[Jake McNevin]

Hi, Im trying to get my 1980 twinstar up and running again but have hit a road block. I recently replaced the old cylinder head (which had a stripped spark plug port) with another used but unstripped cylinder head. Being the scrub that I am, at the last timing step I dropped a bolt down the cam chain port and in to the body of the engine. After removing the engine, the cylinder head, and the cylinder body I was able to shake the bolt out then put it all back together (with new gaskets). Now when I try to kickstart the bike, the engine makes a very weird bubbling sound out of the left engine cylinder. I tried using the electric starter at no avail. The engine isn't close to turning over. Any idea what could be causing this and how to fix it? I am pretty fresh to motorcycle mechanics and still have a lot to learn. I also rebuilt the carb due to a small gas leak in the main injector and it is no way tuned correctly. I have attached a clip of the sound the engine makes. Thanks for the time

 

[cmonSTART]

Personally I don't want to download and open a zip file from someone I don't know. Can you upload a video to Youtube? We can link to it here.

I'm curious what the "bubbling" sound is - is it a compression leak sound I wonder?

Also, by "turning over" do you mean running, or engine physically turning?

Welcome!

 

[Jake McNevin]

Thanks for the interest! Here is a link to the youtube video:

By "turning over" I mean running, Im slowly catching on to the jargon

Thanks

 

[cmonSTART]

I would be curious to see what a compression gauge says when you kick it over. Can you double check the valve timing and clearance? It might be a normal compression sound - hard to tell. It does sound a bit odd though.

 

[Jake McNevin]

Thats a good idea. I'll see if I can borrow a gauge from a friend/shop and if not pick one up somewhere. The valve timing may be off, there weren't any of the same distinctive markers as described in the repair manuals and I may have misstimed it. I will try a couple of other potential positions and see what happens. Ill pick up some feeler gauges and check the clearance while I'm at it. Thanks a bunch

 

[cmonSTART]

No worries - proper valve timing is one of the more critical things you need to pay attention to when building an engine. You can really do damage to a lot of engines if you get that set incorrectly - valves and pistons tend to contact each other when the engine is turned, which can get really expensive.

Some engines it doesn't matter, but many it is a really big deal. Suggest you take a very very close look at things and make sure everything is assembled exactly correct.