Scooterotica

Jonhunter wrote:Hi Colin
My set up is as above with a bgm stator, kytronic, af six plate road, I was already very happy with my set up and a few of my mates said i should leave alone as it was going well!! I had a 35mm mikuni with a franspeed race and varitronic,
But i fancied trying something different, So i went with the above, i cant take the credit rodger at pro design did it for me
There was porting welding and maching involved, but i can report i love it, i think its better on fuel, its up on bhp and torque, and starts 1st or 2nd kick every time hot or cold, still getting used to the way it rides but as i say very pleased.
As i said it was already really nice but i find it hard to leave things alone
Cheers
Jon

Thanks for the feedback, the Atomic reedvalve uses Yamaha reeds doesn't it? anyone using any other manifold? I have an MB shorty but apparently they won't fit

I am aware that the slightly shallower angle of inlet port gasket face is slightly shallower than that of a standard barrel, which changes the angle of any manifold slightly and puts it closer to the engine mount upright of the casing. I found that this stopped me from fitting one of the short reed manifolds and had to take a considerable amount of alloy off the DJ manifold to get it to clear the frame but this could be reduced by fitting a shorter rear shock.

It would be useful if others could confirm which reed manifolds fit with no work, little work, considerable work or simply don't fit.

Adam

coaster wrote: I have an MB shorty but apparently they won't fit

What's the reasoning for that Colin? Does it contact the cylinder head?

corrado wrote:

coaster wrote: I have an MB shorty but apparently they won't fit

What's the reasoning for that Colin? Does it contact the cylinder head?

I'm not sure Martin, I read somewhere that Ron said they won't fit but the reason. Frame clearance would most likely be the reason though.

With regard to the Atomic manifolds, I note ScootRs offer a small and large version in both stud spacings. It would also be good to know which one was used in the example above as the small one doesn't (apparently) need any fins to be trimmed off.

Does Ron do a piston with windows ready for an Avanti fitted with a reed valve? I've got the ScootRS small version of their reed valve and thinking of fitting over this winter to reduce spit back and improve fuel economy. Anyone done this already.

mick1 wrote:Hi Jon

Did the new set-up fit into the frame ok ? With the 62mm crank and packers it must have been a very tight fit or did the frame have to be modified ?

Mick

I'm in the middle of doing mine, Atomic Ultimate with a 3mm packer under the cylinder. Surprisingly little fin trimming required as the area affected is the scallop already shaped in the fins to clear the frame. However, even with a 295mm rear shock, the manifold was hitting the frame and I needed another inch to get the shock on. Managed to find that by grinding away the top of the manifold but discovered how little meat there was there to begin with I managed a temporary repair and managed to get the shock on but it will need offset cones. I might take it off and reshape the inside slightly with Devocon so that I can grind a little deeper and do without the offset cones.

coaster wrote:the manifold was hitting the frame and I needed another inch to get the shock on. Managed to find that by grinding away the top of the manifold but discovered how little meat there was there to begin with I managed a temporary repair and managed to get the shock on but it will need offset cones. I might take it off and reshape the inside slightly with Devocon so that I can grind a little deeper and do without the offset cones.

Had the same issues with the small Atomic reed [on my Mugello 225], eventually filed through to thin air but there was clearance inside the manifold to fill it with JB weld and it's been fine 2 years on, I think I took about a mm off the base too as I didn't want to fit offset cones.

corrado wrote:

coaster wrote:............. I think I took about a mm off the base too as I didn't want to fit offset cones.

Was that achieved by milling or did you use a file/emery paper? I could also loose the gasket which must be 1mm at least

Hacksawed some 1mm grooves first then combination of rough file, belt sander and flatting on glass sheet with progressively finer emory paper.

Well , I dropped the engine, removed the manifold and applied a layer of JB weld to the inside and ground away some more of the top of the manifold. Decided to try it without the offset cones but is still fouled on the frame but took it for a decent run of 45 miles but the vibration I could feel indicated that it was definitely touching even with me sitting on it. So dropped the engine again and ground off some more with the dremel and also fitted the offset cones. Off for another spin and noted after a mile or so that the revs were hanging. Home again and dropped engine yet again, removed manifold and found I'd broken through the ally on the manifold during my last bit of fettling. More plastic metal and now running like a dream, vibration gone

Still running in so taking it gently but it pulls from 20mph in top with no bogginess all the way up to 55mph where the power starts to really kick in. Still experiment with jetting, the carb is still jetted for the TS1 that I've had in the scoot for the last year but it seems to be pretty close. No idea on fuel consumption yet. Another bonus is that the Atomic manifold is a fair bit shorter than a standard phbh inlet manifold and the rubber van be mounted with a slight angle in towards the rear with the result that a breathsweet ubend fits without squashing under slimstyle panels