Honda XL600R - The Covid Year

The current lockdown situation has encouraged me to make a start on rebuilding the engine of my 1984/5 Honda XL600R. I thought, if you’re bored, you might like to join me for some entertainment

Why the rebuild? Two or three years ago the top-end (and more) destroyed itself when one of the cam sprocket bolts backed out until it could back out no more. At that point, everything that should be moving came to a very sudden stop.

Not long afterwards, I stripped the engine right down to assess the damage and track down the parts needed. It’s only now that I’ve ‘picked up the ball’. Here’s the damage...

Toasted camshaft. That’s not going to polish out

The egg shape and stress cracks in the cam sprocket are the least of the problems, because -

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It’s trying to be a banana too

Bent exhaust valves

Modified clutch drive sprocket

...and clutch basket!

I think I’ve now got most of the parts to rebuild it, I’ve just found the last pieces (hopefully) - a secondhand clutch and clutch drive gear.

Getting decent parts is the main issue for these bikes. Consumables are available, but apparently camshafts and clutch baskets are not considered ‘consumables’.

Stay tuned!

Quote from flyfifer

There is one good thing ---- you can definitely see which bits are out of specification.

The stuff Craig used to fix Jennifer's bike probably won't do it !

?

Of course, I do have some JB Weld and an old file

‘Out of specification’... I like that!

Quote from outrunner

Jim, try Ebay Germany as I found a lot of stuff there for my Kawasaki rebuild and some bits for the XBR 500.

Andy.

Cheers Andy, I got quite a few bits from German and French eBay and from the USA when I originally built it in 2012/3 - all very useful. I’ve made good use of CMSNL also - particularly their parts diagrams giving Honda part numbers.

Fortunately, I was able to find the bits in the UK this time, saving on postage. I think/hope I now have everything I need

By way of further reading, if you’re interested, here’s a link to the original build thread over on ADVrider.com - Yet Another XL600R Project

Now the damage has been inspected, it’s time to start building.

First clean up the crankcases, mask ‘em off and spray on some satin VHT paint. The Rayburn comes in handy for a couple of baking cycles to harden off the paint.

Then it’s in with the bearings, crank and balancer shaft...

Followed by the gearbox, selector forks and drum...

A quick check to make sure nothing’s been left out and bolt up the cases. There’s something strangely satisfying about new gaskets and oil seals!

On goes the giant piston (with new circlips)...

...and then the barrel, freshly honed and with a nice coat of VHT satin

These engines only go back in the frame with the top end and cam cover on (the next job) but I’m going to leave as much as possible out of the side cases, just to make the engine a little easier to manhandle. I can put the alternator, clutch, oil pump, kickstart mechanism, etc. in after the engine’s back in the frame.

PS. The replacement clutch and drive pinion arrived by courier today

Head’s Up!

First, here’s the replacement cylinder head -

Next, remove and lap in the valves (brand new camshaft in the background )

I thought I should give it a good clean up and a coat of VHT satin to match the rest of the engine. Not sure how long it’ll last on the head, we’ll see!

Beer o’clock and it’s back in with the valves...

Then it’s on with the camchain and guides, drive gears and cylinder head, torque it down and we’re done for the night

Next... cam chain tensioner, camshaft, cam timing, cam cover and setting the valve clearances.

Now the head's on it's time to put in that brand new cam, and MAKE SURE THOSE TWO CAM SPROCKET BOLTS ARE TORQUED DOWN CORRECTLY AND LOCTITED!!!

Nice!

(Note to self... Next time read the workshop manual. It would have been easier if you'd installed the camchain tensioner before putting the cylinder head on.)

I’m short of the 8 x 20mm locating dowels, but that hasn't stopped me cleaning up the replacement cam cover and cam followers.

The followers are a more complex arrangement than usual because of the radial valve layout. You can sort of see how the arrangement works here - each cam-follower has a sub-rocker so the angle of pressure on the valve is directly parallel to the valve stem, thus preventing any lateral forces and subsequent wear on the valve tip.

I believe Rudge-Whitworth were first to create a mass produced radial valve motorcycle engine sometime in the 1920's and it's been played with by various manufacturers but mainly in prototypes or limited production race engines. The idea is to create a better shape for the combustion chamber, improving gas flow. How much difference it makes I don't know, but I guess it plays a part in making the XL600R the most powerful XL/XR series 600cc engine Honda ever made, producing a heady 44 bhp.

Cheers Steve, I’m really enjoying myself with this build, and you’re right... it’s going together almost like I’ve done it before

I’m just waiting for the locating dowels now, so I’m going to make a start on the rolling chassis. I pressure washed it today before I start stripping it down for refurb.

At this stage I’m not sure exactly how much I’ll do to it. My intention was to refresh the paint job which is a bit tatty in places, but I’m finding it impossible to get hold of the right paint (Honda Rio Red) in rattle cans at the moment. I guess there’s no rush though

Hopefully the thread is providing some entertainment for a few folk which is just as valuable as getting it back up and running

While I’m waiting for the locating dowels I thought I might as well take a look at the rolling chassis. My intention is to refinish it but getting hold of the red paint is a real problem at the moment.

First, roll out the rolling chassis (I’d already removed the tank, seat and side panels) -





And then the long laborious task of stripping off all the bits and pieces - less than an hour’s leisurely time investment saw it down to this...





You’ve got to love these old trail bikes, there’s nowt to ‘em.

The paint on the frame is chipped in a few places (understatement) and has also developed a serious bloom in visible places. While I’m building the bike to use, I might as well make it look half decent while it’s torn down so I’m not exactly sure what to do now.

I’d prefer to finish it in the same red again (Honda Rio Red), but as I said earlier, getting paint is problematical due to the current lockdown. If I redo the frame in black it’s a far easier proposition but I don’t think the red tank and plastics will look right then. But there’s no rush, I’ll give the frame a more detailed inspection and make a decision later.

Any thoughts gentlemen? Hold out for Rio Red or go Black with White tank and plastics or another colour entirely?

Aye up John, good to hear from you.

It’s a nice idea but I daren’t have it blasted. It’s an oil-in-frame bike, so Sods Law dictates that some blast media would find it’s way from there into the engine! I’m not going to risk it

On the plus side, I’m going to spray the swingarm today and found a surprise item I’d forgotten about . I’ve also tracked down some Rio Red paint at last so it looks like it’ll be staying red .

There's an Otis Redding song, 'These Arms of Mine'... Now I don't know if Otis was singing about his XL600R swingarm, but I thought I might as well inspect 'these arms of mine', give them a clean up, re grease the bearings and so forth. First job, strip off the chain guard, etc.

Leaving me with this.



Not in bad shape but, since I had some silver paint in the workshop and the weather's been so good, I thought I might as well take the opportunity to freshen it up. First order of the day? Key the surface, de-grease and give it the Rayburn 'overnight warm up' treatment.



Followed by a few coats of finest rattle-can silver.



I always find the hardest bit about painting motorcycle bits is not to rush the job. Fortunately, lockdown means I'm in no hurry so I've made a point of going easy with the application of paint. I left the arm to harden off on top of the stove for a couple of days before lacquering and I'm really glad I did, because while rooting around in my XL bits and bobs I found an envelope that contained a couple of Pro-Link sticker I must've bought first time round. Nice surprise!

And, here's the final result! It's got half a dozen coats of lacquer on it and I'm calling it done. As usual with these things, photos flatter the finish but it's not half bad in real life! I'm really pleased with the result.





Making the most weather that's ideal for spraying I decided I might as well refinish the fuel tank too. Again, this wasn't in too bad a shape to start with, but first time round I made a mistake with paint compatibility and one side of the tank had an orange peel finish. I didn't strip the tank this time, but sanded it down flattish and gave it a full can of petrol-resistalacquer - lots of thin coats. I'll leave it for a couple of weeks to properly harden off, give it a flatting with 2000 grit wet and dry, then T-Cut for the final finish. Again, not perfect, but I'm really pleased with the result so far!





Still no sign of the locating dowels I've ordered, but on the plus side I have tracked down a supply of Rio Red (R-63) aerosol paint for the frame. I'll be ordering a couple of cans on Monday.

TTFN. JRT!