Low compression in #6 cylinder

[Doc X]

Have purchased used 2000 Valk Interstate with 33800 miles on it. Took bike to the  Honda dealer and to the tech I know and have great confidence in.
All fluids changed, compression check, new plugs, and air filter. One thru five cylinders were at 155 and number six cylinder at 115. The Tech said that all intake valves were crudded up and # six was beyond words, the guy must have found nickel gas to use. He told me to use Chevron gas for the next 1000 miles and bring the bike back in for another compression check. I have also been using the Techron additive in each tank full , now for 700 miles, and have noted that my oil temp runs 215* with my Tru Temp oil temp guage. This is at 75mph on a 80 degree day, but my VTX 1800 will run 190* at 75mph on a 80* day. Will the Techron additive raise the bikes temp, and am I looking at a engine overhaul in the face? The Tech said he thought the Chevron gas would get the compression back up by cleaning those valves.

Thanks For Your Ideas,
Doc X

[fudgie]

I think that sounds right. My other HD bud had 240 deg on his dip stick temp if I recall. But this was 2001. Oil cooler and sitting traffic on 80 deg day.

Did your fan come on?

[Doc X]

Yes, my fan came on when I was at 10mph but the noise was such that I could hear it
Doc X

[98valk]

checkout www.auto-rx.com

[RP#62]

The oil temp on my '97 Tourer has run around 210° at cruise for the last 10 years or so.  Of course, being in Arizona, the oil temp is usually around 120° sitting in the garage even when its not running.
-RP

[DFragn]

The Tru-Temp oil temp gauges can be out of adjustment and indicate inaccurately. Especially if the face dial is used to remove the dip stick. To recalibrate them loosen the lock nut under the gauge and stick it in a pan of boiling water and turn the dial to calibrate.

Valves crudded up: Dump a whole 12oz. bottle of Techron in there for several tanks. It should work it's magic for you.

Approximate Boiling Temperatures of Water
 
Altitude

Temperature

Sea Level

212 degrees F

984 ft.

210 degrees F

2,000 ft.

208 degrees F

3,000 ft.

206 degrees F

5,000 ft.

203 degrees F

7,500 ft.

198 degrees F

10,000 ft.

194 degrees F

20,000 ft.

178 degrees F

26,000 ft.

168 degrees F

[Doc X]

OK, whole bottle 12oz of Techron in each tank fill up the next two times . DFragn,  Is there anyway you can check your tank for crud in it without having to take the tank of ?
Thanks,
DocX

[Patrick]

My concern is how the compression test was performed.. Was the engine cold, warm or hot??  Was a little oil added to #6 when it was found to be a little low?? I would just try the test again, with a warm engine[not hot] and see what happens.. Its strange that you mention #6 being low.. Thats the same cylinder that was low on mine and it turned out to be an improperly installed piston[apparently dropped which pinched the lands].. Honda being the great company they are,, offered no assistance.. If the new test doesn't show anything different then I'd wonder about a fuel-lock.. #6 is susceptible to fuel locking and maybe some damage occurred[bent rod,etc].. I don't want to worry you,, I think  a new compression test will show everything is OK,, this monsters are pretty bullet-proof..

[DFragn]

OK, whole bottle 12oz of Techron in each tank fill up the next two times . DFragn,  Is there anyway you can check your tank for crud in it without having to take the tank of ?
Thanks,
DocX

Not really. Unless you can see signs of rust through the filler cap. Easiest way is to pull the tank then the petcock then the screen if it doesn't come out with the petcock.

[Robert]

First the oil temp is ok in fact I would like to see it a little bit higher. The next if the valve is the problem it would take 10 minutes to make sure and about another 10 to cure the problem. take off the intake runner and look at the top of the valve if there is a problem you will be able to see it and if there's crud then carefully chisel it off with the valve closed and blow it out with compressed air, Done, no Techron no playing around instant results. I like what Patrick said and he brings a good point up to verify with the intake off do a leak down test. By putting compressed air in #6 with the intake off you will be able to see if the valve is seating by the air leaking out and if not then take off the oil cap and see if air is coming out there. Basically where ever the air goes so goes your compression. Once the intake is off you can see the valve and have enough room to take off the carbon. Techron is good stuff but if you have that much there then really the only way to really get rid of it is by a physical cleaning. If carbon is the problem holding the valve open which I kind of doubt then the longer you wait the more chance you have to destroy the valve by burning it. If its not seating then you may also be able to see the spot where its not and determine what to do. I have not seen real deposits on valves since they stopped using leaded gas the only thing that may do it other wise is valve stem seals leaking but that would have to be quite a bit and more than likely you would see smoke out the back.