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Discussion Starter #1
Hi,
I'm not an engine expert. So maybe I didn't do it right.

I have the VN1600 service manual.
I borrowed a compression tester and wanted to measure the cylinder compression.

1. warm-up bike. I just let it idle for some minutes until RPM droms below 1000 and cylinders got hot.
2. remove all ignition cables
3. remove one spark plug of each cylinder
4. connect gauge
5. pull throttle to max and press engine start

The manual demands a pressure of 340-590 kPa

The rear cylinder reads 585 kPa - fine
The front 785 kPa !
I repeated the measurement, always the same.
What's wrong ?

I have only one simple idea. During warm-up I found that the rear cyliner got warmer than the front.
Could it be, that the front was still too cold, so that the oil was too thick ?
:confused:
 

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I'm not an expert and I don't own 1600 but few ideas came to mind, I'll drop them here. Too much carbon buildup can cause high compression, or maybe something wrong with exhaust valves cause higher compression because air is not leaving combustion chamber properly? That front cylinder shouldn't be cold if you warmed up the engine. Looks like front cylinder is not igniting properly, don't know if it's because of too much compression...
 

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Discussion Starter #3
The engine runs without problems. Start on warm/cold weather without pulling choke.
Top speed of 190 km/h - no problem. Spark plugs have all the same color.

The different heat up of the cylinders is not extreme.
I think it will level after some time.
While riding, the front cylinder will stay cooler anyway - the well known "V2 problem"

In the meantime, I found a that high compression could mean
carbon in the cylinder. But that a pressure difference of 200 kPa
would be still o.k. (better less, of course...)

I got the bike a few weeks ago. I think that it wasn't moved much
in the past, maybe only short distances at low speed. So, the engine
could get "dirty".

I also heard, that such things may get better if the bike is moved.

... any other ideas ?
 

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I am curious as to why you are looking for a problem with a bike that, " The engine runs without problems. Start on warm/cold weather without pulling choke.
Top speed of 190 km/h - no problem. Spark plugs have all the same color.

Very old saying: If it aint broke, don't fix it.
 

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Discussion Starter #7
The story is a little more complicated ;-)
I bought the bike from a dealer with 1 year warranty on used bikes.
I'm happy with the bike. Though, on engine start, I feel that the alternator works hard. Since that battery is full and the engine reponds quickly, no real problem. Actually, I thought this is normal on such a big engine.
In a motorcycle magazine, they tested an Indian Chieftain for 50000km and found damaged valves. But there was no noticeable performance loss.
They found the problem with a compression check.
My neighbour rebuilds old bikes. This magazine article in mind, I borrowed a compression tester and found this issue.
With the help of this forum, it seems very likely, that the KACR device is broken for the front cylinder.
I did some research in the service manual and Youtube. Repairing it, is a pretty big task.
Without the warranty. I would leave it as it is. Since the bike was not moved much in the past years, the KACR might just got dirty and maybe
get back to normal after a couple 1000km's. But there's also a risk, that the damage gets worse. So why waiting - then it's better to claim the warranty - I paid for it....
 

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The story is a little more complicated ;-)
I bought the bike from a dealer with 1 year warranty on used bikes.
I'm happy with the bike. Though, on engine start, I feel that the alternator works hard. Since that battery is full and the engine reponds quickly, no real problem. Actually, I thought this is normal on such a big engine.
In a motorcycle magazine, they tested an Indian Chieftain for 50000km and found damaged valves. But there was no noticeable performance loss.
They found the problem with a compression check.
My neighbour rebuilds old bikes. This magazine article in mind, I borrowed a compression tester and found this issue.
With the help of this forum, it seems very likely, that the KACR device is broken for the front cylinder.
I did some research in the service manual and Youtube. Repairing it, is a pretty big task.
Without the warranty. I would leave it as it is. Since the bike was not moved much in the past years, the KACR might just got dirty and maybe
get back to normal after a couple 1000km's. But there's also a risk, that the damage gets worse. So why waiting - then it's better to claim the warranty - I paid for it....
OK, a lot of information you originally left out. Since it is still under warranty, I would return the bike to dealer and let them do the diagnostics and necessary repairs.
 

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Those KACR's have been known to "explode". Now whether the problem starts out as not working and goes from there, or they come apart as the first and only step, I do not know.
Also, I am assuming you meant starter works hard where you said alternator.

The KACR should work, so get it repaired under warranty.
It might mean the difference between a start and a no-start on a cool morning.
 

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Haven’t been on here recently...
We bought a house in January and been busy ridin and what not.

Trying to test the compression, due to the KACR’s, is a total waste of time and effort...
The readings will usually show the front cylinder reading a bit higher than the rear....
If you truly want to run a test that will give you some indication of the condition of your engine then a “leak down” test is the way to go.

With all the positives that you mention, it doesn’t really sound like you have any serious issues.
These motors are pretty bulletproof and quite different than the Indian motors...

As always...
YMMV

Ride on,
Luckymann77
 
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