P2 gearbox in a T5 ???

[john.t5]

Mate has a silly fast T5 motor but it's top end ain't great, I had a look at putting a P2 4th in for that little bit extra top but it doesn't fit, so I thought I would ask for people's thoughts on putting the whole 200 gearbox in?

Comments please...

Cheers,

John

[Juan]

I wouldn't fit the 4 cog.

Is it still running the 20 tooth clutch? If so you could try either a 21 or 22 tooth instead to lengthen the gearing.

[john.t5]

22 tooth in it...

[Yanker]

John, T5 (36t) and P2 EFL (35t) OR P125x (36t) and P200e (35t) cogs are interchangable Note the OR

ORSod it and go 23/65

[Jack221]

Just to go back to the beginning for a moment. Is it revving all the way to the redline in 4th?

[john.t5]

Its's a 22t clutch fitted, it revs to around 7600 in 4th.

[Jack221]

You should get this revving a bit higher in 4th before you up gear. I'll bet it revs over 8000 in third. When you get it to rev as high in 4th, as it does in 3rd then go for the upgear and probably even then I would just fit a P200 65 tooth ring gear with the 22 clutch.
Its not what you want to hear but if you up gear now the top end will be even slower without more power. My 221 Polossi has trouble with the standard P200 4th but with a T5 4th it revs to 8300 in 4th the only problem then is hanging on to it

[soulboy]

that must be something special to pull 22 tooth clutch whats the spec

[john.t5]

It's a reed valve 172, 30mm delly with a bit of porting work, done by Damian Wass, it's very torquey and destroyed a welded cosa clutch twice, now has a billet BGM basket in it. Pipe is one of those Serie Pro Taffy race replica which is like putting another kit in, it hits about 8k in 3rd but there is no let up in power, from you hit the power in 1st it takes no time to hit top end but just doesn't seem to rev out, it has been dynoed by Dan at 18.4BHP and 18.2 lbs of torque, he had suggested adjusting the gearing for better top end. Any suggestions on how to get those extra few hundred revs in 4th would be good too! Bike isn't mine unfortunately but I have kind of fostered it this year

[Jack221]

With that set up you already have all you need and exactly the right exhaust. The rest is just porting and know how This is the part that bores most guys to tears but in amongst all the degrees, angles and mathematics is where the real power is hiding.
If it was mine (or yours!) I would put the 21 tooth clutch back in and tune it to do 9000 rpm in 3rd gear and about 8500 in 4th.
If you are really interested in more power you will need to give me some numbers so I have an idea of where you are; what size main jet do you have in? What squish clearance does it have? How many degrees main transfer duration? How many exhast duration?