Replacing fork seals

[Clumzi]

I found the pdf on basscliff's site, but, for a monster n00b, on a scale from 1-10, how bad is it to replace the fork seals? What are some crucial tips and hints?

[Nessism]

I’d give the job a 5/10.

Tip: get your hands on a spark plug socket that has a 19mm hex on the outside bottom. Take a long socket extension, or piece together a few smaller extensions, and stick it into the socket backwards. Use this socket to hold the damper rod inside the fork from turning when you remove the hex key screw on the bottom of the fork – this screw must be removed in order to pull the forks apart. Very simple process if you have the proper tool.

Another thing which is not actually a tip, but 15W fork oil is the most popular weight. Pick up a jug when you get new seals. Fill up the forks to within 5.5” of the top with the springs removed and the forks fully compressed.

Hope this helps.

[salty_monk]

If you have the air sprung forks you can release the circlip on the seal & put air into them until the seal pops out... took about 170psi with a bicycle track pump to get mine to pop out though.

You still have to remove the forks from the bike though to slide the seal on & off.

To get right oil level... cut the straw on a spray bottle to the right length, rest the cap on the top of the fork leg & pump any excess oil out. Works great & is very quick.

Dan

[Clumzi]

Thanks for the tip. Also, might I save myself some time and trouble by finding a parts bike in the area and just swapping out the front end and hope the seals in those forks are in better shape? Would save me some serious time, right? -nick

[Suzuki_Don]

I found the pdf on basscliff's site, but, for a monster n00b, on a scale from 1-10, how bad is it to replace the fork seals? What are some crucial tips and hints?

What model bike is it?

I know on the early 550s at least and the 650s the spark plug hex does not work. There is not a corresponding hex inside the forks to attach to. Don't know about the later 550s, but I imagine they are the same. The method I used on my 550 and 650 forks was to empty out the oil, remove the springs (2), fully extend the inner tube and cut a broom stick so only 2 thread at the top of inner tube is showing. Insert the top cap nut and screw it in as far as you can, this locks the damper unit in the bottom of the lower leg and allows the removal of the allen bolt from the bottom of the leg. Replace allen bolt in same manner.

Hope this helps.

[p_s]

I know on the early 550s at least and the 650s the spark plug hex does not work. There is not a corresponding hex inside the forks to attach to. Don't know about the later 550s, but I imagine they are the same.

Later 550s work with a spark plug hex. I don't remember which one though.

[RJ]

If you are very careful you can pry the seals up with a small, sharp screwdriver. Be sure that the inner tube is protected with a leather best, thick cardboard, etc. so that if the screwdriver slips it won't damage the tube.

[Suzuki_Don]

If you have the air sprung forks you can release the circlip on the seal & put air into them until the seal pops out... took about 170psi with a bicycle track pump to get mine to pop out though.

You still have to remove the forks from the bike though to slide the seal on & off.

To get right oil level... cut the straw on a spray bottle to the right length, rest the cap on the top of the fork leg & pump any excess oil out. Works great & is very quick.

Dan

Hey Dan great idea on the fork level procedure. I made up a dip stick to fit my forks, but your idea is quicker and much less effort.

[salty_monk]

Thanks Don, it's an old trick I found working on Mountain bikes. The fork legs are so skinny it's a real pig to find a level.

The 80 550 I did recently I didn't have to put anything down the legs to get the bolts out, maybe I was just lucky but there seemed to be a chamfer on the damper rod & it that would lock it out enough to tighten or loosen the bolts.


Clumzi - No! The bulk of the work in my opinion is removing the wheel, brake calipers, forks from the trees etc. If you have to dismantle that parts bike you'll be doing the time consuming bit twice & you'll still probably have junk forks....

Dan

[Suzuki_Don]

Clumzi - No! The bulk of the work in my opinion is removing the wheel, brake calipers, forks from the trees etc. If you have to dismantle that parts bike you'll be doing the time consuming bit twice & you'll still probably have junk forks....

Dan

Yes I agree Dan. I couldn't believe how easy it was to do the seals and bushes on the 650 froks and the 550 is even easier as the inner tube pulls straight out after the allen bolt is removed. As there is no teflon bush on the bottom of the early 550 forks.

[hikermikem]

I just replaced the fork seals on my 850GLZ. Not a hard job, but getting the dampering rod out could be tricky, I did just what Nessism suggested & had no trouble.

Went to Harbor freight & purchased a cheap set of extensions - used the spark plug socket trick & it came right apart. I believe there's some OEM thread sealant on the allen head threads from the factory so it might take a little force to initially break them...

I found that a 1 1/2" schedule 40 "threaded pipe connetor" had the perfect OD to install the new OEM seals. That part is a little tricky as well, if you don't have a press or the proper tool to press them down straight to the groove. No big deal, but you have to make sure you don't get them cocked. Put a little grease on the seal OD first to help them seat.

Just a suggestion, perhaps you want to consider installing progressive springs at this time ?? Many members here recommend them...

Good luck,

mike

[Clumzi]

Awesome, this all helps a bunch. I found a guy with an '81 650 parts bike up in Federal Way. I'm getting the carbs and front fork off of that thing. If the seals seem to be in good shape on those forks I'm gonna throw them right on. The carbs I know will need to be rebuilt, but now at least I have a spare set in case I **** up .

My bike is a 1980 550L, for what it's worth.

[catbed]

good luck when you have to replace those fork seals too. you could replace both and have a spare set later on.

[hampshirehog]

All above is sound advice but you can get some seals which are a real PITA and this is where you have to change tack.

Sometimes the allen key can get 'alloy welded' (ie corroded in place) and you have to use an impact socket to shift it. I even had to drill the head off one to get the swine out and then grip what was left in a vice to undo. Tip - smear a tad of copperslip on to prevent this happening in the future.

Second, some seals can also be a pig to get out - especially where some owners for some reason like to 'seal' their oil seals with Locktite or similar. In this case it's worth having a go at it with a blowtorch to burn off all the rubber on the outside of the seal. Stinks like crazy but it does work.

[Clumzi]

All above is sound advice but you can get some seals which are a real PITA and this is where you have to change tack.

Sometimes the allen key can get 'alloy welded' (ie corroded in place) and you have to use an impact socket to shift it. I even had to drill the head off one to get the swine out and then grip what was left in a vice to undo. Tip - smear a tad of copperslip on to prevent this happening in the future.

Second, some seals can also be a pig to get out - especially where some owners for some reason like to 'seal' their oil seals with Locktite or similar. In this case it's worth having a go at it with a blowtorch to burn off all the rubber on the outside of the seal. Stinks like crazy but it does work.

See, this makes me feel even better about getting another set of forks. When I replace the forks that are on there with this set and pull the bastards apart and run into this ****, boy will I be glad for getting the spare! Same thing with the carbs, you just never know .