I have 1979 XS650 Special II. The engine only has ~16k miles. I've noticed some sparklies in past oil changes and would like to inspect the cam chain guides for wear. Can the top cover of engine be removed with the engine still in stock frame or does engine need to be removed for enough clearance?
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Cam chain guide wear
- Thread starter 79Dano
- Start date
Are the sparklies magnetic? Cam chain guide wear wouldn't be magnetic, it's aluminium. Are there any bits of black rubber/plastic guide in the drained oil?
It's an engine out job unfortunately.
It's an engine out job unfortunately.
Hey Dano. It's not uncommon to find some small aluminum bits at oil change as well as small black plastic/rubber in the filters. Also,
the lower( sump) filter uses brass? screen and one small section is notorious for tearing loose. This will make a real mess of your oil, the gold color being the clue there.
the lower( sump) filter uses brass? screen and one small section is notorious for tearing loose. This will make a real mess of your oil, the gold color being the clue there.
Thanks for the advice. I may be a little over concerned. I think I will just keep monitoring oil at changes for the black plastic from the guides. Part of what got me pointed in this direction was when watching chain tensioner pop in and out with engine running surprised me a little. My understanding is that the tensioner is adjusted with the engine not running. The tensioner rod should be flush with adjuster screw. I started thinking that the chain guides may be shot and the chain is snagging on rough surface of guides. It doesn't make any unusual sounds though.
Yes, with the engine ticking over, the tensioner rod oscillates a little in and out. That's normal.
Monitor the oil and the sump for black bits of guide. Then act if you see any. Good luck.
Monitor the oil and the sump for black bits of guide. Then act if you see any. Good luck.
Yeah, I originally followed the procedure for static adjustment outlined in both Haynes and Clymer manuals. Backlighting it with a flashlight and running a fingernail across to get it "just right" ha! Later reading @5twins and others descriptions of setting tension at idle. The static setting is a good starting point, with about 1mm of in and out at idle. Another advantage of adjusting while running is that you may hear the effect that your adjustments are having.
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It's generally accepted that watching the rod to have about a 1-2mm in out movement at idle (or plugs out e-starter speed) is the (best, proper) way to set the cam chain. Setting the cam chain with the engine not running can result in a too tight cam chain which (may, will) increase guide wear.
Yes, I adapted the "check/adjust while the engine idles" method from the SR500. The factory shop manual for that bike gives the static method for adjusting but then tells you to start the engine and observe the plunger for movement to check your adjustment ......
I figured this would work on the 650, and it does, and it's pretty much foolproof. The first time I did the chain on my 650 using the manual's static method, it was all messed up, lol, and I ended up with it way too loose. Adjusting it while the engine idles is easy. I tighten it up until the plunger stops or almost stops moving, then back it off just enough to get the small amount of in-out movement required. It doesn't hurt anything to have the chain adjusted too tight for that short period of time. You can also demonstrate to yourself what a too loose chain sounds like (rattles like loose valves) by simply loosening the adjuster way up. Besides the increased movement of the pushrod, eventually the motor will start "ticking" like the valves are too loose.
I figured this would work on the 650, and it does, and it's pretty much foolproof. The first time I did the chain on my 650 using the manual's static method, it was all messed up, lol, and I ended up with it way too loose. Adjusting it while the engine idles is easy. I tighten it up until the plunger stops or almost stops moving, then back it off just enough to get the small amount of in-out movement required. It doesn't hurt anything to have the chain adjusted too tight for that short period of time. You can also demonstrate to yourself what a too loose chain sounds like (rattles like loose valves) by simply loosening the adjuster way up. Besides the increased movement of the pushrod, eventually the motor will start "ticking" like the valves are too loose.
Update. I found black plastic in sump strainer. It was more than a little but not enough to account for the entire stopper guide. I pulled the engine and disassembled top end today and found the front stopper guide completely stripped of black plastic. I could see where chain was rubbing of the aluminum but not too bad. I ordered new front stopper guide. My question is should I split the case on lower end to clean out. There must be more black plastic somewhere?
Deffinitely no.
As I see it: As the plastic wore down, most of the particles were microscopic. Most of the bigger bits were removed during oil changes. Remaining pieces clinging to the engine aren't going to hurt anything and will settle to the bottom of the engine and stay there.
What he said. Spliting the cases would be overkill IMO. Maybe couple of low-mileage oil changes after the repair.
Are all tensioners black?
I ask due to the fact we had troubles on an engine family's tensioner/snubber black nylon 6/6.
We changed it out with natural colored nylon 6/4 and no more troubles.
I ask due to the fact we had troubles on an engine family's tensioner/snubber black nylon 6/6.
We changed it out with natural colored nylon 6/4 and no more troubles.
Yes. I tensioner on back side of the engine was ok and so I did not replace it. The front stopper guide was bad and I replaced it with another part that had a black colored material bonded to the aluminum shoe. It looked like an exact copy of the original.
The bike is back together and running again. The engine runs better and dosen't lug down and chatter like it use to when I slowed to make turns. I use to downshift to second to avoid the rattle. Now I only down shift to 3rd which feels like a more appropriate engine speed. I recognize now that the chain was due to replacing a long time ago. The bike only has 16,500 miles but is a 79. I am original owner.
The bike is back together and running again. The engine runs better and dosen't lug down and chatter like it use to when I slowed to make turns. I use to downshift to second to avoid the rattle. Now I only down shift to 3rd which feels like a more appropriate engine speed. I recognize now that the chain was due to replacing a long time ago. The bike only has 16,500 miles but is a 79. I am original owner.
