Front fork seal and spacer part numbers

[Suzsmokeyallan]

If you are buying the present style of seal for your stock front forks on the GT750, remember you will need this metal spacer as an upgrade.
This is because the new seals are thinner than the original ones and so they will sit lower in the fork leg recess.
This spacer has a lip around the outer edge which needs to face upwards when being installed first under the oil seal.

51168-30B00 (replaces 51168-45031) front fork seal spacer
51153-19D10 (replaces 51153-34200) front fork oil seal

[holysmoke]

Allan,
The seals sit pretty tight in there to begin with. Is it critical?

[Suzsmokeyallan]

These present oil seals you can now get 51153-19D10 also fit the GS 650 and 850 models with the same fork seal design in the casting, so it was done for a reason on the later models.
They only cost a few dollars each and are made of steel so they will last forever, therefore its worth the retrofit and peace of mind that the seal will sit square and right under the clip as originally intended.

[uzidzit]

Harley Davidson 35mm seals for the sporty(in the early eighties) are the correct height and diameter for the gt-750 without the spacer. I bought a bag(10) of them at a indy bike shop for $12, guess what they are marked ndk made in japan.

Vesrah supplies the seal ~2mm short but gives you a spacer ring, at least in the last set i bought.

[water cooled]

Allan,

I read your posts above regarding the GT750 Fork Seals. As you know, I swapped a GT250/380 MAB front end onto the dragbike and needed to perform a front fork seal replacement.

The installed seals are out and show the following: ARS RSD 33 46 12.5 1-V C-10 on one side and ...C-13 on the other side of the seal.

I ordered the replacement seal which shows the following: NOK BR2651E 33-00 14.
The new Suzuki P/N is 51153-02B00

I measured the old and new seals and found that the new is slightly shorter .44" or 11 mm and the old measured .50" or 12.5mm

You mentioned that the new seals for a GT750 require a spacer adn I suspect the GT250/380 does as well but I cant find any information on the spacer... do you have any suggestions?

[Suzsmokeyallan]

Sure Kevin, the spacer comes from the GS650 or 850 models of the early 80s which carry the same fork oil seals. The spacer has a rolled lip on its outer edge which faces up towards the seal in application.
This is actually a Suzuki modification since the 650 and 850 forks are designed in the same way as the GT750 forks where the seal fits.
The new seals as you noticed are thinner and so they are using this spacer to stack it up from the base of the fork leg towards the snap ring.
What you noticed is a change of supplier imprinted onto the seals, ARS versus NOK brand.

[water cooled]

So, from the research I have done, the NOK seem to be a decent aftermarket replacement. The spacer you mentioned for the GS650 and 850 models would work for the GT750 but the GT250/380 sliders I use would require something different if I understand correctly. Otherwise, it sounds like I should install the seals so the top is close to the C-ring.

[Suzsmokeyallan]

I think the spacer its more of an update to allow the seal to have a space under its lip so the fork fluid can flow around the space and keep old fluid from just sitting there.
You could cut a 650/850 spacer and carefully close it in to the diameter of the smaller forks.

[water cooled]

ok....

I noticed that a product called "Leak Proof" sells these forks seals. They are the only set that I found that had what appeared to be a spacer. Here is an example:
http://www.thunderproducts.com/Leakproofforkseals.htm

All other fork seals seemed to be sold by themselves with no spacer. It seems that the leak proof seals have what you're describing. The seals I received are open on both ends and show the spring. I understand that on the pressure side it should help sealing but on the atmosphere side it seems like a dirt trap if the fork dust covers are not installed. My fork brace is a split design and the dust covers slide onto the fork brace so there is plenty of space for all sorts of stuff to get in there. I'll just have to keep an eye on them and clean them out every season... Thanks Allan.

[Suzsmokeyallan]

You're most welcome, I'm glad I could shed some light on this for you, and thanks for your link to the leak proof seals.
I hope your 2011 season is a good one, and please post up your latest results as your schedule allows.

[BlkY2k]

Hate to drag this back up guys but I went to install my new seals today and the new one are thicker than the old ones by about the thickness of the original spacer. Do I remove it? 72 Gt550 - new seal #51153-19d10

[Suzsmokeyallan]

Post up a pic of the old and new seals you have side by side so we can see whats going on there. The OEM seals had a stepped spacer pushed onto the bottom of the original seals.
The replacement one today are basically the original seal minus that bottom piece to which end Suzuki made the washer/spacers to compensate.
The 51153-19D10 new seal should not be taller than what you have, it should be shorter.

[BlkY2k]

A buddy of mine has my calipers but I do have a steel tape here. The new seal is 28/64ths by itself. The old seal is 24/64ths and with the spacer it is 32/64ths. If I use the new seal and spacer that puts me at 36/64 but without it I am short ??

[BlkY2k]

I tried to install with the spacer and I couldnt get the split ring to lock. I can get photos if need be. Thanks

[BlkY2k]

Aaaarrggg, next time maybe I`ll read first. I didnt get the new spacer, I was trying to get the old one to work. Looks like a trip back to the dealer. Damn, thats 120 mile round trip, for what $3 worth of spacer? Stu[id Stupid Thanks Guys