Low Compression

Engine, exhaust & cooling mods or problems. If it has to do with cooling, anything within the crank case, or exhaust, it goes here.
bikerbill
Posts: 86
Joined: Tue Mar 02, 2010 2:07 pm
I ride: 1997 Vulcan 500LTD named Hidalgo

Low Compression

Postby bikerbill » Tue Apr 09, 2019 6:30 am

Hidalgo is sick. Very sick.

For some time now I have noticed that Hidalgo has not seemed as peppy as Sioux. She is sluggish to start and she is sluggish to accelerate. It has been taking more and more throttle to keep up highway speeds making fuel economy very poor. I had chalked it up to the headwinds we have out here in the plains region of Texas but decided to look deeper.

Last weekend I decided to freshen and balance the carburetors. While adjusting I found that the left side carburetor idle fuel mixture does not respond as well as the right side. Also there is a more definite pulsing of the vacuum on the left side. The spark plugs are nearly identical in their 'read'.

Last night I attempted to perform a leakdown test. When bringing the piston to TDC I will hold my finger over the hose verify that the cylinder is on its compression stoke but had difficulty determining even that. I finally determined that the leakage seems to be coming thru one or both of the intake valves. I was not in the mindset to do a valve adjustment so I will do that this weekend. Here's hoping that a simple valve adjustment will bring back the compression/leakdown numbers.

If there is truly a problem with the valves I will be torn on whether to pull the cylinder head and repair them or to install the spare engine that I acquired a couple of years ago.

What is the consensus on repair vs replacement of Hidalgo's engine?
--
'Biker' Bill
'97 EN500LTD 'Hidalgo'
208,000+ miles so far
VROC #3833
IronButt #6024

SlipStreamer Enterprise II, Vista Cruise,
Cobra Spots, Drifter solo seat,
Pro-Tac backrest, ScottOiler,
F&S luggage rack, LED & HID lights,
4-gal AUX fuel tank

bikerbill
Posts: 86
Joined: Tue Mar 02, 2010 2:07 pm
I ride: 1997 Vulcan 500LTD named Hidalgo

Re: Low Compression

Postby bikerbill » Sun Apr 14, 2019 9:53 am

After much self-consultation I made the decision to replace the engine. So, at 204,098 miles Hidalgo's original engine was replaced. The new engine started immediately after transplant showing that Hidalgo has accepted her new 'organ of combustion'.
--
'Biker' Bill
'97 EN500LTD 'Hidalgo'
208,000+ miles so far
VROC #3833
IronButt #6024

SlipStreamer Enterprise II, Vista Cruise,
Cobra Spots, Drifter solo seat,
Pro-Tac backrest, ScottOiler,
F&S luggage rack, LED & HID lights,
4-gal AUX fuel tank

User avatar
Triangles
Site Admin
Posts: 796
Joined: Sun Dec 27, 2009 10:35 pm
I ride: '94 Black Cherry Vulcan 500, '06 Candyfire Red Vulcan 500 LTD
Location: Toledo Ohio
Contact:

Re: Low Compression

Postby Triangles » Sun Apr 21, 2019 8:09 pm

I'm disappointed only 204k miles!!! /s
I'd say you got your money's worth out of the engine. LOL. It would be interesting to do a tear down on the old engine to see what condition the internals are in, like the timing chain, valves, cylinder walls, etc. I'm guessing that the valve adjustment didn't solve the compression issue?

I though you had already swapped the engine at a little over 100k miles?
ImageImage

bikerbill
Posts: 86
Joined: Tue Mar 02, 2010 2:07 pm
I ride: 1997 Vulcan 500LTD named Hidalgo

Re: Low Compression

Postby bikerbill » Sun Apr 21, 2019 9:24 pm

Triangles wrote:I'm disappointed only 204k miles!!! /s
I'd say you got your money's worth out of the engine. LOL. It would be interesting to do a tear down on the old engine to see what condition the internals are in, like the timing chain, valves, cylinder walls, etc. I'm guessing that the valve adjustment didn't solve the compression issue?

I though you had already swapped the engine at a little over 100k miles?


I did a rebuild at 108k miles using the original cases, crankshaft, balance shaft, and clutch basket. Most other internals got replaced with parts from a 2002 motor with about 11k miles on it, including its timing chain and primary drive chain.

I decided to replace the engine, instead of checking the valves, based on recent performance issues which culminated with the most recent valve issue. I think she's been weak for a while and I was just not wanting to believe it. Also the top gears in the transmission have been whining for a while so I knew that those would have to be replaced also.

Based on Hidalgo's life I have concluded that the Vulcan 500 engine is good for about 100,000 miles when ridden the way that I ride, which is fast, hard, and long. YMMV
--
'Biker' Bill
'97 EN500LTD 'Hidalgo'
208,000+ miles so far
VROC #3833
IronButt #6024

SlipStreamer Enterprise II, Vista Cruise,
Cobra Spots, Drifter solo seat,
Pro-Tac backrest, ScottOiler,
F&S luggage rack, LED & HID lights,
4-gal AUX fuel tank

User avatar
Triangles
Site Admin
Posts: 796
Joined: Sun Dec 27, 2009 10:35 pm
I ride: '94 Black Cherry Vulcan 500, '06 Candyfire Red Vulcan 500 LTD
Location: Toledo Ohio
Contact:

Re: Low Compression

Postby Triangles » Mon Apr 22, 2019 9:04 am

Good to know thanks for the update. Guess I'm good for 70k more miles... LOL I wish I had the opportunity to ride more but life keeps happening.
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