Malossi 172 top end speed

[dek]

I run the following T5 malossi 172 with a si 26/26g carburettor, 125 main, bgm big box, pinasco race crankshaft, 21 tooth clutch and kytronic ignition smart booster set at 24 btdc on curve 1.

It accelerates in 1st 2nd and 3rd very well and has plenty of torque for the hills, but change into 4th on the flat doesn't make much difference to the speed from 3rd 60mph on GPS flat out.
I expected more top end speed for that setup, should it be? If so what is holding it back.
Cheers

[adrian]

Can't answer your question, but my dr180 goes better than that with a standard clutch and 24 carb from a p200, also bigbox touring exhaust and I hit 67 on gps flat out, so something doesn't see right. I only weight 10 stone 😁

[scooterg]

I’d say 60 in 3rds pretty good
That’s 3rd though think 4ths fecked 🤣🛵🤣🛵🤣🛵🤣🛵

[scooterbooter]

I think your trouble is that in fourth your not getting into your power band. I think I would try bringing the power in earlier .

[ironsloth]

Sounds like you’re gears have been messed with, have you got the standard T5 gear tree?

[dek]

I am not sure and did ponder that possibility.
I will need to take apart and check