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Discussion in 'Thumpers' started by crobox, Dec 27, 2012.
Is this Ron DT?
yeah, ron here. lets ride!
Hey Ron- good to see you on here! No big surprise, really.
Well it'll be a little while before I'm ready to go for a ride. I've sold 3 bikes in the last year, two of which were runners. And this bike is currently the closest thing I've got to a runner... so like I said it will be a little while. But when this bike is done, anyone reading this thread will know it!
See you around
When I picked up my head from my buddy who did the valves we talked a bit about "gasket matching" and other ways to reduce turbulence in the intake and exhaust passages.
Here is how the intake passages matched up to the insulating spacer before I did any work:
And after some die grinder and dremel work:
I know it looks like the inside surfaces are all full of grinding marks, but they are from a pretty fine sanding drum and are quite smooth to the touch.
I did similar smoothing work on the exhausts, although I didn't do any diameter enlarging on those the way I did on the intakes.
And after re-assembling and bolting down the head and cam, putting the crank at TDC, and pulling the forward side (the "pull" side) of the cam chain taught, I found this:
You can see that the witness marks on the sprocket do not align with the gasket mating surface. I'm pretty sure this means the cam chain is stretched. I posted this pic in the main XL600 thread for feedback, and I'm including it here just for continuity.
How about rotating the engine to see if in fact there are the three cam marks.
The surface of your intake ports should not be smooth anyway , but you should polish the exhaust ports.
I received the 3/4" x .120 wall stainless tubing in the mail yesterday, and made some progress today on the rack / pannier mount system.
Here is what it looks like now:
The larger diameter (3/4") tubing coming out towards the sides of the bike will be one of the main supports for the panniers. This tube is supported pretty directly by the rear-most mount points of the frame (which you can see I beefed up earlier with triangulation in the sub-frame), so most of the weight on the rear rack, and much of the weight of the panniers, will go straight down into these points. There will be two other points of attachment to the bike as well. You can also see the diagonal tubing that I added, which goes from the very rear of the top rack down into this same area just discussed, the mount-points at the rear of the bike frame. I made a provision to run the turn signal wires within these diagonal tubes, which you can see mocked up (the green and orange wires disappearing into the tube). Purpose-specific tabs on the rear rack carry not only the turn signals, but also the rear fender.
Yep, I'm gonna do that is soon as this guy lets me!
nope. No third mark.
Looks like you will be purchasing a new cam chain.
I put a cam chain in mine at 40K, and the marks still didn't line up perfectly. I wasn't too concerned since they rarely line up perfect on any bike or car I have worked on. It ran fine, and was much quieter.
Hmmm... conflicting opinions.... what to do? what to do?
I'll take Sunday to think it over.
Seems wise to replace it. But saving money and time is always attractive.
Simply writing that last line makes me think I'll end up replacing it....
I'll add my .02.
I rebuilt two XR5 RFVC engines not too long ago. One 83 and one 84. One was running and needed freshening up because it consumed some oil, the other was literally a parts bike with the engine in pieces, along with another 84 parts bike (enough parts to build the second bike).
First, the cam sprocket for these old RFVC only had two marks on them, like yours. I think the extra alignment mark came later.
When putting the top ends back on after the valve replacement, I tried to use the cam chains that I had on hand. All three of the used cam chains showed stretching just like yours.
I decided that I was only going to do the rebuild job one time (famous last words, I know ) so I bought two new chains from XRsOnly.
Both new chains lined up the marks perfectly upon installation.
The bikes do perform well after the rebuilds, which is what I was after.
I reckon a good doctor would be able to do something about those feet!!!
Excellent build thread.
I am going with the consensus, and my gut.... I just ordered a cam chain from XRs Only.
I was excited to get the engine back into the frame soon, but I have plenty of other work to keep me busy on the bike till the chain arrives.
I found a few minutes to sneak to the shop and, knowing that I'm gonna replace the timing chain this coming week, I decided to pop off the clutch-side cover. Everything looked pretty good except for this:
That's the little tube which is, I think, one of two outlets from the oil pump. It obviously went in crooked during the last assembly of the engine (whenever that was...). The sort of amazing thing is that the seal between the cover and the pump was apparently good. All components in the cam and valve area, as previously noted, are in very good condition, so oil was definitely getting up there.
I am particularly nervous about this area... the way that the oil pump outflow goes into the side cover. When I was 19 or 20 years old, I replaced the clutch on my first XL600R (see page 1 for pix) and managed to forget an O-ring during reassembly. My head got fried in short order and I had to have an expensive repair done at Golden Gate Cycles (way back when it was on Van Ness).
For all you who have done this before... once I correct the little aluminum tube problem and replace the associated O-ring, does everything else here look to be in order? The larger hole in the background slightly to the right mates up with the other, larger output of the oil pump, but there does not seem to be a replaceable O-ring or other type of seal there... there is a seal there held in place by a circlip, but there's definitely no replacement for it in my "full engine rebuild gasket and seal kit". Anything I need to know? I don't want to make the same costly mistake again....
The seal behind the circlip in the picture is the passage for oil to the crankshaft. It is a seal since it mates to the rotating crank. If it is soft and pliable and not torn, it is still usable. Seals are cheap though, and if you are ordering the o-ring anyway....