The Beast is sick... low compression -- 75 / 40 / 90 / 90 psi

[exdirtbiker]

I haven't rode the Beast since last Sept.
I think I only put 50 miles on it since I bought it.
I haven't had the time to play with it.
It never ran "sweet". It got worse as I rode it. The carbs were "wierd" and cleaning them didn't help...
I probably made it worse.
I was going to have the local guy do a "dyno tune" but decided to check compression first...
That's when I stopped riding it.
I got 75 / 45 / 90 / 90 psi. I parked it. ... fast forward 10 months....

Today I finally checked valves again and all are right at .005" - .007" like I set them last year. ( Web cams require .006" )

Low compression and valves don't seem to be moving? Bad bores ?

I have not pulled the head yet, but I think that is the next step.

I saw someone on ebay has a 1100cc kit for a whopping $140. http://www.ebay.com/itm/131238388638?_trksid=p2060353.m1438.l2649&ssPageName=STRK:MEBIDX:IT

another seller has kit with coated pistons... for $277 - maybe same parts with coating??? http://www.ebay.com/itm/331386875811?_trksid=p2060353.m1438.l2649&ssPageName=STRK:MEBIDX:IT

I'm not spending any $$$ until i find the problem... not even sure if I have have any $$ to spend yet :-(

Any suggestions on how to proceed are welcome, even if you highlight my stupidity. ;-)

 

[dorkburger]

Ive noticed you're absence and what was wondering what became of the Beast. Good luck with it.

 

[zuzu]

Those pistons you looked at, one set is located in China and the other Canada. I dont think I would trust the ones from China...

 

[Guest]

Those are horrible numbers for sure, how did you do your compression test? hot engine? throttle wide open while doing the test? and you're saying the valves are not moving??

 

[JayWB]

Do a wet compression test and see if the numbers change much. And make sure the throttle is wide open. And the battery fully charged.

 

[exdirtbiker]

and ANOTHER 3-4 weeks got past me...
Thanks for noticing, -Burger !

Testing- WOT, all plug wires grounded, very charged battery, all plugs out, motor cold.
"Valves not moving " was not a good description... I meant valve clearances EXACTLY where I left them last year so I am thinking I have not "toasted the valves"... but that is a guess on my part.

Then I loaned my compression tester to a friend who reported " got really bad numbers on a brand new engine so I removed your connector/hose thing and gained 40 PSI reading".

Hmmm.... WOW. could I really be that lucky ???...

Busy erecting a 24 foot above ground pool in back yard. .. maybe time for bike next month ??? GAAAHHHHH !!!! I lost the whole summer ! WHAAAHHHH !!!

 

[dorkburger]

Hope springs eternal........ hopefully you get some good #s next try.

Good luck with the pool. We just had to have the wall on ours replaced this spring. Rust thru and a resulting hole in the liner....after 3 years.....painful. The pool store (At Home Recreation) was of minimal help until my sister in law made a little noise on Facebook by liking a post by another unhappy customer. She was literally contacted within a half hour....that would be the only positive thing ive ever had to say about FBook....

 

[exdirtbiker]

I tried with another compression tester... 100 / 50 / 110 / 110 ..

Is there any way this story can end without my pulling the head off the motor ??? I will do wet test, but I think the heads coming off anyway. No ???

Neighbor is the Machine Shop guy from local NAPA... he took all the equipment home when NAPA stopped doing machine work on regular basis. so fixing a "head problem" will take me a day... err.. him 2 hours... and a trip to liquor store.
If it needs bore job.... ughh.
The money isn't as bad as the time required.. I have many projects going at the same time. I'm afraid to start another one that won't get finished for 6 months.
But on a positive note... my son just got a '83 GPZ 750 for his first bike. with fresh paint. It's gorgeous. And it's a "loaner".

 

[Guest]

Sure sounds like a head pull. You're pretty lucky with your neighbour there, he'll have all the tools for measuring the cylinders, rings etc... and everything else. Your engine has a 1085 done to it though, I'm not sure what that means if you need new rings or if you need to re-sleve. Hopefully some of the performance builders can chime in on the matter.

 

[exdirtbiker]

...I'm not sure what that means if you need new rings or if you need to re-sleve. Hopefully some of the performance builders can chime in on the matter.

the 1100 kits offered for this bike makes me think I could go "a little more"... but if it has a good scratch then I will need new jugs. Jugs are cheaper than a bore job.. but any used jugs will need new boring? Dang

I been more thunking... could a stuck ring give these results? the plugs have a lot of carbon on them...
what do you guys suggest to free a stuck ring? ( I know I am hoping for a miracle )

Get 'er hot and fog with Seafoam ?

But. .. on another positive note... Granddaughter just born !!! Off to meet her !

 

[chuck hahn]

50/50 mix of Acetone and any ATF is the usual soak for freeing a stuck ring. ( Cold engine ) ... Fog it so it gets around the cylinder walls well and let is sit a day or two. Restart it outside as its gonna smoke like crazy for a good time till the sauce burns off.

 

[exdirtbiker]

Thanks again to EVERYONE here that has helped me along the way...
and I just noticed.. my "title" has turned to "Forum Mentor" ??? Mentor ? are you kidding ??? I still don't know my $#%@ from my *#$* !!! He he he...

Where can I get acetone ? Home depot ? Auto parts store? I guess I should dump and save oil before I put that stuff in the hole. ( 20 miles on fresh oil)

EDIT- seems acetone is available EVERYWHERE... since I don't need much, I'm headed to the Beauty Supply store !

 

[chuck hahn]

Auto parts or paint store, home depot, lowes, all will have acetone. yeah wipe the drain pan good and clean and reuse the good oil is a good idea. Just remeber you gotta put another drip pan down inder the oil pan as the sauce is soaking...and that you need to refill the oil when ready to fire it back up.

I would fire it up and let it run till all the smoking is over and then a good little jaunt to rattle the rings a bit...then retest the compression.

 

[chuck hahn]

One last thought..Before you put the plugs in and try firing it back up, stuff some rags down in between the fins and above the plug holes and roll the engine over a few seconds. This will throw any excess out the holes and reduce any chances of hydrolocking a cylinder and causing connector rod damage. Slop as much out the holes as you can and then go for firing the engine back up. Its a bit messy but it wipes up easily...LOL

 

[exdirtbiker]

Wet test--- compression jumped to 125-
re-installed plugs, got it hot, fogged with Seafoam, pulled plug and added more Seafoam, locked up garage.
Will re-evaluate Sat.
(it was the easiest option, and I had very limited time)

 

[blowerbike]

why not do a leak down test?
i never liked the wet test because when you add liquid you loose space and artificially raise the compression/cranking pressure.
a leak down test will tell the tale.

 

[exdirtbiker]

Fogging and soaking with Seafoam did NOTHING for me. Except now the bike barely runs worth a $n1t.
Started it, idled until the smoke cleared ( most of it) then took it for a mile or 2 to put a load on it. It actually stalled on me approaching a turn.
Same compression readings... engine warm, throttle wide open.

"when you add liquid you loose space and artificially raise the compression" ... yes, I saw the numbers jump to 130 -135 on first try. then I cleared the gauge and did it again. and again. and the readings settled out at 120-ish.

I still don't trust my gauge, but I still get one hole 50% lower than the others. (#2)

I might have time to play with it again next month.. :-(

 

[exdirtbiker]

Looks like I may have time to play this weekend.
If the jugs are bad...
I don't think mine can be bored again. Can they? They are already at 1085. What are the chances I can go from 73 to 73.5mm ?
Do all the 8V 1000 jugs from 77 to 80 fit? I read somewhere certain 1100 jugs also fit. Anyone certain of exactly which ones?

I know I'm jumping ahead a bit, since I haven't found the true cause of my problem... But I enjoy exploring all the options.

 

[exdirtbiker]

It finally happened... I had time to play.
and I learned quite a bit...
Like.. this bike has NEVER had a big bore kit, looks like the original pistons are in there !
2.756 in bores = 70.002mm. all bores look new.

Piston skirts look used but OK.

Pictures later today...

 

[exdirtbiker]

The bores look great..




The oddball color valve is not the hole with low compression


looks like someone did a little work in here...



I don't see any sign of ring problems...