Pulled my drain plug and oil strainer cover today to find the dreaded cam chain guide bits. When replacing the guide, does it also make sense to replace the chain as well since I'm already in there?
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Cam Chain Guide
- Thread starter NP2650
- Start date
Yes... absolutely. Might as well do a full top end refresh while it's apart.
Yes it does. If the bike has anywhere near 20K on it, I replace the chain. Even if the mileage is less, I'll often replace it if it's stretched much. The chains can and do last much longer if properly cared for (kept correctly adjusted) but most haven't been.
Top end overhaul. Valves relapped or recut as required, guides as required, new rings... pistons if needed. Just generally inspect and mic everything, then replace what's not up to spec.
You gotta pull the engine and remove the top end. Might as well go all in. There's a top end rebuild thread in the Tech section. I hear tell it's fairly well done.
https://www.xs650.com/threads/xs650-top-end-buildup.52041/
You gotta pull the engine and remove the top end. Might as well go all in. There's a top end rebuild thread in the Tech section. I hear tell it's fairly well done.
https://www.xs650.com/threads/xs650-top-end-buildup.52041/
What Jim is saying is since the head has to come off other things can and possibly need to be done. Post pics as you go, ask questions and the members will help make things as painless and economical as possible.
Yes, it's quite a bit of work getting into one of these what with having to pull the motor, so you might as well fix all that needs fixing while you're in there.
Thanks gentlemen. I assumed as much, but I was hoping that just maybe it might be less involved. With less than 10K on the bike, I might wind up replacing some serviceable parts, but getting in there is most of the work anyway. I've rebuilt a number of engines, most car and truck engines, but it's always a bit daunting the first time around on a different type of engine until you learn all the tricks/pitfalls. I did rebuild an XS750 engine with a bad shift drum, but that was close to 40 years ago. I checked out the top end rebuild thread in the Tech section, and will be a great help, but I'm sure I'll still have plenty of questions. First step is to find or build an engine stand from the plans in the Tech section.
Well, with less than 10K miles, you may get away with not replacing much. Of all the motors I've been into, there was one that didn't need rings (end gaps were still in spec). All the rest needed at least rings, some needed an over-bore. But we're talking 20K+ motors here. For sure you'll want to replace the front cam chain guide. They're routinely failing now due to age, not mileage. Also the valve guide seals, again an age thing. For the cam chain, remove (or fully loosen) the tensioner and see how much slack the chain has. How much can you lift it off the top of the cam sprocket? Make a decision based on that.
Yes, do build the simple angle iron engine stand, it's so much nicer and better than those bent plate types TC Bros and others sell. They are absolute junk (ill fitting and hard to install). I know because someone gave me one and I tried it. Boy am I glad I didn't pay for the thing, what a waste of money, lol.
I make my stands in 2 "flavors" .....
The slightly larger one on the left, with the front and back angles extended out a little bit, I call the "traveler". It's a little more stable so is better for transporting a motor in the back of a pick-up or van. Also, I now cut down the angle at the tops of the uprights more so it's easier to get at the bolts and install/remove them .....
I make my stands in 2 "flavors" .....
The slightly larger one on the left, with the front and back angles extended out a little bit, I call the "traveler". It's a little more stable so is better for transporting a motor in the back of a pick-up or van. Also, I now cut down the angle at the tops of the uprights more so it's easier to get at the bolts and install/remove them .....
As engines go, the XS is relatively easy to rebuild. With the experience you stated, it should easily be in your wheelhouse.
Fwiw, I wrote that top end thread for someone who never took any engine apart. He managed it just fine and that engine soldiers on to this day.
Looks like I caught this situation just in time. The "plastic" part of the guide had come completely off the aluminum and was down in the crankcase. There is some wear on the tensioner (picture). I would just replace it, but OEM is no longer available and I wonder about the quality of the aftermarket ones. Any suggestions; just leave it or replace with aftermarket?
Gary hoos hoos racing, many satisfied users here.
http://www.hoosracing.com/650productpictures.html
down a bit on the left.
http://www.hoosracing.com/650productpictures.html
down a bit on the left.
I have four thousand miles on the Hoos guide. Happy happy.
jpdevol
Hacker of Frames,Wires and other things
I'd run the existing stock tensioner - pic shows slight wear and I'd be suspicious of Mike's/Yambits/ Heiden tensioner quality too (got a couple rebuilt 20k engines with originals in them)
I already bought the cam chain guide from Gary, but was asking about also replacing the tensioner.
Yes tensioner issues/ failures very rare, especially if cam chain tension is kept set correctly.
Yes, your rear tensioner looks fine. They all get those grooves in them but as mentioned, they don't fail like the front ones.
Sometimes you never know what you're going to find. While pulling the head, I noticed that two of the valves, one exhaust and one intake, each had a little buggered area on the side. I also saw that someone had installed thread inserts in the plug holes. Today while dropping off parts at the machine shop they informed me that two of my valves, the buggered ones, were also slightly bent. Looking at things we surmised that whoever installed the thread inserts had run the tap in so far that it hit the valves that were open at the time! Dang, I wonder how much force they had to use to keep cranking on that tap enough to bend valves? Looks like I'm in for a fresh set of valves.
I've said it before and I'll say it again...some people should never go near tools!
Sins & tales of previous owners...ugh.
