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Engine to frame botton Cross tube clearance

Submitted by philip_warren on Fri, 12/08/2022
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Commando

Hi,

 

I'm the lucky owner of two 1973 interpol commandos fitted with combat engines. They have VIN numbers that are 15 bikes apart so they should be identical. I am half way through a full restoration of one machine and having fitted replacement isolastics and cradle, find that the crank case is hitting the bottom cross tube. 

Looking at the other running machine as a datum, I see that the one that I am working on has a straight cross tube while the running bike has a curved cross tube. Neither frame has been touched since leaving the factory.

Can anyone shed any light on this conundrum and suggest how I might reintroduce clearence?

 

I attach photos of both cross tubes and crank case clearences to illustrate the problem.

 

Thanks. Philip

Attachments
IMG_3237.JPG
IMG_3241.JPG
IMG_3238.JPG
IMG_3239.JPG

Submitted by alan_hesslewood on Fri, 12/08/2022

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Hello Philip,

You say the frame hasn`t been touched since leaving the factory but Commando isolastics couldn`t function without the necessary clearance as you have found now, so unless it`s been used like my brother`s 750 Commando which someone across the pond had replaced the rubber isolastic bushes with teeth shattering solid steel spacers then it must have been "repaired" incorrectly by someone else. My ex police Mk3 hadn`t been taxed since 1980 which would have been when the police finished with it after 5 years hard service I presume, so did yours come directly from the police back in the day?

Regards, Al.

Submitted by julian_wells on Sat, 13/08/2022

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What are your grounds for believing that the bike left the factory like this?

As Al says, the signs are that someone has meddled (judging by appearance, very neatly, but nonetheless wrongly) with the frame. Assuming that is the case, one has to wonder what else has been similarly meddled with.

Let's hope you have not picked the wrong machine to restore.

 

Submitted by philip_warren on Sat, 13/08/2022

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Thanks guys, I got the bikes directly from the police in The Gambia, so if there was any mucking about, it would have been done there. Unfortunatley the Andover Norton part is currently out of stock. Any ideas who else might be able to supply?

Thanks 

Submitted by philip_hannam1 on Sat, 13/08/2022

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Get in touch with Norman White.

Fixing bent Police Nortons was his bread and butter in the 1970s.

 



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