Tach Drive Plug?

[RustyTank]

Howdy. I recently replaced my 1979 GS850G stock gauges with an electronic gauge. I need to plug the tach drive hole. Wondering what other people are using, if there's something standard or aftermarket, etc?
While doing a search I found a thread from 2016 regarding this subject and BWRINGER commented about Suzuki part #26442-45000 that was used on many Suzuki models that moved from mechanical to electronic tachs. I looked it up but had a difficult time determining whether it would fit my year/model. If anyone has any insight I'd appreciate it. Or, as mentioned, any aftermarket or home grown ideas.

[gsrick]

I may not be the coolest option, but couldn't you just use the end from the cable that normally screws onto it and plug it with some RTV silicone, so the oil doesn't leak?

[RustyTank]

I may not be the coolest option, but couldn't you just use the end from the cable that normally screws onto it and plug it with some RTV silicone, so the oil doesn't leak?

I actually have thought doing something like that gsrick. I wasn't sure what compound to use as a sealant though. So yea, maybe!

[GregT]

AFAIK, all the cable tach drives are the same OD so you'd assume a plug for the later engines would fit.

Alternatively, the diameter of the shaft from the drive gear is 8mm - so replacing it with a capscrew and nut is feasible.

[RustyTank]

AFAIK, all the cable tach drives are the same OD so you'd assume a plug for the later engines would fit.

Alternatively, the diameter of the shaft from the drive gear is 8mm - so replacing it with a capscrew and nut is feasible.

Thanks GregT. Great info.
I imagine some sort of o-ring will be necessary to stop any oil leakage. I'll go to the hardware store and see what I can find.

[GregT]

Thanks GregT. Great info.
I imagine some sort of o-ring will be necessary to stop any oil leakage. I'll go to the hardware store and see what I can find.

The stock oil seal in the drive body should still work on a stationary bolt shank. Flat washer on the outer end should complete the job.

[Steve]

Why not just remove the tach cable and be done?

There is a band that goes between the body and the head, and another seal (lookls like a valve seal) between the body and the shaft. With those two in good condition, there will be no need for silicone or any other crap. Just remove the cable.

.

[RustyTank]

Why not just remove the tach cable and be done?

There is a band that goes between the body and the head, and another seal (lookls like a valve seal) between the body and the shaft. With those two in good condition, there will be no need for silicone or any other crap. Just remove the cable.

.

I'll be honest with ya bub, I don't totally understand what yer sayin

[bwringer]

Agreed -- you can just remove the cable, leaving the fitting and the tach drive gear in place, and it will not leak unless the seals are bad. Please don't goober RTV silicone or whatever in there. You will see the end of the drive gear spinning around but it won't hurt a thing.

In fact, if there's any RTV in your garage, keep that crap at least 10 feet away from your motorcycle at all times. But that's another rant for another day...


Anyway, if you want a neater solution, that plug I mentioned aeons ago will work just fine on your bike; the sealing "band" (it's sort of a flattened o-ring) is the same part number (26451-45000) for the plug or for the stock tach cable fitting, so you know the diameters are the same.

Here's the fiche from a random later model GS450. This is a model that had a cable drive tach early on and then moved to an electronic tach. Suzuki just plugged the hole instead of redesigning the parts. :

https://www.onlinecycleparts.com/oemparts/a/suz/50d3f1fbf8700230d8b4bcf3/cylinder-head

Sometime in the 2000's, Suzuki finally stopped drilling this hole on the GS500 cylinder head, but the blank area on the casting was still there.

And yes, I've held both parts in my hand. That plug will fit your GS850.

One of Suzuki's most endearing traits is their reliance on parts bin engineering and their great reluctance to redesign anything unless absolutely necessary. This leads to a lot of interesting parts compatibility like this, and really helps us keep these old bikes on the road.


Here's my page that shows the normal tach fitting, the tach drive gear, the sealing band, and the seal.

http://www.bwringer.com/gs/tachcableseals.html

[gsrick]

Agreed -- you can just remove the cable, leaving the fitting and the tach drive gear in place, and it will not leak unless the seals are bad. Please don't goober RTV silicone or whatever in there. You will see the end of the drive gear spinning around but it won't hurt a thing.

In fact, if there's any RTV in your garage, keep that crap at least 10 feet away from your motorcycle at all times. But that's another rant for another day...


Anyway, if you want a neater solution, that plug I mentioned aeons ago will work just fine on your bike; the sealing "band" (it's sort of a flattened o-ring) is the same part number (26451-45000) for the plug or for the stock tach cable fitting, so you know the diameters are the same.

Here's the fiche from a random later model GS450. This is a model that had a cable drive tach early on and then moved to an electronic tach. Suzuki just plugged the hole instead of redesigning the parts. :

https://www.onlinecycleparts.com/oemparts/a/suz/50d3f1fbf8700230d8b4bcf3/cylinder-head

Sometime in the 2000's, Suzuki finally stopped drilling this hole on the GS500 cylinder head, but the blank area on the casting was still there.

And yes, I've held both parts in my hand. That plug will fit your GS850.

One of Suzuki's most endearing traits is their reliance on parts bin engineering and their great reluctance to redesign anything unless absolutely necessary. This leads to a lot of interesting parts compatibility like this, and really helps us keep these old bikes on the road.


Here's my page that shows the normal tach fitting, the tach drive gear, the sealing band, and the seal.
http://www.bwringer.com/gs/tachcableseals.html

I didn't know about the plug and I don't want to start an argument, but millions of people have use RTV on a billion things with no problem. Ultra Black works great for sealing oil leaks when you don't have a brand new gasket to use. It never fully hardens, so it doesn't shrink and crack and if used properly does not get into the engine or the oil passages. Many vehicles don't use gaskets and use RTV instead, such as valley pans and intakes.

[RustyTank]

Agreed -- you can just remove the cable, leaving the fitting and the tach drive gear in place, and it will not leak unless the seals are bad.

If you want a neater solution, that plug I mentioned aeons ago will work just fine on your bike; the sealing "band" (it's sort of a flattened o-ring) is the same part number (26451-45000) for the plug or for the stock tach cable fitting, so you know the diameters are the same.

Here's the fiche from a random later model GS450. This is a model that had a cable drive tach early on and then moved to an electronic tach. Suzuki just plugged the hole instead of redesigning the parts. :

https://www.onlinecycleparts.com/oemparts/a/suz/50d3f1fbf8700230d8b4bcf3/cylinder-head

Sometime in the 2000's, Suzuki finally stopped drilling this hole on the GS500 cylinder head, but the blank area on the casting was still there.

Thanks Ed. Now I understand what Steve was saying about the cable.
I ordered the plug and sealing "band". We'll see how it go's.

Thanks everyone.

[Steve]

I didn't know about the plug and I don't want to start an argument, but millions of people have use RTV on a billion things with no problem.

True, when used PROPERLY, RTV can work well. The problem is that too many people operate on the "drag racer's philosophy".
If 'some' is good, 'more' is better and 'too much' is enough. The RTV itself is not the problem, it's the gobs of excess that squeeze out, then flake off and get caught in passages that block oil flow.

.

[greg78gs750]

i was gonna say, the 83 1100 es has a plug for the elec tach....but i was beaten to it

[Wingsconsin]

More interested in the product choices and process to move to electronic Tach --
And then a GPS Speedo too --
That would get me curious for a future retro-mod on my 850L .

[eil]

I looked into this a few years back when converting my 1981 GS750E from mechanical to electronic tach. Your three options are:

1) just remove the tach cable like others have said and call it a day.

2) You can buy a "blank" OEM tach gear sleeve. I don't remember what models had these but some did. Maybe the later 450s when they switched to an electronic tach.

3) You can make your own blank by filling the existing tach gear sleeve with JB Weld. These sleeves and gears are a dime a dozen on eBay, you won't be ruining a valuable part.