timming chain and cams ?

[boba]

I have a 79 gs850, I replaced the cylender base gasket and head gasket, Following the instructions in the manual for this bike, everything was put back together the way it said, but i dont understand this..

The timming mark is lined up correct with the mark on 1-4, the pistons are at top center. The intake cam gear, has #3 stamped with arrow pointed straight up. counting pin @ arrow 20 pins over should be the exhaust gear and #2 arrow stamped on it (20th pin) and pointed straight up, and lined up with the gasket surface should be #1 w/arrow.

I have this peice with a gear in it that goes over the cam chain in the middle. when I put that on the exhaust gear moves backwards. then the arrows are now pointing at oh I would say 1or2 minutes before the hour if you were looking at a clock withc would be if i took and moved the gear itself back 1 pin. that would make 21 pins between arrows. (all this is set to #1 piston under clutch handle side.) should the pin count and arrows be lined up straight with this idle gear peice on of off. cause there is a lot of slack without it. (picture attached)

Now what should the cam lobes be doing? and what way should they be pointing??

currently they are pointed inward. on #1 and outward on #4 . If I move the crankshaft in running direction, the intake is going to open on #1.

But If i read the book right and understand what it says, With the cam gears lined up 20 pins and the arrows in the right place, the points timming mark lined up, shouldnt #1 be at the fire instead of what appears to be intake? cause intake is going to open and piston goes down.

 

[Nessism]

1) Line up the 1-4T mark on the crankcase, and make sure No 1 piston at TDC (remove a spark plug and look for the piston at the top)

2) Make sure 1 mark on Exhaust cam sprocket is parallel and pointing to the gasket surface

3) Count the pins between 2 on the exhaust cam and 3 on the intake cam - should be 20th pin as you noted.

Don't worry about 3 pointing up or what ever, time the exhaust cam to the crank, and then time the intake cam to the exhaust.

Good luck and hope this helps.

 

[DimitriT]

As Nessism points out the trick is to align the exhaust cam with the chain and crank and then the intake cam to the exhaust cam.

So before you put the chain over the exhaust cam make sure the chain is not kinked or
bound up in any way near the crank. I usually turn the crank one or twice while holding
the chain in my hand to make sure it is moving freely. When placing the chain over the
exhaust its then important to make sure there's no play in the chain from the exhaust
cam sprocket down to the crank, and that the timing mark for T 1-4 is lined up.

Once you have the exhaust cam lined up you can put the caps on it and use the pin count
to line up the intake. You no longer care about the timing mark since the exhaust cam
is your reference.

 

[Nessism]

As Nessism points out the trick is to align the exhaust cam with the chain and crank and then the intake cam to the exhaust cam.

So before you put the chain over the exhaust cam make sure the chain is not kinked or bound up in any way near the crank. I usually turn the crank one or twice while holding the chain in my hand to make sure it is moving freely.

Be very careful to never turn the engine over with the cylinder head installed - with the cam chain loose that is. Some of he valves will be open, so turning over the engine will bend valves.

One other thing, the factory service manual shows the use of a pair of vice grips to clamp down on the exhaust cam and hold it in place. I've never tried this but it seems like a good idea. Get the crank in the proper place, install the cam chain in the proper position on the exhaust cam and then crank down on the cam with vice grips to lock it down. After you have the exhaust properly indexed, do the intake cam next.

 

[efjay_62]

I too am going thru the headaches of trying to set the cams. After spending the better part of the afternoon yesterday wrestling with them, I gave up out of frustration with just the exhaust done. Everytime I would try to tighten the intake came down, it would turn under the valve spring tension (along with many other battles along the way). Probably wouldn't matter if the whole bunch turned, but it was turning the intake cam ONLY, so the timing would have been off. I eventually discovered I had a kink in the chain at the forward side of the motor below the exhaust cam, so when the intake cam would turn, it would turn the crank as well,but the exh wouldn't turn until that slack was pulled out. I'm getting ready to go try it again and the vise grip trick could be very helpful, but I'm not picturing how you guys are doing that. I don't have an FSM, just a POS Clymer that came with the bike, and the bike isn't here so I can't go out and peek at it. Where are you guys clamping the cam, and what too?

 

[Nessism]

 

[efjay_62]

Thanks for the pic Nessism! I came down to shop (it's just a couple miles from where I live) to take a gander and another stab at setting the second cam and that's kinda what I figured. I actually managed to get the intake cam set on the first try without even using the vice grips, bolted the idler down, set the tensioner and gave her a couple of rotations and all appears to be in order. :dancing: The only question is when I bring it back around to TDC 1-4 the 2 arrow points straight up (at the same angle as the head) but the 3 arrow points slightly forward of that, but the 1 arrow on the exhaust points straight to the gasket surface, and the notches on the end of cams point towards each other. Now I am a newb at DOHC motors and more specifically motorcycles all together, but from what I've read and by my book it's good. Please tell me if I'm wrong however. I really don't want to have to go back. Thanks.

Edit: Oh yea. Yes I set the chain 20 pins arrow to arrow, and verified afterwards.

 

[DimitriT]

Thanks for the pic Nessism! I came down to shop (it's just a couple miles from where I live) to take a gander and another stab at setting the second cam and that's kinda what I figured. I actually managed to get the intake cam set on the first try without even using the vice grips, bolted the idler down, set the tensioner and gave her a couple of rotations and all appears to be in order. :dancing: The only question is when I bring it back around to TDC 1-4 the 2 arrow points straight up (at the same angle as the head) but the 3 arrow points slightly forward of that, but the 1 arrow on the exhaust points straight to the gasket surface, and the notches on the end of cams point towards each other. Now I am a newb at DOHC motors and more specifically motorcycles all together, but from what I've read and by my book it's good. Please tell me if I'm wrong however. I really don't want to have to go back. Thanks.

Edit: Oh yea. Yes I set the chain 20 pins arrow to arrow, and verified afterwards.

I'd say you're good. Another gotcha is the timing mark. There are several marks on the plate and it usually looks something like:

| 1-4 | 2-3

you want to line up the leftmost line. Careful you don't line up the middle line.

Once you line up the 1-4, you need to have the "2" arrow pointing up and the "1" arrow
pointing parallel to the gasket surface (as you said).

So if you got the exhaust cam lined up with no kinks on the chain and you counted the
20 pins to the intake's "3" mark, I think your good.

 

[efjay_62]

Woo Hoo! Man it's amazing how sometimes just walking away and taking a break from something can make all the difference. I was wrestling with those things for hours yesterday getting almost nowhere. Now some of that may have been my own doing with things like forgetting to put the chain guide in and not noticing until AFTER I had the exhaust cam dialed in and torqued down. Gave up on it for the evening, went back to it this afternoon, and the thing almost put itself together. Couldn't believe it. I knew it just shouldn't be that dang hard. Turns out it wasn't. Thanks for the pointers!

 

[boba]

Im glad efjay got the same information I did, and it helped. I think I have everything done correctly, I did get the bike started and it seemed to run a little better than when I first started this project. But I still dont understand what way the cam lobes are supposed to be pointing, but then- I think I just answered my own question about it. it will start and run.

 

[jadesystem]

Good advice as my head gasket and valve cover gasket will arrive from Flatout today. I will install everything together after doing a manual valve job on my 1150 head, but could did imagine this is a hassle after reading all of the blogs.

The Suzuki manual is pretty straighforward with the timing marks
between exhaust and intake cam sprockets alignment of 21-links in-between. And yes, never turn the crank with a loose chain via the cam tensioner. I should be fun putting this together, as my biggest obstacle
is not dropping the head washers into the crankcase at the camchain opening.

I had to fish-out one of the dowel pins that is sandwiched in-between
the head and the valve cover that fell-in. Luckily I used a telescopic magnet to fish it out saving me the hassle of draining the oil and removing the oil pan.

The TDC is cylinders #1 and #4 at the alignment marks at the crank -
you know you are in the ballpark when it aligns with the intake and exhaust marks with the 21-links in-between.

 

[Steve]

But I still dont understand what way the cam lobes are supposed to be pointing, ...

The only things that really matter are outlined above:
ONE. Set the timing marks on the crankshaft to TDC for cylinders 1&4.
TWO. Set the exhaust cam so the #1 mark points forward to the edge of the head and #2 points straight up.
THREE. Count pins from the #2 mark on the exhaust cam to the #3 mark on the intake cam. Make sure you include the pins over the marks, not just between them.
FOUR. Install the idler gear (I think only the 850s have them). Yes, the intake cam will move, but it is still properly engaged to the timing chain, so it does not matter.

It is important to KNOW how many pins to count on the chain for YOUR bike because there are different counts for different bikes.
Jadesystem mentioned 21 links (pins) for his 1150, 20 is correct for many other bikes, and 19 is correct for the 650E (even though 20 is correct for the 650G :-k).

.

 

[jadesystem]

I will do this later today, and will comment on the procedure from my
own standpoint. Should be interesting and alot of fun. As I recall, the
ends of the cams have a notch that point inwards. Together with the
timing marks at the ignition plate, the alignment marks at the intake
and exhaust cam sprockets - with 21-links in-bewteen - making this alignment procedure foolproof.

The only issue I may have regarding the prior blogs is the cam installation
with the loose chain. I literally have to reassmble the cams and sprockets assy together with the cam chain on the head and onto the engine
case. This is a different procedure I am accustomed too versus working
on Hondas where-as I just install the cam sprocket with the loosened chain onto cam via the assembled head.

Should be interesting to do.

 

[posplayr]

Pos proof

Pos proof

As I recall, the
ends of the cams have a notch that point inwards. Together with the
timing marks at the ignition plate, the alignment marks at the intake
and exhaust cam sprockets - with 21-links in-between - making this alignment procedure foolproof.

Ken I think it is 20 teeth separation between the sprockets and i can attest it is not "fool proof" .

Also make sure that the 1 on the exhaust sprocket is exactly at the level of the valve cover mounting surface (not off a little).

That sets the cams with respect to the crank.

Bill saved my A$$ on that.

Jim

 

[posplayr]

20 pin alignment

20 pin alignment

It is important to KNOW how many pins to count on the chain for YOUR bike because there are different counts for different bikes.
Jadesystem mentioned 21 links (pins) for his 1150, 20 is correct for many other bikes, and 19 is correct for the 650E (even though 20 is correct for the 650G :-k).

.

Is the 1150 really 21?

OK I checked my manual.

Even though I don't have an 1150, I did pick up a manual as the 1100E's are similar motors. Looks like they use the same 20 pin counting alignment

 

[Steve]

Jadesystem mentioned 21 links (pins) for his 1150, ....

Is the 1150 really 21?

OK I checked my manual.

Even though I don't have an 1150, I did pick up a manual as the 1100E's are similar motors. Looks like they use the same 20 pin counting alignment

Please notice that I chose my words carefully.

I never said that 21 was correct, only that "Jadesystem mentioned 21 links ..."

The emphasis of my post was to know what you are supposed to have, then count it out carefully, several times, if necessary.

.

 

[posplayr]

Steve

Steve

Please notice that I chose my words carefully.

I had noted that deft avoidance of any ownership. I just thought I would bowl right through that cleverness with my newly acquired knowledge

Jim

 

[jadesystem]

Hi Steve,

Yes you are correct. It is 20 pins between the exhaust #2 12:00 o'clock
arrow mark cam sprocket and the Intake #3 12:00 o'clock arrow mark
cam sprocket as the 1st pin as reference. It all lines-up against the cam chain pin with referencing.

Sorry about that !!


.

 

[Steve]

Hi Steve,

Yes you are correct. It is 20 pins between the exhaust #2 12:00 o'clock
arrow mark cam sprocket and the Intake #3 12:00 o'clock arrow mark
cam sprocket as the 1st pin as reference. It all lines-up against the cam chain pin with referencing.

If we are going to be all correct and picky and all that stuff, let's get it RIGHT.

It's 20 pins including the pins over the marks.

The #1 pin on the chain is aligned over mark #2 on the exhaust cam. Pin #20 is aligned over mark #3 on the intake cam.
Strictly speaking, that leaves 18 pins between the marks, but the book also counts the pins over the marks, for a total of 20.

Yeah, I know that's exactly what you were saying, too, but I still count the links several times before I put the cover back on. I made that mistake once as a rookie (won't admit how many times since then), so I did not want to mis-guide any of the other rookies that might be reading this. :-\\\

.