So I finally got my head and cylinders back from my engine guy and I'm ready to put everything back together.  The bike has been sitting since the winter, and I'm jonesing hard to get back on it.

I got new valve springs and my guy installed and fit the valves to the head, I personally cleaned the valves up, did a port polish job, and machined the gasket surface, my guy honed my cylinders, I got new rings, I cleaned off the pistons, I have all the gaskets I need, I have a new 17 tooth front sprocket, I have a printed off copy of the service manual, and I have a lot of tools.

Now, is there ANYTHING I might need to know before I start work on this?  Any suggestions or recommendations or anything to look out for?


I'm extremely excited and I don't want to forget something crucial in my hurry to git 'r done.

Please other guys chime in on this and add more advice.
Dunno what happened to your bike Watcher, but a couple of things I'd want to do as follows:

1: Remove the sump cover and oil strainer (substitute good socket head screws for the crumby allen screws when you reassemble the strainer).
Before you reassemble, pour copious amounts of kerosine down through the crankcases to clear out any debris that might be in there. Then blow out with compressed air and wipe with rags. You just want to make sure there's NO crap left in the crankcases from possible previous damage, -flushing out the cases may mitigate any potential disasters later.
(The design of the cylinder / bolts makes it virtually impossible to stop debris falling down into the crancase when you pull the cylinders off so a flush is a good idea).

2: Check or replace the camchain and tensioner. Knowing what I know now (once bitten, twice shy!) I'd probably just buy and fit a new tensioner and camchain. Not a lot of money, but you'd know that it could potentially save you a wrecked engine. You don't need to split the crankcase to replace the camchain, just beg, borrow, steal the right chainbreaker tool, break the old chain, link it to the new chain, pull it through carefully, disconnect the old chain and assemble the spring-clip. (Ooooh and do make sure the camchain tunnel is filled with rags so when the spring clip pings out it doesn't drop down and lodge between a rod and crank or something!!!

I don't have anything really useful to add. Except maybe follow the service manual to the letter, and take your time.

A Motion Pro chain rivet tool has attachments to do a cam chain as well.

Ummm .. Make sure one section is done with no leftover bits before adding the next section? .... 'Measure twice cut once' ideology!?

Piston rings are VERY brittle , be very carefully and slow when putting them on or else they break.
Re the cam chain, it's probably the best oiled part of a bike, so it wears slowly, I would think of replacing only if the engine is older/ higher km/ been abused.
Make sure you have a torque wrench.
Careful with the crank sealant, not too much to not block oil passages, and do make sure all passages are cleaned out before you start. Don't get too excited when done, break the engine in gently (gentle acceleration and lots of engine braking) checking compression a couple of times along the way.
Most of all have fun!!!  It's a great little engine to work on.


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In regards to the cam chain, one of the reasons why this build is so exciting for me and has taken so long to do is that I've been virtually unemployed for the last few months.  Buying a new cam chain to play it safe is kind of out of the question as even a $50 chain would take me an unknown length of time to buy...

Is there a way to check if its in spec?  The bike says it has about 30k on the clock, but I have reason to believe its not accurate.
Previous owner claimed engine rebuild, and while some parts looked basically new there was a lot of evidence of burnt oil (it didn't burn much oil for me, I never had to top off the crankcase between changes), and the bike itself has some minor structural damage which makes me think it was a crashed bike.  The engine could have 30k, it could have 100k, I don't know.
All I know is the valve springs were weak, that's what prompted the rebuild.

From shop manual:

Fantastic, thanks so much!

Cam chain was in spec, engine went together smoothly, engine went into the bike smoothly, engine fired up on the first attempt, about the fifth time around!

Revs much better than it did before the build, didn't take it on the road yet since its uninsured at the moment but I ran it at a high idle for about 20min to heat it up and get the juices going.  So far so good!

I was so relieved when it fired right away, JackDaniels was had all around in celebration!  Even the bike got some!

Congratulations!


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