Sharp tapping in upper cylinder/head, brassy oil. help

[Greenbush]

Hello guys. I'm working on a friends 79 XS650. Unfortunately the previous bike builders lost
My buddy's shop book. Tryin to locate.
Here is the deal, when it's running it has a sharp metal tapping noise that seems to come from the middle of the cylinders but seems in the lower part of the head.
I drained oil and it swirly with brass flakes, like black
metallic paint..yikes.
So, I have the clutch plates out, cam chain tensioner unit out, tappet covers off and oil filter housing
Off and when I rock the crank back and forth I hear it. It's almost as if the cam srocket is loose. I'm a bit freaked by all the brass in the oil. The oil and filters have been changed recently by previous techs.
There's no smoke coming out of the exhaust when running nor on the plugs. What bearings in these engines or brass? Figure valve sleeves but what else?
Any ideas? Besides taking head off, right now. Probably around corner.
Excuse typos. On my dummy phone.

 

[5twins]

The front cam chain guides on these motors are notorious for going bad. If the rubber strip on the guide falls off (and they do), your oil will have that metal flake appearance to it. The guide is aluminum though, not brass. The ticking could be caused by the rubber missing as well. Whatever it is, looks like the top end is gonna have to come apart. That's the only way you'll find out for sure what's wrong.

 

[Greenbush]

5twins, this is what I was thinking. I cleaned up and put the tensioner back in. When I was testing it for adjustment the tension rod would pop out of the tension bolt in a snapping motion. But now that I've removed, cleaned and replaced the tensioner, that snapping return on the tension rod has gone away. And the tapping noise that I heard when rocking the crank has quieted a lot.
Figured this bike would need a new tensioner or guide pretty soon.
Thanks

 

[gggGary]

Aluminum bits in yellow oil will look like brass, the "sharp tap" is classic loose cam chain noise. I'm with the front guide is shot theory.

 

[yamaman]

Bottom end (ball bearing) and g/box are usualy pretty good on these (unless itss been flogged or very high miles). If your pistons and bores measure up, a new set of rings, valve seals, front cam chain guide and your going to have a pretty sound engine. Follow the great tips in the tech section fos top info on how to pull it out, down and back in again, no leaks and no hassles. Carbs often need attention, the carb guide will walk you through that. A 79 should have points, check the ATU is working well. That will just leave the dreaded electrics, pull, clean and dieletric grease all connectors, that can save a lot of grief later on. Lots of top info in the tech section, and lots of good help on the board, so doing one of these is a breeze. Cheers

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[gggGary]

Figured this bike would need a new tensioner or guide pretty soon.
Thanks

Gotta say this:
No, not "pretty soon", NOW. The XS650 engine has lots of nice big durable ball bearings in it, you are bathing them in metal contaminated oil.Also the gears, pistons, cylinders, cam etc. This is not a good thing. The XS just has screens not filters, some of that metal is circulating through the pressure oil system, cringe.

 

[Tomterrific]

Gary is correct, the brass you see in the oil is silver colored by the amber colored oil. Second cam guide also. A classic XS650 problem.

 

[Greenbush]

Gotta say this:
No, not "pretty soon", NOW. The XS650 engine has lots of nice big durable ball bearings in it, you are bathing them in metal contaminated oil.Also the gears, pistons, cylinders, cam etc. This is not a good thing. The XS just has screens not filters, some of that metal is circulating through the pressure oil system, cringe.

Gary, I know it needs it. But my buddy just spent near $4,600 on making it a damn good looking Evel Knievel lookin Street Tracker with some other short sighted bike builders that didn't make sure the engine was totally solid before making it PURDY. So, I gottah break it to him softly. He shoulda come to me with this build first or consulted me. Shit, I woulda done it for $3,000.
The clutch was slipping. This and carbs was what I was to clean up the build with. Holy crap, when I got the carbs all cleaned I noticed the slides were turned out of position on the diaphragms. LOL

Question, is it possible for the cam chain to jump off line on the front guide so that it's riding half in and half out, grinding the rail frame of the guide? I feel that since I removed the Tensioner unit( reached in and tickled it, along with rotating the engine a number of times or slightly rocking the crank to issolate the loose tapping sound) cleaning it and correctly reinstalling it and adjusting that the chain seems much quieter and nice and snug. Granted I've not started it again, but the noise I seemed to hear before is nearly gone when turning the engine(by hand) or rocking the crank.
Could it be that the chain jumped the channel on the front?
Also, what does everyone suggest flushing the engine to get the rest of the Flakey Flakes out?

 

[5twins]

I see lots of pretty bikes that basically run like shit, lol. The front guide is basically flat across, there's no channel for the chain to jump out of. Maybe the chain adjustment was just too loose. Start it up and see how it sounds now. Most of us set the chain adjustment while the bike is idling. That way you can hear when it's too loose (it rattles) and see when it's too tight (plunger stops moving in and out).

 

[Greenbush]

I see lots of pretty bikes that basically run like shit, lol. The front guide is basically flat across, there's no channel for the chain to jump out of. Maybe the chain adjustment was just too loose. Start it up and see how it sounds now. Most of us set the chain adjustment while the bike is idling. That way you can hear when it's too loose (it rattles) and see when it's too tight (plunger stops moving in and out).

LOOKS PURDY..........SITTING ON THE SIDE OF THE ROAD. LOL


Is it possible for someone to install the tensioner unit up side down? Causing the pin head to push on the wrong spot and not in the dimple?



Also, when I go to rotate the clutch basket it has a slight bit of play when rocking back and forth before it turns the engine. Thoughts?

 

[Belle]

Listen to this link it takes a few but it is the clearest quality I could find--

There is a sharp ringing out sound in that engine--its the 'saki flathead 2cycle but it makes that noise for a particular reason..the pistons are returning from the top of the cylinder...they are so close that any closer & they will break against it & KABLOOM. This engine sounds great.

If you look at your buds engine do you see good gaskets in all of the right places or do you see crap gasket crap, therefore, lowering the head onto the piston creating greater compression but putting the whole affair into a bit of detriment.

Also, have ya checked valve/rocker setting?

High compression is totally cool until it all gets too hot & KABLOOM

also, is the cam leashed down good & tight

 

[Greenbush]

I see lots of pretty bikes that basically run like shit, lol. The front guide is basically flat across, there's no channel for the chain to jump out of. Maybe the chain adjustment was just too loose. Start it up and see how it sounds now. Most of us set the chain adjustment while the bike is idling. That way you can hear when it's too loose (it rattles) and see when it's too tight (plunger stops moving in and out).

5twins- HELP!! I got a friggin issue with the clutch that killing me. The inner rubs on the case cover when disengaged. I pulled it apart three times and numerous times mocking a full assembly to see if it was rubbing. I double checked the matching marks aligned(good). Then I did find that the push rod was not all the way into the actuator on the left case. Thought that bought me the space. But NO. I started her up and as soon as I pulled in the clutch it starts scrapping the case. F to the U to the remaining two letters. Was tryin to get he buttoned up for a classic ride today for my buddy. I was up until 2AM chasing this. Following two different books.
FYI, engine is much quieter after playing with the cam chain tensioner. But looking to replace guides for sure.
Note, main basket is seated all the way in. Gear is lined up with crank gear and right up on the main case, so the issue is in the pressure plates assembly. Marks are lined up. HELP me oh Obewan, you're my only hope.

 

[5twins]

All I can think of is that maybe someone assembled the clutch basket incorrectly. There are a bunch of spacer washers and a flat bearing involved. Some of the washers go behind the outer hub, some and the bearing go between the outer and inner hub. There's a certain amount of washers and a certain order they go in. Maybe someone screwed that up or put an extra washer in there somewhere. An extra one would move the assembly out closer to the cover. Here's the proper assembly sequence .....

I found scrape marks on the inside of my cover the 1st time I took it off. Apparently someone in the past had done something similar to whatever was done to yours. It was OK when I got it so I don't know exactly what they did .....

 

[Greenbush]

Well, I took the whole thing out three times. Double and triple checked it. The main case is all the way in place for sure. Any further and the primary gear will hit the main case. So it's in the clutch assembly it's self. What years are there 6 plates and 7 plates? Also I did not notice any difference in the steel plates, is there supposed to be?

 

[5twins]

Early models up to about '73 had a 6 plate clutch. The plates were a half MM thicker (3.5mm) than the newer plates (3mm), that's why there were only 6 of them. A 7 plate unit was used up into '78 and '79. The exact change over point is unclear. The parts diagrams show the 7 plate unit in the Standard model, the 6 plate version in the Special. By '80, there were only Special models and 6 plate units.

Your bike falls in this "gray" change over time period. The only way to know for sure what you have is to inspect the inner basket. The later updated 6 plate unit has a spring-loaded steel plate in the bottom of it retained by a thin wire that fits into a slot cut into the outsides of the basket ribs or teeth. The older 7 plate basket has none of that and just holds a stack of plates.

The steel plates are all the same to the naked eye anyway. That "damper" plate used in the bottom of the later 6 plate unit however is slightly thicker than all the other steel plates (1.6mm vs 1.4mm).

Examine your inner basket. Maybe someone stuck an extra plate in there if it's a 6 plate unit. Did this clutch ever work right without rubbing or is this the 1st time you're starting the bike (so you don't know)?

 

[Greenbush]

Thanks. I ordered plates from Sudco. They said they get them from Vesrah. Are you sure 3.5mm are not available? These plates may be too thick.
The bike came to me with a slipping clutch, but not rubbing on the case cover. The plates I took out(fiber) didn't look that worn. I measured them, but my battery is dead on my slide, so I'm looking a the printed numbers.
There were 7 friction plates when I took it out. I checked them for warping on a 1/4" steel plate. There was no separation from the plate to plates. So, I put what metal plates back in that came out. I'm wondering if the Fibers I got are thicker. If they are 3.5mm then that would create 3.5mm too much mass in the clutch. Correct?
The only thing I can think of beside the possible 3.5mm plates is that the clutch boss is not going in as far as it should, pushing the whole plate grouping out. Question, when the boss slides in place, should the seat, where the two washers for the nut, sit past, flush or outside the threads on the primary shaft? Looking at the schematic on this tech image it seems that the boss sits past the threads. Mine stops just before the largest part of the shaft. About 2mm, a guess of memory.

I gotta check those washers again. Crap.
This is driving me bonkers. AND I GOT OTHER CHEET TO DO. GRRRR.
I dread having to take that cover and gasket off again. So much 1104 gasket mate after three times placing and replacing.
Thank you so much for lending your time to read and give input.

 

[5twins]

These clutches usually slip because the springs get weak, not because the plates are worn. I've never found a worn plate or replaced any but I always replace the springs. Yes, maybe they sent you plates that are too thick. Try the old ones. If you haven't changed springs, I suggest doing that. Get one of the good brand name sets from 650Central, not the no-name ones from Mikes.

 

[Greenbush]

I measured the springs and they were up to spec height. I think whom ever replaced the clutch before didn't line up the marks on the inner and outer plate racks. I do remember that I could slightly wiggle a couple fiber plates while the clutch was engaged.

 

[5twins]

My stock springs measured to spec as well, so did my stock fork springs. Both were no good, too weak. Springs can get weak without sacking. Take my word for it, new aftermarket springs and original plates (if in spec) is all you need. I've done this to every wet clutched Jap bike I've owned for the past 35 years or so. All those clutches slipped and this fixed them all.

 

[Greenbush]

Good point. Friggin plates from Sudco were $130 for 7. SH#T. I need to go get a battery for my vinyl slide so I can get a digital read out and remeasure the removed and new plates.