question about 1980 650 special

[JLov]

I have a 1980 xs 650 special II i bought that was stock and had 17,000 miles on it just got done rebuilding it but i did NOT rebuild the engine i have rode it a few times seems fine, just wondering is there anything i need to do special to the engine since i did not rebuild it considering the miles and how old it is?

thanks!

 

[figure8]

Go to an auto parts store and rent a compression tester. If your readings are above 100 psi your good to go. If it ain't broke don't fix it.

 

[TwoManyXS1Bs]

Read this thread on head retorque:

http://www.xs650.com/forum/showthread.php?t=2034

 

[gggGary]

Plus 1, head retorque is required maintenance.

You did drop and check BOTH oil screens?

Might not hurt to run it a bit, shut down, pull the plugs spray in some rust buster. let it sit overnight then run it again. After long sitting the rings can get pretty gummy in their grooves. Other than that, run it and see if you have any issues. Sometimes they just go back to running like they AREN'T 35 years old.

 

[fredintoon]

Hi Jlove,
and while you are re-torquing the head, ditch those 4 rubber/steel laminated sealing washers and replace them with solid copper washers or even with Dowty seals.
Copper washers are cheap and are available all over.
Dowty seals are expensive and hard to locate, it's just that us old aircraft guys love them.

 

[figure8]

Glad you guys posted that up, I've never seen that thread about retorquing the head. Weekend project!

 

[angus67]

Whats a dowty seal?

 

[fredintoon]

Whats a dowty seal?

Hi angus,
these things:-
http://www.potterassoc.com/pdf/bonded_seal_information_and_sizing_chart.pdf
AKA bonded washer.
You will note that the XS650's original sealing washers are also "bonded washers" but they are the wrong type for what they need to do.

 

[Gibson]

I've got over 17K miles on my 76 C model. When I bought it about year ago, It was last inspected in 1984. It was a can of worms. But engine internals ok. It doesn't burn oil, and has good compression. I agree with 'if it ain't broke...don't fix it' . Rode over 1k miles this summer and still going strong...

 

[gggGary]

I'll butt in that I reuse the rubber washers, probably 7 or 8 engines retorqued so far no leaks...... My take is that it isn't the washer that's the problem, old aluminum engines gaskets studs relax over time, I do head stud retorques on high mile cars too. It's worked several times to stop head gasket oil leaks. I just loosen and retorque torque to yield head studs too. I am such a scuff-a-law.

 

[5twins]

Well yes, the original rubber washers on those outside 4 studs work for sealing purposes, but they will allow those acorn nuts to come loose again ..... and again ..... and again.

Gary, for as many as you do, you might want to look to McMaster-Carr as a washer source. They have some nice thick American sized brass washers that are a perfect fit and about a dollar less a piece than the ones from Mike's .....

http://www.mcmaster.com/#95395a240/=1073ont

 

[gggGary]

Yup I have some of those mcMasters in stock but don't change out the rubber washers when I do retorques, a couple of my motors have several thousand miles on them now. But I'm jus' a dummy.

 

[5twins]

Well .... a penny saved I guess. I choose to save my pennies elsewhere. You "flip" a lot of these. I hope you at least inform the new owner that he should change those washers out. I work on a lot of these locally. I change the washers and they pay me for them. It's only like $10. They would never do it on their own. I also upgrade the dreaded type D tensioner assembly on any I can. I'm always watching eBay for $15 to $20 type E assemblies. We have to look after these bikes and not too many of us really know how to do that.

 

[rainycity]

Would (or could) the head not being re-torqued properly cause a slight popping when decelerating or would that most likely be a carburetor issue?

 

[gggGary]

Would (or could) the head not being re-torqued properly cause a slight popping when decelerating or would that most likely be a carburetor issue?

I would put that in the more likely carbs category. Not a substitute for an overhaul, but synching carbs is a worthwhile maintenance item.

 

[Brassneck]

Or exhaust leak...

 

[rainycity]

Exhaust leak,,, Thought I fixed that once already, *lol*

 

[5twins]

If you have BS34 carbs, the mix screws need to be opened up to between 3 and 3.5 turns out or the bike can pop a lot on decel. The E.P.A. strangled the piss out of those puppies, lol.

 

[Gibson]

76 model carbs I think are the 38s. I wonder if it could be the shaft seals. It's only really low idle problem.

 

[rainycity]

I went to that mcmaster-carr website and was wondering if there a specific stock number on those replacement washers and I`m pretty sure I have the BS34 carbs beings how its a stock 1981 and I`ll try opening the mixing screws between 3-3.5 and see what it does.