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Frame modification necessary for S3 when using 60/110 crank and RT225?

Posted: Tue Sep 01, 2020 11:23 pm
by ulyssescale
So far I have built 3 of these motors now. All using 60/110 crankshafts and RT225 kits.

After installing the engines into the S3 frames, the cylinders, with cooling tin installed, are touching the front right part of the frame loop. Is the only good solution for this problem to trim an amount off the frame loop? I noticed on a recent picture posted to Rimini Lambretta Center's Instagram, that they trimmed about 3mm-4mm off this part of the frame. Anyone else trim their frame to accommodate a longer cylinder set-up? I am not a fan of offset cones.

Re: Frame modification necessary for S3 when using 60/110 crank and RT225?

Posted: Wed Sep 02, 2020 5:35 am
by Minority
Fitted one to same spec (SX200) and didn’t have this problem. Could you maybe have the longer S2 rear shock fitted? The Rimini offset cones with the flat sided engine bar are excellent for topend clearance issues without the possible offset cone downside of twisting cones.

Re: Frame modification necessary for S3 when using 60/110 crank and RT225?

Posted: Wed Sep 02, 2020 6:36 am
by ulyssescale
Using a Protech rear shock in a late-Jet frame with late-Jet case. I’m using a CST3 exhaust so I’m not really interested in lowering my engine.

Re: Frame modification necessary for S3 when using 60/110 crank and RT225?

Posted: Wed Sep 02, 2020 10:15 am
by drunkmunkey6969
ulyssescale wrote: Wed Sep 02, 2020 6:36 am Using a Protech rear shock in a late-Jet frame with late-Jet case. I’m using a CST3 exhaust so I’m not really interested in lowering my engine.
Well, you only have 3 choices:

1) Offset cones - this is a very easy solution, and the least hassle, the CASA ones with a flat-edged bar are a great choice... but you have already stated: "I am not a fan of offset cones."

2) Fit a shorter rear shock - this is easy, but has a larger cost attached... but you have stated: "I’m using a CST3 exhaust so I’m not really interested in lowering my engine"

3) Get the grinder out - let us know how you get on :D

Re: Frame modification necessary for S3 when using 60/110 crank and RT225?

Posted: Wed Sep 02, 2020 10:48 am
by ulyssescale
drunkmunkey6969 wrote: Wed Sep 02, 2020 10:15 am
Well, you only have 3 choices:

:D

I knew this was gonna be the situation. I was hoping someone would tell me something I hadn’t considered. I have the Casa flat-sided bolt with offset cones in my SSR265 and it’s good. I’ll just go with that. Cutting pieces off my frame seems like a last resort. But if it comes to that, I guess I’ll just take a deep breath and put on some safety glasses.

Thanks everyone.

Re: Frame modification necessary for S3 when using 60/110 crank and RT225?

Posted: Wed Sep 02, 2020 12:03 pm
by Warkton Tornado No.1
If it only the tinware &/or cylinder head, I know which I would sacrifice rather than the frame.

Offset cones are all very well if they can be fitted & kept synced as per RLC's, but it is yet another 'variable' IMO......

Re: Frame modification necessary for S3 when using 60/110 crank and RT225?

Posted: Wed Sep 02, 2020 1:14 pm
by Meds1
Is there enough room to reshape shape the cowling to stop it fouling on the frame.

Re: Frame modification necessary for S3 when using 60/110 crank and RT225?

Posted: Thu Sep 03, 2020 8:27 am
by ulyssescale
Meds1 wrote: Wed Sep 02, 2020 1:14 pm Is there enough room to reshape shape the cowling to stop it fouling on the frame.
No. I’m using carbon fiber tin.

Re: Frame modification necessary for S3 when using 60/110 crank and RT225?

Posted: Thu Sep 03, 2020 1:38 pm
by Minority
The Protech rear shock is available in two lengths, are you sure you haven’t got the longer one?

Re: Frame modification necessary for S3 when using 60/110 crank and RT225?

Posted: Thu Sep 03, 2020 1:58 pm
by Warkton Tornado No.1
ulyssescale wrote: Thu Sep 03, 2020 8:27 am
Meds1 wrote: Wed Sep 02, 2020 1:14 pm Is there enough room to reshape shape the cowling to stop it fouling on the frame.
No. I’m using carbon fiber tin.
In the interests of sharing information, is the "carbon fiber tin" an issue because:

a) no way will any head cowling fit even with some modification?
b) you do not want to modify the cowling in such a manner?

If we know the reason, we all learn & those of us trying to help will avoid making the same 'mistake' in our attempts.