[tnhunter]

my vulcan 1500b started running rough the other morning. The rear cyclinder plugs fouled out, looks like oil foul and now she smokes like crazy from that pipe. I removed the oil fill cap while it was running last night and discovered the was a lot of vacuum in the crank case. Is this normal? Can there be another reason she is smoking besides rings or piston holed?

 

[wiredgeorge]

Older Vulcan 1500 models in the A/B/C families had problems with "piston rocking". This was due to the holes where the wrist pins are inserted were not dead center. The piston will begin rocking slightly as the bore wears and the bore will not wear evenly. Eventually, the bikes affected begin smoking and using oil...lots of oil. The Vulcan combustion chamber is also fairly small and tends to get a lot of crud on the valves; especially the exhaust and they tend to stick open (not seat good) with age. A symptom of these problems will be some oil in your air cleaners which is essentially blowby and eventually high crankcase pressure.

The fix is to use later (meaning redesigned) .20 over pistons (the first oversize) with new rings and wrist pins and clean up the valves or replace the exhaust valves and valve stem seals.

 

[T-man]

Wiredgeorge, I think you mean 0.020 oversize pistons.

T-man

 

[Scary Harry]

Whoo-ee !!!
.20 would certainly result in a large increase in volume and a big boost in go. But then everything is bigger in the hill country of Texas.

Just kidding , George. we all knew what you meant, even if the key board did not.

 

[wiredgeorge]

Bwhahahaha Sorry TWENTY THOUSANTHS! not 2 tenths of an inch! Those ol' water jackets would have to be hogged out bhwhahahaha

 

[tnhunter]

I still havent torn her down. Really not looking forward to that, I am hoping for a cheaper and easier fix. The weird thing is she doesnt smoke until she warms up. Shouldnt it be the other way around? Wouldnt I get crankcase pressure if there was blow by? I am sure it will eventually have to be dismantled just was hoping someone might know something that could avoid it.

 

[QKENUF4U]

BEFORE you tear it down do a COMPRESSION TEST and LEAK DOWN TEST

 

[grunt]

QKENUF4U

The VN1500 has a compression release built in to help in starting. Unfourtanetly you can not perform a compression or leak down test.

 

[joey]

Both compression and a leak down test can be performed. The automatic compression release does not matter.

 

[wiredgeorge]

The compression release will foul up any compression test. I suggest you have a look at Manjo's bubf site for info on doing a compression test. I think he has posted some info there:

www.gis.net/~manjo

 

[joey]

A compression release wont mess up a compression test or a leakdown. If it does that would be a first.

 

[oregano]

u could at least compare the compression of the front and rear cyclinders. compression testers are cheap and everyone should have access to one since u will eventually need one a few times :S