79 GS1000E Engine questions

[Dalisword]

Hi, I posted here in the past and received a lot of helpful information that got my bike running again. Alas, it was short lived, I had just redone the head gasket and camshaft(s) cover gasket as they were leaking and needed replacing. I also sprayed out the carb well. The bike started up and ran like a dream. After about 100 Miles (I rode this in a matter of 2 hours) something happened . Suddenly while coming back into town, my bike started instead of running it sounded more like a buzz almost. It had no power whatsoever and I ended up limping the last 3 miles home. I got it home (to my parents house because it was closer) and let it sit because i was in the process of moving. Finally I got a chance to come back to the bike. I completely tore down the carbs and soaked, new gaskets, new o-rings etc rebuilt them. I was having some troubles with running lean so I drilled out the main jets from 95 to 110 while I was at it because I have a 4 into 1 exhaust on the bike. I finally got the carbs finished today, put them back on the bike and now it starts and "runs" just like it did (with less popping which leads me to believe i still need bigger jets cause it still pops a little which is a totally different monster in itself. So... after going through the carbs and cleaning them to an immaculate state the bike still hardly runs... could I have burnt a valve? I just did a compression check and the compression is all over starting from left to right i got cyl 1 barely peaks at 5psi but doesnt hold the vaccuum. Cyl 2 peaks at about 50 psi but doesnt hold pressure and drops as it cranks. Cyl 3 does the same thing as cyl 1. Cyl 4 does the same thing as Cyl 2... What is the problem? If it is in fact a burnt valve, I will be calling the guy that does heads in the GS forum (Larry) tomorrow because I now live 2 hours away and cant work on it constantly. And I'm getting sick of spending all this time to no avail. PLEASE HELP!!!
-Dali-

 

[tatu]

Any obvious signs of leakage round the head gasket area?

 

[Dalisword]

Oil, but it's always leaked there. That's what got me into this whole debacle. I'm thinking (hoping not) the block might need decked... Unless my brand new snap-on torque wrench was off, and I overtorqued the bolts.

 

[Big T]

Okay, did you ever set your valve clearances?

Burning a valve would on affect one cylinder

Where did you set your carbs?

 

[rustybronco]

I just did a compression check and the compression is all over starting from left to right i got cyl 1 barely peaks at 5psi but doesnt hold the vaccuum. Cyl 2 peaks at about 50 psi but doesnt hold pressure and drops as it cranks. Cyl 3 does the same thing as cyl 1. Cyl 4 does the same thing as Cyl 2... What is the problem?

Sounds like it's time for a new compression tester. or at least check the schrader valve in the end of the hose and the compression release near the gauge for leaks. once the pressure gauge goes up on the gauge it should rise with each compression stroke until the cylinder can't compress the air any further. it should never leak back down until you release the pressure on the gauge.

 

[BadBillyB]

Sounds like it's time for a new compression tester. or at least check the schrader valve in the end of the hose and the compression release near the gauge for leaks. once the pressure gauge goes up on the gauge it should rise with each compression stroke until the cylinder can't compress the air any further. it should never leak back down until you release the pressure on the gauge.

My thoughts exactly, the scraeder valve is either bad or needs cleaning. Compression testers use a special valve, with very low spring tension. They must be free of debris. Pull the valve cover off and check your valve clearances. Check your valve timing while your in there.......Billy

 

[Dalisword]

My thoughts exactly, the scraeder valve is either bad or needs cleaning. Compression testers use a special valve, with very low spring tension. They must be free of debris. Pull the valve cover off and check your valve clearances. Check your valve timing while your in there.......Billy

Ya know, I was wondering the same thing, ill check it out next time I'm there, If my memory serves me correctly I had the same problem when I was checking a customer's compression on his car so you're probably right. Would there be any kind of correlation between the cylinders 1,3 and 2,4 being the same? shouldn't one of the cylinders be on the compression stroke, and one on the exhaust stroke at the same time?

Okay, did you ever set your valve clearances?

Burning a valve would on affect one cylinder

Where did you set your carbs?

I didn't check the clearances yet because I didn't take the valve cover off, could that be an issue even though it ran well at first?

 

[Steve]

I didn't check the clearances yet because I didn't take the valve cover off, could that be an issue even though it ran well at first?

Apparently you didn't clean the carbs, either. :-k

... I also sprayed out the carb well.

Just "spraying out the carb well" will not clean the carbs the way they NEED to be cleaned.

Besides, not only do they need to be cleaned, they need new o-rings, too. You can get them from cycleorings.com.

.

 

[Dalisword]

Apparently you didn't clean the carbs, either. :-k

Just "spraying out the carb well" will not clean the carbs the way they NEED to be cleaned.

Besides, not only do they need to be cleaned, they need new o-rings, too. You can get them from cycleorings.com.

.

Dear Steve,
Please read the first post before you start telling me I didn't do things. I clearly stated in my first post the first time I cleaned the carbs, I sprayed them, the second time I cleaned them I tore them down, scrubbed, blew out, put in new gaskets, and o rings. I do appreciate everyone's help, keep it up!

 

[mike_of_bbg]

Did you rebuild and reset your cam chain tensioner when you changed the head gasket? Check the cam timing. Could be a bad compression tester but you'd expect it to be bad the same way across the board. You holding the throttle wide open while doing the compression check?

As a quick check you can see if you can hold a finger over the spark plug hole while cranking WOT. Not a precise gauge but you can't hold back running PSI.

 

[Suzuki_Don]

So are you saying you removed the head and replaced the head gasket and did not gap the valves when you were reassemblying it.

 

[Big T]

I didn't check the clearances yet because I didn't take the valve cover off, could that be an issue even though it ran well at first?

It's not an issue in that the clearances suddenly chamged and made the bike run bad

It's an issue in that, once you get your carbs cleaned again and adjusted, changing the valve clearances will affect your carbs, causing you to adjust them again

You don't know how well it will really run until you're sure the valve clearances are right

So, while your carbs are soaking again:

1. Check the valve clearances
2. Set any that are off
3. Put the carbs back on - set the fuel screw at about 7/8 turn out and air screw about 1 1/2 turns out - be sure to be careful turning the fuel screws in, don't break them off
4. Tweak the air screws for best idle
5, Sync the carbs

 

[tatu]

It sounds like you will have to start the diagnosis again, a new compresion tester, check the valve clearance. Establish where you are. I don't think that a carb issue will produce a buzzing sound, but out of sync carbs will produce a popping and if you've pulled the carbs chances are they need to be balanced.
Drilling main jets is not a good thing to do because the holes have to be exact and accuracy at that level you can't do with a drill, each oriface will be different now. So balancing will be at best difficult and will vary due to throttle opening.
I don't think that a 4 into one will affect the mix (could be stand to be corrected, but not in my experience) However, air intake does, you don't mention if you have the original air box.
Do you know for sure that all cylinders are firing?
We need more information.

 

[2bluthumbs]

If you didn't release the cam chain tensioner after installing the head the bike would run fine until the chain jumps the sprocket. Thereafter the timing would be off and the bike wouldn't run very good. The chain running off the sprocket would make a "funny" noise. Take the valve cover off and take a look see.

 

[Dalisword]

So, while your carbs are soaking again:

1. Check the valve clearances
2. Set any that are off
3. Put the carbs back on - set the fuel screw at about 7/8 turn out and air screw about 1 1/2 turns out - be sure to be careful turning the fuel screws in, don't break them off
4. Tweak the air screws for best idle
5, Sync the carbs

I hadn't checked the valve clearances, I'm beginning to think that could have been a bad thing, I'll check those but it wont be a while until I go back and get a chance to work on it again.

It sounds like you will have to start the diagnosis again, a new compresion tester, check the valve clearance. Establish where you are. I don't think that a carb issue will produce a buzzing sound, but out of sync carbs will produce a popping and if you've pulled the carbs chances are they need to be balanced.
Drilling main jets is not a good thing to do because the holes have to be exact and accuracy at that level you can't do with a drill, each oriface will be different now. So balancing will be at best difficult and will vary due to throttle opening.
I don't think that a 4 into one will affect the mix (could be stand to be corrected, but not in my experience) However, air intake does, you don't mention if you have the original air box.
Do you know for sure that all cylinders are firing?
We need more information.

I think all four are firing because I just replaced the plugs and they're all black, our local suzuki dealer won't balance them unless I bring them in on the bike, is there anyone around Iowa that will do them off the bike? (If that's even possible?) I have the original air box and I have a uni filter for it but with it running lean i bought a paper filter to see if that would help at all, so i do have both filters. I was hoping to use the drilled jets for size purposes only, I figured if I could stop the popping then I would buy the actual size, I'm a college student, so I'm sure you can understand my financial situation. Will snap-on do anything with my compression tester such as rebuilding the valve or do I need an entire new one?

If you didn't release the cam chain tensioner after installing the head the bike would run fine until the chain jumps the sprocket. Thereafter the timing would be off and the bike wouldn't run very good. The chain running off the sprocket would make a "funny" noise. Take the valve cover off and take a look see.

I released the tensioner, but didn't rebuild it because it seemed to be fine still, and I actually had reset the timing a few times thinking something slipped, to no avail. So what I'm getting from you guys is I should probably sync the carbs (with non drilled "real" jets), check the timing and tensioner again, re compression test, etc... Another question, the oil that is leaking from the head gasket area, do you think it could be warped? do I need to get the block decked and checked? One more question, when setting the timing, there are two different marks (i dont remember exactly what they were cause it's been a while.) but there's the two different sides, then within those sides there are two different timing marks, what is the other one that you don't set it to?

 

[tatu]

Re carb balancing: On my last rebuild I could only borrow the old original suzuki ball type vacuum gauges and these were very old and in a bit of a state, consequently I failed. However, As it had new rings, reground and shimmed valves I know the engine to be in good nick.
I pulled the carbs wound off the throttle idle so that the slides were full down and with the fuel vacuum pipe blocked and tops off, adjusted the slides up to a small open clearance and then blew through the stub of the carb gently winding the slide adjuster screw down till the throttle sealed, I did this till all sealed, locked up the screws tops on and back on. For me it worked and it runs perfectly.
Unorthadox, deffinatly, and there are other factors to consider (state of valves, rings, ect) Big T's guide as to screws position is the right place to start.
Your dealer is entirely correct in not doing off the bike.
This is only to give you a place to start from.
The only way to know if the head is warped is to take it off and check it.
Timing the valves are done when the 1-4 tdc marks line up in the window (Not the 'F' mark) and the cam lobe marks align with the head.
Have you checked your points and ignition timing?
None of these things will give you a buzzing sound.

 

[mike_of_bbg]

A proper sync can only be done with a running engine and carbs on. It's not uncommon to do a "bench sync" with the carbs off; usually by getting the throttle plates barely open and using a feeler of some sort or light source to ensure initial even openings of the throttle plates. That's done so that, when it's time to sync for real, the carbs are not so far out of whack that a vacuum sync can't be done easily.

Sync should be done AFTER you check/adjust your valve clearances. The clearances affect the "breathing" capacity of each cylinder.

Quite frankly, I find it very very unlikely that carb synchronization is your issue. Carbs going out of sync is a gradual process over time, not normally a sudden event which corresponds with unusual noises and catastrophic loss of power requiring one to "limp home". Sync-ing your carbs is a fine idea, after they're tuned and all other engine issues have been sorted out.

A valid compression test is a good start. Of course you're holding a questionable tool, and that won't do. IIRC, Snap-On's warranty is basically just like Craftsman's in that once you escape the realm of standard hand tools you're looking at 1 year. If you have a Snap-on dealer near you go to them and see what they can do. Maybe it is just a bad Schrader valve and you can fix it for $1. Some parts shops will loan tools, so check with them to see if they can loan you a compression tester. Borrow one from a friend, or just buy one (what, ~$20?). If there's an HFT near you they sell one for $10.

You can also try out your current compression tester on something else to see if it will give a reasonable result. Maybe the tester is not THAT bad, but your motor is!

What kind of head gasket did you use? Was it an OEM Suzuki? MLS or standard? Did you have to install the corner crush washers and rectangular o-ring for the cam chain tube? Did you re-torque the head after the first few runs after replacing the gasket? Weeping oil from the head gaskets is unfortunately common, and not necessarily a sign of a blown head gasket. Though it seems that once they start weeping oil that replacement is the only option.

You said you checked the timing - is that ignition or cam timing? I could easily see a cam chain coming loose and skipping teeth. The loose chain would cause buzzing. The timing impact of the skipped teeth could definitely cause loss of compression and power.