Montreal Manchild with an '81 Honda CB750K
- Thread starter Jimbonaut
- Start date
I did mate, when the engine was turning over I sprayed a can of Honda cylinder cleaner (forget exactly what it was called but it knocks out carbon deposits, much like Seafoam) and the compression definitely improved. There's still a discrepancy however between cylinder #1 and the other three - I'll have to dig out the numbers but something like 140 on #1 and 160 on the other three. Thanks for the info on how to turn the motor over while it's on the bench, thanks bud I'll definitely be doing that.
Good catch on the o-ring too. While I was rooting around in the cam chain tensioner bolt hole I noticed the very shredded remains of what must've once been an o-ring. I've ordered another one and hope that'll help with the leak.
I'm wondering about the helicoil manoeuvre. Think I'd rather avoid it if possible - if I simply Loctite that bolt in there would that be a decent enough stop gap?
Good catch on the o-ring too. While I was rooting around in the cam chain tensioner bolt hole I noticed the very shredded remains of what must've once been an o-ring. I've ordered another one and hope that'll help with the leak.
I'm wondering about the helicoil manoeuvre. Think I'd rather avoid it if possible - if I simply Loctite that bolt in there would that be a decent enough stop gap?
Cookie
God help the child who grows out of everything
Loctite will be a band-aid fix. If those threads are really gone (like they were in my F) then a heli-coil is your best bet.
140, compared to 160 isn't that bad on a stone cold, dry engine. Put a half cupful of ATF in the cylinder; it should come up the rest of the way. Then do it to the remaining 3 cylinders to keep them shiny for the rest of the winter.
140, compared to 160 isn't that bad on a stone cold, dry engine. Put a half cupful of ATF in the cylinder; it should come up the rest of the way. Then do it to the remaining 3 cylinders to keep them shiny for the rest of the winter.
Maritime
Over 10,000 Posts
Cookie said:
+1 that's close enough you shouldn't need to tear the motor down, at least maybe until next season. Run it for a while first. things may go back to normal, they may not but the 140+ compression will not make performance so bad you can't enjoy it. If you were racing it would be different.
on the cam chain tensioner bolt. that needs to snug down and hold the spring part in the right place. if it is lose your chain is going to be and cause you grief. How much metal is there, you may be able to tap it out 1 M size or go 1 standard size up( this is like a 1/2 step between say 8-9mm) and get good threads then swap the bolt to one the same length to hold. I am saying this based on the parts fiche on BB. there is a tang that slides under that bolt and it looks like you losen the bolt while engine is running then when it runs quiet you tighten the bolt, that holds the spring in the right tension. as the tensioner wears you do it again in 20K or whatever the interval is. If that is what is in the repair manual, then that is why the bolt need to hold tight. Folks over tigthen them all the time, 3-4 of my old bikes with that style tensioner had stripped threads.
Yeah that doesnt sound too bad, could just be stuck rings from not running. I'd guess you could let it cycle through a few times and they might break loose for ya. If it was lower around 100 then I would be more worried about it.
Nice one fellas, think I'll leave well enough alone for now then as far as the piston rings are concerned. The rate I'm going, if I start an engine teardown I might actually get this rubber on the road in 2025.
This bolt however is a different story. When the engine was running it sounded pretty good, no rattles or anything that would immediately point to a loose chain. Also, I didn't see any aluminum in the oil, but admit I could have missed it. Little apprehensive about the helicoil routine, it's a one shot deal as far as I can tell, but if that's what it takes then that's what it takes. I like your suggestion Maritime, I'll look into tapping the hole out as well. Thing is, the bolt itself has a saddle about half way down (for the o-ring I'm guessing) so finding a thicker bolt with that same saddle might be tricky.
How's your foot holding up? Hope you're on the mend mate, best wishes from MTL
This bolt however is a different story. When the engine was running it sounded pretty good, no rattles or anything that would immediately point to a loose chain. Also, I didn't see any aluminum in the oil, but admit I could have missed it. Little apprehensive about the helicoil routine, it's a one shot deal as far as I can tell, but if that's what it takes then that's what it takes. I like your suggestion Maritime, I'll look into tapping the hole out as well. Thing is, the bolt itself has a saddle about half way down (for the o-ring I'm guessing) so finding a thicker bolt with that same saddle might be tricky.
How's your foot holding up? Hope you're on the mend mate, best wishes from MTL
farmer92
Coast to Coast
Personally i would not helicoil that hole unless i was taking the engine apart.
you have to drill out, and then tap the hole, and risk of shoving the metal flakes into the engine.
and i agree with the heat cycles,and dump some penetrating oil down after each heat cycle
did that with a gs550 when one cylinder was low, compression popped right back up after 2-3 warm up/ cooldowns
started with 3 cylinders at 140 and one at 100, now all 4 around 150. if it sat awhile the rings can really get stuck in there.
you have to drill out, and then tap the hole, and risk of shoving the metal flakes into the engine.
and i agree with the heat cycles,and dump some penetrating oil down after each heat cycle
did that with a gs550 when one cylinder was low, compression popped right back up after 2-3 warm up/ cooldowns
started with 3 cylinders at 140 and one at 100, now all 4 around 150. if it sat awhile the rings can really get stuck in there.
Maritime
Over 10,000 Posts
Foot seems better, so far looks like antibiotics worked. If I could get my shower install finished I'd actually be able to work on my bikes LOL. If the threads are almost ok on the hole, there is locktite thread repair that might hold up vs regular locktite. I don't think that bolt is supposed to be torqued very high, hence a lot of them being stripped by folks so you may be able to try that with a fresh O-Ring and it may do the trick, I haven't personally used it but you can do a little google and see if it could work.
Yeah Farmer, that's how I see it. Pretty sure I'd have to remove the head so that no metal shavings fall into the engine - I'm not trying to cut corners here but, well, I'm trying to cut a corner. Kinda, not really, but yeah. Shit.
Think I'll look further into the hardcore Lactate option
Lactate.
Autocorrect at its finest
Think I'll look further into the hardcore Lactate option
Lactate.
Autocorrect at its finest
Cookie
God help the child who grows out of everything
The Jimbonaut said:
... I think that's for another thread, Jimbo lol.
And Mike is right: those bolts get stripped because people tighten them (note that I didn't say "over tighten"). The Honda manual, Clymer manual, YouTube etc. All say the same thing: loosen the bolt, when it stops being noisy then snug it up. It has a lock nut that is supposed to be tightened to hold it in place, and even that is only like finger tight plus a quarter turn!
Unless you're the PO of my F, who tapered the end of an 8mm bolt to fit the hole with a grinder, then rammed the bolt into place...
My C still has the original tensioner bolt setup on it. If my daughter cooperates at nap time tomorrow, I'll put up a pic of what it looks like.
Cookie
God help the child who grows out of everything
As promised, Here's the pic of the tensioner bolt with its lock nut.
Don't judge me on the filthy enhine; I haven't started cleaning off the grime yet...I'm still not sure if this is going to be my rider or if I'm going to swap the engine into my father-in-law's F as was the original plan.
Don't judge me on the filthy enhine; I haven't started cleaning off the grime yet...I'm still not sure if this is going to be my rider or if I'm going to swap the engine into my father-in-law's F as was the original plan.
Attachments
Good man, thanks for the photo Cookie - compared to my engine yours looks pristine! This actually helps a lot, it looks like there's a small spacer washer between the bolt and the spacer nut? Mine is missing.
Also, does your bolt have a saddle about half way down its length? Is this where the o-ring sits? Mine's missing the o-ring too. I'm thinking that might be why so much oil has blown all over the front of my engine. Speaking of which, spent the last two days with cans of degreaser and a toothbrush trying to clean all the crap off the front, and that's not even the worst part. The worst part is out back, around the drive chain sprocket. With that cover off, is it cool to spray degreaser over that part of the engine? It's not going to go anywhere it shouldn't, right? I'd love to get the sprocket off but it's not budging for love or money so I'll just do the best I can around it.
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Also, does your bolt have a saddle about half way down its length? Is this where the o-ring sits? Mine's missing the o-ring too. I'm thinking that might be why so much oil has blown all over the front of my engine. Speaking of which, spent the last two days with cans of degreaser and a toothbrush trying to clean all the crap off the front, and that's not even the worst part. The worst part is out back, around the drive chain sprocket. With that cover off, is it cool to spray degreaser over that part of the engine? It's not going to go anywhere it shouldn't, right? I'd love to get the sprocket off but it's not budging for love or money so I'll just do the best I can around it.
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Not that the paint on my engine is looking too great anyway, but would carb cleaner be a bit aggressive on the paint? Sure would do a number on the oil though...
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Cookie
God help the child who grows out of everything
Carb cleaner is a tricky subject. Some will eat paint and coatings, some won't even effectively chew up old grease. If the paint on your cases is shot anyway, I'd say give it a go. You can always repaint at a later time after its all clean.
Also, here's a link to an eBay listing showing what the tensioner bolt and nut look like. They don't come with the other ring, but not having one could certainly be a major part of your leak!
http://m.ebay.com/itm/152420279052?_mwBanner=1
Also, here's a link to an eBay listing showing what the tensioner bolt and nut look like. They don't come with the other ring, but not having one could certainly be a major part of your leak!
http://m.ebay.com/itm/152420279052?_mwBanner=1
Cheers Cookie, here's what my bolt looks like -
That saddle on the bolt has to be where the o-ring sits, no?
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That saddle on the bolt has to be where the o-ring sits, no?
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Flipped the engine over and now cleaning up the oil pan...
- and also cleaning up the rest of the engine that somehow looks even dirtier upside down. Bit like a Colombian girl I once knew.
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- and also cleaning up the rest of the engine that somehow looks even dirtier upside down. Bit like a Colombian girl I once knew.
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Cookie
God help the child who grows out of everything
I did some digging and yes, that's where the o-ring rides.The Jimbonaut said:Cheers Cookie, here's what my bolt looks like -
That saddle on the bolt has to be where the o-ring sits, no?
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Just wrapped up exhibiting at the Montreal Bike Show - pretty inspired by the rides I saw there and the builders I met. Hopefully made a great connection with a cool guy who can bend and weld a seat hoop for me, and now that the weekend's dust has settled I'm looking forward to getting crap under my nails again.
Got a bunch of parts coming in from Bike Bandit and about to place a big order from Dime City - fixing to start the rebuild and get my stink all over this thing.
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Got a bunch of parts coming in from Bike Bandit and about to place a big order from Dime City - fixing to start the rebuild and get my stink all over this thing.
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Maritime
Over 10,000 Posts
Hey Jim, did you have the items shipped direct to MTL from BB? If so you may get hit with a big tax and import fee bill to get them released. I always send my parts to a holding place in Maine then cross over and get them. That might be worth it as you are only about 1.5 hours from VT and could use a place there. I had a $35 order end up costing me 75 in the end the one time i had BB ship into Canada.
