper i think) you've nailed that,everything else sounds cock on the only thing left is YOU..

and if you want to ride at 'probably' the best p65 club look no further than

http://yorksclassictrials.co.uk/index.htm

dont go by reputation read the event reports on the site and come and have a look, loads of B40 and c15 better still ride! 10 quid to enter 8 if your over 65 and you can join the club on the day for a fiver

Thanks for the offer. I've been a fan of your site for some time and Mr Whitton has been trying to talk me into riding at one of your events for a while. However a few problems. Firstly it would take me over two hours minimum to get to your events but the biggest problem after reading your regulations is my frame is illegal, my front forks are illegal and my fork yokes are illegal. So not a lot of point. Saying all that though the videos and photos do look very nice and i am amazed how quickly you get your results on the website. Usually the same night as the trial.

Thanks for the kind words about the bike though. The carb i have may be a bit big at 26mm from what you said. Will give it a go if i can finish the damn thing in the next couple of weeks. Might take it up to Micks (Bracken Rocks) and take a 24mm carb with me, if i can find one, to try back to back.

Watching some of the bikes today at the Peak Classic trial the cubs definately seem to find grip when the B40's were spinning out. Constant or constantish throttle does seem to be the order of the day.

What ignition advance is good for the B40? or is it just play around till it feels ish?

Any extra tips for building an awsome B40 ?

Edited February 12, 200620 yr by Old trials fanatic

paul jackson ace builder from these parts regularly fits pvl to bikes he'd be a good start point for how to set it up, i understand a lot of it comes down to where you got the pvl from as they may not all be the same!

It's one of Alan's PVLs.

Hopefully barring catastrophies i will have it up and running in the next few weeks. Then it's shakedown time and see what falls off, doesnt work, jams, breaks etc etc. There's a world of difference between building a bike in the shed and making it work and stay together out in the real world.

Thats why i posted on here hoping to pick peoples brains and hopefully benefit from their experiences so as not to make too many mistakes with mine. It's always expensive and time consuming when you have to scrap it and start again.

Still all part of the learning curve. Thats probably why pre 65 bikes are so expensive to buy.

Will post some piccys and a diatribe when i eventually get it running.

here is a B40 that we are putting together, when I say we, my mate Colin is doing the graft I'm dipping my pockets and searching ebay

http://www.achnasheen.uk.com/htdocs/b40trials.htm

Edited February 17, 200620 yr by Steve+Cub

Nice one. What forks are they? Some centres get a bit touchy about the forks and yokes. Mine and Yorks seem to accept modern internals inside Norton etc outers. Any yokes seem acceptable as long as the clamp bolts are inboard of the legs not out side of them.

Good luck with the bike apart from the forks it looks pretty std B40. You may struggle with the ground clearence. Just about every B40 round these parts has had the engine lifted a bit to help.

Post more piccys as the build progresses please.

Edited February 17, 200620 yr by Old trials fanatic

Nice one. What forks are they? Some centres get a bit touchy about the forks and yokes. Mine and Yorks seem to accept modern internals inside Norton etc outers. Any yokes seem acceptable as long as the clamp bolts are inboard of the legs not out side of them.

Good luck with the bike apart from the forks it looks pretty std B40. You may struggle with the ground clearence. Just about every B40 round these parts has had the engine lifted a bit to help.

Post more piccys as the build progresses please.

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Forks are Ceriani's which seem to be OK with some clubs. ground clearance is similar to my cub, so hopefully wont be too much of an issue