GT750 build

[Manky Monkey]

The man knows what he's talking about.
I've been in the garage all day so I'm off for a long soak in a hot bath. Give me a shout when you've finished building it! Back soon.

[baldyshinehead]

, i would consider a triangle rather than just a single tube.

could you expand on that please. remember im only learning 

[tbone]

bottom rails can be done a few ways. i`ve used 2 methods to date, firstly
lay your new rail up against the old one and mark a line along the rear cradle down tube, cut along this line with mr angle grinder, cut the original bottom rail back and join your new one the same way as the top one. then weld your new lower rail to the down tube.
secondly (n a bit trickier) grind the bottom corners off the rear cradle downtube and insert a longer bar to join your new rails, i would suggest u want at least 6 inches to sleeve over if you do it that way.This involves less welding but its harder to find the centre of the corner without takin too much off with the grinder.

[baldyshinehead]

thanks tbone, 
I am being sent the details on that wooden frame thingy, i will post them as soon as i get them.

update on that. I will have to send it to yoda and ask nicelly if he will put it on his site as the file is a little large, 4.3meg 

[tbone]

have done a quick sketch, not sure how it will come out tho, u no n pics lol.
Anyway there will be forces acting on the top n bottom rails (am sure some wise guy will no the proper name for them).
a curved tube between the rails will absorb these forces beacuse it will flex ( not that youll ever see it move)
a triangle will allow the rails to flex to sort of, but a staight tube will just push against the opposite rail.
hope that makes sense.

[baldyshinehead]

yes tbone that makes perfect sense. that is what i was going to do or something very similar.  thanks again

[tbone]

its wot were all here for, to learn as we go n hopefully help each other out.

[tbone]

lol forgot to mention to bend the bottom slugs before they are welded in place, then you can leave your bottom rails straight, if you use the second method i described earlier. If memory serves me well your gonna need 20mm diameter bar for the slugs ( dont take my word for it tho, please measure the internal tube dia before you buy it ).
anyhows solid bar of that approx dia is a bugga to bend so anyone got any suggestions on that please?

[baldyshinehead]

of course i`ve been asuming you have a tube bender or access to one to bend the bottom rails. if not you can still use the same method and by bending your slugs to the right angle can keep your bottom rails straight

the slugs are sorted so that i can keep the bottom rails straight.

[tbone]

have been thinkin of different ways to try n mount axles so would be interesred to hear your thoughts please mate

[baldyshinehead]

another thing that i need to decide on.
the main ways i have seen are
the way MM does it ( seen it somewhere on here ),
using 2 drilled and tapped slugs that weld to the axle and you just bolt into them,
or using a peice of 2 by 3 box section cut and welded to the axle with holes in for the bolts. ( i like the way this one looks )

I will try to find pics of each one

[Manky Monkey]

We go for a simple two part clamp made from a 4" long length of 2" diameter tube, sliced in half lengthways, with a piece of 4mm flat plate along each side & an 8mm bolt hole in each corner. Then we add a locating tab that bolts to a similar tab on the axle tube to stop it turning or sliding in the clamp.

[baldyshinehead]

thanks MM.
here's the other 2
( sorry stolen pics from somewhere )

[tbone]

ive only ever used 3 x 1" box with a hole cut in it for the axle to recess into and then welded a strip over the front to lock it in place and then weld the whole thing to the axle.
i must admit, i like the look of those clamps tho.

[Manky Monkey]

Never seen the 2nd one used before -very tidy but a lot of stress on a very small area. Not sure I'd want to entrust the back end to just 2 bolts. Can't quite make out how the 1st one locates. A flat plate on the end of the frame leg bolting to the flat surface of the box section welded to the axle? Much better but again, personally I'd rather see a clamp that holds the whole axle tube rather than something that bolts to one face of it. Just personal choice.