Kickstart knocked a whole in my case.

[IhateMA]

So here's goes my first post.

I picked up a 1980 Special for 120 bucks. I was told by the P.O. that he had no idea the last time it ran, but it felt like it had good compression guessing by kicking it. Guy has been building track bikes and stuff for years so I trusted his judgment.

Got her home and did the normal things. Changed the oil, checked for spark, checked out some of the electrical, (found the starter clutch is bad)and cleaned the carbs.

I decided yesterday to see if I could get it running. Something to show me it's worth putting time into. So I put the carbs on and filled them with gas, hit the choke, and 3 kicks, it fired up.

So throughout the next couple hours of messing with it. Trying to get it adjusted to idle off choke, it would keep dying, I'd keep kicking it to get it running.

Finally, I kicked it about 4 times (bout the 100th time in the course of a couple hours)

to get it started back up, the kick start lever just banged further forward than it's supposed to go, and oil drained out on the ground while it was running.

Does anyone know why this would have happened, and what internally may be broken if anything?

I plan on pulling the engine out and patching the hole with some JB weld, I've done it before on lawn mowers, tractors and what not, so I know it works.

Any insight would be deeply appreciated.

 

[Petew]

The kickstart gear journal in the case was undoubtedly cracked and broke through. This allowed the shaft to jump and crack your case. I can wager you will find something like this inside your cases...

 

[IhateMA]

I've read down probably 20 threads about kickstarters and their journals and It crossed my mind that what you said may have happened, but no one mentioned it knocking a hole in the back of the case.

My feeling is you are probably right. I'll have to pull the clutch cover to verify, but at least Ill have electric start once i fix the starter clutch.

I appreciate the response

 

[xschris]

Replace the case or find another motor. My guess is that you kicked it so hard the journal broke. Then you kicked it like that and the shaft caught something or twisted and pushed the case out. There must have been a lot of force for this to happen. I have never seen this before.

 

[spectra]

Dang do you have thighs like tree trunks that is definitely not something I have seen before........
Hell if you were close I have a case that I would let go cheap or donate to the cause.......but looks like you are a ways away.......

 

[IhateMA]

No, my thighs are more.... sapling size I guess. I ain't a big dude. I felt, if anything, I wasn't kicking it hard enough to get her go in lol. And thanks for the offer at least. I'm going to try to get outside today and get the clutch cover off to see if the kickstart journal is broken. I'm hoping that it didn't trash any of the internals, and that I can just remove the kickstart, plug the holes and make it electric/pop start only.

 

[xschris]

That's not a plug it kind of hole. That's a shattered case. The structure has been compromised and being that close to a motor support I would not even try it.

 

[kshansen]

That's not a plug it kind of hole. That's a shattered case. The structure has been compromised and being that close to a motor support I would not even try it.

I would tend to agree, does not look good from a structure stand point. I think I would be looking in to a new set of lower cases!

If once you get it apart you decide to look for new parts I have a 1977 that I have been thinking about partsing out and I have a way to maybe getting the cases to just south of Albany NY that would only be about an hour west of you.

I did a quick look on Ebay and there are some available there but one thing that bothers me is the fact that some are selling the upper and lower crankcases separate. I have always been under the impression that these cases are matched at the factory and machined as an assembly

 

[xschris]

Nope. The cases for the bottom end don't matter as much. The top end head and rocker box are the ones that need to match. I would keep in mind the top part of the lower cases do have three numbers stamped on the back of it on the lip that sizes the crank bearings for the motor. If you use the same top I don't think it will matter. I know others have used lowers from donor motors with no issues.

 

[IhateMA]

I've not even dug into it yet to see if there is further cracking or anything in the case. But being a man of logic, everything everyone is saying makes perfect sense to me.

If once you get it apart you decide to look for new parts I have a 1977 that I have been thinking about partsing out and I have a way to maybe getting the cases to just south of Albany NY that would only be about an hour west of you.

I run up I 87 pretty much every single day so its pracrically on my way. What would you want for it if it turns out I definitely need a new case?

 

[kshansen]

Nope. The cases for the bottom end don't matter as much. The top end head and rocker box are the ones that need to match. I would keep in mind the top part of the lower cases do have three numbers stamped on the back of it on the lip that sizes the crank bearings for the motor. If you use the same top I don't think it will matter. I know others have used lowers from donor motors with no issues.

That maybe so but I was also going by the fact that Yamaha only sold them as a set.

If I had my option I know I would prefer a set that came from the factory as a pair.

 

[kshansen]

I've not even dug into it yet to see if there is further cracking or anything in the case. But being a man of logic, everything everyone is saying makes perfect sense to me.


I run up I 87 pretty much every single day so its pracrically on my way. What would you want for it if it turns out I definitely need a new case?

I would say unless you are in a hurry it might be best to see what you find out about yours first and then maybe do some checking to be sure the cases from a 1977 will in fact fit your 1980. I would also like to wait till weather turns bad for riding before I commit to pulling this bike apart and strip down the engine.

 

[NewHavenMike]

I cant imagine it being too hard to crack a hole in cast aluminum. Thats a good spare engine now.
Big decision for you though whether to build the bike back or part it out...
Replacing an engine case is sort of a big job.. I dont think you can just swap out crank bearings to the other case. Stuff like that will be costly.

What ever you do, DO NOT remove the connecting rods from the crank. Those bolts are one-time use and I had a VERY hard time finding them.

 

[IhateMA]

I would say unless you are in a hurry it might be best to see what you find out about yours first and then maybe do some checking to be sure the cases from a 1977 will in fact fit your 1980. I would also like to wait till weather turns bad for riding before I commit to pulling this bike apart and strip down the engine.

O yeah, I plan on checking into mine before I think about buying anything for it. My goal is to get this thing running well, reliably, and get it street legal as cheap as possible. So if I feel the case has enough structural integrity to justify some JB weld and run it. That will be my route. But I like to look ahead just in case of the worst "case" scenario.

I cant imagine it being too hard to crack a hole in cast aluminum. Thats a good spare engine now.
Big decision for you though whether to build the bike back or part it out...
Replacing an engine case is sort of a big job.. I dont think you can just swap out crank bearings to the other case. Stuff like that will be costly.

Ive patched aluminum crankcases before and its worked well, i cant imagine this not working since its not broken next to a bearing or mount that I've noticed. But If it turns out this engine is toasted, JB won't work, and fixing it would be too expensive, I'll track down another engine, like literally anything that will fit and run and do a good old engine swap. I paid 120 for this thing with the goal of making it a cheap legal reliable learner bike.

 

[IhateMA]

I took the clutch cover off this morning. To my surprise, this is what I found.

It's not broken!!

It looks to me that the cam looking piece somehow smashed into the back of the case hard enough to punch a hole in it.
The whole kickstart gear slid right out with practically no tension on the spring. And to my understanding that torsion spring should be a PITA to install therefore should be under a lot of tension and shouldn't just slide right out no problem.

That would lead me to believe someone else has this apart, improperly installed it allowing a piece that isn't supposed to move, to move, and cause damage.

Seeing how the hole is right next to the journal and I believethat cam piece rests right there, I feel I'll have to ditch the kickstart since it'll never be strong enough to hold it.

What say you XS400 experts?

 

[kshansen]

Not ever having a XS400 apart I'll leave it to someone more qualified to make positive answers.

That said I would say from the thinness of the case at the broken parts it is not "major" structural area.

You don't happen to have a friend who does TIG welding do you? It might be possible to weld the broken part back in place.

I had a gear fail on my 1988 Sportster at 36,000 miles, cracked the case but no pieces broke out. Lucked out finding a guy to TIG weld it with motor still in frame. Bike now has 118,000+ miles on it and that repair is still holding good and no leaks!

 

[IhateMA]

Not ever having a XS400 apart I'll leave it to someone more qualified to make positive answers.

That said I would say from the thinness of the case at the broken parts it is not "major" structural area.

You don't happen to have a friend who does TIG welding do you? It might be possible to weld the broken part back in place.

I had a gear fail on my 1988 Sportster at 36,000 miles, cracked the case but no pieces broke out. Lucked out finding a guy to TIG weld it with motor still in frame. Bike now has 118,000+ miles on it and that repair is still holding good and no leaks!

Those were my thoughts on it. And I do have a friend who is a professional welder and loves to TIG, but doesn't have a TIG welder, and I trust no one besides him and my self to work on my stuff. So JB Weld it is.

 

[NewHavenMike]

My only guess is, the spring had no tension, which it should. And the gear didnt reset it self so when you kicked it again it went too far and you gave it an extra turn too far.. That spring took some effort for me to get it in place.

 

[IhateMA]

So I finally pulled the engine today. And patched up my hole.
Outside and inside.

Patch pieces, cuz it needed some material to fill the hole. I used some thin aluminum sheet I got at the local hardware store

After I bolted on the pieces and laid some JB Weld in between the layers of aluminum and around the edges

I probably have the engine back in tomorrow and I've got to get the starter clutch working. So with all intents and purposes, I'll find out if this patch works here in a couple weeks.

 

[Jeff0133]

JB weld...
I'd be weary...considering temperatures/pressures involved...I am one to hate being stranded with my bike
...but that being said...hope it works for you