Yet another broken chain guide

So I found this: http://xjbikes.com/Forums/viewtopic/t=4181.html

And that seems exactly what has happened to me. It's nearly the beginning of riding season and splitting the cases, to replace a crappy plastic part.

I hate to sound like a half-a$$er, but am I absolutely courting disaster if I keep riding it after fishing out the pieces?

 

It's not the way to go but sometimes we need to do it to keep going, do what you have to do, just know the risk is there that you'll have to do it again if you don't do it right, my Grandfather used to say that doing a job twice was the only punishment for not doing a job right! (he also died of cancer after his doctor failed to remove his whole prostate) He was a smart man and a good man I wish that wasn't a true story
Shaun

 

Like I said in my response to your other thread, pull the cover and make sure there isn't just a problem with the mousetrap shift/return mechanism. Yes it could be the broken chain guide issue but be sure it isn't something simpler first. The only way to BE sure is to look. Plus you can look thru the hole while you're in there and see if there are any obvious pieces...

If it is the guide, it's disintegrating. Other pieces will continue to break off. When, how big, how many, how many already broke off and made it through to the pan... You can't know. If it fails completely you stand a chance of doing LARGE internal damage. But be sure before you decide what to do.

 

Yeah I'll check it all out. Lol...I just wish someone would pipe up and say "Oh yeah, I pulled a piece of mine out but that was years ago and I haven't had any problems since".

Wishful thinking.

That thread I posted also mentioned a noise. Thinking back, my starter made that noise. Kind of a howling. It did it 2 times, and for 2-3 seconds each time. I was starting the bike in extreme cold either for a ride, or to keep the battery bumped up because I don't have a tender. Apparently the noise is the chain guide coming apart. I thought it was the bendix for the starter failing to retract right away, as happens in older cars sometimes.

 

My stater makes a crap load of noise for a couple of seconds every time it starts. Its a little more pronounced in the cold.

Get a battery tender. They are $20. Then you will KNOW that the battery is fully charged regularly.

 

Ok, I pulled the shift linkage, and shift cover off the engine and found 2 pieces of broken chain guide inside the guts of the gear box. I had to shine a light all around to find the pieces. There were 2; one was the size of a quarter, one was the size of a dime. I had to break up the larger piece to get it through the hole, so I had 3 pieces in all. The cavity that you dig in is pretty deep. To overcome this, I bought what's known in Navy parlance as a "bilge picker". It looks like a tiny claw attached to a tube with a plunger at one end. You can find these anywhere.

After fishing out the pieces, I put everything back together and ran through all the gears several times with the bike on the center stand. I bumped the rear wheel by hand to help engage all the gears. Once that was done, I completely reassembled the bike, and put new oil in it. Still on the center stand, I started the engine and ran through all the gears with no problems.

For future reference, pictures are attached. Note the holes at the upper left, and lower right corner of the gearbox where you can dig for these pieces.

I'm glad I fixed this, but I'm not glad that my engine is essentially a timebomb that could grenade itself at any time, or perhaps never. :x

 

You know, I was playing around last night with a couple of bare engine cases and some misc. bits (but no crank or gearsets), and I might be wrong, but it seems almost possible that with the judicious use of a few long extensions and swivel adapters or "flexible" socket extensions, that you just might be able to replace that chain GUIDE with the engine still together......no need to split the cases. You'd have to go in thru the sump (oil pan); from there, the rear mounting bolt for the chain guide is pretty much a straight shot.......the forward mounting bolt is way up front, just to the left of the cam chain tunnel, but it might be possible to get in there and get it out with some combo of extensions and swivels......

Once the bolts are out, you should be able to snake the old guide out and a new one into place. Of course, you would need a magnetic adapter to hold the bolts in the socket as you manuever them into position. And since the bolts are supposed to be lock-tited into position, you'd need some way to clean the tapped holes and make sure they are oil-free (some type of long extensions on a spray can of brake cleaner, etc.).

If anyone has a complete engine out of the frame already, it might be worth a shot at seeing whether it's possible........the big question is whether you can rig up a set of extensions to access the front mounting bolt.....if you can, then there's no reason why this task couldn't also be performed with the engine still in the bike (you'd have to flip the bike onto it's back, and remove the exhaust collector, but that's still alot easier than splitting the cases!).

If someone can give it a shot, even on a junk engine, that might be some really useful information. As Sushi notes, once the guide starts breaking up, it's very likely that it will continue to do so, and then you risk grenading the engine (or worse). Given that this is such a common problem on these bikes as they age, perhaps some sleuthing is in order......


NOTE: it may be that the 550 guides and the 650-900 guides require two different methods of access and removal, so what works on one engine (550) doesn't work on the others (650-900), or vice-versa.

 

This is making me nervous...sounds like it's inevitable for us all.
Do you stock these parts Chacal?

 

Hey Capt, well yes, actually I do. The guide itself is cheap (about $30 or so), it's the process of getting to it that's always been such a nightmare.

But as these engines get some years and miles on them, this is becoming a much more common issue.......so maybe it's time to explore alternative methods of replacing this item. The engines themselves are pretty bulletproof WITH PROPER MAINTENANCE (like, you know, oil changes and valve adjustments and engine synchs), but the starter clutch drive and this primary chain GUIDE are the two items that are so "internal" to the engine, and which require periodice repair or replacement, that a solution which does not require complete engine teardown might be welcomed by everyone.......

 

Even proper maintenance won't keep a rubber part from hardening and disintigrating over time. Chacal's got a fine idea. Half-Century has a parts bike or parts engine. Perhaps he would be willing to look into it. I'd certainly be willing to assist as grunt laborer.

 

I would be happy to let you hack on my parts bike.
There is not space to take it apart and leave it apart in my garage.

 

Hm...how would you feel about transporting it to the Ft. Meade auto hobby shop? Or perhaps just the engine.

 

It would have to me towed on a motorcycle trailer or pushed up a ramp to a truck. Do you know someone who has that capability?

 

Yeah, I figured it had to be towed and not ridden. I'll look into borrowing a motorcycle trailer. It would probably fit in the back of my pickup truck but rolling it up there seems like a major effort. I'm still recovering from surgery so it's probably not the smartest move on my part.

I'm sure I can come up with a trailer, even if only for a day.

 

It does roll freely. I have two teenage sons that can help push it.
If you can get a flatbed trailer I would spring for a wheel locked stand to hold it down during transport.

 

Haha Ok so I know this was like 12 years ago, however. On the off chance that this will be seen one day. Did you get the bike there? Did it work? Can I go in through the pan?