Suzuki 2 Strokes

Sorry, I'm a little confused. Which surface on the bearing are you grinding away?

The lower part of the inner race where it presses down onto the lower tree. When you have a stock lower bearing and compare it to the one in the photo you will see the differences.
The inner race has a lower section thats close to 5mms thick below where the rollers sit, I reduce it to 2.5mms.


Here you can see the bearing apart and inverted after the modifications.

I must be having an off day here…. any chance you could draw in an arrow to the part you machine down. I can't see any machining marks on the picture. What did you use to grind it down with? My machining budget is pretty much topped out at this point in the game….

I must have done it too good if you cant see any marks from my work. Grinding and machining on any hardened surface of a bearing requires a lot of patience, a steady hand with tools and a digital vernier to make sure the thickness is retained so it sits squarely. For this I simply used the top part of the inner race as a reference for maintaining correct thickness when thinning it from the base side.

The part I worked on is the flat surface on the bearing in the centre thats facing upwards. After I ground down the height by 2.5mm and refinished the surface I had to put back the radius where the inner diameter hole and the base surfaces meet. I also removed a slight portion of the race holding the rollers so the dust seal that was now closer to it did not drag on it. See the captions for the colours below.



Remember the bearing is upside down so you are looking at the lower facing sides that go against the lower tree.
Red is the surface area that was ground down by 2.5mms and refinished back to a stock look.
Blue is the area of race cage that was trimmed just enough to allow the dust seal to pass without scraping against it. The seal got closer to the race after grinding and refinishing the red section down by the 2.5mms.
Yellow is the section that was radiused back to stock since it disappeared when I ground the red part down by 2.5mms

Awesome, thanks. Much clearer now... So you used files to do this? I can't imagine how long that must have taken you. I had to drill through a bearing race once and it took FOREVER.....

Nope you cant file hardened steel, it has to be ground and then the surface refinished. The race surface has to remain 100% parallel to the top one so it sits square like the original when its installed. Thats why you need to use a digital vernier to check progress to make sure you are grinding perfectly level as you reduce the thickness.

Am confused by this old topic that doesn’t have any working pics. (Thanks to Photobucket!)

Am working on the GT550 cafe build. Got the All-Balls bearing kit.
Have the dust seal & lower inner bearing installed on the lower triple tree.
Also have the steering column ground back ~ 6mm per the instructions.

If I install the outer races and assemble the triple tree, then how will this affect the dimension between the upper & lower triple tree?
Will the fork ears be held in place tightly?
Do I need to use an additional bracket cushion to hold the ears in place? (The cushions are still available and are only a few $.)

I've done 2 so far and just used emery tape wrapped around the centre upright, pulling each end sequentially - and measure carefully. You can't put filings back...........

Suzsmokeyallan wrote:Every bearing set I've bought to retrofit onto a GT750 or RE5 has had the same issue. Basically the lower inner race is a bit too tall and so the dust seal rides outside the frame head tube and besides that the trees are to far apart so the head light ears fit slack.

I had the same problem on my gt380. I bought a new set of bearings from Pyramid parts instead of All Balls. I will see if they have managed to get the correct size lower bearing. Yet to attempt fitting them.

Alan H wrote:
I've done 2 so far and just used emery tape wrapped around the centre upright, pulling each end sequentially - and measure carefully. You can't put filings back...........

That part is the easy bit Alan. The problem is the lower bearing being too tall for the lower yoke to sit high enough.

jabcb wrote: If I install the outer races and assemble the triple tree, then how will this affect the dimension between the upper & lower triple tree?
Will the fork ears be held in place tightly?
Do I need to use an additional bracket cushion to hold the ears in place? (The cushions are still available and are only a few $.)

No the fork ears will not be held tightly. Maybe a second set of cushions would work, but the ultimate solution would be to alter the bearing seat height as smokey has done.
On my GT380 the problem caused by the bearing height difference is that the lugs for the steering lock do not line up. How no-one has figured this out at the bearing manufacturer's development stage is scandalous! What sort of engineer thinks that a 3mm difference is acceptable?

Your luck may have run out on Pyramid. I got a set from them as well thinking they were aware of the lower bearing stack height issue but it was the same thing, approx 2.5mm too tall. What I also did not like about their bearings were the lack of rollers in the races of the bearings they used compared to the ones used by All balls.
Things may have changed so kindly update me on the issue. I've got one more lower race to do soon, so I'll be grinding another one again.

It hadn’t occurred to me that the steering lock might not line up properly.

Some PO of my GT550 cafe build had trashed the frame bracket for the steering lock. So I had a replacement welded on. Could have easily accommodated the height differential at that time. Just did some quick measurements & looks like it might have worked out ok.

The T500 cafe build will have a GT500 triple tree. The T500 & GT500 have different steering lock designs. Will have to weld on another bracket. This time I’ll sort the issue out before getting the frame powder coated.

Suzsmokeyallan wrote:Your luck may have run out on Pyramid. I got a set from them as well thinking they were aware of the lower bearing stack height issue but it was the same thing, approx 2.5mm too tall. What I also did not like about their bearings were the lack of rollers in the races of the bearings they used compared to the ones used by All balls.
Things may have changed so kindly update me on the issue. I've got one more lower race to do soon, so I'll be grinding another one again.

I'll let you know. I have a few days off soon and hope to catch up on sorting the bike out.

Ok. So I finally got it sorted kinda. I did what smokey allan did.
For those that wish to do the same. I suggest you get a set of Pyramid bearings and a set of All Balls.
I butchered two sets. Took the bottom bearing of the Pyramid kit and the top bearing of the All Balls. I had to machine down the butt of both top and bottom bearing races considerably to make everything fit. It still wasn't as compact as the Suzuki unit but as good as I could get under the circumstances. If you do this, don't forget to chamfer the ground edges so that no sharp edges cut into the bearing rollers.

Working on the 1972 GT550 cafe build.

The bearing grinding is way beyond my skill set, so I did a bit of research.
The All-Balls kit is 22-1005. It has lower bearing 99-3508 (27x48x14mm) & upper bearing 99-3505 (25x48x15mm).

The available All-Balls taper roller bearings are listed here:
https://www.allballsracing.com/media/pr ... eChart.pdf

Bearing 99-3508 is the only listed 27x48 bearing. I did some research & didn’t find another bearing that is thinner.
Bearing 99-3509 is 25x48x13mm. That’s 2mm thinner than the kit bearing.

My steering stem was modified per All-Balls instructions. I ordered the thinner top bearing & just installed the lower triple tree.
The All-Balls dust seal for the top bearing touches the steering tube. Both dust-seal sealing bumps look to be in contact with the tube.
There is a bigger gap at the bottom bearing but the steering stop is functional. (My steering stop was repaired so I don’t know if this applies to the stock stop.) Looks like the first dust-seal sealing bump might be in contact with the steering tube.

Am going to use the stock fork ears but they are at the painter’s. So the final results are TBD.

Noticed something interesting. All-Balls bearing 99-3515 is 30x48x12mm.
So a sleeve for the lower bearing between the 27mm OD stem & 30mm ID bearing would solve the problem. Don’t know how doable that is.
A custom bearing with a 27mm ID & everything else per the 99-3515 specs would work, but it would be shockingly expensive.