Hellllpppp need info

[RaZ]

I have been looking for what seems like ever for some info. I need to know the installed height and seat preasure of the 79 gs 1000 valve springs. My mechanic buddy/roadracer says my springs are probably wore out from sitting so long and will most likely cause valve float when i put the reworked head on. The only info i have found when it comes to springs is "heavy" (I am looking for measurable statistics here). Would also like to know the proper valve clearance as i belive the info in the book I have is wrong. I dont have it here with me but it was in the .0012-.0015 range I belive. I know it was definitly in the forth place decimal. Seems awful tight for an air cooled motor??!?!??

[Nessism]

Valve clearance is 0.03 - 0.08mm (0.0012 - 0.0031 inch). Most people around here like to set the clearance on the wide side of the range if possible since the valves tend to recess into the head with usage.

No clue about valve seat pressure. You might want to look up Jay from Ape (owner?) who hangs out here on occasion. Tons of knowledge there.

Good luck.

[Steve]

Can't help you with exact specs for your 1000, but I took a look in the factory manual for my 850 and found this:
The inner spring should require 29.3-34.0 kg to compress the spring 23 mm.
In English, this is 64.59-74.96 pounds to compress 0.91 inch.
The outer spring should require 50.4-58.3 kg to compress the spring 27 mm.
In English, this is 111.11-128.53 pounds to compress the spring 1.06 inch.

In real-world terms, I don't think the springs would be weak enough to worry about valve float. After all, the red line is there to prevent valve float. How often do you plan on reaching or exceeding red line? If you plan on living in the upper ranges of the tachometer, it would probably make sense to change the springs. For normal, more sane operation, what you have will work very well.


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[derwood]

no offence intended but i think your mechanic buddy/road racer is out to lunch on this one. The only practical spec for the valve springs is uninstalled height, the installed height would be determined by the distance from the head to the keepers on the valve stem with the valve closed.Weak springs or strong springs would not affect this, only valve seat recession would. not that it matters. There are VSI washers available to compensate for valve seat recession.

[RaZ]

This bike has been sitting for several unkown years.My buddy says that is one of the worst things besides excessive heat for a spring. We are goin to check my current springs and see what the seat preassure is at installed height. If they arent up to spec then they are goin in the trash and new ones will be put in their place......This bike will be more or less a weekend warrior so it will see the redline abuse. I do not want any valve float / broken valves. But on the other hand if the springs are still with in spec I dont want to have to shell out the money for new ones.

[RaZ]

Can't help you with exact specs for your 1000, but I took a look in the factory manual for my 850 and found this:
The inner spring should require 29.3-34.0 kg to compress the spring 23 mm.
In English, this is 64.59-74.96 pounds to compress 0.91 inch.
The outer spring should require 50.4-58.3 kg to compress the spring 27 mm.
In English, this is 111.11-128.53 pounds to compress the spring 1.06 inch.

Steve from the way that is writen i would assume that is from uninstalled height?
I did some measurments the best i could and came up with an installed height of around 1.4 inches. Would still like to know the seat preassure or at the very least a confirmation of the installed height......

now i realy wonder why the spring info i am looking for is realy hard to find and sorta seems like top secret info. Hel go look at any cam maker for a car and they tell you how much seat preassure and installed height you need for that paticular cam

[bwringer]

now i realy wonder why the spring info i am looking for is realy hard to find and sorta seems like top secret info. Hel go look at any cam maker for a car and they tell you how much seat preassure and installed height you need for that paticular cam

I think that's simply because it's never been a problem - the GS shim over bucket valvetrain is dead reliable with redline at a conservative 8-9,000 rpm. I've never even heard of a problem with valve springs or valve float. Not to say it can't happen if you're an idiot and overrev by 5,000 rpm, but you'll likely break many other things before you break the valvetrain. If you want to spin something that hard, go buy a new YZF.

These are not car engines -- they are conservatively engineered air-cooled motorcycle engines, and many of the principles that apply to built-up liquid-cooled pushrod V-8s simply have no application. (That's a nice way of saying your buddy is worrying you about the wrong things.)

If it really bugs you that much, cough up the money for new valve springs from Suzuki and then forget about it.

Also, throw away that feeler gauge marked in inches and spend the lousy $5 for a metric feeler gauge set. It's too easy to make an expensive mistake if you don't think in metric. The valve clearances on an 8 valve GS are supposed to be .03mm - .08mm cold. This is indeed a VERY small clearance, and it's very important to get it right and check it regularly.

[RaZ]

He is just cautious his bike had a weak set of springs on it and it cost him the championship race at road atlanta a few years ago.He is a fast rider and realy didnt have any compition localy so he never had to push his bike to redline.But since it was the championship race alot better riders from all over the country were there.He just didnt have the power down the back straight to keep up with the guy that won it altho he did come in second. He replaced the spings and came back to win it the next year. and semi retired after that.

With that being said i dont have the $$ to realy buy new springs if i dont have to.

[Nessism]

If you really NEED to know the seat pressure why not measure the installed height on your head and then calculate the seat pressure based on the spring rates provided by Steve? Add the inner and outer spring rates together. I agree with bwinger though, you are not likely to need new springs unless you are planning to run the engine for extended periods of time at redline.