So carbs, not so much, lets talk sparkys!

[Big Rich]

I think Jessie will agree with me, but a cold compression test is useful for checking for differences between cylinders. A warm compression test will tell how bad a cylinder is out of spec.

As far as the "thumb over the spark plug hole" trick - that just tells you that the motor isn't seized and there's not a golf ball size hole in your piston. 10psi will move your finger, but not move a motorcycle......

[adidasguy]

I got in a brand new original 1990 service manual. Nice! I was just quoting the manual.

[J_Walker]

well, I don't have the tool to check the compression, really don't want one as a birthday gift either.. So i'll be taking the heads off tomorrow and checking the valves.. anything I should be looking for? Other than burnt charred nasty valves or crushed/bent/non spinning valves.

[Big Rich]

You can borrow a compression tester from advance, auto zone or pep boys. Go and ask for one to use. You have to pay for the item in deposit, but when you take it back, they credit all the money back hoping you will now buy parts from them.

Just in case you missed it........

[J_Walker]

You can borrow a compression tester from advance, auto zone or pep boys. Go and ask for one to use. You have to pay for the item in deposit, but when you take it back, they credit all the money back hoping you will now buy parts from them.

Just in case you missed it........

Well the guy who was suppose to pay me my money, for stealing/breaking something of mine is now currently in jail for 3 days.. and I wanna figure out whats wrong before the end of this month... i'll see, but advanced auto discount near my house, are a bunch of A$$holes! long story short, they are thief's and scam artist. I'll call someone that May be able to help me. don't know if he has the tool or not..

[BaltimoreGS]

Might just be a terminology mistake but you only need to take the cylinder head cover off to check the valves, don't take off the actual cylinder head.  You'll need a decent feeler gauge ($10 or less) and basic hand tools.  You don't even need the feeler gauge to make sure the valve shim buckets move.  Let us know what you find.

-Jessie

[Twisted]

Use Kerry's video - http://video.google.com/videoplay?docid=-2015554469142545363

[gsJack]

I think Jessie will agree with me, but a cold compression test is useful for checking for differences between cylinders. A warm compression test will tell how bad a cylinder is out of spec.

As far as the "thumb over the spark plug hole" trick - that just tells you that the motor isn't seized and there's not a golf ball size hole in your piston. 10psi will move your finger, but not move a motorcycle......

Well maybe I've made it sound too simple but the finger in the hole compression test or perhaps more aptly descriptive "thumb over the spark plug hole" trick will tell you a lot more than that.  If you learn how to do it, it will tell you if you have enough compression to start and run well enough so it's a good place to start.  Once you've pulled the plugs to check for spark it only takes a minute to check for adequate compression first and when you're working on an unknown engine it's a good place to start.  Check compression, ignition, and then carbs.  I always give mine a quick finger compression check when I change bike plugs and I've never used or felt the need to use a compression guage on my bike engines for 170k GS500 miles and a prior 230k thousand miles on 4 previous Hondas. 

Now, as far as checking spark by putting a loose plug in the plug cap and holding it against the cylinder head that too is just a good starting point in checking for ignition but it will not tell you if that plug is firing in that engine under running compression.  At some compression pressure it will stop firing and that's how we use to check plugs before replacing, now if they pull them they just toss them and replace.  Plugs are cheap compared to current shop labor rates.  But this check will at least tell you that the pickups/module are making and braking the circuit to produce spark, another good starting point at least.

To be continued in next post--

[gsJack]

My 02 GS had a too tight valve bucket (tappet) from the factory and a finger/hole compression check showed no compression in that cylinder when cold.  As tight as that bucket was when cold it would start and run roughly and then quickly warm and loosen the bucket in a minute or so and the engine would then smooth out and run properly for the rest of the day.  I let it go for 20k miles hoping it would wear in but it stuck too tight one freezing cold morning and broke an exhaust valve when first cranking that I had to replace.  Buckets loosen and valve clearances increase as the engine warms with an aluminum head and overhead valves because the aluminum expands faster than the steel parts as the engine temps increase.

This same engine began running on one cylinder intermittently during this early 20k mile period and this was confirmed by pulling the plug wires at idle like was done above.  In my case the problem turned out to be a plug wire that was loose in the coil.  The coils are sold as an assembly with the spark plug wires bonded tight in place so if you have a loose plug wire it's going to be a problem.  Other possibilities for the engine to be running on one cylinder that have been experienced by forum members include a bad ignition pickup, a bad spark plug even though it was a new one, or a carb problem.  On a newly acquired bike the valve clearances should be checked as soon as possible although it would be rare to still have no compression on a cylinder after it's warmed due to a tight valve because the valve clearances increase a considerable amount as it warms.  But a too tight exhaust valve will have a shortened life.

[The Buddha]

10 psi wont move your thumb, atleast 50 psi ... more if its got good access which a naked GS does.
Cool.
Buddha.

[J_Walker]

Where can I get valve shims? if I turn out to need them, was watching that video. Suzuki GS500 Valve Adjustment, one. also where could I buy feeler gauges?

[BaltimoreGS]

Any decent auto parts store should have feeler gauges and possibly Sears' tool section.  Harbor Freight has them too.  I like to mic a new set of feeler gauges just to make sure they are accurate (especially if cheap).  You can get valve shims from a local Suzuki dealer or online.  I just ordered some from an online company but have not received them yet.  I'll give their name if they turn out to be a good source.

Technically Kerry checks the valves with the cams in the wrong position but his way should work.  Next time I have an engine open I want to check and see if the reading his way is the same as the reading doing it the way the Suzuki manual says.

-Jessie

[Big Rich]

Sorry Jack, while it may work for you i feel confident in saying it's not for everybody. The actual compression tester gives cold hard numbers. Know what I'm saying?

And sorry to you too Buddha - I'll change the expression to 50 psi next time as well.

[J_Walker]

K, I got a list of what I need for the most part, just have to find people who have the parts/stuff or the place. Trying to get a 3 shop stop with all my stuff.. Putting together a big list. been talking to Adidas, hopefully ill be able to order parts soon. Thanks for the info, Btw how is kerry's wrong? how are you suppose to do it?

[BaltimoreGS]

K, I got a list of what I need for the most part, just have to find people who have the parts/stuff or the place. Trying to get a 3 shop stop with all my stuff.. Putting together a big list. been talking to Adidas, hopefully ill be able to order parts soon. Thanks for the info, Btw how is kerry's wrong? how are you suppose to do it?

Before you buy anything, post your list here to see if anyone has it cheap or if you even need it at all.  All you need for the valves is a feeler gauge to begin with, you don't need valve shims and a valve shim tool if everything is in spec.  And even if it isn't, until you have a valve shim tool and remove and measure the old shims you will not be able to determine what size shims you need to order.

Kerry faces the cam lobes straight up when he checks the valves.  Suzuki has you align the R/T mark on the rotor to orient the cams a certain way to check the valves.  I have never checked to make sure the readings are the same on both methods.  If you check out the first part of Adfalchius' top end rebuild video she checks the valves the way the Suzuki repair manual says to.

-Jessie

[J_Walker]

Picture for all you picture whores.



Looks like it'd run?

feeler gauges, Shims, calipers, valve shim tool, whole new engine head gasket[I think that's the name], center stand, rear/front break caliper, rear break disc, new tires, rejet kit, various bolts, torque wrench,right heel guard. and some more stuff that I may have missed.. Will edit later. Seems like I need all this stuff. for now and later...