valve adjustment

[ford_raccoon]

I adjusted my valves yesterday to the loosest clearance on my 79 gs850. I started it and it ran pretty good and seemed to have more compression than before. But after having it running for about 15-20 minutes it started running the same as it did before. Is it possible that I need to adjust them again. Oh and one more note I was expecting some valve noise as per how I adjusted them but its still as quiet as before I adjusted them.

[twr1776]

Here is some info if you have not looked at it yet from Cliffs site. If you are confident you did the valves adjustment correctly and your carbs are clean with new o-rings move on to the air leak & ignition area. That is most likely where your problem is. Most here go in this order adjust valves, clean carbs (fully dipped not sprayed), air leaks, & ignition/charging system.


***********Quoted from Mr. bwringer************

Every GS850 [and most other models] has (or had) a set of well-known issues that MUST be addressed before you have a solid baseline for further troubleshooting. It's a vintage bike, and it's quite common (as in, every single GS850 I have had contact with) that there are multiple problems that have crept up and slowly gotten worse over the years. It's not like a newer vehicle, where there's generally one problem at a time.

These common issues are:

1. Intake O-rings (install NEW OEM or Viton only - common nitrile O-rings will quickly deteriorate from heat)
2. Intake Boots (install NEW -- these cannot be repaired)
3. Valve clearances (more important than most people think)
4. Carb/airbox boots
5. Airbox sealing
6. Air filter sealing
7. Petcock (install a NEW one)
8. On '79 models, install new points or Dyna electronic ignition (or at least verify that the old points are working correctly)
9. On all models, it's fairly common to have problems with the spark plug caps. These are $3 or $4 each, and often worth replacing if you're keeping the stock coils/wires.
10. Stock exhaust with NO leaks or holes -- good seals at the head and at the junctions underneath.


What I have noticed at the rallies is that very, very few 850Gs are actually running right. Make VERY sure it's actually running the way it's supposed to before busting out the modifications.

Brian's E-Z and fun plan for GS850 happiness:

1) Seal the airbox and air filter with weatherstripping.

2) Ensure no intake leaks. Spraying WD-40 or water doesn't tell you much, since very small air leaks can cause problems even though they won't suck in enough WD-40 to make a difference. Replace your intake boot o-rings and boots if needed, and seriously consider spending the lousy $28 for new airbox/carb boots.

3) Ensure clean carbs with correct settings, new o-rings, and original OEM jets. No, not just squirted with something. I mean completely disassembled.

4) Check/adjust valve clearances (Manual calls for every 4,000 miles. This is not optional.)

5) Ensure healthy electrical system.

6) Seriously consider upgrading coils and plug wires.

7) Install new, stock NGK B8-ES plugs gapped to .031".

8 ) Fine-tune float height and idle mixture screw to ensure best off-idle transition.

9) Clean air filter and reinstall with only the lightest oil mist -- over-oiling and/or letting the filter get dirty is a common and critical mistake, and will make the bike run funny at low speeds and run rich. This may take a few tries.

10) Make sure the exhaust seals are sealing.

11) Ooh, much better now, huh? You're gonna need upgraded suspension - Progressive or better fork springs and shocks. Set suspension sag appropriately.

12) Upgrade brakes with new pads and stainless lines to deal with all that extra speed.

13) Install new petcock, since I'm going to head to the roof with a rifle if I have to read about yet another #2 plug fouling and failed hillbilly attempts to rebuild the petcock and/or deny there's a problem.

14) Oh yeah -- check compression somewhere in there to ensure the valves and rings are reasonably healthy.

15) You'll probably need new OEM clutch springs -- the clutches last forever, but the springs get tired after 20 years or so under pressure. E-Z and cheap.

[bwringer]

The correct valve clearances are still very, very small compared to most engines, so you won't really hear them tapping.

Your problem lies elsewhere.

[Steve]

... But after having it running for about 15-20 minutes it started running the same as it did before. ...

Was it running poorly before?
(You didn't really say.)

You made no mention that you adjusted the valves to correct a problem. Since it's a normal maintenance item, we think nothing of adjusting the valves. Since it appears to now be running like it was before, what are the symptoms?

The clearance on these valves is so small (when cold) there is no chance for them to make noise.

May I suggest another tool for your toolbox? Look at the last part of my sig for info.

.

[ford_raccoon]

Ok sorry to skip a step and lead yall to where I am and not knowing where I've been. The bike was running but very poorly would not accept throttle till the engine was hot, then when you would twist the trottle you could hear the engine sucking in huge amounts of air but the engine rpm would not increase. Sound like if it was bogging. So I checked the carbs they are clean with newer o-rings and gaskets. I put NEW intake boots between the head and carbs and adjusted the valves. It seems to run better thats for sure, but I went to take it for a ride around the block and she had NO power, would rev fine but would not accelerate hardly any. So now at this point I am stuck

[ford_raccoon]

Well I just pulled my carbs to check them as it has to lie in the carbs. I find out 3 of the 4 fuel mixture screws (if thats what they are called on the bottom of the carb) are broken off in the carb. Somebody forced them in there and now they are stuck so I'm trying to figure out a way to get them out. I'm not 100% sure this is the only cause but I know its part of it.

[Nessism]

A long awl can be used to push those broken fuel screw tips back out of the carb bodies. After you get them out I suggest getting a carb O-ring kit from cycleorings.com, new carb boot O-rings, and some GS750 carb kits from Z1 Enterprises (this is the only easy way to get new fuel screws). Break the carbs down all the way and clean them out by soaking the carb bodies in carb dip followed by installing the new O-rings. Keep those carb kit parts for back up, the stock Mikuni brass parts are higher quality than those aftermarket parts but you can use them if necessary. The GSR homepage has a VM carb rebuild tutorial in The Garage section. Please use this for reference and do the cleaning job right - don't just spray some carb cleaner spray on them or you will most likely have to do the job a second time to do it right.

Good luck.

[Theo]

A long awl can be used to push those broken fuel screw tips back out of the carb bodies. After you get them out I suggest getting a carb O-ring kit from cycleorings.com, new carb boot O-rings, and some GS750 carb kits from Z1 Enterprises (this is the only easy way to get new fuel screws). Break the carbs down all the way and clean them out by soaking the carb bodies in carb dip followed by installing the new O-rings. Keep those carb kit parts for back up, the stock Mikuni brass parts are higher quality than those aftermarket parts but you can use them if necessary. The GSR homepage has a VM carb rebuild tutorial in The Garage section. Please use this for reference and do the cleaning job right - don't just spray some carb cleaner spray on them or you will most likely have to do the job a second time to do it right.

Good luck.

Actually it is possible to get those screws all by themselves.

http://www.z1enterprises.com/detail.aspx?ID=2568

[Nessism]

Actually it is possible to get those screws all by themselves.

http://www.z1enterprises.com/detail.aspx?ID=2568

z1's site seems to be down but I've never seen pilot fuel screw being sold separately.

[Theo]

z1's site seems to be down but I've never seen pilot fuel screw being sold separately.

Great. Now z1 is making me look like a liar.

[PKcb650]

I got them from Z1, can't post the link Z1 site down now.

[Nessism]

Great. Now z1 is making me look like a liar.

You guys realize of course that BS/CV carbs have different pilot screws compared to VM carbs which have seperate pilot fuel screws and pilot air screws right?

[Steve]

Actually it is possible to get those screws all by themselves.

http://www.z1enterprises.com/detail.aspx?ID=2568

Right idea, wrong screws.

He has a '79 850, which means that he has VM carbs. As Nessism mentioned, getting the carb kits from K&L seems to be the only way to get those screws.

.

[PKcb650]

Sorry, didn't realize he had 79.

[Theo]

You guys realize of course that BS/CV carbs have different pilot screws compared to VM carbs which have seperate pilot fuel screws and pilot air screws right?

Right idea, wrong screws.

He has a '79 850, which means that he has VM carbs. As Nessism mentioned, getting the carb kits from K&L seems to be the only way to get those screws.

.

ooops . I could have sworn I saw CV mentioned somewhere. Sorry.
-Theo