OzVMX Forum

Marque Remarks => Spaniards (Bultaco, Ossa, Montesa etc) => Topic started by: farmer58za on July 31, 2011, 07:09:03 pm

Title: Montesa M7 case screws: Why??
Post by: farmer58za on July 31, 2011, 07:09:03 pm

Hi All

Is there an underlying engineering reason why Montesa adopted M7 case screws and bolts for their engines? Or did General Franco's cousin have a huge shipment of the things going for a "very special price" ?

Regards
David

Title: Re: Montesa M7 case screws: Why??
Post by: Mike52 on July 31, 2011, 07:17:37 pm

Why did the Russians invent their own metric thread system for the Belarus tractor. ???
To piss off anyone trying to fix them or because they could ?
Ah the mysterys of life ;D

Title: Re: Montesa M7 case screws: Why??
Post by: David Lahey on July 31, 2011, 08:02:54 pm

While we are having a bleat about Montesas how about:
The cylinder hold down nuts being an odd size internal hex
The gearbox output sprocket being mounted on a taper
The primary gear being mounted on a taper

The M7 thing is not confined to Montesas either, I seem to recall that OSSAs have them too

Title: Re: Montesa M7 case screws: Why??
Post by: farmer58za on July 31, 2011, 08:41:11 pm

Ah, Franco's cousin was in there too...........

Quote from: feetupfun on July 31, 2011, 08:02:54 pm

The M7 thing is not confined to Montesas either, I seem to recall that OSSAs have them too

Title: Re: Montesa M7 case screws: Why??
Post by: mx250 on July 31, 2011, 08:59:42 pm

I though M7 must be the perfect size giving strength, durability and weight. ;D

Title: Re: Montesa M7 case screws: Why??
Post by: dutchtwinshock on August 01, 2011, 06:44:41 am

M7 is a normale size italy france and spain
You can get them in every homeworkshop

Title: Re: Montesa M7 case screws: Why??
Post by: Davey Crocket on August 01, 2011, 12:09:22 pm

YZA's and B's (250/360) use 7mm bolts in the cases around the crankshaft....extra stenght around the crank I guess without having to make the cases thicker if they went to 8mm.

Title: Re: Montesa M7 case screws: Why??
Post by: Slakewell on August 03, 2011, 08:09:01 pm

KTM use them on sprocket bolts