Frame modification

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Frame modification

Post by slowdirt »


Hello we are building a bike (based on a 125 Kawasaki) for the 125 class and have already raked the frame - as attached -to lengthen the wheelbase a touch. Please can anyone confirm if we can run this in M-G or have we moved to A-G by adding the piece to the down tube?

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Re: Frame modification

Post by hawkwind »

Hi there .....because you have modified the "frame" rule 7.F dot point 1 states you cannot modify the frame members technically you must run in A ( special construction) I suggest you contact Graham Hadley ( chief scrutineer) and get it from the horses mouth so to speak.
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Re: Frame modification

Post by Stayt`ie »

that appears to be a lot of rake, im guessing that it will put your wheelbase out further than 10* of oem wheelbase,, this will put ya into Special Construction,,,,,
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Re: Frame modification

Post by ChrisACT »

The requirements for this class include:
An OEM frame must be used. Steering head angle may be altered, but must remain in its original
location. Swing arm length, type and mounting method may be altered. Brackets, braces, mounts,
gussets, etc. may be moved, modified or removed. Perimeter type frame engine cradle tubes
must remain unmodified. Spar-style main frame spars must remain unmodified. “Main frame
spars” are defined as the large formed tubes which connect the steering neck to the engine
mounts and swing arm pivot.
Apologies for the thread hijack ...

So does that mean the part of the frame which, on a modern bike, would be considered the subframe to which the seat is mounted could be modified within the rules?

I'm running an old DT175 frame and the subframe is actually part of the frame itself. Would it be possible to remove the rearmost part of this to allow better seat fitment?

See in this pic the bit at the back which angles upward. Can I chop or modify it? Perhaps extend further rearward horizontal to the ground instead of angling upwards?

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Re: Frame modification

Post by Greg Watters »

Personally i would consider the subframe as a seat and tail bracket , its not changing the wheelbase or geometry
but check with Grum as he has final say

Can i ask why the rake job, i would have thought the original rake/trail was well suited to slightly loose surface and well in excess of capable speeds
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Re: Frame modification

Post by AuotonomousRX »

This type of question, that relates to Rule Interpretation, should really go to the appropriate member of the Tech Committee ... for bikes that is Graham Hadley ....

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Re: Frame modification

Post by DLRA »

All office bearers are listed on the Contact Us page.

Chief Motorcycle Inspector - Graeme Hadley -
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Re: Frame modification

Post by ChrisACT »

DLRA wrote:Chief Motorcycle Inspector - Graeme Hadley -
Thanks for that. I've sent Graeme an email.
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