Setting the valve timing

[Dean0]

G’day all, it’s been some time since I was last here.

I decided it was about time I got more acquainted with my R3T, what better way than to tackle the 48,000km service, starting with the valve clearance check.

In 0.125 0.095 0.125 0.165 0.152 0.152
Ex 0.205 0.215 0.245 0.245 0.145 0.245.

After installing 10 new shims and re installing the cams I went about setting the valve timing. The procedure of setting the timing marks up using the jig is straight forward enough but as pre advised, it’s all down to the point where the cam tensioner is installed. After numerous attempts, I just cannot get the timing marks to line up perfectly after rotating the engine four times.

I’ve had advice and encouragement along the way from my good friend afar, he is a wealth of knowledge and experience with the R3 engine, be it highly modified with dialled in cams, but he has never set an engine to stock timing marks.

Other advice has said that it is normal for the timing marks not line up perfectly due to stretching in the timing chain. I have already verified the chain is in spec and good.

Having done a thorough search of the forums I find very little on the subject.

I would greatly appreciate any help or advice from others that are familiar with setting the valve timing on a stock engine.

On upside, I did manage to measure the final valve clearance.

In 0.125 0.115 0.125 0.120 0.127 0.127
Ex 0.185 0.185 0.180 0.185 0.180 0.180

Dean.

 

[Rocket Scientist]

The two different bikes I've done the cams on ended up being retarded a bit. If I jump a tooth then they are advanced by much more than they were retarded. I left both in the slightly retarded position. I figured it was from chain stretch.

 

[Pedro]

It is important that the chain is tight across the top of the sprockets and there is no slack on the opposite side to the tensioner when whe chain is around the crank sprocket. So as all the slack is taken up with the tensioner. I hold a little tension on the crank and push the tensioner in a little to snug up the chain

 

[Dean0]

The two different bikes I've done the cams on ended up being retarded a bit. If I jump a tooth then they are advanced by much more than they were retarded. I left both in the slightly retarded position. I figured it was from chain stretch.

Thanks for the reply Fred… just want to confirm with ya, when you say the cams ended up either retarded or advanced if you skip a tooth, you are referring to the cam positions when the dot on the crank is in the TDC position?

 

[Dean0]

It is important that the chain is tight across the top of the sprockets and there is no slack on the opposite side to the tensioner when whe chain is around the crank sprocket. So as all the slack is taken up with the tensioner. I hold a little tension on the crank and push the tensioner in a little to snug up the chain

Cheers Pedro... thanks for the tip.
I reckon I'm getting all the slack to the tensioner side... I might be overly concerned that all 3 timing marks line up perfectly after the four rotations.

 

[warp9.9]

Cheers Pedro... thanks for the tip.
I reckon I'm getting all the slack to the tensioner side... I might be overly concerned that all 3 timing marks line up perfectly after the four rotations.

Pedro is right and if you can not get things lined up with the marks make sure you error to leaving no slack on the non-tensioner side. You will have to judge as to whether moving the gear a tooth will alter the valve event drastically and positively. Now your in a area that people reading can now see why two identical bikes with the same tunes can produce different numbers on a dyno. If your chain is new it will stretch a wee bit while running things in. use that to your advantage as the chain stretches you could have the timing come in depending on which way you you went with the slack. Either way I have seen them off a tooth and run fine just down a little on power (on a Dyno)
Also do not worry about the marks on the cam gears as much as does the fixture fit in right. Your looking at it and if you could see that good with your eyes why would there be a need for a fixture Even with my eyes being Vernier Calibrated I would use the fixture

 

[Rocket Scientist]

Thanks for the reply Fred… just want to confirm with ya, when you say the cams ended up either retarded or advanced if you skip a tooth, you are referring to the cam positions when the dot on the crank is in the TDC position?

Cams were being held by alignment tool.
Could not get the crank right on the mark. Either advanced or retarded. Went with retarded as it was closer to the mark than if I went to the advanced.

 

[Rocket Scientist]

Pedro is right and if you can not get things lined up with the marks make sure you error to leaving no slack on the non-tensioner side. You will have to judge as to whether moving the gear a tooth will alter the valve event drastically and positively. Now your in a area that people reading can now see why two identical bikes with the same tunes can produce different numbers on a dyno. If your chain is new it will stretch a wee bit while running things in. use that to your advantage as the chain stretches you could have the timing come in depending on which way you you went with the slack. Either way I have seen them off a tooth and run fine just down a little on power (on a Dyno)
Also do not worry about the marks on the cam gears as much as does the fixture fit in right. Your looking at it and if you could see that good with your eyes why would there be a need for a fixture Even with my eyes being Vernier Calibrated I would use the fixture

What would be your thoughts on moving it to the advanced position ? What effect does advancing the cams have ?

 

[Dean0]

Pedro is right and if you can not get things lined up with the marks make sure you error to leaving no slack on the non-tensioner side. You will have to judge as to whether moving the gear a tooth will alter the valve event drastically and positively. Now your in a area that people reading can now see why two identical bikes with the same tunes can produce different numbers on a dyno. If your chain is new it will stretch a wee bit while running things in. use that to your advantage as the chain stretches you could have the timing come in depending on which way you you went with the slack. Either way I have seen them off a tooth and run fine just down a little on power (on a Dyno)
Also do not worry about the marks on the cam gears as much as does the fixture fit in right. Your looking at it and if you could see that good with your eyes why would there be a need for a fixture Even with my eyes being Vernier Calibrated I would use the fixture

Thank you Scott for your reply.

 

[Dean0]

Cams were being held by alignment tool.
Could not get the crank right on the mark. Either advanced or retarded. Went with retarded as it was closer to the mark than if I went to the advanced.

Cheers mate, same here...


after the chain tensioner is set and engine rotated 4 times and crank timing mark set at TDC the cam timing marks are retarded by approximately ½ a tooth, I then bump the crank slightly forward clockwise so as the cam alignment tool/fixture slips back into place, the crank timing mark is then positioned ATDC by a ½ a tooth… If I deliberately and jump a tooth, the crank timing mark is then positioned BTDC by ½ a tooth on the crank sprocket.