So I just Recently got a mint xs650. Only issue is a knock on the right side when idling and under throttle. Just tore the engine down and cam chain guides are fine. Valve lash was set .003 on intake, and .006 on exhaust and no change. I have No idea what else it could be. I regret Pulling the motor out and apart now. Any help would be appreciated.
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1980 XS650 right side engine knocking
- Thread starter Gfoer1022
- Start date
Perhaps you took a video that could help diagnose? Was the frequency of the knock equal to rpm or half that?
While it's apart may as well measure everything; pistons, rods, etc. Check for play in crankshaft roller bearings. Visually inspect cam, rockers and rocker shafts. Remove right side-case and look for clutch wear and check crank gear tightness.
BTW, avoid buying green colored gasket kits for reassembly, try to find black or dark grey colored gaskets.
While it's apart may as well measure everything; pistons, rods, etc. Check for play in crankshaft roller bearings. Visually inspect cam, rockers and rocker shafts. Remove right side-case and look for clutch wear and check crank gear tightness.
BTW, avoid buying green colored gasket kits for reassembly, try to find black or dark grey colored gaskets.
Check your con rod little ends?
I think it was half the rpm but honestly can't be too sure. I plan on just doing the big bore kit while it's apart so I will check all that. I am assuming that it has to do with the rockers or something in the top end, since I used the ol screwdriver to the ear method and it's definitely coming from somewhere on the top/right half of the engine. The valves and pistons had quite a bit of carbon build up as well, not sure if that has any effect. And thanks. I am pretty sure I already got the black gaskets, but I will make sure before I put it all back together.
Will do, thanks!
Well, I feel like an idiot. lol. I took apart the tensioner bolt and spring assembly a bunch of times, and make sure that it had the brass washer that everyone is always missing, but completely missed the fact that it didn't have the rubber damper in between the bolt and spring. So ordering that $8 part along with the big bore kit that I might as well put in now that I have it all apart.
You should have "either or", either the 2mm thick copper washer or the 3mm thick rubber/metal washer - but not both. Which one is correct for your assembly will depend on the length of the adjuster screw .....
The longer 60mm screw gets the 2mm thick copper washer, the shorter 59mm screw gets the 3mm thick rubber/metal washer. If you mismatch the parts, you'll get one of these two conditions .....
You won't be able to set the cam chain tension following the manual instructions of making the plunger end flush with the adjuster bolt.
The longer 60mm screw gets the 2mm thick copper washer, the shorter 59mm screw gets the 3mm thick rubber/metal washer. If you mismatch the parts, you'll get one of these two conditions .....
You won't be able to set the cam chain tension following the manual instructions of making the plunger end flush with the adjuster bolt.
Alright so I have The 60 mm, so you are right I should have the small copper washer. I think I was Excited to think I found The issue. But it does look like somebody at one point had the washer on the wrong side of the spring because there is an indent ion that is about the exact size of the plunger. So not sure if the cam chain was just super stretched out by it being way to tight or what. But I also Ordered a new timing chain and both guides. And I’m working on removing my valves to clean, but everything looks pretty solid there. I do Have a bit of a gouge looking spot in my camshaft. Not sure if it’s a big deal or not, since the contact patch is so big I’m assuming the rocker arm wouldn’t even have an issue with it, unless it was raised but the rocker arm shows no funny wear.
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That indent on one side of the copper washer is normal, I see it on all of them. That "ding" in the cam lobe probably won't cause any issues. It's on a low section of the lobe, not the high part that pushes the rocker arm open. Just make sure it doesn't have any raised edges.
Alright thanks. It isn't raised as far as i can tell.
The cam has taken a massive hit it is surface hardened and it can perhaps been a threaded screw or so by the looks of it
I would look at the other side . and look for a small screw somewhere for damage.
And the cam bearings I have had going out
I replace them
The sound can be as mentioned excessive play small end conrod
Valve stem play those have tight tolerances stock
A picture of pistons skirts can give an indication ( if they are out )
I would look at the other side . and look for a small screw somewhere for damage.
And the cam bearings I have had going out
I replace them
The sound can be as mentioned excessive play small end conrod
Valve stem play those have tight tolerances stock
A picture of pistons skirts can give an indication ( if they are out )
