Timing question

[Herzie]

Hi guys,

Today I had to do some work to my bike. I noticed that the timing looked like it was off even though the bike has been running fine. Last fall I had done the timing myself but had to take it to the mechanic for other reasons. The mechanic told me that the timing was way off and that he had set it correctly (the bike ran fine after this).

So today I had a look at how the camshafts were positioned with the TDC mark aligned as per my Haynes workshop manual. I found that the timing marks did not line up at all.

The workshop manual says that when TDC is set the EX camshat no. 1 mark has to align with the top of the header gasket.

I snapped some pictures for you to see. Can anyone elaborate as to what I'm to make of this? This timing seems off to me, but the bike was running fine?! The pictures are snapped with the EX camshaft no. 1 mark correctly aligned showing that the TDC mark is off by quite alot.

Just to clarify, I'm no expert, so if you'll please explain in layman's terms

 

[Guest]

You need to put the timing faceplate on there with the timing marks on it.

 

[bwringer]

The quickest way to tell if a GS engine is in time is that at 1&4 TDC, the notches in the right end of the camshaft will either point directly at each other or directly away from each other, and they will be parallel with the gasket surface of the cylinder head.

Sort of like this:

O>-----<O

or this:
<O-----O>

Here's a handy guide to finding TDC:
http://bwringer.com/gs/tdc.html

 

[Suzuki_Don]

+1. I'm with Bill on this one. There is a tinny metal plate that screws on to that housing that has the timing marks pressed into the plate. Cannot check timing if this is not in place.

 

[Spyderman]

+1 need the timing plate in place to see if it's timed properly
as for the cams well the arrow needs to be level with the valve-cover gasket surface not the #1

 

[Herzie]

Thank you for your replies.

I snapped a few more pictures. There are no timing marks on the outer plate. The timing mark is the point just beneath the top mounting screw behind the plate. I took another picture that shows this better. Please note that I cranked it to align (more or less) with the TDC in this picture.

Here's a picture of the front plate held in place. The only mark is the green line that I didn't draw. What's the purpose of this line? It actually correlates to were the TDC was located (which then wouldn't actually BE the TDC) when the camshafts were positioned correctly (no. 1 mark LINE on top of gasket) as described in my first post. Does that tell you anything?

If I were to align everything as it was when I opened it up yesterday the 1 and 4 pistons would not be at TDC when the camshafts were correctly positioned. Then why did the bike run fine? This much "off-ness" should result in a poorly running bike right?

 

[Nessism]

The proper way to set the timing is to align the T mark and then look at the cams, not the other way around. Please do this and shoot another photo of the exhaust cam position, and the position of the cam notches as Bwinger mentioned. My guess is that it's off by one tooth.

 

[Herzie]

The proper way to set the timing is to align the T mark and then look at the cams, not the other way around. Please do this and shoot another photo of the exhaust cam position, and the position of the cam notches as Bwinger mentioned. My guess is that it's off by one tooth.

I know the right way to do it, well I've read it I'm just wondering why the bike was running fine when the timing seemed off by quite a bit. I don't know how bad the bike would feel with the timing being of by the amount that I've described?!

 

[Don-lo]

I would verify TDC by seeing where piston#1 comes to it's highest position (hold a pencil down the spark plug hole). I fixed a KZ1000 that had a sheared locator pin on the crank end, so TDC indicated was actually not.

 

[Nessism]

I know the right way to do it, well I've read it I'm just wondering why the bike was running fine when the timing seemed off by quite a bit. I don't know how bad the bike would feel with the timing being of by the amount that I've described?!

I?m confused by what you are asking...you want us to tell you why your bike runs well even though the timing is off? Only thing I can suggest is that the engine design is fault tolerant, and by fixing this problem you can judge for yourself how "bad the bike will would feel" with the timing off.

 

[Herzie]

I guess I'm not really asking anything, but just wondering if I'm doing something wrong since the bike ran fine even though the timing (as I see it) was off.

I am definitely not ruling out that I have misunderstoo the process of setting the timing correctly.

 

[Guest]

Line up the TDC 1&4 first.
Lock down the cam chain tensioner and remove. Take off the intake cam. Pull the chain up and line the arrow on the exhaust cam at the top of the head and pull the chain up and over the exhaust sprocket. Now count the links from #2 to #3. They will be either 18 or 20 it depends on your model. Also count the links over the arrows.
While holding the cam chain from slipping tighten down the intake cam and reinstall the cam chain tensioner. Don't forget to "cock" the tensioner, unlock it and tignten down the lock nut. When you release the tensioner keep you hand on the intake sprocket so the chain doesn't jump.
Rotate the engine several times and make sure it's still in time.

 

[Herzie]

Line up the TDC 1&4 first.
Lock down the cam chain tensioner and remove. Take off the intake cam. Pull the chain up and line the arrow on the exhaust cam at the top of the head and pull the chain up and over the exhaust sprocket. Now count the links from #2 to #3. They will be either 18 or 20 it depends on your model. Also count the links over the arrows.
While holding the cam chain from slipping tighten down the intake cam and reinstall the cam chain tensioner. Don't forget to "cock" the tensioner, unlock it and tignten down the lock nut. When you release the tensioner keep you hand on the intake sprocket so the chain doesn't jump.
Rotate the engine several times and make sure it's still in time.

Thank you for this walkthrough, I'll give it a go

 

[Nessism]

As a refinement to what Chef Bill suggests...

Set 1-4 at TDC by aligning the 1-4 T mark.

Look at the notches on the ends of the cams - they should point at each other when the cams are properly indexed.

Look at the #1 mark on the exhaust cam sprocket and decide how many teeth it is off - most likely one.

Mark the cam chain and sprocket in some way to reference how they index together. When you reinstall the cam you need to make sure your reference marks are moved in the proper direction - for example: cam is rotated one tooth relative to where it was originally. Doing this will save a lot of time since the EX 1 mark will not properly align until the cam is bolted down.

Using a pair of vice grips will help clamp the cam down into the head before the installing the cam caps. If you use the cam cap bolts to clamp the cam down may cause you to strip a hole in the head.

Reinstall everything and do a double check by looking the notches in the cams.

Good luck and hope this helps.

 

[waterman]

Line up the TDC 1&4 first.
Lock down the cam chain tensioner and remove. Take off the intake cam. Pull the chain up and line the arrow on the exhaust cam at the top of the head and pull the chain up and over the exhaust sprocket. Now count the links from #2 to #3. They will be either 18 or 20 it depends on your model. Also count the links over the arrows.
While holding the cam chain from slipping tighten down the intake cam and reinstall the cam chain tensioner. Don't forget to "cock" the tensioner, unlock it and tignten down the lock nut. When you release the tensioner keep you hand on the intake sprocket so the chain doesn't jump.
Rotate the engine several times and make sure it's still in time.

20 is the magic number for pins to count from #2 to #3. Pins not links, 2 pins per link.