No compression after valve job still....

[hockey911]

I have 0 compression in either cylinder........

what i did....

Replaced 1 exhaust valve, lapped all 4 with grinding compound + suction cup... replaced stem seals... new head gasket...


I dont know what is wrong, i timed the bike, rotated the engine a few times by hand verified no interference issues....

Ran the starter with (old) sears compression tester (rubber type)

not getting any compression in either cylinder....

however when i place my hand over the intake boot i can feel a strong force pulling my hand in when the bike is cranking....

also can feel air moving from exhaust........ any clues...

i really dont want to pull the motor apart again..... :?

 

[Datsa Noydb]

If you can feel air moving at the intake and exhaust ports, I would seriously suspect your compression tester.

Get one that threads in to the spark plug hole.

 

[BigD_83]

Are you at wide open throttle when turning over? If so, I agree with Datsa Noyb

 

[Datsa Noydb]

He mentioned putting his hand over the "intake boot", rather than mentioning "carb intake", so I was guessing the carbs are not even installed.

 

[Guest]

Check your cam chain timing

 

[8ball]

You shouldn't feel ANY force pushing out the intake boot!! Only suction. The intake valves should be closed every time the piston moves up

 

[Datsa Noydb]

You shouldn't feel ANY force pushing out the intake boot!! Only suction.

Where did you get that idea?

Re-read his original statement:

... when i place my hand over the intake boot i can feel a strong force pulling my hand in when the bike is cranking....

 

[Guest]

Bad gauge...

 

[Nessism]

Please tell us you performed a valve adjustment.

Assuming yes, I'd double check the cam timing. It's sometimes difficult to see the marks on the advance unit.

 

[BigD_83]

He mentioned putting his hand over the "intake boot", rather than mentioning "carb intake", so I was guessing the carbs are not even installed.

Yes, point taken. I seem to be terminologically challenged over here in holiday land...

 

[hockey911]

Hi all happy holidays!


Timing, i set the timing on the lower to T| (lined up the | with the | ), placed the exhaust cam pointing out, placed the intake cam in and made the two upper arrows 18 links apart from each other and put the tension on, i may still need shims... i just bought a feeler gauge and it appears that all of them are far out of spec..... well i cant get the smallest metric feeler under the cam and the bucket...


maybe * this is causing my issue?


this is how i set my timing... a picture is worth a thousand words lol
http://ww2.justanswer.com/uploads/motoforge/2010-09-04_002115_GS450camtiming.jpg

 

[Nessism]

Hi all happy holidays!


Timing, i set the timing on the lower to T| (lined up the | with the | ), placed the exhaust cam pointing out, placed the intake cam in and made the two upper arrows 18 links apart from each other and put the tension on, i may still need shims... i just bought a feeler gauge and it appears that all of them are far out of spec..... well i cant get the smallest metric feeler under the cam and the bucket...


maybe * this is causing my issue?


this is how i set my timing... a picture is worth a thousand words lol
http://ww2.justanswer.com/uploads/motoforge/2010-09-04_002115_GS450camtiming.jpg

There are two T marks. One for the right cylinder and one for the left. You need to put the crank at T for the Right cylinder. Pull the spark plugs and make sure you can see the piston at the top through the spark plug hole.

Regarding the valves, wish I was surprised. You should be ashamed.

 

[hockey911]

There are two T marks. One for the right cylinder and one for the left. You need to put the crank at T for the Right cylinder. Pull the spark plugs and make sure you can see the piston at the top through the spark plug hole.

Regarding the valves, wish I was surprised. You should be ashamed.

Do you know what diameter shims i need for a 1982 gs450tx?

 

[Who Dat?]

The diameter will be 29.5mm. The thickness will depend on what you have in there now. You said you can't get your thinnest feeler in, but did not mention the thickness of the feeler. The clearance on these valves is VERY thin, 0.03-0.08mm, which is close to 0.0015"-0.003". Those are usually the thinnest feelers in a set.

Be careful if you get your shims at a multi-brand dealer. Kawasaki and Yamaha have shims that are 29,0mm in diameter and look very close, you have to measure them. Shims are available on eBay. You can also order them from Z1 Enterprises for about the best price going. Many have also joined the GSR "Shim Club" and reported success and happiness, so look that one up, too.

While you are in this process, look up member "Steve", he has a spreadsheet that helps you figure out what shim you need and helps you keep track of what is in your bike and what it will need next.

 

[hockey911]

Figured it out.... it was the shims.....

K&L shim starter kit ordered!

She holds compressed air when the shims are out (not cranking the motor)... and leaks like a son of a gun when the shims are in.... thanks!!

 

[Guest]

Hockey, how did things turn out after you changed your shims? What kind of compression readings were you getting? I am going through a rebuild and am still have compression under 100. Going to double check the timing and then measure the cam gap.

 

[hockey911]

Well my motor is dead right now (spun crank bearing)

If i remember it was around 150psi

 

[hockey911]

If you cant figure it out, remove the shim and perform a leak down test

https://www.youtube.com/watch?v=WgrfT0LFMhc

 

[Guest]

The K&L kit only goes down to 2.30mm, if you need a thinner one contact me. Ray

 

[gs11ezrydr]

Usually if you can spin the shims in the buckets by hand without much resistance most of the time they are not tight enough to effect compression while cold maybe when they get hot and expand they might. Now if you can't turn or spin them that means they are tight that will cause low compression by placing pressure on the valves. Like the other post said the clearance in very minimal. Just an old fashioned way I do a quick inspection. Then get out the thinnest feeler gauges. And check them. The feeler gauges don't lie. Got to watch with shims that are too thin they cause the bucket to make contact with the retainer and cause the valve to drop into the cylinder. Go to only the thinnest that is in the service manual shim chart to be safe. Thinner shims might get your clearance but gambling with possible engine damage. But like Ray said some of the kits don't go down to the safe minimum thickness only the Suzuki O.E.M.do. Some kits Like Hot Cams I have seen go beyond the safe minimum for certain models. Working at a dealership I see this often.