Modified steering stem?

[Anthony]

I just bought a new set of All Balls tapered steering bearings for my '76 GS750. They came with a paper saying that the steering stem would need to be modified in order for the bearings to seat properly. Here's what it says verbatim.

"Instructions for 22-1005. In order to put tapered steering bearings on an early Suzuki (Pre 1979) the steering stem must be modified as per this sketch. An undercut must be added below the upper bearing diameter as per sketch. This will allow the top bearing to seat properly."

I'm tackling this myself and if it wasn't a bit daunting before it is now. Has anyone had to do this modification? Not sure what the next step is.

On an unrelated side note, I'm also looking for retro Suzuki "S" decals to put on a newly painted tank. Any suggestions where I might find them?

[Agemax]

cant see why you need to modify the steering stem? buy the correct bearings and you wont need too!

[TheCafeKid]

Those ARE the correct bearings. Because the stem in the 77 (76) is STRAIGHT, and stock it uses regular ball bearings, to install tappered bearings an undercut is needed to allow for the bearing to seat. It would need to be MACHINED..but i didnt understand the schematic, where it exactly IS that you are to machine. SO, they are sitting on my shelf, next time i change tires, the hole fork will come out in favor of a set of 78 forks i have, which have a machined stem already...

[Agemax]

Those ARE the correct bearings. Because the stem in the 77 (76) is STRAIGHT, and stock it uses regular ball bearings, to install tappered bearings an undercut is needed to allow for the bearing to seat. It would need to be MACHINED..but i didnt understand the schematic, where it exactly IS that you are to machine. SO, they are sitting on my shelf, next time i change tires, the hole fork will come out in favor of a set of 78 forks i have, which have a machined stem already...

dont quite get your grasp on this guys! taper roller bearings are cylindrical bearings that are on an angle set in an angled seat. the centres are straight.

[Anthony]

I'm still struggling for a grasp myself. I was assuming that as long as the ID and OD of the new bearing match it would be just a straight swap. And yeah, the ****ty MS Paint drawing that is with it is very confusing to say the least.

[Agemax]

I'm still struggling for a grasp myself. I was assuming that as long as the ID and OD of the new bearing match it would be just a straight swap. And yeah, the ****ty MS Paint drawing that is with it is very confusing to say the least.

if it is a kit for the right bike then it should be a straight swap bearing for bearing, there should be no machining involved

[Anthony]

It says right on the package "GS750 77-79", so I know the're for the right bike. I'll know for sure on Monday when I get back to the shop and get the problem in my hands.

[n1elkyfan]

I actually e-mailed all balls about it and this is what they sent me in reply

Hello Coley. The operative word is “may” To determine if you do need to turn it down check if there is a shoulder on the shaft near where the top bearing seats that will interfere with the top bearing sitting flush. If so, any local machine shop can do it. If you do not have one handy, you can send it to us and we will machine it No charge.
Stefan

[SqDancerLynn1]

Can't get a better anser than that !!!

[Agemax]

maybe but bearings, including taper roller bearings are off the shelf items and you should be able to buy a direct replacement bearing set for your bike which will fit with no modification. if you cant then i suggest you look for a new parts supplier

[SqDancerLynn1]

Read the post!! His bike has the 1/4" ball bearings NOT the roller bearings he is installing. IT is an upgrade that may need a minor modification to fit !!!

[Anthony]

I understand now. The old ball bearings with the races are quite a bit thinner than the new tapered bearings, close to 7mm. The bearings sit on a small lip on the steering stem and since the new bearings are thicker you have less room to tighten the steering stem ring down and therefore cannot get the whole works tight. The bearings just bottom out on the lip.

If the lip on the steering stem was lower the bearings would simply slide further down into the tapered races in the head tube. It is not even a very exact thing as the depth of the threads on the top of the steering stem allow for a bit of play. And even if the bearings could slide further down they'll just stop when thy hit the races anyway.

What I don't understand is why the drawing that came with the bearings says that you need to make an incut (i.e a further reduction in the width of the steering stem) in one small place. The new bearings fit fine (ID to steering stem width) Making an incut would make them loose.

I'm going to have the small lip on the steering stem extended (machined) down by 7mm (as per the drawing) at the same width as before (no incut) this should allow the new bearings to slide down untill they seat in the new races. I'll try to get some before and after pictures to make this a bit clearer.