A Little Advice Please!!!

[Boozy Creek Beast]

I am working on my winter projects at this time and could use a little advice. My Bike is a 1980 GS1100E with an new 1166 kit and a V and H header. I am working on installing a Stage 3 Jet kit, Individual Air Pods, and Adjustable Cam sprockets. I have been trying to find a step by step procedure for adjusting my timing using the New Cam Sproket. At This time the only one I could find was provided by Biker 66 http--medlem.spray.se-biker661-index.html. This is my first time trying this mod and at this time I have no reason not to belive Biker 66's layout but I thought I would ask a couple of others that may have done the work if this is the correct procedure or is there a better way to do it. Any advise would be appreaceted.

The Beast

 

[Boozy Creek Beast]

here is the web site for the Procedure:

http--medlem.spray.se-biker661-index.html

 

[Boozy Creek Beast]

And for the 3rd and final attempt:

http//medlem.spray.se-biker661-index.html

Go to Modifications and then to Camtiming.

 

[ArttuH]

I have used that procedure without problems.

I just had hard time to believe the numbers which I first measured from the stock engine. The timing was about 10 degrees off from the factory specification.

 

[Mike McNaney]

10 degrees off isnt unusual for aftermarket cams. All companies recommend degreeing in their cams for the application (racing)

A stock cam should'nt be that far off. Are the cams aftermarket?

 

[RacingJake]

Here some more info on it, but before you ever start the bike up double check the timing and valve to piston clearance.
GS 1100/1150 - 0.050 Int., 0.075 Ex at the least, more is safer

Timing cams


"""This one is a little bit trickier, not difficult, but you will have to think about what you are doing.


What you need

Of course you've got to have slotted sprockets on the camshafts, it'll be bloody difficult changing their timing if you don't.
You will also need a dial indicator, some way of attaching it in a suitable place, a piston height indicator, a degree wheel that will fit the small end of the crankshaft and a steel wire.
A real piston height tool would be nice. I don't have one so I drilled through an old spark plug, chamfered the edges and put in a long enough bolt. It only needs to indicate the uppermost centimetre of piston travel or so. Or, put a large screwdriver down the spark plug hole. Just make sure it won't scar the piston or get pinched in the plug hole.
A piston stop can replace the piston height tool. Look for 'piston stop' in the mods menu.

A degree wheel is best purchased at your local dealer, I made my first one out of cardboard, it works but. . .


Begin

Remove valve- and ignition cover and spark plugs.
Check valve adjustment.
Mount your degree wheel on the crankshaft and fit a piece of steel wire under a clutch cover bolt to use as a reference.




Two ways of finding TDC

This is important, do it carefully!

Install your piston height tool in No1 spark plug hole.
Mount your indicator to read on the piston height tool.

The principle is to turn the crankshaft clockwise until your indicator shows the piston has reached its highest position, then adjust your degree wheel/steel wire setup to indicate 0º.

So, turn the crankshaft to a position, say 0,2mm BTDC and make a reading off the degree wheel.
Turn the crankshaft past TDC to the same indication, 0,2mm ATDC and make another reading. Divide the difference between the readings by two, add the result to the lower reading.
Rotate the crankshaft to whatever you ended up with and adjust the steel wire to 0º.



Or, use a piston stop. Make sure no1 piston isn't at TDC and mount the piston stop. Carefully turn the crankshaft both ways until the piston touches the stop, making a reading off the degree wheel at both stops. Remove the piston stop. TDC is located between these readings.


Now the actual timing !

Move your dial indicator so it measures against one of the valve spring washers on No1 intake, zero it or make a note of the reading with the valve closed.


This is my setup.

Turn the crankshaft until the indicator shows .5mm valve lift, write down the reading (R1) off the degree wheel.
Turn the crankshaft again past valve max lift until it returns to the .5mm reading, write down the reading (R2) off the degree wheel.
Use the readings R1 and R2 in the following formula :



R1 + R2 + 180 / 2 - R1



Example: R1 = 15 R2 = 59

15 +59 +180 = 254 (duration)

254 / 2 = 127

127 - 15 = 112º

If the timing is off you need to loosen the sprocket bolts and turn the crankshaft correspondingly.
Recheck timing before you tighten the bolts to specified torque, clean the threads and don't forget to use Loctite.

Move your dial indicator to measure against one of the valve spring
washers on No1 exhaust and do it all over again on the exhaust cam.

For a GS1100 80-83 with standard camshafts Motospeed recommends 109º/108º respectively for intake/exhaust, Cope Racing recommends 110º/110º.

Quote:
On your bike, the cams are not degreed to a specific setting, they are degreed within a range. On the early GS's the range can be about 100-115+ degrees. This is the main reason two identical bikes will perform differently right out the door. If you have the cams degreed around 110, this will result in more top end/horsepower, but the low/midrange torque will suffer. If you degree the cams around 100-102 you will have more low end torque. I had both my intake and exhaust cams timed at 106 degrees for what I consider the perfect compromise between top end/horsepower and lower/midrange torque.
Higher degreed cams (112-115+) will result in slower warm ups, a hotter running engine, the carburetion is difficult to set correctly and a narrower powerband.
With your cams timed at 104-106 degrees, you'll have a broader powerband, better throttle response and the best compromise between peak and low rpm power, gas mileage will be at it's best too."""

 

[BadBillyB]

I always use a homemade piston stop tool made from a gutted spark plug, a good quality dial indicator and the biggest degree wheel you can find (the bigger the more accurate)......Mounting the degree wheel was always the most hassle. I used a very large aluminum degree wheel, maybe 10" or so, and super glued it to the left end of the crank. This way I could turn the motor from the ignition side without worry of bumping the wheel. It takes 2 people to do it this way though. One turns the motor and the other marks the wheel.....Once you find exact TDC, check your factory mark behind the ignition plate and make sure it is accurate as this is the mark that you will use and trust when you set your ignition timing....If you understand the meaning of the lobe center numbers it will help you to understand the procedure. Intake cam LC is measured from TDC to Max lift......Exhaust LC is measured from Max lift to TDC....Good article from the pages of Star Racing
http://www.starracing.com/Cam%20Lobe%20Center%20Explained.htm

 

[Boozy Creek Beast]

Thanks for the help. I have not started the work yet and at this time I do not think I am going to. I am a little uncomfortable with this process. I am not planning to race the bike so I am wondering do I need to worry about that little bit of gain. I am running the orginal Cams so I am wondering if it will help much at all. I think I am going to hold off on the Cam Timing and work on the Carb. adjustment that I am going to have to do after I rejet to a stage 3 with pods. I am sure I will be asking for some advice for this project as well. Again thanks for all of the help!!!!!

The Beast

 

[ArttuH]

10 degrees off isnt unusual for aftermarket cams. All companies recommend degreeing in their cams for the application (racing)

A stock cam should'nt be that far off. Are the cams aftermarket?

The cams are stock. If I remember correctly the timing was something like 106/115 In/Ex. So the intake was pretty close to the spec but the exhaust was a way off. When I first got these numbers I thought that I did something wrong and repeated the measurement several times but finally I had to believe.

It's pity that I didn't degree the cams when the engine was normally aspirated. Now the engine was already turbocharged and therefore the results of the adjustment weren't so clear.