4G HS cruising, heard noise, engine died, won't start

Lots of problems lately, including the fact that my modem just crashed momentarily, and this is the second time I am writing this!

The first problem I had, I fixed, but I'l tell anyways; the spring on the butterfly valve broke, and I lost all throttle control, and to stop, I had to shut the engine off; I was still about 2 miles from my Blacksmithing class, so I decided to pedal, and pull start the engine, and when I need to brake, I would just shut the engine off. Was able to fix the spring, by using needle nose pliers to rebend the spring at the end that broke, and wrap around , and now the throttle action works much better than it ever has.

New problem ... was riding at full throttle, as I always do, and heard a loud noise, and the engine died. I pulled over, and the only thing that I could see, was a nut was missing off of the pull start mechanism. I tried to pull start it, and nothing, wouldn't even turn the engine over, and it felt like there was no tension/resistance in the pull cord.

I pulled it apart, and couldn't see anything obvious, I also checked/cleaned the spark plug just in case, but nothing.

I called Terry Blow at Blow By U cycles, and he said to pull the engine apart and it was probably the driveshaft?, at least I think that is what he said; i'm tired, and just had a beer.

Is there anything else I should check before pulling the rest of the engine apart, already pulled off the magneto w/my gear puller, before I realized I have to take half of the engine off.

Now, part of my question is whether you have any suggestions before I pull the engine apart (it did sound like something broke). Has anybody else heard of this? Oh, and the magneto would turn freely in both directions w/out any tension except when the magnets crossed paths (if this means anything).

Thanks, sorry for rambling.

Corgi,

Can I disassemble the engine while it is still on the bike? And what will be evident? Will something obviously be broken? Thank you.

Thanks everyone. I have already taken the pull start and the magneto off; when I get home from work, I will check the valve clearance, etc. I can still spin the shaft by hand, which tells me something is loose. I'll drain the oil, and separate the case; hopefully nothing just falls out that I will have to figure out where it goes; it's actually a little bit like working on an old vw. I'll let you know what I find.

So, I've pulled the engine off of the bike; the valves are moving fine, and inside of the spark plug hole, nothing. Today (hopefully) I will finish pulling apart the engine.

The funny thing is that now that I have the engine off, I can hear whatever broke shaking around in the case! I think I have all of the bolts off that need to be off, and the oil is drained, I will pull it apart and see what I see.

so the "link lever" (name given on parts diagram) broke into a bunch of pieces at the bottom end. The other end is fine and still connected to the piston. Now I get to disassemble more of the engine to get to that.

Also, I believe that I damaged the case when I removed the magneto. I now have two holes in the case from where the gear puller was, and I'm pretty sure that they weren' there before I pulled the magneto.

Questions: Are the link lever and the case available separately? or do I have to buy a new engine?

Thanks, I actually looked there right after I posted that question. Now, I have a new question.

How do you get the piston out? I tried just pulling it through, but could not get past the crank. So I decided I would have to remove the crank. I loosened all of the bolts holding the side cover on, and the bolt connecting the centrifugal clutch to the crank. Now I cannot remove the clutch from the crank. Do I need to use a punch? I believe the answer to be yes, I just don't like banging on metal needlessly, when there is the possibility of destroying it. Thanks.

scotto- said:

You say the link lever broke....the link lever is the connecting rod. I'm thinking that you mean the rod cap, which is referred to as the link lever cover and as well, the shifting fork that is bolted to the bottom of the cap, which I refer to as the oil slinger.

link lever = connecting rod
link lever cover = connecting rod cap
shifting fork = oil slinger

here's some pics

Click to expand...

Yes, those are what broke. Now how do I get the crank to come out so that I can remove the piston? (please refer to my previous post.

Well, everything is apart, and it looks like I need a new connecting rod, connecting rod cap, oil slinger, and a new case b/c of too much torque on the gear puller. Not sure how much it will cost; of course this all happens about 2 months after the warranty expired. I'm noticing that the metal use for these HS engines is pretty low quality. It's like pot steel. The way this rod cracked (will have pictures as soon as I find my camera) and shattered is unacceptable. I've kept up on maintanence and it had plenty of oil!!?? I wish I could be assured that the replacement parts were better, but I know that it will be more of the same. This bike has come to be a lot less reliable than I would have hoped for.