Scooterotica

Maybe disengage is the word..?

Take a look here, is an old post i've found googleing, read the 1st comment from Diablo http://s4.zetaboards.com/ScooterboyWorl ... /863381/1/

This issue has been discussed a few times. I have been trying a 22/65 in mine to see how it goes. When I changed the clutch a few weeks the 22/65 had been in for something over 3000 miles all the gear teeth looked perfect on the 22 clutch and 65 primary cog, so put it back in and carried on

I use 22/68. This was best thing i did i can leave in 4th at 30 mph and it will pull all the way to wot without dropping down. It does rev but performs very well. I ride sometimes with mates with rbs and it holds its own against them. Top speed is good i have gps it at 80 but that's with head down in perfect conditions. Its good for 70 plus withnormal riding

Jack221 wrote:This issue has been discussed a few times. I have been trying a 22/65 in mine to see how it goes. When I changed the clutch a few weeks the 22/65 had been in for something over 3000 miles all the gear teeth looked perfect on the 22 clutch and 65 primary cog, so put it back in and carried on

Ok so you experienced no wearing and i assume no disangagment/slipping either... good to know...

Do you think 22/65 is a good compromise between top speed and bottom end? I have a kytronik variable ignition that helps a lot at lower revs so i might go for 22/65... Whats your Malossi settings?

LI150 wrote:I use 22/68. This was best thing i did i can leave in 4th at 30 mph and it will pull all the way to wot without dropping down. It does rev but performs very well. I ride sometimes with mates with rbs and it holds its own against them. Top speed is good i have gps it at 80 but that's with head down in perfect conditions. Its good for 70 plus withnormal riding

Thanks, that's exactly what i wanted to know... may i ask you what is the rest of your set up?

Ported casings
sip head
28mm dellorto
fuel pump
mtech
banded old style clutch
jl right hand

hopes this helps

im thinking... since i got a large carb i should try to make the engine rev as higher as possible to take advantage out of it, right? ... So i'd probably raise the cylinder base with a 0.5mm gasket, get a 1.4mm squish, put the Sip head that has a lower compression ratio, get it to a squish of 1.4mm and fit a 22/65 with t5 4rth..Using the gear calculator with this kind of gearing if i was able to reach 8.500 rpms in 4rth gear i'd reach the "virtual" speed of 138km! on the other end to reach that goal i need enough power to pull the fourth like a train with that gear ratio combined with all the rest of the set up. Does it make sense?

Noplastic wrote:im thinking... since i got a large carb i should try to make the engine rev as higher as possible to take advantage out of it, right? ... So i'd probably raise the cylinder base with a 0.5mm gasket, get a 1.4mm squish, put the Sip head that has a lower compression ratio, get it to a squish of 1.4mm and fit a 22/65 with t5 4rth..Using the gear calculator with this kind of gearing if i was able to reach 8.500 rpms in 4rth gear i'd reach the "virtual" speed of 138km! on the other end to reach that goal i need enough power to pull the fourth like a train with that gear ratio combined with all the rest of the set up. Does it make sense?

You are thinking about this exactly the right way round. Decide how high you want the engine to rev. Then after you have the engine ported and set up to achieve that desired rpm, then adjust the gearing in 4th, to achieve about 500 rpm less than the max rpm that you can "easily" get to in 3rd. Doing this with the clutch cog means less messing about. I wouldn't really fancy running on a 21/65 but you might want to consider 22/67 but all with T5 4th gear to close the gear gap.
As long as there isn't any negative profile on your head and you have alignment lugs, the squish can be a little bit tighter.

My 221 is a Polini iron barrel and Malossi piston. Has a std 35 tooth 4th, the 22/65 primary and 350/10 wheel. For me this is ideal gearing on this engine. It makes easy 8500rpm in 3rd but will hold out to 8800rpm and in 4th does 8000rpm on the motorway, as long as its not into the wind.

Jack221 wrote:

Noplastic wrote:im thinking... since i got a large carb i should try to make the engine rev as higher as possible to take advantage out of it, right? ... So i'd probably raise the cylinder base with a 0.5mm gasket, get a 1.4mm squish, put the Sip head that has a lower compression ratio, get it to a squish of 1.4mm and fit a 22/65 with t5 4rth..Using the gear calculator with this kind of gearing if i was able to reach 8.500 rpms in 4rth gear i'd reach the "virtual" speed of 138km! on the other end to reach that goal i need enough power to pull the fourth like a train with that gear ratio combined with all the rest of the set up. Does it make sense?

You are thinking about this exactly the right way round. Decide how high you want the engine to rev. Then after you have the engine ported and set up to achieve that desired rpm, then adjust the gearing in 4th, to achieve about 500 rpm less than the max rpm that you can "easily" get to in 3rd. Doing this with the clutch cog means less messing about. I wouldn't really fancy running on a 21/65 but you might want to consider 22/67 but all with T5 4th gear to close the gear gap.
As long as there isn't any negative profile on your head and you have alignment lugs, the squish can be a little bit tighter.

My 221 is a Polini iron barrel and Malossi piston. Has a std 35 tooth 4th, the 22/65 primary and 350/10 wheel. For me this is ideal gearing on this engine. It makes easy 8500rpm in 3rd but will hold out to 8800rpm and in 4th does 8000rpm on the motorway, as long as its not into the wind

You have a Polossi then, 8.800rpms for a torquey cylinder like yours is an excellent result. The new Malossi kits, especially the Sport version are going on that direction too...i like revvy kits, this one modified by Worb has plenty of potential i hope i can fully exploit.
By the way, i closed the engine today with 22/65, didn't have 67-68...this should be a good ratio to start with... As soon as i'll put it back on the frame i'll try the set up i have in mind, let's see how far i can go! Thanks for the good tips! I might get back for some more!