1981 GPz1100 B1 Rstomod / ELR "Tribute"

Seeing that painting is now squarely in my sights, having procrastinated far too long...
I grabbed my drill and angle grinder, and prepped the tank for welding the new pet-cock mounting.

First, I removed the level sender... (It has been functioning fine, and upon closer inspection, seems to be in ok shape!)

I then half-filled the tank with fresh water and shook it violently to release 40 years of "crud" that had accumulated.
Rinsed it 3 times... and left it to dry out in the sun.
Then, having previously measured and marked the new position for the pet-cock, I set about preparing the surfaces for welding;



The '81 and '82 GPz's with fuel injection had two outlets, one on each side,towards the rear of the tank,and not the traditional form either...
they were threaded "protrusions", to which the fuel pump and regulator were plumbed.

I had previously laser cut a plate to suit the new pet-cock, and welded on two bosses that I machined from 12mm, 316 stainless steel
( M6 blind thread, internal ) 

 



Once I was happy with it, I loaded the tank into my car and headed to my buddy's for expert welding...  

 

 



I was quite satisfied with the welding!    
To quote Allen Millyard: " I was well pleased with that! " 



I reinstalled the level sender and piped in a new inline filter and added gallon of gas...



All good.

And so, again, another (rather intricate) "to-do" item completed.
(without any drama, thankfully!)

H. 

Beautiful work! Plus welding while wearing shorts! 

Top job the parts and welding skills!

given the problems others have had with leaks when fitting conversion adaptors this is absolutely the right way to go (especially wi.th welding skills like that

 

It's a squeeze to get the petcock relocated when converting to carbs, isn't it!

 

"A very tight squeeze, it is" as master Yoda would say...
"Measure twice, one must!" 

(The BS34 CV carbs on my build consume even more space right there)

Nice work Mr. Slayer61!

H.

So, the clutch was "draggy" is how I can describe it, with an unsettling "clunk" when selecting first gear, accompanied, sometimes, by the machine lurching forwards if the front brake wasn't engaged...  even though I had set the lever "free play" according to the manual.

I ordered a set of "after market" clutch plates, delivery of which I took yesterday.

 

I put them in a thick plastic bag and added a ½ cup of SAE 40 mineral oil to soak overnight as per instructions on the packaging... I know, who thought there could be anything valuable written on the box, right??

Determined to get to the bottom of this "clunk"  behaviour, I removed the clutch cover...

Looks good 'n clean in there, I thought...

 

Just as I started to loosen the first clutch spring bolt, I saw it...

 

Two clutch friction plates together, without the steel plate in-between. One "extra" plate! Why? Oh why?

Upon inspection, the friction plates were at the end of their service thickness, so had to be replaced anyway. The inner drive surface (which is directly onto the inner aluminium hub surface) looked ok, as well as the  surface of the outer drive hub.

 

I assembled the clutch pack, starting with a friction plate and alternating with a steel plate, ending with the 9th friction plate that mates to the outer drive hub. 
I double checked, thinking how anyone could make such a "mistake" with something so so rudimentary...

 

I checked again, before fitting the hub and buttoning up the 5 clutch spring bolts.

 

After closing up the clutch cover, I set the cable/lever free-play again, as per the manual.

I can report that first gear now engages without a "clunk" (well a minor one at best) and the clutch is nice and "progressive". It is now easy to find neutral, with the "neutral finder" mechanism working as it should.

Yaay!

H.

In answer to your question "why" I think it's another case of "the guy down the pub said his big brother always fits an extra plate because it's better !!!
There is however a story behind this, back in the day before the Internet, upgraded parts weren't always easy to find so a mod that used to be done was an extra "steel plate" but this was part of a bigger piece of work. Because the steel plates are stamped they are not always flat so you get reduced friction as the full surface of the plate is not in contact ( if you hold the steels together and hold them up you can often see daylight between them) It was quite common to have the steel plates "surface ground" to get them flat which gave significantly more grip without increasing the spring rates. The extra steel plate was as a spacer to make up for the reduction in the total "stack" height after the plates had been ground

And then there are the "extra plate" clutches like Barnett sold.  Beware, though, those clutch plates are narrower than OEM and more easily notch up the basket.

A popular mod to get more clutch pressure is to shim an extra washer under the clutch springs to get more preload.

I was thinking about why the clutch felt "draggy"...
The answer is: because the additional plate reduces the clearance between ALL the  plates (steel and friction) when the clutch lever is pulled.
But why? : 
Because the release mechanism has a certain mechanical movement distance, created by the clutch lever being pulled to the handlebar, and the resulting clearance between each plate (required to properly disengage the clutch) is a simple ratio, of that movement, and the thickness and number of plates in the stack.
 More plates = LESS CLEARANCE = less  "disengagement".

H.

wrote:

And then there are the "extra plate" clutches like Barnett sold.  Beware, though, those clutch plates are narrower than OEM and more easily notch up the basket.

I guess the mod I described is the "red neck" version of the over the counter products from Barnett