Questions on valve adjustment Help!!!

[jimfj]

1979 GS425 16xxx miles. Bike runs pretty good and just wanted to check valve clearance as part of maintenance. This is my first time at doing this. Spec for this engine 0.03mm to 0.08mm

My smallest feeler gauge is 0.04mm or .0015 inches. I cannot get this to go under any of the 4 cam lobes. When I am trying this they are set at a 180 degree angle to the cylinder head surface. Or the pointed end of the lobe is facing up between the saddle bolts.

Am I doing something wrong or are they just this tight?

Is the guage supposed to go all the way under the lobe, between the lobe and the shim?

Please help with your answers

Thank you,

Jim

 

[paintmann111]

I could be wrong, but I thought the point of the lobe (the one on the left side of the bike, first lobe) should be facing towards the forks (front of bike).

 

[jimfj]

the Clymer manual that I'm using says to have the lobe for the valve you are checking straight up.

 

[Nessism]

For the four cylinder engines, when adjusting the exhaust valves you want the exhaust cam lobe facing directly forward, parallel to the cam cover surface. For intake valves, you want the cam lobe pointing straight up, at 90 degrees to the cam cover surface.

It's very common for the valves to be tight; they receed into the head as the system wears. Sometimes you need to go down two sizes if the valves have been neglected in the past.

Good luck.

 

[jimfj]

This is a twin or two cylinder, Does the lobe facing forward apply here too.?

Jim

 

[Nessism]

Found this for a GS500 twin, 450 should be the same.
http://gstwin.com/adjust_valves.htm

or this video... http://video.google.com/videoplay?docid=-2015554469142545363

Edit: Regarding the video, the guy just positions the lobes pointing away from the valves and doesn't get fancy by checking the cam position. On a twin I think this is okay but not a four - since the adjacent valve skews the cam in the bearing journal clearance if the cam is not in the correct position.

So setting the vaves either by the factory method or just pointing way should be fine on a twin.

 

[Steve]

For the four cylinder engines, when adjusting the exhaust valves you want the exhaust cam lobe facing directly forward, parallel to the cam cover surface. For intake valves, you want the cam lobe pointing straight up, at 90 degrees to the cam cover surface.

This is almost complete information. :shock:

When checking exhaust valves, the outer cylinder's (#1 or #4) cam lobe is pointing forward, the inner lobes (#2 or #3) will be pointing UP. Do not move the crank, you can check both of them. Then rotate the crank 180 degrees so the outer cylinder on the other side of the engine is pointing forward and the inner one is pointing up. Again, you can check both valves without moving the crank.

On the intake side, the outer cylinder's lobe will be pointing UP, the inner one will be pointing BACK. Check both valves on that side, then rotate the crank 180 degrees and check the other side.

The theory here is that both valves are untensioned which makes the clearance more consistant than if #1 was depressing the valve while trying to measure #2. On your two-cylinder engine, I would think that measuring with the cam lobe pointing away from the valve would be good.

What you need to do is to remove all your shims (one at a time) and note the size. There should be a number printed on the bottom side that indicates the thickness in millimeters. Look to see if you have one or more that are thinner than the others, move it to one of the other locations and measure the clearance again. This will help give you an idea what size shim you will need and minimize the number of shims that you will have to buy.

I will also send you a copy of my spreadsheet that will help you keep track of your shim sizes from one adjustment to the next. 8-[


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[Nessism]

Thanks to Steve for adding the detail I forgot. Team work at it's best.

 

[Wire Wheel Katman]

Turn the engine to TDC (firing) on no.1 cylinder and the cam lobes will be in the correct position to be checked (pointing upwards and outwards). Then turn the engine to TDC (firing) on no.2 cylinder and check those valves.

 

[BassCliff]

Hey howdy hey!

Hey howdy hey!

Mr. jimfj,

Looking at Mr. Nessism's link, I didn't realize that, on the new GS500s, you need to remove the carbs to adjust the valves. I'm sure you don't have to on the older GS400s, GS425s, and GS450s.

I've looked back over your posts and noticed that I've never given you the official "unofficial welcome". So here goes...

Let it be known that on this day you are cordially and formally welcomed to the GSR Forum as a Junior Member in good standing with all the rights and privileges thereof. Further let it be known that your good standing can be improved with pictures (not you, your bike)! :grin:

Perhaps you've already seen these, but I like to remind all the new members. In addition to the carb rebuild series, I recommend visiting the garage section via the GSR Hompage and check out the Stator Papers. There's also a lot of great information in the Old Q&A section. I have some documentation on my little BikeCliff website to help get you familiar with doing routine maintenance tasks (note that it is 850G-specific but many tasks are common to all GS bikes). Other "user contributed" informational sites include those of Mr. bwringer, Mr. tfb and Mr. robertbarr.

And here are some quotes from one of our dear beloved gurus, Mr. bwringer, with ideas on basic maintenance needs (depending on initial condition), parts, and accessories.

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

Carburetor maintenance:

Replace the intake boot o-rings, and possibly the intake boots. Here's the procedure:
http://bwringer.com/gs/intakeorings.html

Here's an overview of what happens with this particular problem:
http://cycleorings.com/intake.html

You'll also want to examine the boots between the carbs and the airbox. There's a good chance these are OK, but check them over.

And finally, if things still aren't exactly right, you'll want to order a set of o-rings for BS carbs from the GS owner's best friend, Robert Barr:
http://cycleorings.com

Once you receive these rare rings of delight, then you'll want to thoroughly clean and rebuild your carburetors. Here are step-by-step instructions that make this simple:
http://thegsresources.com/gs_carbrebuild.htm
*************End Quote*************
**********<quote Mr. bwringer>**********
Every GS850 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:

Intake O-rings (install NEW OEM or Viton only - common nitrile o-rings will quickly deteriorate from heat)

Intake Boots (install NEW -- these cannot be repaired)

Valve clearances (more important than most people think)

Carb/airbox boots

Airbox sealing

Air filter sealing

Petcock (install a NEW one)

On '79 models, install new points or Dyna electronic ignition (or at least verify that the old points are working correctly)

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.

Stock exhaust with NO leaks or holes -- good seals at the head and at the junctions underneath.
**********<end quote>**********
***********Quoted from Mr. bwringer***************
http://denniskirk.com
Put in your bike model and see what they have.

I would definitely double and triple the recommendations to use Cycle Recycle II and Z1 Enterprises as much as possible. These guys are priceless resources. Z1 tends to have slightly better prices, CRC2 has a wider range of goodies available. If you're near Indy and can bring in an old part to match, CRC2 has a vast inventory of used parts.

http://oldbikebarn.com seems to be slowly regaining a decent reputation, but it's still caveat emptor. They don't have anything you can't get elsewhere at a better price anyway.

OEM Parts/Online Fiches:

http://www.babbittsonline.com/
Decent parts prices. Spendy shipping. Don't give you part numbers at all. Useful cross-reference if you obtain a part number elsewhere. Efficient service.

http://bikebandit.com
Fastest. Middlin' prices. Uses their own parts numbering system to obfuscate price comparisons -- can be very confusing for large orders. Cheapest shipping, so total cost usually isn't too bad.

http://flatoutmotorcycles.com
Slow. Cheapest parts prices, crazy shipping costs. Don't expect progress updates or much communication. Real Suzuki part numbers.

http://alpha-sports.com
Exorbitant parts prices. Different type of fiche interface that's quite useful at times, especially with superceded part numbers. Real parts numbers. Shipping cost and speed unknown due to insane, unholy pricing.


Stainless Bolts, Viton o-rings, metric taps, dies, assorted hard-to-find supplies and materials, etc.:
http://mcmaster.com
Fast, cheap shipping, good prices. No order minimum, but many items like bolts come in packs of 25 or 50. Excellent resource.


http://motorcycleseatcovers.com
Great quality, perfect fit (on original seat foam), and available for pretty much every bike ever made. Avoid the textured vinyl -- it's perforated.


http://newenough.com
You DO have riding gear, don't you? Great clearances, always outstanding prices and impeccable service.
***************End Quote**********************

Here are extra links:

Cycle-Re-Cycle Part 2
http://crc2onlinecatalog.com/

The ever popular Z1 Enterprises
http://www.z1enterprises.com

The Rice Paddy (salvage/used)
http://www.ricepaddymotorcycles.com

Ron Ayers Motorsports
http://www.ronayers.com

Thanks for joining us. Keep us informed of your progress. There's lots of good folk with good experience here.

Thank you for your indulgence,

BassCliff
(The unofficial GSR greeter)

 

[Steve]

Dang, Cliff, I hope you have that 'welcome' saved somewhere so you can just copy-and-paste it. :shock:


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[BassCliff]

Need extra fingers?

Need extra fingers?

Dang, Cliff, I hope you have that 'welcome' saved somewhere so you can just copy-and-paste it. :shock:

I'm a fast typist. (j/k!) :---)

Thank you for your indulgence,

BassCliff

 

[Steve]

That's what I have suspected. 8-[


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[jimfj]

Thank you for the welcome!!!!!!!!!!!!

The valve adjustment is finished. :-D :-D :-D

Here are a few things I learned and or tried while completeing the job.

I was able to save and reuse both gaskets,

I did this by myself with the help of the Clymer manual and your online help.

It isn't half as hard as it sounds like it is, but it pays to be slow and methodical

I used the "wire tie" method of holding the valves open instead of purchasing the special tool. It was very, very easy to get the tie underneath the valve. Tons of clearance and made the shims fairly easy to grab with a small screwdriver and tweezers.

I do not believe my bike had ever had this done or it was so long ago that Reagan was president when it was. I had almost no clearance, ie .01 mm in some cases. I now have between 04 and .07 on everything.

Harbor Freight has a 32 blade set of metric and SAE feeler guages for $2.99. Decent quality.

The spreadsheet from Steve Woodin is awesome and he deserves MUCHO thanks for makeing it available.

Check with a local source for shim availablity before you crack the cover if you are in a hurry. Don't be content with a dealer saying "Yeah we got those" Ask what sizes they have and how many. I ran into a little bit of a problem finding just what I needed.

The Results:
The bike starts easier, and mine started well before, I thought.
The engine idles like a sewing machine.
The engine is much, much, smoother all the way through the power band, no more surges and it feels much tighter coming on and off the throttle.
Being a 425cc motor, you tend to use all the horses when you really get into the throttle so any little improvement or problem, makes itself known.

This will take me a little less than an hour next time--start to finish.

This bike will run like new with a carb synch but it was pointless till I got this done.

Again to everyone Thank you for the help and advice. It is greatly appreciated and I hope this might help someone else.

Jim

 

[Steve]

The spreadsheet from Steve Woodin is awesome and he deserves MUCHO thanks for making it available.

You are quite welcome. That is why it's available. 8-[

Anyone else interested a copy? Click on my name for my e-mail address, send a request. PMs don't work, I need to reply with an attachment.

This bike will run like new with a carb synch but it was pointless till I got this done.

I am glad you got these done in the proper order. You are right, there is no sense balancing the vacuum until you get the valves set to the engine can pull as much as it can. \\/


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