Simo, post up some photo's of your 74 frames and lets see what your up against.
Okay Geoff here goes. First the current bike with 75 model frame:
Gratuitous shot of bike because I think she look stunning wearing her new MX treads
Top Shock Mount (note the corrosion under the powder coating. This is why I hate powder coating as I mentioned somewhere else when someone was asking whether to paint or powdercoat). Note the frame curves around 2 inches below where it meets the frame rail under the seat. This is the only difference between 74 and 75 model TM frames I believe and results in the shocks being moved around 1/2 inch forward :
Lower Shock Mount:
Best Frame I have:
But has issues in this area including a hole in the frame (easy fix I know) but has had other crap welded on and one of those welded on bits has completely ruined the brake pedal stop. Also has a few other issues but is the best candidate I have at the moment:
It’s frame number:
The frame I was actually building before realising I was running out of time and buying the ex Vergotis TM. But note that the rear sub frame, whilst looking factory stock to me, is completely different to all the other TM frames I have. Instead of running reasonably parallel and then turning 90 degrees behind the seat and over the rear mudguard, it seems to rise to that same point but in a straight line ... looks factory welds to me but definitely not consistent with the other bikes. Likely that if I had of finished this one not knowing it was different the result would have been the same. So I assume it’s no good for my purposes:
It’s frame number:
And finally, the one I mentioned that had been badly butchered. Worthy of a picture if only to see how badly it’s been turdinated:
Now, an interesting thing on the swingarm. I have confirmed the swingarm fitted to the ex JV bike is the same length as any of the other ones (just over 500mm from pivot centre to the end) but it looks like the mount is in a different spot as shown in the pictures:
Ex JV Bike:
And another one that looks completely unmolested in any way (ie not strengthened or anything):
Notice how the ex JV one has the mount in front of the end of the swingarm tube whereas the other one it seems to be behind it? I guess if the 75 frame leant the shock a ½ inch or so forward then moving the lower mount on the swingarm forward would straighten the shock up again (ie reduce the “lay-down effect”? So probably it’s in the same position as it would be on a standard 74 frame after all this.
Anyway that’s what I have to work with at the moment. I would like to get the bike going so I can enter the next race QVMX meeting at Biddadaba in a couple of weeks but I really want to hold out and get the best frame that I can that cannot be questioned in any way.