Cam chain wear check

[fazil]

I've bought a second hand cam timing chain from ebay long time ago. Seller has claimed that it has low miles but I don't know if it has any wear or not. Is there a way to find out if it is good or bad? I couldn't find any specifications on the service manual.

 

[FinalImpact]

Manual states replace as set based upon gear wear. When the "contact patch" of the tooth (not the empty space of the teeth) has lost 1/4 of its facing, replace the gears and chain set.

So, you have nothing to go on. Either toss it or run it on the "new gear" set. maybe save the OEM chain for the original cams if you need to put them back?? :don'tknow:

 

[greg]

you'd probably have to compare it to the existing one to check for stretch

tbh I don't think new ones are that expensive, I had mine replaced along with the CCT, and it was only around £30 IIRC

 

[fazil]

I can compare them when i open up the engine.
May be best is to put a new one. New one is around $40 here.

 

[ozgurakman]

I changed mine at 30k kms (18000 mi) because of heterogeneous chain slapping.

you can understand this -when your bike's crankcase cover and timing cover is open- turning the crankshaft with #12 socket. You'll feel crankshaft will rotate some freely and some hardly. Also when crankshaft turning hardly, stop immediately and check the chain tension between two head cams. repeat it for chain's loose point.
If chain has different tensions, your chain has some uneven wear.

 

[FinalImpact]

I changed mine at 30k kms (18000 mi) because of heterogeneous chain slapping.

you can understand this -when your bike's crankcase cover and timing cover is open- turning the crankshaft with #12 socket. You'll feel crankshaft will rotate some freely and some hardly. Also when crankshaft turning hardly, stop immediately and check the chain tension between two head cams. repeat it for chain's loose point.
If chain has different tensions, your chain has some uneven wear.

I think I'm following you but I don't think thats a fair assessment of chain wear.

The action of the cam lobes compressing the springs induce resistance to cam rotation which can Slow the cams travel OR Once PAssed the Lobes Center, can speed it up depending on "what side" of the lobe is acting on the valve set. So at any point in time, the intake could be forced clockwise or counterclockwise while the exhaust is going with it the same direction or even against it making slack between the cams.

In short, the springs the cams are trying to compress may make the chain loose on ANY of its three sides depending on "when in the cycle" you check the chain tension. A stretched chain **could** run the tensioning device out of travel and it **could** allow the chain to contact areas outside the guides.

Because these are oil soaked, its more likely they wear evenly and its the cam chain tensioner which cause most of the grief on engines with less than 50,000 miles.

Also comparing two used chains may not show any difference yet both could beyond service limits although I doubt either are.
I found the manufacture once while comparing R6 parts to FZ parts using this "92RH2015/120" and it had the stretch limits. A quick search didn't find it.

 

[ozgurakman]

I noticed new chain made bike's idle more smother. And you're right Randy, can lobes would force the chain...

Also I were compared new and used can chains length and noticed new were 4-5 mm shorter.

 

[FinalImpact]

I noticed new chain made bike's idle more smother. And you're right Randy, can lobes would force the chain...

Also I were compared new and used can chains length and noticed new were 4-5 mm shorter.

That's a lot in a short amount of miles. Automatic tensioner or manual?

To your point, as a chain stretches, the CAM timing from the crank is delayed or retarded from its "original" location and you can notice new parts suddenly have an engine that makes more power again. I've felt that before on a cage.

 

[Marthy]

I'm approaching 50K miles mark on the FZ6R and it starting to rise some ???

How much mileage can I put on the timing chain? I need to replace the CCT again, might go manual this time and be done with it. While I'm there its not that much more work to swap the 3 gears and chain... and double check valve clearance.

Edit: Just ordered the manual CCT, hope it fit...

 

[Marthy]

Just wanted to share... FZ6R with 48K miles.

Timing chain... from left

To right.

Stretch almost 2mm on 13" or so. Not sure of the max tolerance but glad I change it.

 

[FinalImpact]

Maybe its the picture, but if you line up the pins, its seems like the pins start and nearly end in identical places. If this is true, is it really that stretched or does one simply bend a tighter circle?
It seems like this is where the chains were total length appears to make one look shorter than the other??

Any chance you measured the pin center to center over the longest span?

Our beloved 530 drive chain is 5/8" (0.625") pin to pin. So there must be number for the cam chain. PN: 94591-49120-00, CHAIN, 92RH2015/120 links

OK - here it is; but I don't see the wear limit. Http://www.chiaravalli.com/pdf_moto/CHT_MotorcycleDivision.pdf

Appears to be 6mm pin to pin (0.2362").

 

[Marthy]

I still have the old one. I can measure it. Any specific measurement over X links?

The top pic was from one end, and the bottom pic is the other end. I tried the best that i could to line them up... but we clearly see it stretch quite a bit IMO.

 

[FinalImpact]

Is that the same as FZ6? 120 links? ^^ PN i listed?

Measure as many as you can on pin center.

50 links should be 11.8109"
50*0.2362198" = 11.81"
299.9991mm

Thanks!

So, I did I read right somewhere that you took the FZ cams out of the R? A guy from the R forum is looking for some. Pretty sure you saw that.