Scooterotica

Have got me a T5 classic with a malossi 172 kit, pm pipe and 30mm carb with a 122 main jet.
It revs like crazy and pulls lovely...............until it reaches an indicated 60-62 (as fast as i can get it and i'm only 12 & a half stone ) then is ok for awhile but speed starts to drop and you have to change down to get it back again.
Should it go better than this? i've read of 70+ for this set up but is that being optomistic, or could the rings be worn or something else?
Cheers for your input....hopefully

me mate Stee has a malossi 172, JL righthand, standard 24mm carb, SIP cylinder head, and 21 tooth clutch, and that flys, and goes right off the clock. definately something wrong with yours. what gearing have you got in it?

I dont know tbh. i'll have to take a look i suppose , this is the state of tune it had when i got it, i whipped the head off and measured the cylinder to make sure it was a 172. guess i'll have to go further.

My T5 get to a speedo reading of 65 mph, so i would guess yours isn't running to its full ptential.

My T5 classic which was standard apart from a 28mm PHBH could manage 64 mph (measured on a Garmin running watch) sitting bolt upright and carrying luggage so as said, there is definatwely something amiss with yours. Does it rev out in 2nd and 3rd?

If you can try a different pipe you might be pleasantly surprised. I know some people love them on the 172 but I was not impressed with a PM pipe on mine.

Also check out the gearing; if you have a 21 tooth clutch drive, combined with the PM pipe (which is very peaky) it might explain your lack of 4th gear pull, it certainly killed mine in 4th gear. If it is a 21 tooth, go down to 20 if you can and see if that makes it better. If it is 20 teeth already, it might just be a combination of bad jetting coupled with the PM pipe, or something more serious. But I would start with the pipe/gearing first.

Is it reedvalved? If not, the 24mm standard carb is plenty enough for the 172 kit in it's standard trim.

@ coaster, it revs out lovely in 2nd and 3rd just cant get to top revs in 4th and it fades from approx 62mph (tops) down to about 53mph and i have to change down again to get it back up to speed
@ bottontobutton, its not reed valved, i'll try to borrow another pipe to try before checking gears.
Thanks for the input so far.

I would also say it was the pipe had a pm on my old T5 could never get it to rev in 4th

gee wrote:@ coaster, it revs out lovely in 2nd and 3rd just cant get to top revs in 4th and it fades from approx 62mph (tops) down to about 53mph and i have to change down again to get it back up to speed
@ bottontobutton, its not reed valved, i'll try to borrow another pipe to try before checking gears.
Thanks for the input so far.

As already suggested, it sounds like you have the wrong gearing for the power curve.

I bet you find its been fitted with a 22 tooth clutch sprocket ,which would work fine if it was ported tuned and reedvalved...
21 tooth should be ok though with that pipe .