WJL AKA Wrenchjohns Legacy 70 XS1 in gggGary's hands

[Mailman]

Maybe you experienced guys caught this right away, but it just dawned on me. I didn’t make the correlation between the notches circled here and the crack. But now I believe the cause of the crack was a thrown chain that wadded up around the front sprocket.
My uncle used to be a heli-arc welder back in the late 60’s and 70’s and he told me how many cases on Brit bikes he repaired due to that very scenario.

 

[madmax-im]

Thats a rather astute observation Bob...

 

[Mailman]

Could you perhaps V that crack a little, clean it and for a temporary fix , apply a little JB Weld?

 

[GLJ]

Gary
This my spare engine that is in my bike now. It had thrown the chain at some time in it's life. Not saying it's a permanent fix but it's been holding for 2000+ miles. When I put my original engine back in and get it sorted I think I'll get this welded.

 

[mrtwowheel]

Here in Michigan, some of our best aluminum welders are in the boat repair world, find them in the marina's. I would think that Wisconsin would have a bunch too.

PS, Love your hovercraft and airboats.

 

[gggGary]

Maybe you experienced guys caught this right away, but it just dawned on me. I didn’t make the correlation between the notches circled here and the crack. But now I believe the cause of the crack was a thrown chain that wadded up around the front sprocket.
My uncle used to be a heli-arc welder back in the late 60’s and 70’s and he told me how many cases on Brit bikes he repaired due to that very scenario.
View attachment 152195

Yeah I have two sets of empty cases, exactly the same deal. it's always the worn out chain, sprocket that does it. Common on lots O bikes.

So I got a case I can experiment with the screw it together trick.....

 

[scrapmetal]

Got the bikes unloaded. Replaced the parts I removed to get them both on the trailer, Rode Madness for a bit then installed a new pair of baseball bats on WJL ( WrenchJohn's Legacy) 1970 XS
Fired it up, fiddled with some carb adjustments. Runs and idles fine now. Added some gas and rode it 'round the country block. All seems good to great. Engine is quiet, revs freely, clutch is working fine, tranny shifts well, saw an indicated 70+ several times. Handling, suspension, brakes all seem "period correct". Love it.
Bike was sitting and idling for these pics. So far it's a "one easy kick" starter.
Allison took a great little video of me riding it but it's phone sideways and apparently modern computers no longer know how to do such complicated things as turning a video 90 degrees.
More to do, mostly clean adjust check the usual, but it seems ready, even anxious to try some local trips.
View attachment 151360 View attachment 151361
Luckily we have some good weather for the next few days.

jealous, what a beautiful bike

 

[gggGary]

PS, Love your hovercraft and airboats.

???

 

[mrtwowheel]

???

We don't have them here, well I've never seen one in Michigan. Take a trip to Oshkosh and you'll see one after another on trailers.

Scott

 

[gggGary]

Took a good close look at that empty busted case. As bad as the outside looks the amount of damage to the wall inside of the case is fairly small, you can see the crack starting on the left of the shift shaft bore and extending out.

most of the leak is prolly around the shift shaft bearing.

 

[wrenchjohns]

Having a bad day.
View attachment 152179

Was inspecting, cleaning, and expecting to change the clutch push rod seal.......

I hadn't seen this and I really hope you can find a good workaround.
john

 

[gggGary]

Running a 16 tooth front sprocket, not recomended.

Since this bike has been on the road " for a while with no issues beyond a slooowww drip I'm going to use bumper epoxy in the crack and around the shift shaft bearing housing and ride on. It won't be a race bike but will not baby it either, just keep an eye on things. Now back to that slight miss fix'n. After mms subtle hint I went round the throttle cable n synch another time. Will be going through points, coils etc too. Weather's crap so garage time is as good as it gets.

 

[member28833]

Running a 16 tooth front sprocket, not recommended

*Noted, good pic. I’ve wondered about using an 18 tooth front sprocket instead of going down on the rear to say, a 32 or 33 . Does using a 18 tooth up front affect the chain routing around the guide area in the cover adversely in any way ? Longer shocks too will now complicate this slightly as well.
Thx, -R

 

[5twins]

Yes, it's too tight in there, in my opinion. Allow the chain to get too loose and it can start cutting into stuff. Don't change the front from stock size, reduce the rear one or two (I prefer one with an 18" wheel). The European models came with 17-33 gearing and I feel this is ideally matched to this motor's power output.

 

[member28833]

Got it. Been thinking about this awhile. thx..

 

[5twins]

I think this bike greatly benefits from this very slight gearing change.

 

[Mailman]

Two questions,

So the 16 tooth sprocket caused that, because it allowed the chain to ride too close to the case?

And , what is bumper epoxy?

 

[gggGary]

Two questions,

So the 16 tooth sprocket caused that, because it allowed the chain to ride too close to the case?

And , what is bumper epoxy?

Yes, the wear round the sprocket, this has 16 tooth and a o-ring chain, not enough room to clear the housing round the counter shaft seal. But my guess is the crack was a separate issue from long ago.
Bondo brand black bumper epoxy that remains slightly flexible. I use it often where a rigid (brittle) bond will just break again. Since there may be a bit of movement here? and the goal is no oil leak, I figger the flex is a good thing. Pic of that bare case after a "stress test " and some grinding,

that case was worse than this 70 is....

 

[gggGary]

Now just need to keep my paws off it till it's set... once set it can be sanded painted.

Will mix another batch, apply around the counter shaft seal.

 

[Mailman]

I think that looks like a very practical and likely durable patch. Should hopefully last until the engine needs to be torn down for rebuilding.