Compression test

[Rusty McNeil]

Prior to getting prepared to set the valves on my bike
(23,000 miles) I did a compression test tonight.
I got readings of 170-175 Psi on all cylinders letting them all go through 5 compression cycles. They also all came up evenly and uniformly so I feel pretty good about the numbers.

Not having ever done this on the Max though I am curious if anyone else has done a compression test on a good running Max and what numbers did you get?

Thanks in advance!

Rusty

 

[maleko89]

All of my cylinders are between 170-185 psi. They used to be higher but that was due to carbon buildup.

 

[Rusty McNeil]

All of my cylinders are between 170-185 psi. They used to be higher but that was due to carbon buildup.

How many miles on yours?

I guess mines pretty normal?

 

[maleko89]

61,000 miles. According to service manual it may be on the high side...but I prefer that. I've been using Lucas Upper Cylinder lub and that seems to help with the carbon buildup as my compression has lowered 10-15 points over the last year.

 

[Rusty McNeil]

61,000 miles. According to service manual it may be on the high side...but I prefer that. I've been using Lucas Upper Cylinder lub and that seems to help with the carbon buildup as my compression has lowered 10-15 points over the last year.

I'm guilty of letting my bike idle, ALOT! I like the way it sounds too much and so I usually start it every few days and let it fully warm up trying to tell myself that it's good for it but knowing I'm probably carboning up the valves (3.25 out on idle screw)

Last time I had the carbs off I could see carbon crust buildup on the intake valves.

Is there a sure fire, true and tested way to get rid of this?

 

[maleko89]

I asked a chemist guy I know the same thing. Here's his response on fuel treatments. In short, BG44K is one of the best.

The Honda stabil and other fuel stabilizers work sufficiently to retard fuel evaporation and decomposition. However they do not contain any cleaners. If you only use them for off season fuel treatment, they will work fine. Using valid fuel cleaners with some regularity is more important than off season storage in my book, since a clean system provides far less trouble than anything else.

Seafoam is also a good cleaner to use as is Regain, Wynn's Powercharge, Techron Fuel System cleaner, which all provide decent cleaning. As you may guess I do prefer BG Products line of fuel supplements like Supercharge and the like. BG Supercharge is a light dose, but good fuel system cleaner for "keep clean" use and also provides excellent fuel storage. It has about twice the potential for fuel stabilization as compared to Stabil branded additives. Supercharge contains anti-oxidants (stabilizers) plus a light dose of polyether amine cleaner. Also, BG44K can't be beat for potency when it comes to strong polyether amine fuel system cleaners. Other branded PEA cleaners often are 25-75% less potent than BG makes.

Personally I would discontinue the use of the Lucas Upper Cylinder stuff. Essentially the product is metals free (ashless) and appears to be a light mineral oil. The product may function well as an upper cylinder lubricant, but based on the observed chemistry, may not function well as an injector cleaner. It appears to be identical to a simple base oil...like that found in motor oil...only without any additives. In our industry "upper cylinder lubricants" have no validated function and do not provide a pronounced benefit. They provide a perceived benefit true...but upper cylinder lubrication is accomplished by the resident motor oil film, so that nothing else really needs to be added to the fuel side of the cylinder beyond what the engine oil already does. However I am aware of the tremendous following that Lucas has and the many myths that surround their products...so don't feel bad that you use the stuff. By and large though...Lucas brand products tend to be very weak and do not compare to the quality of other major brands. In my personal opinion they are a lot more hype than help.

I hope this info is what you wanted to know.

Best wishes,

Michael

 

[DanQuin]

+1 on the Seafoam. I use it periodically to clean out all my engines. Just be prepared for A LOT of smoke The neighbors will notice.

I wouldn't recommend the frequent idling though. The motor doesn't make enough oil pressure at lower rpm to avoid damage. That why oil manufacturers classify prolonged idle as extreme use.