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one year anniversary, bead blasting, inspection and frame


By superwesman - Posted on 15 April 2011

This post will be a little retrospective.  On April 6th 2010, I bought my first motorcycle, which I am now rebuilding.

In my first post on this rebuild, I mentioned that with "lots of luck and perseverance, by April 6th 2011 Claudia will unrecognizable as the bike I bought earlier this year."  While that is certainly true, my intention was to define April 6th as my deadline.  I'm not even halfway finished at this point, but I've learned a lot and I really am making progress.

I haven't posted a lot here, but I've been pretty busy with this project.  I stripped down my frame a bit more.  I've got all the electrics and dials off the front and the handlebars are removed.  I put on my clubmans to mess with the rearset positioning, but I didn't get very far.

I went through the factory service manual and inspected every engine component that I could with the tools I have.  My cylinders are in good shape and don't need to be bored out.  I ordered a set of piston rings as well as a chain/sprocket/sprocket set.  Unfortunately, I bought an o-ring chain which is more expensive and, though it will fit, running it will allegedly damage the bike!  Fortunately, someone posted something about it on the honda twins forum and I happened to see it.  I talked to the ebay seller (sledpartsguy) and he was cool about letting me swap out the chain for a non-o-ring version.  Consider yourself educated!

I measured the diamater of my camshaft lobes and found them to be about 1/10th of an inch larger than what the FSM lists.  I came to learn that the earlier models had a different cam with a smaller diameter.  Apparently, Honda never updated the service manuals.  I have one manual from 1969 and another that is from 1972 or 1973 - because it has information about the disk brake on the G model - and both list the same cam diameter.  The manuals have a wear limit of about 1.45" and the diameter of my lobes are about 1.56".  Consider yourself educated!

I got some more bad news while I was in here.  My rocker arms are all in bad shape.  Some are really bad.

I found a dude in Indiana who is going to set me up with a new set and some other parts that I need.  I may also need new tachometer and points housings because mine both have these strange wear marks on the top.  I assume that all of this carnage is caused by the cam chain tensioner issue.

I'm not sure whether these need to be replaced.  I'm going to pose the question on the forum to get a consensus.  

The only other engine parts that look questionable are my shift forks.  

I've got a set of these in my parts engine, so I should be use those if I decide to replace these.  A few of the ears are close to the wear limit and are a bit rounded.  These ones have markings on them - a 3 and a symbol that looks like pacman.  The ones from the parts engine do not.  

I had trouble with my dial gauge while checking out my crankshaft.  The problem is that the crankshaft kept moving while I was rotating it to check for out of round.  I measured it the best I could but I don't have much faith in my numbers.  Another problem arose because I bought a bore gauge with a range of 2"-6".  There are several smaller bores that need to be measured so I'll be picking up a cheap set of telescoping bore gauges that don't have dials.  That is what I should have bought in the first place.  

I picked up my engine cases from the bead blaster this week.

before after

They look great and my next step is to paint and polish them.  I'm going to have to wait for the weather to get a little warmer in order to do any painting, so I'll focus on polishing first.

There is some nasty looking stuff that might be metal bits inside some of the cases.  You can see a few here in the clutch cover.

I took a tip from my friend and put it all through the dishwasher to clean out the slude and ensure that there are no glass bead remnants left inside.

I ran them through 4 times, each time using less soap.  The cylinders and a few other smaller steel pieces flash rusted.  I'm going to clean them off tonight and spray them with WD40 to keep them from doing it again.  

I got a free K4 frame from a guy in Milwaukee!  

My engine is a K4 and the frame It had when I bought it was from a G model with a front disc brake.  The guy in Indiana is going to set me up with an earlier front-end too because I don't like the rubber boots on the later model forks.  I'm also going to ditch the front disk brake because I like the aesthetics of the drum brakes and I like not having the master cylinder on the handlebar.  Yes, I know that this is a functional downgrade.  Drum brakes work and it's my bike and I can do what I want.

I also managed to get the cam chain tensioner bits from my parts engine.  It was really difficult.  I ended up wailing on the pistons with a hammer until the cylinder block started to rise up.  I didn't actually get the pistons all the way out of the cylinders, but I opened it up enough that I could slide out the pieces I want.

I picked up some lapping compound and a tool for spinning them and I'll lap the valves and do a leak-down test tomorrow.

I wasn't kidding when I said I was busy!