Timing Chain pin to pin measurement - 1978GS750e

[martin_montreal]

I was wondering if anyone has a Timing Chain Length Spec so I can determine if I need a new chain or not. I always thought I heard a bit of noise. Now the valve cover is off for valve adjustments and I was hoping I could measure pin-to-pin with a micrometer to extrapolate to determine total chain length. I would then need to know how long is too long to determine if I should change it while I'm in there... I looked everywhere and could not find say, total length of chain, number of pins or a spec. for a certain number of pins, UNLESS page 228 of the OEM manual "Cam Chain 20 Pitch Length of 157.8 mm 6.213 inches means 20 Pins? If so, then I need input from the results per the images for an extrapolation for 25% of that i.e ~1.55325 inches -
https://drive.google.com/open?id=1rweZdRsJuiI5VLGEQifEriC1wtpZbcRK

 

[Gorminrider]

I can't see your link. It requires permissions.

But from various manuals I have ...The maximum "service length" is measured across 20 pins. Anything more than 157.8mm (6.213 inches) means you should replace the chain.

 

[martin_montreal]

I can't see your link. It requires permissions.

But from various manuals I have ...The maximum "service length" is measured across 20 pins. Anything more than 157.8mm (6.213 inches) means you should replace the chain.

Apologies. It was supposed to be a shareable link but apparently only for my domain. I fixed it so you should be able to see the images now! That was the spec that I thought it was but was unaware it was a maximum. If so, based on my images, is it too long? I divided 6.213 by 4 and am unsure if it's 5 spaces or 5 pins... I could only do that number of pins due to the chain tensioner.

Beginning to search for Canadian providers just in case, I was wondering if it needs to be an endless chain i.e. if I have to remove the cams for this etc. or if I can simply remove my chain, using a chain disassmembly tool, connect it to the new one, pull it through, disconnect the old from the new and assemble with either a master link or clip? I hope so... if so, are any brands not recommended? Thanks!

https://drive.google.com/drive/folders/1rweZdRsJuiI5VLGEQifEriC1wtpZbcRK

 

[Rijko]

I was wondering if it needs to be an endless chain i.e. if I have to remove the cams for this etc. or if I can simply remove my chain, using a chain disassmembly tool, connect it to the new one, pull it through, disconnect the old from the new and assemble with either a master link or clip? I hope so... if so, are any brands are not recommended? Thanks!

Open chain with rivet is fine.
Endless chain would require disassembling the whole engine to get it on the crankshaft.
I usually use the DID one.

https://www.ebay.com/itm/SUZUKI-CAM...296043&hash=item2d07fef960:g:76oAAOxyzGlQ7qvD

Because this is an inexpensive item, i always replace it.

 

[Gorminrider]

Why the "division"? The best place to measure length is between the camchain sprockets, under the valve cover.

 

[martin_montreal]

Why the "division"? The best place to measure length is between the camchain sprockets, under the valve cover.
View attachment 60682

Yes per the comment and the photos, unless (or until) I remove the tensioner, I can only measure 25% of that and extrapolate to 20 pins 6.213". Was looking for a second opinion on whether my image conveys too many or the correct number of pins i.e. 5 chain lengths & 6 pins on my ~1.55". Thanks.​

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I sourced the DiD 219FTSS chain in Canada thanks! Do you know how many links the right fit should be? They sell it in different lengths. I hope it's not too much of a PITA to install. ;-).

 

[martin_montreal]

Open chain with rivet is fine.
Endless chain would require disassembling the whole engine to get it on the crankshaft.
I usually use the DID one.

https://www.ebay.com/itm/SUZUKI-CAM...296043&hash=item2d07fef960:g:76oAAOxyzGlQ7qvD

Because this is an inexpensive item, i always replace it.

Thanks. From the picture, do you think it is stretched too long?. I will try to source same or similar item in Canada if it needs to be replaced.​

​

 

[Rijko]

Thanks. From the picture, do you think it is stretched too long?. I will try to source same or similar item in Canada if it needs to be replaced.​

​

i really cannot tell from a picture.

My reasoning is that these old GS bikes usually have a lot of miles on the clock.
And even the clock cannot be trusted.
Those flimsy chains were not made for eternal life.
Stronger chains are replaced at 70K KM and most GS bikes have more than that on the clock.

So unless you have a low-mileage bike, or proof of a new chain .... why not replace it ?

Even though some will argue their GS has 100K miles on it and still runs like new,
a worn chain has dramatic impact on valve timing.

For 30 bucks i don't take a chance on an old timing chain.

 

[martin_montreal]

Bike bandit list it at 120 Links if I interpreted their parts description correctly and digging deeper into Rijko's ebay UK link, the DiD part number which the CDN supplier lists with different length / links to order is 219FTSS so I hope this helps someone else. Thanks for all your input! When I get the shim tool and calculate what shims I need, I will order the chain with the required shims. Hopefully this is not too much of a PITA to install from the top and I don't drop anything in there during the process. https://www.bikebandit.com/oem-parts/1978-suzuki-gs750-cam-chain/o/m147989sch258367

 

[martin_montreal]

I wondered and have now finally read that the cam sprockets should be changed when swapping in the new chain just like with drive chains?

 

[rphillips]

Is it normal for a GS cam chain to be stretched past service limit? I don't remember seeing one nor have I seen cam sprockets that showed any noticeable wear. They did always appear relatively weak.

 

[Sandy]

Is it normal for a GS cam chain to be stretched past service limit? I don't remember seeing one nor have I seen cam sprockets that showed any noticeable wear. They did always appear relatively weak.

At 80,000 kms out of curiousity I measured mine. It measured only 1/4 of the way between the low side of spec and the high side.

 

[Agemax]

I wondered and have now finally read that the cam sprockets should be changed when swapping in the new chain just like with drive chains?

Where did you read that? They will not need replacing and i very much doubt the camchain needs replacing either.

 

[Grimly]

True of drive chain sprockets, but I've never had to replace a cam chain sprocket nor have I ever heard of one being replaced, except if it was actually maltreated and broken.
As for the camchain itself - my old one was replaced last year at 80K miles and it shows next to no sign of wear. This is in line with the previous ones I've had. In fact, I've never actually had to replace a camchain because of wear on my GSs, only as a precautionary measure, and essentially wasted money doing it.

 

[Gorminrider]

as a precautionary measure, and essentially wasted money doing it. ..

ha-ha! been there done that per wasting$$ but Yes, I've never heard of these wearing badly and certainly mine are fine though not high-mileage... Much stouter looking chains and/or different makes seem to have more problems from my general cruising among bikes I have...

There's sooo much oil coming up with the chain,from the sump that it'd be one of the last things to wear.

IF a chain stretches, it's going to work against the sprockets. I'd expect to see wear on them but steel quality may make that a wrong assumption compared to the wheel chain and sprockets...

 

[martin_montreal]

ha-ha! been there done that per wasting$$ but Yes, I've never heard of these wearing badly and certainly mine are fine though not high-mileage... Much stouter looking chains and/or different makes seem to have more problems from my general cruising among bikes I have...

There's sooo much oil coming up with the chain,from the sump that it'd be one of the last things to wear.

IF a chain stretches, it's going to work against the sprockets. I'd expect to see wear on them but steel quality may make that a wrong assumption compared to the wheel chain and sprockets...

Laptop fried and new one is late so will load pics later. The DID219FTS(S) arrived. A circular chain with no master links, I measured it and 20 pins turned out to be about 5 3/4 inches, 6 pins about 1 1/2 inches. My sprockets on further inspection look just fine to me and after reading here, I wonder if the current chain needs changing. DiD never answered my email from last week - maybe they are closed or understaffed and the supplier thought he was ordering an open chain with a master link, grrr. At least I got the shims & lashes to spec with a few left over that should be of use, the next time I check. So if I close it up and do the chain next winter can I reuse the same breather and valve cover gaskets? I hope this excersise in thus far futility, helps someone else.

 

[Gorminrider]

can I reuse the same breather and valve cover gaskets?

the breather gasket I don't think I've had more than one on and off ...My bikes, the cover comes out without removing it. I don't think much happens up there as to leaks....so you should get away with re-use if it's in good condition.

The valve-cover gasket is a different animal. Usually old ones get flattened, (and torn coming off) and it's probably best to get a new one. They can be very $$$ for what they are so I can't help saying...You can cut your own if you take the trouble to make or get a couple of hole punches. It's not very hard and it's a big money saver making your own gaskets....the "thicker" stuff-usually there's two thicknesses at the autoparts places...TRIM around the outside after it's on-that makes a neater job than you can do on the bench ...the inside can be rough as to fit. Nobody sees it.

But whatever, a new one can last through several take-offs-and -ons...don't overtorque it. Follow the manual torquechart..I think it's about 72inch/lbs to start ...

 

[martin_montreal]

the breather gasket I don't think I've had more than one on and off ...My bikes, the cover comes out without removing it. I don't think much happens up there as to leaks....so you should get away with re-use if it's in good condition.

The valve-cover gasket is a different animal. Usually old ones get flattened, (and torn coming off) and it's probably best to get a new one. They can be very $$$ for what they are so I can't help saying...You can cut your own if you take the trouble to make or get a couple of hole punches. It's not very hard and it's a big money saver making your own gaskets....the "thicker" stuff-usually there's two thicknesses at the autoparts places...TRIM around the outside after it's on-that makes a neater job than you can do on the bench ...the inside can be rough as to fit. Nobody sees it.

But whatever, a new one can last through several take-offs-and -ons...don't overtorque it. Follow the manual torquechart..I think it's about 72inch/lbs to start ...

- thanks. I had to remove the breather cover to get the valve cover off and it was good to clean it. I have both gaskets, have made them before ( for my - now broken 2.cylinder air compressor) but will keep that in mind for the next time.i check the lashes. Instead of.changing the timing chain after a bunch of feedback I will remove, inspect and clean the tensioner before replacing the covers. It would be good to find a video on that. I just hope I don't need any o-rings. PITA for parts this covid19 particularly in Canada.

 

[martin_montreal]

True of drive chain sprockets, but I've never had to replace a cam chain sprocket nor have I ever heard of one being replaced, except if it was actually maltreated and broken.
As for the camchain itself - my old one was replaced last year at 80K miles and it shows next to no sign of wear. This is in line with the previous ones I've had. In fact, I've never actually had to replace a camchain because of wear on my GSs, only as a precautionary measure, and essentially wasted money doing it.

Thanks. Per the above, will just inspect the tensioner before reassembly. Appreciate all the input.

 

[Gorminrider]

- thanks. I had to remove the breather cover to get the valve cover off and it was good to clean it. I have both gaskets, have made them before ( for my - now broken 2.cylinder air compressor) but will keep that in mind for the next time.i check the lashes. Instead of.changing the timing chain after a bunch of feedback I will remove, inspect and clean the tensioner before replacing the covers. It would be good to find a video on that. I just hope I don't need any o-rings. PITA for parts this covid19 particularly in Canada.

hmm o-rings in Canada...oftenplaces that sell Fasteners (nuts and bolts particularly) sell these. Here in Courtenay, Canadian Tire also has a drawer with them. But these are still open in BC....not sure where you are. The one you are likely to need is on the "set screw/lock nut" at least that's the one I've seen drip...ever heard of "plumber's string"? In a pinch, a wrap of cotton string yarn can do wonders.

But really, don't take it apart unless you need to. They should last the life of the bike or at least serious mileage....

Otherwise, if you MUST there's a "take apart" help at BikeCliff's website-specifically in the "engine " portion of "odds and ends" and two recent threads about them too...
Bike Cliff's
BikeCliff's Website
specifically, here:
http://members.dslextreme.com/users/storagecliff/images/engine_odds-n-ends.html#A05