Hi, I am looking for some information/ advice on a B25, what gearing? What oil?, what carb, recommended mods if any

Hi Guy's,

 

Hi Furse.

 

First question before we go any further,

 

 What frame are you using? or what frame do you expect to use? 

 

Then we can go from there. it does make a vast difference. except for the oil, any oil used needs changing quite regularly and I would add an outside paper filter.

 

Regards Charlie.

Hi Charlie,

It's been fitted into a RE crusader frame

sounds interrrrresting, keep us up to speed with the build.....pictures would be great.

 

Hi Guy's.

 

Hi Furse.

 

Thats a good choice!

 

Means you have room for a good carburettor line because they are tricky  with any frame with a single seat post. and you have room for that all important filter.

 

What Swinging -arm are you using? you will need the one from the sports version to get enough clearance for the tyre.

 

What forks are you using? you may have to try a couple of different sets to find ones that suits you.

 

I agree with Bashplate pictures would be great, 

 

Could be a really interesting machine.

 

Regards Charlie.

 

It has the standard swing arm I think as it is very close on one side and would need altering or as you say the 'sports version'

Forks are supposed to be Betor 35mm but I dont know what from as the Rickman brake plate fits to the lug on the leg fine,

I will take some photos but its been tucked away as Ive got the last round of the KIA twinshock tomorrow and been sorting the Fantic.

Looking at it again I think it has the sports swingarm

that's one HUUUUUUGE sprocket

 

70t ! Hence the question on the gearing, it may act as a stabiliser

Hi Furse,

​                 looking good and can see where your coming from regards the gearing .The only other thing (s) I would be looking at is the swing arm.....a little longer, and ya bashplate looks a bit wide at the front....may be just camera angle. Motor sits in there real nice though..well done.

Hi Guy's.

 

Hi Furse.

 

Looking at that picture, and the sprocket.

 

Looks like you need to go down on the engine sprocket,

 

Not that difficult, shorter primary chain,and you will have to reduce the engine oil seal in width and machine of the surrounding alloy to suit.

 

Check what gearbox sprocket you are running too.

 

Hope this helps?

 

You know where to look for further information, on one of my pages.

 

Regards Charlie.

The engine sprocket is 18t, 13t on the g,box I had a 50 for the rear wheel so will try that,

Charlie why do I need to machine seal etc?

Thanks for replies, what is preference on oils?

http://www.trialsbits.co.uk/product_info.php?cPath=85_182_257&products_id=689

Interesting comments by Deryk re sprocket size affecting grip . Squat will increase with smaller sprockets but there's more to it than that as swingarm length, shock length, Spring strength and ride height are all factors too. A certain amount of squat is useful, but too much isn't good either so I'd be interested if anyone's done any recent comparisons, especially as bikes are lighter, softer sprung and have more travel than they did back in the day ?

Ah understand know, Cheers B40rt. Just looked is has been done.