Engine removal

[David Toll]

Hello all,
I am back into my '78 Special restoration after a couple of months' absence. Removed the oil filters and found the telltale signs of black plastic and shiny aluminium - not a lot but enough to give that "Oh no!" feeling. Have read all the threads on this topic and the general consensus seems to be to remove the motor, replace the front guide and chain, check the bores, replace the rings, lap the valves and clean up the pistons and head. The problem I have is that I have never had the motor running for more than a few minutes before I began the strip down process and, even then I wouldn't have recognised the metallic sound of a deteriorating cam guide. The PO had replaced the bushings and the steering bearings, so his maintenance schedule wasn't too shoddy. It is possible that he has replaced the guide and I am seeing the detritus the motor can retain for a period of time after the replacement.
I could change the oil and run the motor for a while to see if the deposit of break down sediment continues but she is stripped down and ready to pull out now. The motor's compression is good but the plugs in situ are black with carbon which makes me suspect that the head may be in the same condition. She has 21,000 miles on the clock which would appear to be the mileage that most contributors cite as time for a few replacements. The bike is an American import in surprisingly good condition so I have no way of checking with the PO.
So, do I pull the motor on the off chance that there may be things inside that need attention, or do I put it back together, complete my rebuild, start it up and run it for a few oil changes and then make a decision? What would you do?

 

[xjwmx]

That is a good question really. Running it would tell you if it needs new rings, but on the other hand some good rings are really cheap. I guess I would choose to take the engine out because you have reason to suspect the front guide. I would replace it even if it looks okay. I might choose to run it instead if there was a way to tell a bad front guide by sound, but I couldn't tell it when mine went bad. I had it apart for a different reason. Shame you can't get good info on what's already been done recently.

 

[Jim]

I would pull it. Couple of reasons, not the least of is that it looks like you're only a few steps away from having it out anyway. Yes, it could be chunks that never got properly flushed when guides were replaced, but that's a roll of the dice since you don't even know if it's been into. Question is, do you want to ride for a few thousand miles with that nagging doubt in the back of your head? Especially when you're that close to dropping the motor anyway...

 

[gggGary]

Summers coming; how much do reasonably expect to ride it? If long hard kilos will happen prolly pull it now. If you would be lucky to get a couple thou on it, maybe it can wait til next winter's wrenching session.... I am not that concerned with carbon build up on a head.

 

[650Skull]

All year round riding on the Gold Coast..........The starter gear has rubber bushing that disintegrates. That's common and could be mistaken for guide.

Have you done a leak down test? compression test?............ if the bike is running maybe use the time now to do some, before tear down tests, and get parts while the bike runs. Round town and down to the shops........maybe sort some other problems out

There is a saying.........if your thinking about it, it probably needs to be done, or soon.

 

[TwoManyXS1Bs]

You could pull the plugs, and peek in there. Also, slowly rotate the engine and peek into the in/exh ports, look at carbon/ash buildups, valve/stem conditions. Post pics if you can...

 

[5twins]

I think most of the metal bits and rubber chunks come from the grinding #4 starter gear. What you found could very well be past accumulation just now being flushed out. It took several thousand miles and multiple oil changes and filter cleanings before my filters started to come out clean. Oil change last week showed a clean lower filter and just these few bits on the side filter .....

Do plan on the rebuild eventually but I think you could ride it a season first.

 

[David Toll]

Thanks for the advice gents. As Skull says, we don't have a riding season down here, it's paradise all the time! The engine is almost free and nearly everyone agrees that it's probably got to come out sometime. I shall pull it now. Full speed ahead!!

 

[JV650]

ON/Off Topic, I've got a maybe dumb question. Why does the motor need to come out of the right side of the frame opposed to the left side. What's the limiting factor? TIA
And Yes it's been a while since I've contributed. Been a busy life with other things.

 

[Jim]

The right rear cases and side cover sit too far back to go through from the left side.

 

[JV650]

The right rear cases and side cover sit too far back to go through from the left side.

Got it! Thank you!

 

[MaxPete]

ON/Off Topic, I've got a maybe dumb question. Why does the motor need to come out of the right side of the frame opposed to the left side. What's the limiting factor? TIA
And Yes it's been a while since I've contributed. Been a busy life with other things.

No dumb questions here JV650 - we're all learning.

Jim answered your question very effectively - and that is the way everyone does it (out the RHS) - but if you try it the other way (out the left) and it goes well, then, hey - tell us about it and we'll all learn something new!

Pete

 

[5twins]

Yes, you can plainly see the width factor here .....

It's not impossible to get it out the left side, just much more difficult. Why do it the hard(er) way?

 

[gggGary]

It's not impossible to get it out the left side, just much more difficult. Why do it the hard(er) way?

You realize you are asking a bunch of guys wrenching, building, and riding 40 year old motorcycles?

 

[MaxPete]

Yes, you can plainly see the width factor here .....

It's not impossible to get it out the left side, just much more difficult. Why do it the hard(er) way?

Yeah - if we liked doing things the easy way, we’d likely be riding something much younger...bikes I mean.

 

[JV650]

Alrighty then. I got it out the RHS with minimal effort, still a little shoehorny as the mounting hole by starter is a bit figgity to clear. I made a slick engine jig to lift and hold the motor while supported by a chain hoist. I'll post pictures of the jig a little later when I reinstall the motor. It's made of 2"x2" box tubing and L-iron. It can be welded or assembled with bolts if you don't have the means to weld.

The bike on my Avatar is the one I'm working on at the moment. I had to send the USD forks in to get rebuilt as it was pretty leaky and admitted defeat trying to replace the rebound valve o-rings to stop the leak, so sent the forks off to get rebuilt. The bike is still holding true to it's name I gave it "Snowball" the rebuild on the forks are running quite a bit more than anticipated. IMHO if you plan on going this direction call Cognito Moto and get their USD outfit. I figure time spent,sourcing materials, scratching your head it'll be worth the coin if that's the direction you wanna go and save yourself the headache.
Don't get me wrong, Having put in about 700 miles on the bike with those forks is pretty cool experience as the rebound control is smooth. You just REALLY gotta want it. I"m pretty sure the cost add was due to wanting to powered coat the tubes to match the rest of the bike. If you can find a solid set and are good with the silver or gold set then your in another $400~500 for Cognito's stem, disc calipers, brakelines and master. Plus about 20~30 hours of fitting it up.

My first mistake on adding USD's was, (No offence to the contributor(s) that did a few early posts on USD's) seeing the shiny USD forks going WAY COOL!, Then buying a 92' GXSR750 forks and diving headfirst down the rabbit hole was my follie.

My first words of caution of this undertaking or any is, If you see someone using the word "Should" a lot it means they haven't successfully completed the undertaking and is best to continue your research for someone using words like "WILL" or "DOES" as this is an action word. If you want Measurements or details on the USD fitting I can do a write up with Photo's just let me know. It's the least I can do for the remove the engine RHS confirmation.
I'm sure this saved me a layer of skin.

So back to project Snowball, When I first purchased the donor there were signs that the chain guide needed replacing soon, a little noise at front of case and some black plastic chips in the filter, that it was time to replace the cam chain guide. That brings me to where I am now.

Any advise of other things I should replacing while I've got the top off? Compression on the bike last tested was around 155ish? both cylinders.

Sorry for the Tangent and thanks for the advise and sticking with me to this point. Guess that's what happens when I haven't logged in for a while

Best! Jim

 

[TwoManyXS1Bs]

...Any advise of other things I should replacing while I've got the top off?

Do a forum search on "what top end", click "titles only".

About 8 good threads...