classic motorcycle forum

Assemble the boxes and see which one works, or look at the assembly drawing/gear positions and see?

Re new pushrods, couldn't you do that old trick of repurposing rods from another engine? Shorten and refix ends as required?
At least you'd know that the material was good for the purpose.

It's a possibility to look into.

Had a nice video call with the Guru yesterday, and learnt a few more useful things. 

Like: when checking the backlash it's best to do this with the timing chest cover fitted and nipped up! 
So - I did that, and:



I'd say that's as close to 1 degree as you're going to get!

The backlash between the timing pinion and camshaft is fine!  We had a conversation about the various options for the timing pinion - they were made with allowances for the backlash (-6, standard, +6, +12, etc, he's seen a -20!) and mine is a -6.  He initially recommended going up to a "standard" if I could find one, but after rechecking (properly!), it's all good, which is a bit of a relief because these things are just not made any more! If I was to find a 2nd hand one, I'd have no idea how worn it might be (which is the same issue with pretty much all the parts for these engines).

I'm also going to make sure that when I'm doing the valve-timing from now on I'm going to have the timing chest cover fitted and nipped up to ensure things don't have too much play: it makes more of a difference than I realised!


Obviously the guru does this so often, he actually has a cut-down cover with the timing pinion exposed so he can adjust it without removing the cover! Very handy, but massively overkill for me, once I've done this and got it as best I can, it won't be getting changed again.  The ignition timing on the other hand....

The guru reminded me of something else: the "critical" valve timing to get right is the Inlet Opening position.  Get that right and everything else will follow : the cams and cam-shaft and gear are all one solid piece, so if it's right in one place, it can't be "wrong" anywhere else, so I'll work off that principle.

We also discussed the bent push-rods, it's just something that happens - they're tubes, not solid.  I need to find some replacements, and we discussed sources. 
This is the worst one: Dial at 0

Dial showing the runout:


FYI: that's the crappy dial, I've discovered that the needle is a little loose and will wander over time. ffs.  It's ok for one-off measurements though.

The other rod isn't as bad, but best to replace the pair while I'm here:




He told me that apparantly one of the main suppliers tried to sell ally push-rod tubes a while back, which wasn't a good idea as they all bent!  The people who'd bought them were (understandably) pretty pissed off and complained bitterly, but he doesn't know if the company still sells them, or what they're made of: I shall investigate!

The current preferred material for race engines, running full power, is chro-moly tubing, but he reckons that I will be fine with regular steel tubing: I need to take the ends off my current rods (the ends are soldered on), and check the wall thickness, then go find some steel tubing of similar (or thicker) wall and see about making some up; well; presuming I can't find some ready made replacements somewhere else.

hey ho... do a job, make a job (as my ex used to say...)


Oh yeah - I also discovered last night that the classic bike track-day that I was sort of attempting to have the bike ready for has been moved to June or July, from May: so that "deadline" is no longer looming as heavily, phew.  What with the discovery of the fork and gearbox leaks I was thinking it wasn't going to be ready, now I still have a vague chance if I still want to aim for it.

Those different tappet settings  when doing the valve timing is a Velocette foible too.
I assume (though I've never given it much thought) that it stops the valve spring operation from affecting the valve timing measurements.
Incidentally, when I was fannying around with the valve timing on my Venom (the timing marks were wrong- another long story) someone more experienced than me said to set the valve timing up just rocking at TDC on the exhaust stroke as a good start, and he was right. It was as near as..
Clearly not satisfactory on a Honda, but for something designed in the 1930s it was OK.

So - I got into the workshop for a lengthy session on Saturday... lots of photos!

First I turned the piston around... :roll:  The gudgeon pins are getting a little easier, but they're still gits to get into place properly.

Then confirmed that the ring gaps were in the right places:




Fitted the ring clamp


Then I fed some oil into the output side main bearing, to make sure it has some. Mainly because I still don't really see how oil gets into that tiny hole... just from splashing up??


I'd decided to use the RTV for the base gasket this time. (Once I'd cleared the dried out stuff in the nozzle.)


It's a lot more controllable than the 3Bond.


I put a layer on the top of the gasket too, once I'd got it in place over the piston.  I managed to not get too much goo in places it shouldn't be!


Cylinder back on. Wasn't too hard this time.


Prepped the head gasket again - both sides this time. Note to self... that mat is NOT fully heatproof... (I'm sure I took a picture of the somewhat heated newspaper the mat was sitting on...)


Before dunking it.


I wanted to redo the head gasket mainly because I'd only heated it up on one side previously and I didn't think it had "taken" properly.

Head gasket in place.



Once I'd spun the head rods up into the head I put the whole thing into the vice again to get things tight.


Fitted the timing wheel - mainly because it give me a decent grip for rotating the thing. (and marked a reminder....)


Stuck the tell-tale into the plug hole:


Fitted the lower valve covers.


Fitted the push rod guide fittings. (Only using the adjustable because they're rather large...)


Valve caps.


Fitted the rocker box


These two oil feed nuts are an absolute !"£%^% to get tight because you can't get a spanner on them.
I eventually (more later) managed to get them as tight as possible, but they need to be loose AS you fit the box in order to get the pipes into the feed holes in the head that feed the valve guides. I may need to find a split spanner or something to get them done up properly. (I'm also tempted to replace them because they're completly knackered).  I had the box on and off about 3 times trying to figure out how to fit the thing properly.


This is the point where I realised that the thread in the rocker box for the hole that holds the valve cover was $%^&&ed.


So the rocker box came off again!


I then spent quite a while trying to find larger screws that would be appropriate. I initially had the plan to drill out the hole to a larger diameter, then thread for a bigger screw.
After I'd started finding screws and had dug out some taps...
I realised that I should figure out what the original thread was...
It's a 1/4 BSF. 
And I've got a thread repair kit for that!

So I dug it out, drilled the hole out and tapped it for the repair:




All good!


Still got plenty of inserts left, but hopefully I won't need many more!


I also shortened the bolt that was in use slightly (it's not a match with the rest of the bolts in use here)


Always round off the end...


And, even though I'd spun the nuts back off the bolt to clear the thread ends, I also span a die down the bolt too.


Now it's a matching length


Test fitting


So - time to start on this side of things....


Cam followers going in.


Timing pinion and cam-shaft into the chest.


Push rods in. Bit of a git to get in tbh, the exhaust especially, the camshaft has to come out to get the pushrod in between the rocker and follower.



aaaaand that's where Saturday's fun ended.  I needed to do some reading to remind myself of the process for timing the valves.  This is, again, where my existing knowledge is completely lacking, I've never done this before, but I'm very aware of the risks involved in getting it wrong!