79 to 81 750L fork swap

[Theo]

So thanks to member Tarbash here, I got a complete fork setup (forks, and triple trees) from a '79 750L. Everything seems to line up, the only thing that I noticed different is the steering stem on the 79 is thinner. I know I can purchase tapered bearings for the '79 but will it have the correct O.D. to fit in my steering head? If not, what are my options to make it work? Also is there anything that is I'm not thinking of that I should check for fitment issues? Thanks.
-Theo

 

[Tarbash 27]

I forgot about that. The first gs750's, 77-79 originally came with ball bearings. They did make a kit to convert to tapered roller bearings. But the lower bearing on the these roller bearings were smaller than the later design bikes that came with roller beaings stock.. The upper bearing shouldn't be a problem.

Do you have the lower triple from your bike? If you do, I would use that. If not than you have to get a lower bearing with the correct outer diameter for your frame and a thinner inner diameter to fit on that stem I gave you.

I had these forks on a 79 750, so it had the smaller outer diameter lower bearing.

 

[Theo]

I forgot about that. The first gs750's, 77-79 originally came with ball bearings. They did make a kit to convert to tapered roller bearings. But the lower bearing on the these roller bearings were smaller than the later design bikes that came with roller beaings stock.. The upper bearing shouldn't be a problem.

Do you have the lower triple from your bike? If you do, I would use that. If not than you have to get a lower bearing with the correct outer diameter for your frame and a thinner inner diameter to fit on that stem I gave you.

I had these forks on a 79 750, so it had the smaller outer diameter lower bearing.

Yeah that's what I've come to realize. I would use the lower triple clamps from the 81 forks but unfortunately the '79 forks are 37mm and the '81's are 35mm. I was hoping that someone might know off hand the correct lower bearing to get that would have the correct O.D. Or maybe there is no problem. Maybe both the 79 and 81 have the same inner diameter bearing races, and if I buy the tapered bearing upgrade from allballs, everything will be fine. I don't know, so I'm hoping someone does. I'm going to send an email to allballs asking them the dimensions of the tapered bearings. Hopefully they are the same as the '81. Thanks.
-Theo

 

[Tarbash 27]

Oh, I thought your bike had 37mm on it.
It should have tapered rolling bearing on yours. No ball bearings. Only the early GS750's had the ball bearings.

If you find a lower triple clamp off an 80-81 GS1100E, that will probably solve your problem. It has 37mm forks with the big lower bearing, and the stem is made for the foward leading axle forks which you have.

It might be easier do that than trying to find a conversion bearing.

 

[Theo]

Oh, I thought your bike had 37mm on it.
It should have tapered rolling bearing on yours. No ball bearings. Only the early GS750's had the ball bearings.

If you find a lower triple clamp off an 80-81 GS1100E, that will probably solve your problem. It has 37mm forks with the big lower bearing, and the stem is made for the foward leading axle forks which you have.

It might be easier do that than trying to find a conversion bearing.

Good stuff. So I'll keep an eye out for a lower clamp from an 80-81 1100E. Do you by any chance know if the stems are the same length?
Thanks
-Theo

 

[Tarbash 27]

I would say probably the same length, if they are different, not so much where you couldnt make it work.

 

[Theo]

Thanks man. I was looking on babbitts and apparently the 80-81 1000gl and the 80 1100LT also used the same lower clamp as the 1100E so that helps expand the search.

 

[Theo]

Well I just want to update this thread so that anyone in the future who might be in the same boat, knows how it turned out. Following Tarbash's advice, I picked up a set of triple trees from an 81 1100E and it's a perfect fit. So now that's one less thing to worry about. Thanks Tarbash.
-Theo