[75CB]

Hey guys, this is my first time posting on this forum. Just as a preface I'm 16 and I've just bought a 1975 cb200t with 12000km on it as my new project bike. I've got experience with doing some mechanic work (in auto shop class I tore apart a motor and rebuilt it), but nothing relating to suspension so this is all quite new to me.

So into the problem

My bike on the left side fork is leaking a bunch of oil, and I'm thinking it's from the seals. I lifted up the fork booty's and compressed the forks and I'm seeing the red oil on the fork stanchions. There's a pretty decent amount coming out.

I'm assuming this means that I'll have to tear down the forks and put in new seals? When I do this I'm also guessing that I can just take out the fork tube, drop in new ez seals from common motor and not have to do anything else?

Would it be bad for the bike to ride it even after it's presumably leaked out most of the oil? Will it damage the fork internals? I wouldn't be riding it far, just maybe 20km or something like that until I can wait for the weekend and tear down the forks.

I've attached photos : In the second photo is what is on the forks after I've compressed it a few times. The rest of the photos was after 1 day since picking it up, driving for 2 and a half hours with the forks compressed in the back of the truck strapped down.

Any help Is appreciated, I'm just trying to get this thing safe and on the road.

Thanks.

 

[Bob_M]

Hi 75CB, Kudos for trying to tackle the fork seal replacement. I replaced the seals on my ‘76 CJ360, but only after watching as many videos that I could locate. There are a couple available from Common Motor and they will help you identify the correct replacement seals and the quirky way the suspension components are held together (there’s a special bolt that comes up from the bottom of the lower fork body).

One of the hardest steps is getting the old seals out without badly marring the aluminum body where each is set. The original Honda seals were firmly driven in place at the factory. I couldn’t get my old ones to budge by prying with a large flathead screwdriver, which is one method that is supposed to work. I had success with a medium crescent wrench by opening it up enough to get one of the faces under the lip of the seal and then pushing down on the handle. The head of the wrench (which is rounded) pressed against the other side of the fork body which provided enough leverage to get part of the seal to budge.

I definitely would not ride the bike without oil in the fork tubes. It’s a pretty easy job to drain and refill them, and automatic transmission fluid can be used (cheaper than specialty fork oil which can be used after installing new seals). BUT unless you’ve got a motorcycle operator license AND are a skilled enough rider to tell if your forks are working properly in spite of bad seals, I do not recommend riding it. Your bike has 47 years of wear and tear, but it’s also unfamiliar to you. At most, take short and slow ”shake down” rides. You need to learn how strong and reliable the brakes are, how reliable is the motor, does the reserve setting on the fuel petcock work, do the wheels vibrate excessively, how powerful is the headlight, etc., etc. You also need to read up on how gasoline that contains ethanol can clog the carburetor on an old motorcycles. That kind of gas wasn’t around in 1976 and the carbs weren’t designed for it.
Hope you enjoy many years of safe riding.

 

[75CB]

Thanks, I looked through some of your posts and it somewhat seems like what might be happening with my bike. I'm getting new tires and doing a few things before I'll do the forks, so I'll update after I've done them.

 

[Polaris]

I would not recommend riding the bike until you fix the fork seals and have had a chance to inspect the fork components for wear and tear, rust, and funky residue from the old oil. You need good functioning forks to maintain the front tire contact patch and steering stability on rough roads and when counter steering. Good forks are also important for the braking process as weight shifts to the front wheel/tire when applying the front brake which should provide about 80% of your stopping power.
You can make it easier to remove the old fork seals by gently applying moderate heat with a heat gun to the periphery of the area around the seal. Wearing a thick glove, you can then grasp the fork and easily pop-out the seal without marring the seal seating surfaces.
While the EZ seals are just drop-in, the OEM seals are not that difficult to install if you lube the outer edges with fork oil and firmly tap them in with a socket as a seal driver and a dead blow hammer. OEM seals are a lot less expensive, and frankly seem more robust than the EZ seals. Be sure to note which side of the seal faces up/down when you remove the old ones so you can properly install the new ones.
With new seals, fresh fork oil, and clean internal components you should notice a definite improvement in the handling and braking of the bike.

 

[Bob_M]

I agree with Polaris about using conventional fork seals. I installed the EZ seals and one seems to be functioning perfectly but the other let’s a minor amount of fork oil seep by. The major advantage of the EZ seals is ease of removal, but high-quality conventional seals ought to last for a long time.

 

[Polaris]

I should clarify that you should apply the heat to the outer metal surface of the fork body, and NOT on the seal itself. The idea is to expand the fork body (but not the seal) so you can more easily remove the seal. That's also why I advise wearing a heavy glove on the hand that grasps the fork body as you want to leverage out the seal while the fork is hot and expanded. Just work your way around the inner bottom lip of the seal and in the seal groove. Apply leverage a little at a time. This will gradually work the seal up in the fork body to the top and out. It is best not to try to pry a large portion of the seal out all at once. If you don't have a heat gun, a hair dryer will do just fine, but it takes longer and you will want to pause every couple of minutes to let the hair dryer cool a little so you don't burn it out (don't ask me, or my wife, how I know this...)