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Effect of one cam being one tooth out

5K views 10 replies 5 participants last post by  blaustrom 
#1 ·
I adjusted my cams for the first time 12 months ago and wanted to recheck them seeing it was the first time I had done them (2014 DL1000). And thought they sounded slightly ticky. So when had to clean air filter after a three day adv ride, took the opportunity to check them. Front were fine but two in the rear (one inlet and one exhaust) were out of spec, one a little and the other a fair bit). So reshimmed them then reinserted the cams, torqued them up and checked clearances and all good. Put everything back together minus tank livery and fired her up to check all was well. Started ok but idle was doughy. Took it for a spin, and doughy acceleration and a miss around 3000. I thought was either an electrics plug not reconnected or a cam out. Checked the cams and sure enough, exhaust cam alignment marks were 'fairly' but not completely aligned. They obviously have to be perfectly level! What helped was the diagram helpfully included in the manual, which showed not just the alignment marks plus where the lobes should be pointing. And the exhaust was at 2 o clock, not 1 o clock. Changed it to one o clock, zipped it up and started it up - perfect sounding idle and rev, and test ride confirmed all good. And no ticky ticky noise.

But shows the impact of a mere one tooth out on the cam!! No idea how to explain what the effect of it would have been - exhaust valves opening and closing slightly later than it should, so slow to let gases out and/or some overlap with intake charge? And what's one tooth in degrees - no idea of teeth number. Perhaps 2 or 3 degrees diff?

At least no apparent damage done, and not out enough to bend valves etc (god forbid).

Has anyone else had cam timing adventures??
 
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#3 ·
It is very easy to get mislead when re-installing the cams (DL1000) because of the spring loaded split gears. They change position while being tightened. So its imperative to check for proper mark alignment after they have been tightened down at least finger tight. I remember I did mine a couple of times until I was satisfied that they were correct.
 
#5 ·
Digging up a year-old thread, but yes, a little bit of a guessing game. I've had my cams in and out several times, trying to perfectly align everything. All 4 of my cam gears seem to be about 1/3 of a tooth off when the F/T line is exactly on the mark. I've messed with it enough now that I'm going to attribute the difference to minor play wear in the cam chains. Every time I move a cam, it's further off than it was before, so I'm going to have to say it's good. I sure hope so anyway. I'd prefer to not take it back apart right after getting it all together. Dang cold in the garage these days.
 
#6 ·
Not all of then do align perfectly. I assume you rotated the engine correctly, counterclockwise. Just found this being a good tutorial: Engine valves adjustment: Can you help me understand the procedure?

I just did a valve check on a new to me 2007 KLR650. A more primitive design but the valve timing and shims are similar. There was no way to get the cam sprocket markings to line up as the manual shows it. So I left it alone and went to the next maintenance item, replace the fork bushings and seals. Yes my garage is also cold and a small propane heater makes a big difference ;-)
 
#8 ·
Looks to me the left gear is one tooth off. It needs to be turned 1 tooth clockwise, assuming you are close to the marks. If not then the right cam needs to be moved on tooth counterclockwise. This is the front Cylinder? If yes you can verify the TDS by taking the center sparkplug out and measure the piston movement. That way you are sure to have the TDS. Cams need to point away from the valves (about 10 and 2 o-clock) and all need to have clearance in that position.

Some more reference pictures here: Cam Timing help
 
#9 ·
That picture was what it was when I originally opened it up, thanks to whoever did the last valve clearance service. That's not the current state. It's back together now. I rechecked my clearances. I'm now at .006" on all 4 intakes and .010" on all 4 exhaust valves. I would have preferred the exhausts out at .012", since they tend to tighten up if anything, but I'm good with .010". I turned the engine over multiple times and inspected my marks, and I feel confident in them now. Even the exhaust cam on the rear bank. I used every light and mirror I had to try to get a good look at the marks on that one. Almost as much fun as getting the rear cam cover back in place. :rolleyes:
 
#10 ·
Re: the link that you posted. I ended up using the white marks on the cam drive gears to verify where I wanted to be. That pretty much verified for me that my cams were right in relation to the drive gear, and that my crank F/T mark is a touch off from when the cam gears are straight up. That was the part giving me fits; at the true F/T mark, all 4 cams were slightly off. Moving them 1 tooth toward perfect would be too much, and it would be off the other way.

Anywho, I think I'm good now. Thanks for you input @blaustrom It is appreciated.
 
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