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Discussion Starter · #1 ·
Does anyone know if a rebuild kit is available for my VT700C? I need to rebuild the engine and was hoping to find something. I'm still looking...


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Doubt there's a "kit". Most people take the engine down and fix what needs fixin' and then do other stuff since they have it apart. For example if you need to do bore, hone, and rings...might as well do a valve job as long as you have it apart.
 

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Discussion Starter · #3 ·
Good point. My engine has 48,000 on it, so I wanted to basically rebuild it so I don't have to do it for some time...


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A rebuild at 48k?

Sheesh, what went wrong with it? Mine has a lot more miles on it than that and still reads 185PSI in both cylinders.

What's going on with it that suggests it needs rebuilding?

--Justin
 

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Discussion Starter · #6 ·
Was just contemplating doing it since I'm going to be tearing it down to paint the frame anyway. I'll check the compression tomorrow.
 

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I rebuilt my 83 back a few mo. ago.
It had terrible oil leak at lower jug gasket on front cyl.
Compression was down.
Cam plugs were leaking.
Compression was down on 1 cyl, worse than other.
Turned out to be burnt valve! Lean, I suppose.
I didn't try to test compression with oil in cyl (to verify rings or valve) BECAUSE it leaked oil so bad it HAD to come out/apart.


Like others mentioned, no "kit" available. After all, you only want to buy what you need.

OEM parts are $$$. For example, ring set..$50! Thats EACH, need 2. Vesrah gasket set, $60-$70. I recommend OEM head gaskets (15 or so a piece). The Vesrah set has head gaskets, but differ from OEM...and I had one LEAK! Search my old post's to read about this.
 

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Discussion Starter · #8 ·
I just tested the compression in each cylinder, though with a couple catches... the oil was drained, carbs off, and exhaust off. I obviously couldn't start and warm the engine as per directions.. oh well.

I did 8 cranks in each side, and both pretty much came up with 120 psi +/- 2 psi. The manual calls for a lot more (170 range +/- 28). Is this cause for a rebuild?
 

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Not quite sure what you mean by +/-28...

As in you got 120PSI in one, and 92 in the other, or you got 120 in one and 148 in the other?

Low numbers in a cold engine are not uncommon, so don't worry too much about that. I would be worried about the spread of them, if you're 28PSI off. They should be within 10% of each other and 28PSI is over 20%!

Did you shoot a little oil in the bore to see if that helped your numbers?

A cold, dry compression test by itself is not nearly enough info to determine if a rebuild is needed.

With only 48k on the clock, I'm surprised your compression numbers are so low. I'd be leaning more at valve seat fouling than bad rings, but I don't know the history of the bike.

--Justin
 

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Discussion Starter · #11 ·
+/- 28 was referring to the manual spec.

I didn't place any oil, but I can do further testing.


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The oil (in cylinder) will narrow down if it's rings, or valves leaking.

+/-28 is right per manual "spec".

Either way, valves or rings...engine must come out for service.
 

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Discussion Starter · #13 ·
The cylinders were actually both within 5psi of each other, they were just low at 120psi. The spec is 170, +/- 28.


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Ah, well within 5PSI sounds like either both cylinders are shot exactly the same way (which is really unlikely) or that the engine was cold and not building compression as high as it should be, which is likely.

Again, help me understand why you suspect there is a problem that needs to be fixed...

--Justin
 

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Discussion Starter · #15 ·
Justin... When I met the previous owner I began to suspect. :)

In all actuality, I'm a student who will be moving to Florida in June with my wife and we're only taking one car. I'll be riding the bike. I figure that since i'm taking it apart anyway to powder coat the frame, and inspect everything, I might as well look into the engine. THAT SAID, if the compression is just low because of the cold/dry compression test I would be ecstatic. I don't know much about engines, but I can wade my way through. Please enlighten.


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