Kick Start Locked Up

[Houseman39]

Hi All, Have been using this forum for a few months but only just made an account - because I ran into a problem. Hoping for some insight - I love to learn so bring on the knowledge! I bought my first bike, a 1980 xs400s, in July. Classic story: it had been sitting in a garage unused for years until I bought it for $800. I fixed some carb problems and electrical problems (with a lot of help from this site) and had the bike running reasonably well all summer and fall (although the electric starter is shot). Sometimes the carbs would act up, and it leaked oil, but It ran well.

I pulled it out last weekend when it started to warm up (winter in GA is short!) and ran it for 50 miles on Thurs no problems. Friday morning I'm 1 mile from home and the bike dies on the highway. I pull over and kick start it thinking just a typical carb issue. 400 meters down the highway it dies again, but this time the kickstarter locked up. A friendly stranger (in the south + on a bike = strangers are wicked nice) helps me push and I go to pop start it but the rear wheel locks up and no dice. I pull the dipstick and the oil is pretty low. I put in in neutral and push it home (fun) and start reading about locked up engines.

I look in through the spark plug hole and it doesn't look like anything wonky is going on (but that hole is so small how does anyone see anything?). I put the bike in its top gear, and if I put a pretty good amount of pressure on the bike I can turn the back wheel both ways (plugs in or out). Maybe 10-20 degrees with each push. Should it be that hard to turn? Still can't get the kickstarter to budge though, after the little bit of play that it has. It sounds to me like the engine isn't locked up (because I can move that back tire) but maybe something is impeding its motion or adding friction, and I just can't get enough torque on the kickstarter (Also took the kickstarter mechanism off this morning - very cool but doesn't look like an issue there). I was reading about valve timing becoming wrong and a valve hitting the piston, but I think that would make it only difficult to turn in one direction during a certain part of the cycle. I've had WD40 in both cylinders all weekend with no changes. If anyone has some insight that would be great! Or if any of my conclusions are wrong I'd love to hear that too. Any thoughts y'all? (hey I'm picking up this southern dialect thing already)

 

[NewHavenMike]

Just to state the obvious, did you check the oil level before AND after your first ride? Did you do any maintenance check ups? When aircooled engines lockup, the piston expands and seizes in the bore, causing lockup. Sometimes, when the engine is cooled it will un-seize itself. This will always cause scoring in the bore and you will have permanent damage. You can run the engine, but its life will be dramatically reduced and performance will suffer until it dies.

When you were riding, did the engine seem to struggle at all like it was under strain? Did you smell burnt oil? was there smoke when you pulled over?

Did you remove the valve caps to see if the valves open when you turn the engine?

I personally, would NOT use WD-40 for anything inside an engine. All that will do is wash away any oil thats there and can cause more damage when you try to start it. You should try using diesel fuel or I personally would use Marvel Mystery Oil and dump it into the cylinders and let it sit for about a week.

But you could have another issue and may not be seized, could be a busted cam chain or something.

 

[Houseman39]

Thanks for the reply. I did all the regular checks of brakes, suspension, tires, electrical, but completely missed checking the oil.

If it cooled off and un-seized itself would it make sense that the engine would still turn, just with a bunch more resistance (like I'm experiencing) due to the scoring?

No struggling or smoking from my engine, it was playing it cool.

Thanks for the tip about WD40. Does it sound like Marvel mystery oil would help in this case?

If I busted a cam chain would that make the kickstarter stick like this?

I didn't take the valve caps off - I'm technically not supposed to work on my bike where it is so I'm trying to do more thinking (read: getting advice) before I start the fun part. Do you think that is an essential diagnostic step?

Thanks for the help!

 

[NewHavenMike]

Taking off the caps is more or less comparable to opening the gas tank and looking inside. If you have free-play in the crank and can turn it to a certain degree before it stops, it seems like the cam chain tensioner could be broken or the chain may have snapped. In that case, it would cause a bind in the chain area.

If you had no smoking/smell then you probably didnt seize. Other than that, I cant think of anything else it would be off the top of my head. Try looking in the cylinders to see if theres any marks from the valves or scoring on the bore.

Describe what happened when you were on the highway. Did it lock up? did it just stall like it ran out of fuel? any noises? I know Ive had a couple panic situations on the roadside and all i had to do was turn the reserve on..

 

[Houseman39]

Cool I'll give it a try. Unfortunately I don't have any play in the crank - just the constant high resistance. How hard should it be (in a normal bike) to push it while in the top gear?

I was riding along at 65-70 mph and it stalled just like it ran out of fuel - that's why I wasn't too worried at first. I started it back up and the same exact thing happened. Nothing locked up, no smells or sounds. The only reason I didn't start it again was because I couldn't get the kickstart lever to budge an inch and the pop start didn't work.

 

[NewHavenMike]

I also find it very hard to pop start my bike, like it cant do it at all. Theres not enough weight on the back wheel and its very tiring pushing the bike to a running speed lol. Did you have both plugs removed when you tried turning the engine over? Could be hydro locking?

If you have tools, you could remove the round side cover on the engine and expose the crank bolt that holds the alternator side together. You can use this bolt head to turn the crank. I wouldnt crank it too hard for fear of snapping the bolt though.

 

[Houseman39]

I got out of class early today so I had time to check some things out. I pulled off the alternator side cover and started playing with that bolt. I couldn't get it to budge in neutral (plugs in or out). Then I threw the bike into 6th gear and rotated the rear wheel (by pushing the bike). When I did that I didn't see any motion in that bolt (even though I still felt that same heavy resistance)(and couldn't get the bike to move in a lower gear). That didn't make sense to me. Where else could the power be going - could it somehow be lost in the clutch before it gets to the engine? This weekend I should have time to look into the cylinders to see what is up with those valves, I'll let you know what I see. Any thoughts about my unexpected findings today?

 

[NewHavenMike]

Have you soaked the cylinders with diesel or Marvel Mystery oil yet? The nest step would probably be to removed the valve cover to expose the valves and cam chain. I think you can do this with the engine still in the frame. In fact, I think you can remove the whole top end while still in the frame. Take pictures.

Could have been a soft seize that turned into a real seize.

 

[Houseman39]

I got out today and pulled off the exhaust pipes and the valve cover. I'm not sure exactly what to look for but I nothing looked too out of place. The 3 things I looked at were: 1)The camshaft timing chain assembly looked to be properly connected and working. 2) The valves look like they all closed - like they should be with the cover off. 3) When I turned the back wheel (in gear) no motion on the camshaft - so the power is getting lost somewhere, but I'm still not sure where. Here are the photos - anything I missed that looks interesting? https://drive.google.com/open?id=1xMjrI-KuSJ3-ytjpY9CGWQhWv_MSX6Iv

I'm tempted to try remove the cylinder head tomorrow to see what is going on. It looks like I will have to turn the engine over to get to both bolts on the cam chain sprocket, but the engine won't budge. Any thoughts on how I can do this? Or do you think it would be smarter to let it soak with marvel mystery oil for a week before I think about removing the cylinder head?

Thanks for the help

 

[NewHavenMike]

If you cant get the engine to roll over and the cam assembly looks OK, Id say its a seized engine. If you had a borescope youd be able to get a better idea of whats going on in the cylinders. But those tools can be expensive and nobody really has them anyway. If you angle your flashlight properly, you can get a glimpse of the cylinder wall and possibly see if its scored or discolored. Those valve cover bolts need to be torqued back on as well.

The engine in my bike was seized when I got it. I had to snap the cam chain to separate the top end. I DO NOT recommend this unless you're prepared for a full rebuild and spend a few hundred dollars.

 

[Houseman39]

Yeah It's not looking good. I'm going to try to separate the chain with a rivet extractor and take the head off if for nothing else than to learn something. Thanks for all the help. I'll let you know what I see (or if the marvel mystery oil mysteriously frees it up).

 

[Houseman39]

I made a lot of progress! But now am looking for some validation of my findings and some wisdom.

I modified a bicycle chain tool to fit the timing chain and removed that without doing any permanent damage (that was the hardest part of all this), and took off the camshaft. Then I took off the cylinder head. Then I took off the cylinders themselves and noticed something:
The cylinders slid right off the pistons (and cylinders looked good inside). Which means they didn't weld together and seize the engine.

I found what is causing my engine to not turn over! With everything off and the pistons exposed I turned the back wheel and the right piston banged against the front of the cylinder(or what is left of the cylinder after taking all those pieces off) and stopped. Then I rotated the wheel the other way and the piston banged into the wall on the back. See the video. The piston was pushing so hard against that wall that it couldn't move. I couldn't tell if 1) it was trying to go up but there was too much friction, or 2) it was just trying to go forward and back, not even trying to go up. I couldn't take the piston off the connecting rod because it was so low that I couldn't get at the wrist pin. This makes me think that that the problem is either in 1) the bearing in the crankshaft, or 2)the connecting rod. Does that sound right?

To get at any of that I am going to have to take the engine out of the frame and split it open, right? Taking the engine off the frame doesn't seem like a big deal. Opening up the crankcase to get at the crankshaft doesn't look like it will require any special tools or anything like that - I can probably do it as long as I am careful with everything I take out. I just need somewhere to work. Once I get in there I can see if my connecting rod is the issue. If so I can buy and install a new one. If the problem is my crankshaft I can fix that somehow (by posting on the forum :-D ). Then bolt it back together and let her rip!

Please let me know where I am wrong, or maybe 'overly optimistic'. I appreciate the help!
https://drive.google.com/drive/folders/1KNoKxWT1IMNz7bLE412gnY3xLMLM2u4o?usp=sharing (pics and video)

 

[not yet known]

Engine turn in neutral.? Without the help of the rear wheel.. Can you put a socket on a bolt and turn it over..

 

[Houseman39]

I tried turning the crankshaft with the bike in Neutral before I took the cylinders off and I couldn't get it to budge. I don't think that would have changed, but please educate me if I am missing something! If so I'll put the shift lever back on and let you know how it goes

 

[spectra]

Looks like the issues are on the crankshaft end. As you said the jugs just pulled right off and well if you cant get the pistons to move now well........

Pull the motor out and split the case.

 

[xschris]

Pull the stater side of to see if the starter clutch or chain is off or locked up. Also the trans clutch side should be pulled as this will help you to see if anything it locking up there.

 

[Houseman39]

Thanks for the help all, I just got hooked up with a place where I can rent out a bay and get all this work done. I'm going to try to maximize my efficiency while I'm in there so it doesn't get super expensive, so I want to make sure I have all the proper tools before I start. I have the basics: Socket wrench, spanners, Allen wrenches, pliers, screwdrivers, etc. I took a look at the manual and It looks like that should do it for me except for when I have to pull the alternator. The Yamaha Manual says I'll need a 'Special Puller'; is that a technical term?

After I get the puller I should be good to go with my basic tools. Sound right you y'all?

 

[NewHavenMike]

You dont need to take alternator part of the crank off, unless you replace the crank. Once you get the side covers off, you can examine the starter clutch/chain to see if thats all in order.

You will need to find new connecting rod bolts, which are pretty hard to find. You can find rods and cranks easily though. Id look on here for a partout and probably buy another engine honestly. Engine builds get expensive very fast. you may be able to get away with just getting another crank and bearings though.

 

[Houseman39]

It's been a great weekend; I split the case today and found the crankshaft was all jammed. Check out the pictures, It looks like the two pieces were rubbing so hard one of them was shaved off. I had to bang on it pretty hard to get the rod off of the bearing.

It looks like I can get another crankshaft and new rods off eBay for less than $80, so I'm going to do that and throw it in. Any words of caution or anything to watch out for when Installing a new crankshaft and rods?

Also, is there any reason to believe the same thing will happen to my new crankshaft unless I diagnose and fix an underlying problem? (I won't sue you if you say 'no' and it breaks again)?

Thanks for helping me through this process (first time having a motor open like this - it was Awesome!)

Pictures here https://drive.google.com/open?id=1D43CtyEz0Y49KHze1oWwUaltH7_CEf1a

 

[Houseman39]

Great News! After waiting *forever* for mail from Washington, Illinois, Japan, and Missouri, I finally got everything I needed (for pretty cheap, too!). This 4 day weekend has been the perfect time for me to put my bike back together (while dismantling my hands). The whole engine is reassembled (new crankshaft and rods), fitted back in the frame, and filled with oil; tomorrow I will give that kickstarter a try and see if I get some fire! I'll be sure to update here with success! or come looking for troubleshooting help...