looking at motorcycle, fork oil leak

[Iahawk]

I'm on the hunt for a 'new' motorcycle..I've found a really nice Honda Nighthawk 650 that I had lusted after in my youth. Bike is in great shape for a 40 yr old bike but not perfect. Current owner has had it for 20+ years and has stockpiled a huge parts supply with the original intent of keeping it (and keeping it running) forever. I was going to go look at it today, buy it and ride it home (200+ miles) but seller called me last night saying he can't locate title, so it's on hold until he finds or gets new title.

Enough with the intro...he also called me to tell me bike has fork oil leak that he hadn't noticed when he put it away last season. With forks the leak would either come from the bolt and washer at the very bottom of from a bad seal, leaking down the fork leg, which would also probably eat the paint away. He has new fork seals in his parts stash and I would have no problem replacing seals and fluid once I get bike home.

In attached pic you can see the spot of oil on the tire. It looks like rolled forward or back, that's why oil is not under fork.
I obviously won't be able to fix this at the seller's location so I'll need to ride bike home. I know it's not the wisest move but unless the oil is pouring out it should be ok, right? I don't have the option of trailering it so it's either ride it home or forget it. What do you think?

(edit - I was all set for an adventure today, riding a 40 yr old bike home for about 5 hours on all 2 lane highways, passing through small towns on a beautiful, sunny day in the 70's...willing to take a chance and hopefully have a good story to tell about it)

[Alan F.]

You'll have no problem riding it with a leaky fork, it just won't be optimal. I've always said that in the 120ish years that motorcycles have been available, every corner has been cut, every repair has been half assed, every inadvisable part combination has been tried, and the bike's keep rolling on.


Don't worry about it too much, but you might want to wipe down that fork leg with a mild spray cleaner to keep it clean so new leakage will be visible.


There are also methods of cleaning a fork seal with a sheet of plastic cut from a milk jug. The plastic is cut into a particular shape and worked between seal and fork tube to clean out that one grain that's causing the leak.


I've never tried this type of thing but I'm tempted.

[rjs987]

I've had a fork seal leak on 2 of my bikes in the past. One of those bikes had been leaking for a little while. Used a SealMate on both and that fixed the problem. The second bike I actually made my own seal mate from a plastic milk jug as Alan mentions. This worked just like the original. The trick is to pull away the dust seal first and then use the SealMate (or home-made version) on the oil seal between the seal and the fork tube all the way around the tube. Leaks there are often caused by just grit that gets between the fork tube and the seal. This tool wipes that grit out.

Of course, this will only work if the leak is coming from the seal. So verify where the leak is coming from before doing too much cleaning.

The danger of leaking fork oil (other than lack of oil in the forks) is not so much paint peeling (that's brake or clutch fluid) but contamination of the brake pads if the oil gets on the disk. Usually replacing the brake pads becomes needed. But if you watch it you can ride it quite far without much issue as Alan mentioned.

[Iahawk]

thanks for the replies, guys. I forgot about that little fork seal cleaning tool...seems worth a try for sure and worth having in the tool box. And RJS, I guess I had brake fluid on my mind when talking about bubbling the paint on the fork..as I'm planning on replacing brake and hydraulic clutch fluid, along with every other fluid and filter, if I ever own the bike.

So it sounds like just wipe it off and pay attention to it leaking on other components until I can get the bike home for a proper fix.

[CROSSBOLT]

Fine looking ride, mountains of spares, no title....worth the wait 'specially if the SELLER is going on the hunt for paper!

[Alan F.]

I agree, there may be a few NLA no longer available parts, so have a look on Partzilla.com or some other and make a list to see if he has any NLA parts in his stash, that'll add value.


I'd like one but I've got enough projects for now.

[Iahawk]

I haven't seen pics of all his spares but he even has an extra full exhaust..those are pricey to buy off ebay if you can find one in good shape, and those 'slash cut' pipes which you have to have... I saw a spare airbox and about every lever plus electrical parts. He is glad the bike is going to someone who will appreciate it and take care of it rather than some kid who will beat on it.

[Alan F.]

I understand good spares of the rubber bits from engine to carbs and carbs to airbox may be a rare and valueable find.

[klaviator]

If it is leaking from the seals I'd consider taping some a paper towel below the leak to catch the fluid and keep it off the brake rotor/pads for the ride home.  Most likely the seals are old and dried out.  You can try putting some Dow Corning Molykote 55 on the seals.  It will lubricate and slightly swell them.  I put it in there with a seal mate.  That has sometimes sealed leaky fork seals for me. 

[Iahawk]

thanks, Klav, those are good suggestions.