couple of Cam questions

[paco13]

I am trying to determine the lift of my cams in my 16V 1100E. Or basically what cams they are, since they were put in before I owned it. was told they were performance and it deff. runs stronger than my friends stock 1100E.

When cam MFRS. list lift #'s (example, 348 webb) is that # gross lift @ valve, or lift @ lobe?

When I measure mine (with dial indicator) @ valve spring retainer I get .349". Note this is with .005" valve lash.
when measure @ cam lobe (same valve's) I get .241"

Of course I have no idea how many miles/how much wear is on these.
They have APE adj. sprockets, the rockers have been ground @ the oil hole, this leads me to believe they are aftermarket, or there were some in there at one time.

Thanx in advance, more questions to come probably.

 

[Guest]

I know the Web cams at .348 lift they say you have to grind the rockers. It sounds like with your measurement it is the travel of the valve.

 

[paco13]

Thanx Chef,
I was pretty sure the #'s were @ the valve but was looking for a second opinion. Whether or not its with 0 Lash or running Lash is another question. But it does look like they are in the nieighborhood of the web 348's.
I think I need to check there timing though. I am having an issue with fuel spit-back soaking the air filters. The idle is kinda lopey and loads upwhen warm. Runs fine on the throttle, and no amount of jetting/float/screw adjustment up or down seems to make a difference. Everything in the carbs is brand new Oem Suzuki or Mikuni, Floats, needle/seats, O-rings etc. There has been porting done to the head.

The compression #'s 150 to 155 across the board Dry on an ice cold engine, this should be good right?

 

[Steve]

It is my impression of valve lift numbers that they reflect valve opening. In the case of 8-valve Suzukis, the lobe height would be the same as the valve lift because the cams are directly over the valves. In the case of 16-valve engines, it would be a bit less, as you have noticed, because of the leverage of the rocker arms.

With the fuel spitting back through the carbs, it sounds like the intake valve is closing a bit late. What can make it close late:
1) Incorrect cam timing. Make sure you have the proper number of links between the reference marks on the cams.
2) Tight valves. Make sure you have the correct clearance, maybe even go toward the larger side of the acceptable range.
3) You say you have adjustable sprockets, you might have to advance the intake a couple of degrees to close it sooner.

Good luck, let us know what you find.


.

 

[Guest]

Try 107 degrees intake and exhaust.

 

[paco13]

Thank you Steve.
Was thinking the intake timing could have something to do with it.
Looks like I might be looking for new cams any way.
When measuring at the valves I am getting about .010-.015'' more valve lift on cyl.'s #1 and 2 than on cyl.'s 3 and 4:shock:. Is it common to have some variance in cam lobes? There is some noticible wear on 3/4's lobes. Could this be from startup/warm up with bike on side-stand, less oil getting to left cyl.'s ?

Now what Cams should I go for? Any opinions?
It has 1170 kit, stock carbs, Dyna S ign. and green coils, ported head but know not what was exactly done, V/H header, Modified clutch basket.
Is ridden on the street.

 

[Guest]

Sounds like you can drop in some Web Cams .348s.
Clicky

 

[Steve]

Could this be from startup/warm up with bike on side-stand, less oil getting to left cyl.'s ?

Who moved your side stand to the other side of the bike? :shock:

All references to left/right on the bike are from the rider's viewpoint when sitting on the bike. Therefore, the sidestand is on the left side (unless you moved it).

Similarly, the cylinders are numbered left to right: #1 is under the clutch hand, #4 is under the throttle hand.

How long do you warm-up the bike? It should not have to sit for more than half a minute or so on the side stand while you get your helmet and gloves on.
If you wanted to be anal about it, you could sit on the bike, bring it off the side stand, start it, put on your helmet, then ride. A properly-tuned bike will be ready to drive off (although gently) in that amount of time.

 

[paco13]

Steve,
Sorry bought that my mistake I meant to say less oil to right side. I'm aware of cyl. numbering left to right. # and 4 are the ones showing wear.

I don't let it idle for long, but was just wondering if over time (like a couple/few years), since at initial start up the bike is leaning to the left could this cause the right (3/4) cyls. to wear a little more than the others? When cold I usually start it and leave it on the side stand while I put my Helmet and gloves on before I sit on the bike. Maybe a minute.

Thanx again.

Chef,
I probly will go with the 348's when I have the cash, gonna have to sell my 750 or 1000 I think to have some money to play with.
Might try the timing #'s you suggested on these to see if it makes a diff and gets me by for a while.
Its in the teens here with snow and ice everywhere, so won't be riding for a while anyhow.

 

[paco13]

Quick update,
Checked timing; intake was set at 116 lobe center @ .040 lift
Exhaust @ 111 LC

Moved Intake to 107 @ .040, am gonna leave exhaust at 111 and see what happens. Won't be able to test right away though
Gonna set lash to .006" on all.

 

[rapidray]

You don't see the actual lift measuring the cam like you do measuring at the retainer because the GS rocker arms are a 1.6 to 1 ratio. Ray.

 

[srsupertrap]

Hi Paco13,

I have been reading the thread with intrest and perhaps this may help identify your aftermarket cam:

1) Many aftermarket cam manufacturers emboss their cams with a P/N or grind, usually at the ends along the rotating axis. That's were Andrews marks their cams. Have a look

2) I would hold off on replacing your current aftermarket cams. Why? The cam lobe finish is usually nitrided or precipitation hardened which translates into one tough surface. I would inspect it for scoring and then measure with a D/C before assuming the worst.

 

[Frankenzuki]

cams

cams

You cannot check the cam centerline at .040" lift. Cam centerline is the absolute peak of the nose of the cam. However you came up with the numbers you did, you did something wrong.

You need to determine top dead center of the piston, then zero your degree wheel at that point. Move your indicator to the valve and rotated the motor until it reaches max lift. go past max lift .050" and recored the number on the degree wheel. rotate the motor backwards past max lift and then to .050" less than max lift. record that number. Add the numbers up and divide by two and that is you centerline

No sense in bending any valves!

 

[paco13]

Thank you all for responding.

Ok both cams have CM G 21 stamped on the ends.

The method I used to get #'s was from Starracings site.
Start @ TDC
go to .040 lift take #
go past max and down to .040 lift before closing take #.
add #'s plus 180 = Duration.
divide by 2 and subtract smaller #.
Is this wrong?
I thought you shouldn't reverse rotation due to chain slack screwing with degrees?

 

[paco13]

Also,
I remeasured .360'' lift taken @ the spring retainer. With .005 valve lash.
and come up with 250 degrees duration.

 

[srsupertrap]

Paco13,

The method Frankenzuki mentioned is the easiest way of determing the cam center line angle with one suggestion. The Star method you described is also a equidistant method of measuring C/L angle.

Degrees are crucial . . . You have got time so remove your stator cover & install a metal degree wheel unless it real warm in NY. Locate TDC on # 1 by installing a positive stop in a spark plug (break out the electrode from a fouled spark plug & install a bolt). Don't depend on the TDC mark located under the ignition cover. You will have to rotate the crank slowly forward till it kisses the spark plug stop (Record the value). Turn the crank backwards slowly till it kisses the stop (Record again). Adjust the TDC Wheel to zero by splitting the difference between those values. Verify TDC by rotating forward & back again and you have TDC when you record the same number either side of the positive stop.

I share your concern about turning the crank backwards because it may introduce slack or backlash intro the measurement. Without going into a lot more detail I have an article on adjusting Cam C/L angles which I can scan & post for you on Wednesday. It's geared for a SOHC cam but the fundamentals are the same. The process of measuring Cam C/L angles takes practice and once you understand the method and then verify the results repeatedly you will always understand the fundamentals of dialing in Cams.

PS: Back to cam wear. I don't recognize the manufacturer you mentioned. I would also inspect the forked cam followers for wear; they may be contributing.

 

[Suzuki_Don]

Hey there SRSUPERTRAP. Any chance you can put a copy of that scanned article on adjusting Cam C/L angles on the post or would you mind sending me a copy as I too am trying to dial in and degree my cams at the present time. Sorry if I am hijacking this thread.
Cheers
Don

 

[srsupertrap]

Hello,
I have found some useful cam degreeing information & articles. Let's see if any of our fellow GS1100 drag racing & monster motor guys can help with following question . . . .

1) Can anyone identify the Cam manufacturer with the CM G21 marks that Paco13 has found. If we can cross reference that information than all you have to do is contact the manufacturer and download their specific cam specifications & degreeing instructions. In lieu of that . . .

2) Here is the article on finding Top Dead Center. The large photo on Page 27 is incorrect, mount the TDC Wheel on the alternator end as stated, not the ignition side. I have found if you mount the TDC Wheel as shown and turn the crankshaft backwards (CCW) you will loose the measurement and will have to start all over again.

http://www.mediafire.com/download.php?b9j9lzzlvnu

3) Here is the Cam Degreeing article that ties it all together. We still need to know your manufacturer's C/L angle. Study the illustrations. Adjust, verify & check again. Once you get the hang of it your final verification & tightening of the cam sprocket bolts should be done in the clockwise direction.

http://www.mediafire.com/download.php?aj0emhylwj9

PS: I would shy away from using Red Loctite on the cam sprocket bolts. That stuff is a mother to break free.

 

[rapidray]

Trust me on this one, as an engine builder, I use red loctite on EVERY cam sprocket bolt I install. If you ever have one come out you will ALWAYS use red loctite too! There is NO difficulty in removing the bolts with the red on them & we even WELD them on really BIG cams to keep them from moving. Even if the bolt doesn't come out, if it comes loose & allows the cam to rotate on the sprocket it can change the timing enough to tag all the valves. Either way it is VERY expensive. Good luck, Ray.

 

[Frankenzuki]

cam timing

cam timing

Well, you're right about the chain slack, if you are using a stock chain adjuster you will have a problem, less so with a mechanical adjuster. If you can check where max lift is and the do it all in one rotation check .040" before and .040" after and do your math from there.

Ray is right about the loctite. If it moves you will probably either have very poor performance or at worst hit some valvetrain.