JB weld Tappet Cover?

Monowakari

XS400 Enthusiast
Messages
34
Reaction score
0
Points
6
Location
Victoria, BC, Can.
Hey all,

After adjusting valve clearances and replacing tappet covers one of them broke with barely any applied torque.
image.jpg image (1).jpg
It broke similar to the ones in the pictures however all of the threads are intact. It broke above the final thread and quite cleanly. Those pictures are not mine! Just googled some examples and found 'em.

I've jb weld-ed it and I'm waiting for it to cure, in the meantime I've ordered a new tappet cover (delivery in 4-8 days but over the border who knows!).

Anyway, will it hold up inside the cylinder head for a week or two until the new one arrives? I only put on 50-75 km's a day, mostly short commuting and some short stints on the highway.

My main concern is the minimal amount of weld in there melting and dripping down into the engine. I'm entirely unfamiliar with this stuff so I'm hesitant to actually run with it. However it holds to ~600F and I cant imagine my engine gets remotely that hot..

At the least: I have a motorcycle test to go to this friday, so hopefully it would work just for that? Around an hour of city riding?

Thanks!

P.S. yeah I'd rather not use jb weld but with no other form of transportation than the bus I want to feel confident before taking the bike out in this condition.
 
I'm not familiar with tappet covers as the Maxim use shims, however, I don't think there is any oil pressure in that part of the engine, just oil spraying around - not enough force to it apart unless you didn't get the mating surfaces 100% clean.
I might worry more about engine vibration weakening the bond than anything else.

I'm pretty sure you are correct and that the temperature won't get to 600. I once had to fashion an oil plug out of a piece of round wood and it showed no sign at all of scorching. If the bond fails, or the new cover's arrival is delayed, you could try drilling several small indents opposite each other into both surfaces so that the J-B essentially forms into them like dowels - to greatly increase the joint strength.
 
If the bond fails, or the new cover's arrival is delayed, you could try drilling several small indents opposite each other into both surfaces so that the J-B essentially forms into them like dowels - to greatly increase the joint strength.

This is a very interesting thought thanks Lou. The more research I do the more I'm getting comfortable with running the bike temporarily with the bonded tappet cover. For now the concern is when I go to reinstall if it will shear during tightening the cover into the cylinder head. I think that as long as I'm not too jerky with the wrench and double check my clearances first, while the cover is off so I don't have to go back in, then hopefully all goes well.

Fingers crossed!
 
I've got 2 of the 4 covers on mine that are epoxied in place. I must say that this was done prior to my owning the bike as the threads on the pugs are crossed & torn up. So far I hadn't seen any leaking aside from the bad o ring. You should be ok for the odd short run or even longer runs with out much idling to cause excess heat.
 
I found one at a local shop a friend told me about for $10. However the first epoxy job I did wan't substantial enough and reseparated. So I drilled "dowel" holes a la Lou and found it to be much stronger with no breaking. But found the one at the shop and this way when the one I ordered online shows up I'll have a backup.

Thanks guys
 
Which shop had the part?
I've been surprised to find some random parts still in stock from the 80s at SG Power.

The motorcycle salvage on Discovery downtown has a few XS parts in their bins. Only open friday & Saturday, 10am to 4pm.
 
Yeah motorcycle salvage under/behind discovery coffee. It wasn't even it the tappet bin, I checked the bin that box was sitting in and got lucky, looks like a few tappet covers fell out of their box into another one and that's where I found a perfect match in good condition for $10!
 
Back
Top