! and 5 cylinders down

[arse21]

Hi folks.
I thoroughly appreciated the help on chasing down popping...however, my research and probing has found cylinders 1 and 5 are without compression. The spark wires have power and spark plugs have spark. This is a 97 Cruiser that I got last year with 18k miles. The bike was dropped hard on right side at some point, shearing down front brake master cyl box, crash bars, and exhaust. I do not know maintenance / repairs done at the time. Bike also burns blue on right side.

Found problem pulling 1 and 5 plug wires chasing down popping issue. Wire connections looked good. Pulled plug wires off coil and checked ohms. Plugs sparked on engine. Compression test showed almost nothing on 1 and 5. I got a little bit of compression with spitting oil down spark tubes. I do not know if anything was ever hugged with on timing belt before or after crash. Again, bike had 18k when I bought her, I have put 7k on.

Changes done so far:
Desmogged - new caps on intakes, plugs on exhaust, and new tube on gas tank
Intake orings replaced
exhaust gaskets replaced (because I am trying to put a cobra exh on) original OEM exhaust on bike.
Carbs tweaked to pilot 2.25 turns out which reduce popping
changes result in 1.5-2k RPM idle when bike is warm

Compression 2 3 4 6 all looked decent. I don't know what work might have been done to the bike.
From exhaustive reading here...Worst case I can't help but to feel that I cant have 2 bad piston rings on a bike that had less than 18k miles ridden for 23 years. The crash, again, don't know what was done...might have ended in some bent valves (I hope in comparison). Don't know if timing was ever hugged with after crash...or during...

So, 97 Valk, 1 and 5 cyl no compression, was dropped hard on right side...am i right in pulling right head for valves? Could I be missing anything else for these 2 cyl not having compression with this low mileage?

If this is somehow a piston ring issue in 18k miles, could I soak the piston heads in MMO or something to lube rings if I pull the heads off? Any other thoughts for repair without engine teardown on an engine this young? Bulletproof me! This engine has seen some crap before I came along...and she wants to live!

[Speedy Coop]

Did you check valve clearances yet? Possible piece of carbon between valve and  seat? Might be worth a look.

[acejr71]

Did you check valve clearances yet? Possible piece of carbon between valve and  seat? Might be worth a look.

I agree.  I have worked on aircraft engines for three decades.  I cannot tell you how many times I found a bad compression reading on one or two cylinders due to carbon buildup on a valve edge.  We would use a prop lock with that cylinder on the compression stroke (both valves closed and seated) With an adapter that threaded into the spark plug hole we then could apply compressed air into the cylinder.  With the cylinder under pressure, you can listen to the escaping air in either the exhaust or intake.  When we determined which valve was not seating, we used a rubber mallet and would strike the valve head and cause the valve to open and shut under pressure.  Called "staking the valves".  9 times out of 10 the action would loosen the carbon and the compressed air would force the debris off the valve seat and edge.  After that compression checks would usually be within mandated limits.
Worth a shot since it does not involve tearing into the engine.  Never done that on my Tourer so I'm not sure how you could sit it up but it's worth a shot to try something like that.  Also, compression rings can "slip" out of alignment and cause leakage.  Normally when the three rings and the scraper ring or put on the piston they are situated in a 12, 4, 8 oclock position.  Sometimes they would move into a position close to the next one and let compression through.  Not very often but it has happened.  When we saw that we would coat the cylinder through the spark plug hole and run the started causing the cylinders to cycle.  (all spark plugs need to be removed.) We would use a penetrating oil in the cylinder.  Takes trial and error to see if that works but also a fix that does not tear into the engine.  Hope this helps some and best of luck.

[arse21]

Did you check valve clearances yet? Possible piece of carbon between valve and  seat? Might be worth a look.

Yes I adjusted the to spec earlier this summer

[longrider]

Maybe adjust both intake and exhaust valves a few thousand loose on those two cyl and then take another compression test.  Just thinking.

[John Schmidt]

One thing I'd do is pull the timing belt cover and double check timing, making sure all the timing marks line up properly. If it landed hard on the right side, no telling what could have happened. If it's off, you might have some bent valves.

[arse21]

Good ideas all around. I will loosen them up a bit more and see what happens as well as maybe "staking the valve" as it were. The bike did land hard / skidded on the crash bars enough to hew about an inch off in 2 places, plus on top of the brake reservoir, plus on the bottom of exhaust. I don't know any other details of the crash but for what I can see.

I will certainly also take the cover off and check timing.

"When we saw that we would coat the cylinder through the spark plug hole and run the started causing the cylinders to cycle.  (all spark plugs need to be removed.) We would use a penetrating oil in the cylinder." - any oil in particular? Like an MMO soak for awhile orrr?

While I am reading my manual through and through, any experience or tips in the event I do need to replace some bent valves?

[Skinhead]

For about 20 bucks you can buy an endo scope camera that plugs into your phone or computer.  Use it to look at the valves through the spark plug hole.

[98valk]

Good ideas all around. I will loosen them up a bit more and see what happens as well as maybe "staking the valve" as it were. The bike did land hard / skidded on the crash bars enough to hew about an inch off in 2 places, plus on top of the brake reservoir, plus on the bottom of exhaust. I don't know any other details of the crash but for what I can see.

I will certainly also take the cover off and check timing.

"When we saw that we would coat the cylinder through the spark plug hole and run the started causing the cylinders to cycle.  (all spark plugs need to be removed.) We would use a penetrating oil in the cylinder." - any oil in particular? Like an MMO soak for awhile orrr?

While I am reading my manual through and through, any experience or tips in the event I do need to replace some bent valves?

I would think if it had bent valves u would have know it a while ago. loud tapping and no power.

if the belt skipped one tooth if will run and not bend valves.

u just have to remove head/s to replace a valve. just need all OEM o-rings and head gaskets to re-install.  while removing valves remove all of them and replace valve stem seals with newer teflon type seals.

[98valk]

"Possible piece of carbon between valve and  seat?"

maybe prime example of why I've posted for yrs about certain fuel additives esp seafoam which shouldn't be used due to the low temperature solvents that solidify on the back of the hot valves.

This also applies to what can happen from using high octane fuel when the compression ratio doesn't call for it. some doesn't burn correctly and actually carbons up the piston tops and cylinder head bowl area.

[arse21]

In reviewing previous posts on cylinders / valves / gaskets, I see mentioned to replace water pipe o-rings as well. Anyone have an idea as to what o-rings these would be?

Hoping to place an order shortly and check stakin the valves first to see if I get compression back...then onward into the valves if that doesn't clear us up.

Also 98Valk, I just have to laugh after reading so many of your posts here about said Seafoam-esque solvents...Hopefully this is in fact the case!

[98valk]

In reviewing previous posts on cylinders / valves / gaskets, I see mentioned to replace water pipe o-rings as well. Anyone have an idea as to what o-rings these would be?

its the water pipe going out of the heads to the thermostat housing.
only the OEM O-ring works. see #11 three of them and one #12. 
after replacing the heads on my bike I didn't touch the #11 and #12 going into the housing, but one yr later the #12 started leaking even though I never pulled the pipe out of the housing.

https://www.partzilla.com/catalog/honda/motorcycle/2000/gl1500c-a-valkyrie/water-pipe-thermostat

[arse21]

Did you check valve clearances yet? Possible piece of carbon between valve and  seat? Might be worth a look.

I agree.  I have worked on aircraft engines for three decades.  I cannot tell you how many times I found a bad compression reading on one or two cylinders due to carbon buildup on a valve edge.  We would use a prop lock with that cylinder on the compression stroke (both valves closed and seated) With an adapter that threaded into the spark plug hole we then could apply compressed air into the cylinder.  With the cylinder under pressure, you can listen to the escaping air in either the exhaust or intake.  When we determined which valve was not seating, we used a rubber mallet and would strike the valve head and cause the valve to open and shut under pressure.  Called "staking the valves".  9 times out of 10 the action would loosen the carbon and the compressed air would force the debris off the valve seat and edge.  After that compression checks would usually be within mandated limits.
Worth a shot since it does not involve tearing into the engine.  Never done that on my Tourer so I'm not sure how you could sit it up but it's worth a shot to try something like that.  Also, compression rings can "slip" out of alignment and cause leakage.  Normally when the three rings and the scraper ring or put on the piston they are situated in a 12, 4, 8 oclock position.  Sometimes they would move into a position close to the next one and let compression through.  Not very often but it has happened.  When we saw that we would coat the cylinder through the spark plug hole and run the started causing the cylinders to cycle.  (all spark plugs need to be removed.) We would use a penetrating oil in the cylinder.  Takes trial and error to see if that works but also a fix that does not tear into the engine.  Hope this helps some and best of luck.

Insofar as keeping the cylinders in place to attempt this valve stake, per your prop lock plane example...do you think this could be managed keeping a wrench on the timing bolt guide so to keep the timing belts and (hopefully) everything else in place?

Hoping to try this first over the weekend as well as checking timing belt placement.

ordered new head gasket and water pipe o rings in the event I do look to get into the head

[Skinhead]

How about just putting the bike in gear?

[arse21]

How about just putting the bike in gear?

Hah, well what's this logic thing? I guess I was wondering more about how little movement can occur to maintain compression to stake the valves like this