First Time Bike Rebuild: Thoughts?

[xs400newb]

xschris, why must the rockerbox and head match? If they came from the same type of engine why does it matter?

Assuming they don't match and you put it back together, what happens?

Adam

 

[xschris]

There are numbers stamped in the head and rocker box, these are machined to fit perfect together. If you use unmatched sets or from other years or engines with different wear amounts it could cause extra wear or play where the cam rides. It would be like using unmatched plane bearings from different bikes. You might get away with it but thats just my 2-cents

 

[drewpy]

yep, they are line bored together at the factory, making them a matched pair.

 

[maxholland1]

I took on off the sides and cleaned them out. How does it look?

 

[maxholland1]

I have rebuilt the top part of the engine and it looks like it might actual run. When I turn the pistons with a wrench, I am getting some air pressure from the spark plug holes. I will do a compression test this weekend. Before I do that, I need to put the side cases back. Can I use gasket glue for those, or must I use a gasket?

 

[maxholland1]

Top end rebuild. The Side cover is on, but without a gasket or screwed on.

 

[16VGTIDave]

If you are replacing a paper gasket, then you can use a sealant. Apply less than you want to, and it will still be too much! It takes very little to give a good seal. Excess will be squeezed out and may cause problems internally.

Assemble once the sealant has skinned over, and do not over tighten. If you have sealant squeezing out all over, take it apart and clean up the mess. Then use half as much sealant and try again.

 

[maxholland1]

What sealant would you suggest?

Does Permatex Orange RTV work?

 

[16VGTIDave]

As long as it is resistant to oil and gasoline, and temps of 250F or higher, yes.

 

[maxholland1]

I sealed the covers. They don't leak.

Checked Compression. Re-threaded side is 120 and the original threaded side is 115! I also need to get a longer spark plug for the re-threaded side. Where can I get that? What size should I get?

I have taken off the back wheel, and the chain stabilizers look bent. What do you think?

Also, I spray painted the bike. It looks pretty.

 

[maxholland1]

Quick Question:

I have a Yamaha XS 400 (1980):

1. what year front brake calipers will fit my bike? Will the 1982 Maxim caliper work on my bike.

 

[maxholland1]

Here are what the chain stabilizers look like and how they fit on the back wheel.

 

[maxholland1]

this is the wiring harness (all custom) and the finished engine with exhaust pipes on.

 

[maxholland1]

Last one: Finished Product.....except I am going to clean up everything and extend the mufflers out 12inches.



AND THE PLACE I DID IT ALL>>>>>ALL IN CUSTOMS