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Timing and CCT's

Old 10-02-2011, 07:41 PM
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Timing and CCT's

So when you line up the front cylinder with TDC index mark on case and the flywheel FT mark, the service manual shows the proper position with the index mark pointing in between "F" and "T". I had been lining mine up with the line that is right before the "F". Which is more accurate?

The reason I ask is because I changed my CCT's and while doing so the front cam jumped. I timed it back out, but I think I'm just a tooth off. It rides great but I noticed when cold it missed a couple times, and after getting off the interstate the idle started to run low (under 900) and it died on me when off throttle. I adjusted the idle higher but I shouldn't of had to.

Tonight I tore it all back down and I adjusted the top cam one tooth out so the FI was lined up flush with the head surface when the chain had slack. I'll ride it tomorrow and see, but I noticed difference in position in the manual while doing it. I want to make sure both cams are lined up correctly if I have to tear her down again. Third times a charm...
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Old 10-02-2011, 07:55 PM
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The way I do it is lined up with the mark. I think the service manual photos may have been taken at a slight angle...
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Old 10-02-2011, 08:27 PM
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Hmm, I found that I could not get my timing marks to line up properly with the case when I had it set to the line after the markings.

It's set in the middle of the F/T and R/T on my cylinders and the cams line up 100% parallel to the measuring plane.

Granted, I did set mine and then check with full cam chain tension and that's what tweaked it when I tightened everything down.
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Old 10-02-2011, 08:38 PM
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Your cams were parallel to the plane when you were set near TDC? So your FI and FE marks weren't lined up? That wouldn't for a happy motor make...

Edit: I think the FT and RT marks on the flywheel are there just so that you can set your rear timing based on your front timing, and know when your at TDC. I'd imagine that it's possible to do both of these without it, but that would take some planning...

Last edited by 7moore7; 10-02-2011 at 08:41 PM.
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Old 10-02-2011, 09:07 PM
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Originally Posted by bass4dude View Post
Hmm, I found that I could not get my timing marks to line up properly with the case when I had it set to the line after the markings.

It's set in the middle of the F/T and R/T on my cylinders and the cams line up 100% parallel to the measuring plane.

Granted, I did set mine and then check with full cam chain tension and that's what tweaked it when I tightened everything down.
Yeah I set the cams into position with tension off the chain. The chain is probably stretched being old so it will rotate the cam when tension is applied.

At least it's my theory.
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Old 10-02-2011, 09:25 PM
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Hm, I don't think these chains stretch that much... when you place the chain over the cam sprockets, it should be as tight as you can reasonably get it on the non-CCT side. This takes a little bit of focus for me because you have to hold the cam sprockets and pull on the chain fairly decently and place it on the cams without them slipping. If you don't do that, I'd imagine the CCT picks up the slack from both sides and messes with the timing.
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Old 10-03-2011, 07:56 AM
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That makes complete sense. Especially since the changes I made yesterday didn't effect anything after my ride to work this AM. I'll tear it down again tomorrow during lunch and do that. Thanks for the input.
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Old 10-03-2011, 09:48 AM
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As long as you realize there are both an "F" mark and an "FT" mark you should be ok.

There is an "F" mark before both the "FT" and "RT" mark which shows when the cylinder should fire at idle and therefore is around 10 degrees or so before the "XT" or timing mark and yes it does make a difference.
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Old 10-03-2011, 11:46 AM
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Originally Posted by 7moore7 View Post
Hm, I don't think these chains stretch that much... when you place the chain over the cam sprockets, it should be as tight as you can reasonably get it on the non-CCT side. This takes a little bit of focus for me because you have to hold the cam sprockets and pull on the chain fairly decently and place it on the cams without them slipping. If you don't do that, I'd imagine the CCT picks up the slack from both sides and messes with the timing.
If you don't have all the slack on the CCT side then it will only tighten as much as the crankshaft will allow it to on one side so you'll end up with a lot of slop.

Both my FI and FE and RI and RE were spot on when I had it set between the FT and RT accordingly.

I found that when I had it set to the marking line, under full chain tension, the cams were skewed towards the CCT side by about 6 degrees. So I just did a full rotation and reset the cams to parallel without really looking at the flywheel marking to see where they would line up on the flywheel and with both cylinders it matched up perfectly between the letters.

And she runs like a top from idle to WOT. No missing, stuttering, hesitation or "bad running" anywhere.


If you're having problems with getting the slack out of the chain just install the front exhaust first then intake, and rear intake first then exhaust.
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Old 10-03-2011, 12:37 PM
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Originally Posted by bass4dude View Post
If you're having problems with getting the slack out of the chain just install the front exhaust first then intake, and rear intake first then exhaust.


I guess that step got left out in some or most of the right ups as for us "old" guys that is just how you do it.

It one of those things you do without even thinking about it but yeah always
put the drive chain on so that the slack is on the cct side.

Cam chain installation is always, crank sprocket,cam, second cam on a DOHC engine, then CCT.

Glad to hear yo got the bike running well. Did you go back to the stock cams?
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Old 10-03-2011, 04:13 PM
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i have a question related to this matter. i just pulled my rear cover to check some stuff out and found that the exhaust cam sprocket is a half a chain link on the high side(RE not sitting flush with the top of the cylinder head) i have tried to adjust it but if i go down a tooth it sets below the cylinder head. there is no in between, could the chain have stretched out on it. after all it is the cylinder that the CCT failed on.
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Old 10-03-2011, 05:40 PM
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Originally Posted by bass4dude View Post
If you're having problems with getting the slack out of the chain just install the front exhaust first then intake, and rear intake first then exhaust.
yeah when 7moore7 said it that made sense. I'm going to pull it apart tomorrow as I can now get to the front cam in about 10 mins.

Thanks guys for the insight. I'll post back up when it's buttoned up and running.
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Old 10-04-2011, 12:59 PM
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Ok I tore it apart on my lunch break and spent some time adjusting. I took some photos for you guys to have a look and let me know if this looks proper to you before I put it back together. I tried adjusting it about a dozen times making sure to work the slack out. The FE/FI CAM marks never really line up with the head surface when it's at the index mark shown but pretty close. When I adjust a tooth in either direction it's much further off. I've rotated the crank several times with tension on the CCT and it stays as shown in pictures below.

Let me know if this looks right (Front Head only).

FT-MARK (Mark between F and T)
Name:  FT-mark.jpg
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Looking down the drive side of the chain (No slack)
Name:  Drive-Side-Chain.jpg
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Size:  84.1 KB

Drive side Cam - FE mark just above head surface
Name:  DriveCAM.jpg
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Size:  91.1 KB

Chain between Cams - No slack
Name:  Chainbetweencams.jpg
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Size:  48.8 KB

CCT side Cam - FI mark just below head surface
Name:  CAM-2.jpg
Views: 10
Size:  91.2 KB
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Old 10-04-2011, 01:16 PM
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Well by your pics I'm not sure about the intake cam.

Everything else looks good but you need to lay a straight edge on the head near the FI mark and then set it as close as you can get it.

Right now I would say you are 1 tooth off on the intake cam but it could be the camera angle and all that. You really need a straight edge to know for sure.
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Old 10-04-2011, 03:54 PM
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Mike,
my rear exhaust cam sprocket look the same as the pics but my mark is on the high side and no matter what i do it is either high or low if i move it a tooth. it is like i need half a tooth. could my chain have stretched out? i keep getting an intake burp and my idle changes with the temp, any ideas?
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Old 10-04-2011, 04:12 PM
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3amta3 mine is the same. Burps when cold and wont idle when warm. Seems like it won't line up right with the crank in the right spot.
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Old 10-05-2011, 07:48 PM
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I put it all back together as the settings pictured above and also cleaned out some junk on the carb inlets, verified all vacuum lines were secure, and it runs fine. Took it out and put 20+ miles on it and ran it up to about 140 on a deserted stretch. Then came back to a slow spot and let it idle and it idled just like it always did.

I'll be loading it up for the trip to the gap this weekend so -fingers crossed-

Thanks for all the input.
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Old 10-05-2011, 08:15 PM
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Originally Posted by 3amta3 View Post
Mike,
my rear exhaust cam sprocket look the same as the pics but my mark is on the high side and no matter what i do it is either high or low if i move it a tooth. it is like i need half a tooth. could my chain have stretched out? i keep getting an intake burp and my idle changes with the temp, any ideas?
Well because of chain stretch they might be off a little bit.
It is just a good idea to use a straight edge when setting them and you just get them as close as you can to even with the top of the head.
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Old 10-05-2011, 08:44 PM
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Originally Posted by 8541Hawk View Post
Well because of chain stretch they might be off a little bit.
It is just a good idea to use a straight edge when setting them and you just get them as close as you can to even with the top of the head.
I think he's got 'em right.

They're parallel (as close as the eye can tell) and they're both slightly skewed from the measuring plane from who knows what.

The only difficult thing is finding a straight edge to fit on the front intake side as there happens to be a frame there!

Congrats on getting her running again!
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Old 10-05-2011, 08:46 PM
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Originally Posted by 8541Hawk View Post


I guess that step got left out in some or most of the right ups as for us "old" guys that is just how you do it.

It one of those things you do without even thinking about it but yeah always
put the drive chain on so that the slack is on the cct side.

Cam chain installation is always, crank sprocket,cam, second cam on a DOHC engine, then CCT.

Glad to hear yo got the bike running well. Did you go back to the stock cams?
I learned that the hard way on my '71 CB750K a few years back. Let's just say the autoCCT decided that the bolt wanted to shear off when the slack clicked it further in. That was a fun rebuild!


And I am running the stock cams for the time being.

I've decided that I'm just gonna have the cams hardwelded. Why shoot for trying to find a substitute for performance when you can instead just make them performance!!!
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