'81-Build Thread-The Handover

[Mailman]

What is your procedure for removing the carbon? I would like to learn. It really cleaned up nice.

 

[littlebill31]

I used paint stripper per 5twins recommendation.
Works great.
Paint it on , wait 15 minutes and use a brass bristled brush and cloth to clean up with water. Them a light coat of oil.
Took 2 applications, but worked wonders.

 

[fredintoon]

Here's a way to clean off the black oil/grease/road dirt buildup from your exhausts.
Caustic oven cleaner gel.
Do NOT get this stuff on your skin, in your eyes or let it contact anything that's non-ferrous. It'll also bleach white patches in your blue jeans.
Soak 3 or 4 layers of paper towel with the gel.
Drape the towel over the black bits and let it fester for a quarter-hour or so.
Hose off, inspect, dry off & repeat if necessary

 

[littlebill31]

Went to 2 machine shops.
Both said the same thing.
Bore is 75.002
But the cylinder stencil states .007

Pistons are shot though, so Im going 1size over.

 

[5twins]

Well, that might explain the rub marks then. If you want the low priced pistons from Cruzinimage, you'll have to go .5mm over which is 2 sizes over. It's no big deal, it won't cost any more for a 2nd over-size bore compared to a 1st over-size. Many places will recommend going 2 over depending on the cylinder condition. 1 over may not be enough to clean up the bores and/or get them straight again.

 

[littlebill31]

He said the pistons were shrunk and, "Damn, didn't you hear all the knocking?" , lol.

I'll probably go for 2 over to be safe.

 

[littlebill31]

Base gasket.....

 

[MaxPete]

Yuk - what a mess littlebill!.

I hope you won't mind a small detour, but since we're on the subject of gaskets and engine clean-up, I do have a related question:

I tried to change the exhaust port gaskets on Lucille last summer but they were both stuck pretty hard so I just left them. Nonetheless, I do want new gaskets in there when I install the new pipes.

Anybody got a good suggestion for getting those stuck gaskets out?

Pete

 

[TwoManyXS1Bs]

Went to 2 machine shops.
Both said the same thing.
Bore is 75.002
But the cylinder stencil states .007

5 microns?
That's about right if your shops were 10°F colder than the Yamaha factory...

 

[littlebill31]

5 microns?
That's about right if your shops were 10°F colder than the Yamaha factory...

It was 62 degrees yesterday, but I'm sure I will never know what Yamaha was lol.

 

[littlebill31]

Forks....

 

[MaxPete]

Eeeeeewwwwwwww! Yukkola.

 

[5twins]

I've found similar before. I guess water gets in past the dust cap and then just sits there. I keep those parts oiled or greased now, just a light coating to ward off future corrosion.

 

[littlebill31]

Thats the left fork. So Im assuming since it leans that way on the side stand the water was able to collect on the fork.

 

[fredintoon]

Yuk - what a mess littlebill!.

I hope you won't mind a small detour, but since we're on the subject of gaskets and engine clean-up, I do have a related question:

I tried to change the exhaust port gaskets on Lucille last summer but they were both stuck pretty hard so I just left them. Nonetheless, I do want new gaskets in there when I install the new pipes.

Anybody got a good suggestion for getting those stuck gaskets out?

Pete

Hi Pete,
if they are too stuck to just pry out, try this:-
Put a L-shaped blade end on a slide-hammer, drive the L-blade into the seal by tapping a tapered wooden rod, (an old hammer handle comes to mind)
in beside it. Leave the rod in place to keep the L-blade in place and a few strokes on the slide hammer should remove the gasket.

 

[MaxPete]

great plan Fred - thanks!

Pete

 

[CoconutPete]

Following.

 

[nj1639]

He said the pistons were shrunk and, "Damn, didn't you hear all the knocking?" , lol.

I'll probably go for 2 over to be safe.

Two over seems to be the norm. I had a set of jugs bored and the machinist suggested two over. Since then I've acquired two more engines, provenance unknown, that were both bored two over by the PO's . Not sure why two over specifically.......

 

[littlebill31]

Got the seals out, finally, and removed all the damn spray paint.

Waiting on new pistons, rings, and valves to arrive so I can get back to the engine. The valve stems are seriously dimpled and pitted so I decided to replace them.

 

[littlebill31]

Got the jugs cleaned up and the new piston came in the mail.
Off to the machine shop.