Locking up while trying to start

[Frenchy]

Ok, any help I can get i will be thankful.
This started about 2 months ago I would shut the motor off, and go to start it , and it would lock up. It would not Kickstart it or use the starting button. It would not turn over. I would have to put it in gear and roll it backwards and it would break it loose then it
starting just fine. This would repeat every week or so.
Well the bike (77 gl1000) started have a stuffer at low RPM's. I went to change the plugs and one plug, the electrode was worn down to the ceramic tip. Changed the plugs and went to start it and now I have a ticking then a knocking in the motor. Checked the rockers and went to adjust them and motor locked up again. Broke it free by rolling it back. It started it knocks now. Any ideas what happened?

 

[mcgovern61]

It is most likely locking up due to hydrolocking. That points to a small gas leak from one or more carbs into the cylinders.

 

[dan filipi]

Sounds like hydrolocking possibly. A carb leaks fuel into a cylinder and because liquid can't be compressed, the piston stops dead while cranking. One way to prevent this is turn the fuel off while running and let it run a couple more minutes to burn off some fuel then turn the key off.... or fix it so it doesn't flood any more.

Gerry beat me to it.

 

[Frenchy]

@Dan & Gerry thanks for the fast reply. That was my first thought as well, but now I have pulled all the plugs and turning it over via button it rotates perfect. I went to adjust the valves and turning it over by hand it locks up at F1 and I have to put it in gear and roll it backwards to unlock it... I have a camera that fits in tight places and cannot see any thing blocking gears. I've looked thru both head oil drains and oil filler and spark plug holes...nothing.

 

[dan filipi]

Locks at F1 aye.....and with the plugs out.. all I can think of right now is piston bumping a valve.
Will it turn free with all the valve adjusters backed out all the way?

 

[joedrum]

Sheesh not sounding good ...but time to take the offending head off or both heads and seewhats up ...was there a belt change or something ...check belts for proper timing

 

[joedrum]

joedrum » Wed Apr 21, 2021 9:03 pm[/url]":1ua9eb83]
Sheesh not sounding good ...but time to take the offending head off or both heads and seewhats up ...was there a belt change or something ...check belts for proper timing

.hmmm just read your post it's sounding not good I'd take the heads off....

 

[Frenchy]

@ Dan & Joe
All rocker arms completely backed off of. Still would lock up now and then...I have a camera I can put down plug holes, oil filler hole and each oil drain hole on each head... Everything looks good... I can put it all together and it will run, but sometimes when I stop and go to start it locks up..then I put in gear roll backwards a few times and it's fine.. no new belt change or timing change runs good...just knocks now...I guess I'll pull the heads and inspect. This motor has around 40,000 miles... I'm at a loss..
Thanks guys will keep y'all informed.

 

[D-50Dave]

I'm wondering where the rest of the sparkplug tip is. :shock:

 

[DaveKamp]

I'm with Joe... pull the heads. If you don't see anything glaringly obvious, bring both cylinders to TDC, and see if they're at the same height. Hydrolocking does two things: 1) washes down cylinders and 2) ruins connecting rods and pistons.

Aside from the broken plug tip, you could have other things in there you really don't want... hopefully the damage is contained...

 

[dan filipi]

“Stop and go to start” oh that’s different!

Don’t pull the heads yet.

These engines and starters are notorious for what you describe especially once warmed up or hot. Since rocking it backward frees it up, the starter will rotate some.
Often the fix is refurbishing the starter and cleaning all the battery connections including ground to engine and starter relay.

I’ve had many many times also it firing back on rotation (backfire) which stops rotation also.

Don’t be too quick to pull the heads if not needed, gaskets aren’t cheap.

 

[Gc33]

dan filipi » 2021-04-22- 5:13[/url]":14mgh5l7]
“Stop and go to start” oh that’s different!

Don’t pull the heads yet.

These engines and starters are notorious for what you describe especially once warmed up or hot. Since rocking it backward frees it up, the starter will rotate some.
Often the fix is refurbishing the starter and cleaning all the battery connections including ground to engine and starter relay.

I’ve had many many times also it firing back on rotation (backfire) which stops rotation also.

Don’t be too quick to pull the heads if not needed, gaskets aren’t cheap.

Certainly not bloody cheap if in Australia....that's for sure,!!!
Im thinking along the line of Dan... One of my engines I tried turning would lock... Plugs were out... Belts were off too... Once I got into it the starter chain was jamming up.. Starter was off this particular engine tho which made it more prone.
To me it sounds like something like a chain is jamming.
Try tried turning it by hand? Do everything you can before dropping the heads.. My 2 cents worth..

 

[Gc33]

In regards to your "ticking", I have an interesting story for you... My 1st gl1000 I had.. A 76, when I was 17-18 years of age. I had an accident on it... We checked it over, everything seemed OK but it had developed this "tick" that increased/decreased with engine speed.
I had absolutely decided that it was tappet adjustment... So I set to playing around with tappets. As I was playing around with one of the inlet rockers I heard this twang and something fly past my left ear.... Rocker was cracked. How it cracked was that when I had this accident the belt skipped a tooth. No mark on the piston and no bent valve... Lucky... Just was enough to crack the rocker arm. So I replaced it.... No more ticking.
I would like to hope that the tip of your spark plug got forced out thru the exhaust valve... Unless it's jammed in the valve leaving it oped for a piston to hit?
Any things possible...