NO COMPRESSION

Hey guys, thanks for chiming in!

Corey, I´m preeeetty sure that I´ve assembled the cams and set the timing as indicated in the Clymer (I own the same manual as you, guessing from the image you posted), counted and re-counted pins and alignment marks, rotated engine manually to ensure there was no binding, etc, etc. Everything was done exactly by the book. Valves were never removed and shims and buckets were put back where they were before disassembling. I took extra care in the whole procedure and read that part of the manual several times before starting the job. So I just can´t understand how in the hell the timing could be THAT far off as to have almost no compression, but certainly something is wrong here. As said, I´m going to the shop tomorrow with the manual and check things once again with the mechanic to see if we can arrive at a precise diagnosis.

BTW, I´ve replaced the cylinder base, head and valve cover gaskets, plus the oil lines O-rings.

Wish me luck and have a Merry Christmas.

Post edited by: kawadruida, at: 2006/12/22 18:12

Sergio, I am going to try and make this clear. If you failed to pull the cam chain taught against the crank sprocket (front of engine) when installing the exhaust cam chain, and perhaps lined things up with the chain a bit bunched, when it is pulled taught by the tensioners and is only a tooth off or perhaps two teeth off, the valves WILL bend. The bend can be very small but the valves won't seat. You can pull the valve out and look at it and it is hard to tell it is bent. The bending happens without any feeling that there has been force applied or much restistance of the valves to that force.

The way you can tell if the valves have been bent is to do a leakdown test. If the shop that is working on the bike doesn't have a leakdown tester, you do it by process of elimination. Two things basically cause low compression. 1. rings 2. valve seat

The valve seat issue can be picked up by the leakdown test but otherwise, you have to disassemble the head and check the valve stems with a dial caliper or put the stems on a plate of glass or something real flat and check them for straightness.... It is easier to point to the valves by checking the rings. If the rings seal when you add a tablespoon of oil, then the rings are the culprit. It is UNLIKELY your cylinders ovaled or the rings lost their bite quickly. This is almost always a SLOW process. So put a tablespooon of oil down each cylinder and check compression. If your compression doesn't jump up, by process of elimination, it is likely you bent valves; most of the time it is because you didn't get the chain stretched out at the front. It is also possible that your misunderstood or mis-counted... even experienced mechanics can make mistakes.

Anyway, I have attempted to explain what I believe is going on. Good luck and have a peaceful and blessed Christmas!

WG, thanks for your patience at explaining things as clearly as you do! I think that the camchain was taut as it can be when I started putting things back together, but, as you say, I´m only human and surely can fail...

Besides, even being mechanically inclined and messing around with bikes and cars since I was a teenager, I´m in no way an experienced mechanic, so changes of screwing things up go considerably higher I guess...

Tomorrow I´m gonna try to sort things out with my new friend, the mechanic:)

Cheers and have a Merry Xmas you too!

PS: Sorry for my english if something is badly written or hard to understand, tis forum is always a good chance for me to polish the language a little more!

Sergio, I have the chance to pull on cam chains about a dozen times a year while rebuilding engines. I have bent valves a number of times thinking I had the cams timed correctly. Most of the time, I don't really feel much when the valves bend.

I know you are pretty handy but the cam chain bunching is one thing that has made an impression on me from personal experience! There have been times I have tugged that chain and thought I had it all the way out and was fooled.

Your English is great by the way... Next time you are in San Antonio, look me up and we can go see 2/5 of the Argentine national basketball team play (for the San Antonio Spurs!). bwhahahaha

WG, you can bet that if I happen to be around Texas I´ll give you a call to hang around a little bit, perhaps pop up some beers if you agree... Actually there are some chances for me to go visit an argentine friend of mine who´s located in St. Petersburg, FLA sometime in 2007, that´s not too far from Texas if my geography is right...

BTW, Manu Ginobili and Fabricio Oberto are big stars up there, right? Thanks to them and some other argentine players, many many people watch the NBA games on ESPN down here and basketball now attracts big crowds in this country of great football (sorry, soccer:P ) heritage.

Cheers.

Manu is the face of the Spurs on TV. He does more commercials and spots on TV than any of the other Spurs and is probably the most popular player. Fabricio just broke into the regular playing rotation this year and is making the most of his time. When the Spurs won the NBA championship two years ago, they didn't raise a banner that said "World Champion San Antonio Spurs" like in previous years in deference to the Argentine team's World Champtionship. The Spurs' banner said "NBA Champions".

Hey guys, I´ve been hanging around the Chit-Chat forum because I´m still forced to move around in my can (1981 Honda Accord saloon, just love retro jap wheels )... My bro-in-law just bought my Z550, he was too fond of the bike to give it back to me, and I needed some cash, my baby-boy was born last August...

My GPz550 never started, so I finally took her to the mechanic. After several attempts to start it and the standard checking procedure that pre-diagnosed a timing issue, the guy decided to tear the top-end apart to take a look. He budgeted me the equivalent to 50 bucks for disassembly and diagnose labor, to be deduced from the final budget in case I approved it.

Once top-end was open, and to my dismay, bad news showed up: all 4 intake valves were bent, 2 of them a lot more than the other pair and the pistons tops showed clear hit marks. Evidently, timing was too far off resulting in that mess.

I´ll never trust my Clymer anymore, I swear everything was done strictly and carefully by the book but anyway something went wrong. One detail: I noticed a slight resistance at one point when rotating the engine manually, which I thought it was normal... Can my bike have another camshaft installed, or is this a chain-jumping issue?

The good side of this story: new intake valves, valve lapping, new valve stem seals, new rings, new piston pins, new cam chain and new gaskets. I expect it to run like hell after this unexpected 500 schmuckaroos bill!

If all goes well, I´ll be riding her by the weekend. Wish me luck!

if thats the worst thing you ever do,you are doing better than most of us!

Yeah, this is my first major screw-up, but still I¨M TOTALLY PISSED-OFF!!!!!!!!!!!

:sick: :pinch: :blink: