Engine Build - Advice needed

[Jack221]

Originally the 21 tooth is from a 150 but you can get them in both clutch types now from SIP. The 21, 22 and 23 all work on the 65 ring gear so it is possible to change them easily to get the highest gearing that will pull 4th.

The MHR 210, a 60mm crank and a 23/64 primary shouldnt all be in the same scooter. A virgin MHR fitted flush, on a 60mm crank will have peak power at approx 9,000 rpm. That would be geared for nearly 100mph on a standard box and 23/64.

[1469leach]

Interesting read this,I've got the old malossi 210 with a 60mm bell crank,jl right hand,30 delay carb,rd350 reed and the 23/64 gearing(36t fourth and 36t third).It gives 182deg exhaust timing and it pulls well from 5500 on to 8000 rpm.I wanted a fast touring motor and this holds road speed well.

cheers Jeff

[Jack221]

Yeah, we are not talking about the old Malossi 210. That works with a 60 crank. In fact the best thing that can be done with the old 210. The 210 MHR is not the same, it has much wilder port timing and will make more of a sprinter with a 60 crank.

Is yours really a 36 tooth 3rd or do you mean 37 tooth? I calculate that in yours the 23/64 together with T5 4th is actually slightly lower geared in 4th than a standard 200? Which is exactly what I am saying for the Richjak with his MHR.

[Richjak]

So as far as gearing is concerned should I use the 23/64 Polini gearbox or the 23/65 standard P200 gearbox (both of which I already have) or should I consider the 21/65 option outlined by Jack earlier ?? just to throw fuel on the fire what about the T5 fourth gear ??

[1469leach]

Yeah it's a 36t third which drt make and a 36t fourth,closes the jump from third to fourth and helps keep the motor in the power band.The final drive ratio with the 23/64 box is 4.77 which is shorter than a total standard p200 box.

cheers Jeff

[Jack221]

Did you up 2nd gear too? If not it will be quite a jump between 2nd and 3rd, like an old 3 gear V90
At least its one way to get over the pulling in 4th issue.

Richjak, What I do is install a standard 65 ring gear then it is possible to use a 21, 22 or 23 clutch to easily change the gearing without splitting the engine. The 21 does mesh a bit loose but it does work. You won't know exactly what you will need until you ride it.

[1469leach]

No I didn't change the second gear cog but it's never been a problem,I think mainly because of the fact that you are only traveling at low speeds when changing into third so there isn't much wind resistance as when your traveling say at 60-65mph.

Cheers Jeff

[ssteam177]

I've just finished a rebuild on a 210 60mm stroke and I removed the upgear kit that I installed on my original build up from 4years ago. Using the std px200 efl gearing with t5 4th gear bgm superstrong clutch 23tooth has made it a lot more user friendly set up it climbs hills in 4th for the 1st time since I've used the malossi cylinder

[Richjak]

All good advice thank you every body who took the time to write (especially Jack) I received the Malossi MHR cylinder kit yesterday - so nice to look at its almost a shame to have to fit it to an engine. I am still waiting for the reed valve kit to arrive from Scoot RS and as soon as it does I will be back to ask more stupid questions on porting the engine casings.

Thanks again

Rich.