'81-Build Thread-The Handover

[littlebill31]

Ok, well here is a new thread showing my build.
This was another member's bike, RVA804.
Please refer to "One problem after another" thread to read some about how this unfolded.

Anyway, he bought the bike and worked on this uncomfortable hunk of metal for a while and couldn't get it running correctly or reliably.
So he did the best thing. He sold it. Sometimes that is the best idea and a fresh start is needed.

Unfortunately, the previous owner before RVA didn't do a lot of good work. Apparently he did a top end job, but after taking the engine apart it is obvious it was a shit job. The cam is in backwards, for one, so you can imagine what else was screwed up. He also spray painted the entire bike. Wiring, grips, carbs...everything. Crap!!

So here are some pics for now and updates to come.
Again, refer to "One problem after another" to catch up.

When I bought it..

 

[angus67]

This will be much easier to follow.
on the name

 

[littlebill31]

First pass at de-cabonizing...

 

[nj1639]

The versatility of these engines, in spite of the things you've come across.....cam reversal, front cam guide shot, leaky head gasket etc. it ran poorly but ran.

 

[MaxPete]

I'll be following littlebill!

Pete

 

[5twins]

That cleaned up nice and pretty easily I assume? Another thing the paint stripper is good for is gasket removal. Those bits of head gasket in the lower right of your pic? Apply a little stripper, let it soak 10 minutes or so, and they will come right off easily. This greatly reduces the possibility of damaging the sealing surface from aggressive scraping.

Some gaskets you're going to find really stuck are the ones on the points/advance housings. I think Yamaha used sealer on them. Coat the gasket with stripper and let soak for 10 minutes or so .....

Then scrape off what has softened. This will only get you part way through the gasket ......

Apply some more stripper, let soak, and most of the rest of the gasket should come off .....

A little more stripper on the remaining bits will take care of them.

 

[littlebill31]

Yes. The carbon came off pretty easily.

Points housing gasket? Whats that, lol. Someone must have forgotten that one, non existent on this engine.

Second application...

 

[TwoManyXS1Bs]

My old 25k miles sprocket looks like yours.
Doesn't work very well as an ashtray.
What can you do with those old/worn things?

 

[littlebill31]

This bike has 18K on the odometer and I have no idea what to do with the sprocket, lol.

 

[robinc]

What can you do with those old/worn things?

Drill some small holes inside the teeth and hang different lengths of 1/2" copper pipe with fishing line. A set of wind chimes for your wife!

 

[littlebill31]

Crusty and rusty.....

Is that caramel....

These are bone dry .....

 

[nj1639]

If you go with the tapered bearings as a replacement then do the interior neck notch, just in case those races ever have to come out. Yeah, smh.

 

[RVA804]

Damn! Looks a bit different now haha

 

[Mailman]

Awesome, looking forward to watching this one.

 

[littlebill31]

Ah, I see chocolate milk was used for the fork oil....

 

[littlebill31]

Both pistons look like this. They actually don't feel gouged. No feeling at all, just look like this.
Left is only intake side, right is both intake and exhaust.

 

[5twins]

Some minor scrape marks directly on the front and back of the piston skirts is what one normally finds. Can't say I've ever seen it off to the sides and higher up like that. That 3 digit number you found stamped on the piston tops (954) is the fractional portion of their size when they were new, as in 74.xxx mm. The bores were just over 75mm and the fractional portion of that should be stenciled on the side of the sleeve that hangs out of the bottom of the cylinder block. The factory new clearance spec is .050-.055mm so you should find something between 004 and 009 stenciled on them. If it's not in that range then my best guess is the guy who "rebuilt" it swapped in some different used pistons of a different size, one not matched to the bore.

 

[littlebill31]

Thanks!
007 is on the bore cylinder skirt.
I'm taking them tomorrow to get measured. I do hope they are within spec.

 

[fredintoon]

Drill some small holes inside the teeth and hang different lengths of 1/2" copper pipe with fishing line. A set of wind chimes for your wife!

Or dress up like a Ninja and throw it at an enemy.
What I did with the one off a VF750F my son bought despite my good advice was to hang it up in my garage as a horrible example.

 

[littlebill31]

I measured ring end gap

Both left and right are...
Top- .013
Middle- .016
(range is .008 - .040)

Oil ring- Didn't have a big enough feeler gauge, but .030 was starting to drag. (.060 is max)

Side gap was under .006 (which is max), but I didn't have my other set of gauges, so .006 was the smallest I had on hand.