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Accelerator Pump Settings

Started by zrx2000, September 24, 2006, 12:51:59 PM

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Jimustanguitar

I was in the garage last night and took several pictures of the accelerator pump setup with both rods installed. It definitely seems like the bent rod is a better fit.

I'll post more pictures soon (awaiting approval from the ROV flickr group)...

Rikugun

#41
Boy that's sumpthin'....almost looks like the bent one is made for that application.  :D  :D

Apparently the stop screw rod bracket has the rod biased towards the center making the bends a necessity. The accell pump sans stop screw has the rod offset to the right negating the need for any bends.
It is far better to grasp the universe as it really is then to persist in delusion, however satisfying or reassuring.  Carl Sagan

JohnAMcG

Yep, mine matches those pics.  Mine is stamped 11H - 012683 , on the tag is JYA11H00 X CA012683
-JM

stuckinlodi

IVe got three 82 visions,  All with the flapper vacumme actuated air box and  two of them have these bent rods!!!!  The one Iam riding doesnt.  I wondering if it was a variant state by state?   Im going to be doing side by side comparisons of my carbs to see what else maybe different.

stuckinlodi

OK so the difference is the stop screw which does (nothing).  If you have one you ruin the bent rod if not you run the straight rod!

Wierd there must be a reason for the screw though.

Jimustanguitar

Quote from: stuckinlodi on June 07, 2012, 04:13:47 PM
OK so the difference is the stop screw which does (nothing).  If you have one you ruin the bent rod

There is a linkage spring that keeps you from ruining the bent rod. After the stop screw bottoms out, the spring should give enough to open the throttle further. The weakest link in the chain looks like the pump lever itself. It's a thin piece of stamped sheet. Looks to me like it would bend before the linkage rod would.

Lucky

so the theory is that the stop screw 'option' is designed to only allow the accelerator pump to provide a shot at the beginning of throttle movement.

probably an attempt to cure the bog without increasing emissions too much, & maybe also to assist fuel milage (every bit helps?)
1982/3 XZ550 Touring Vison, Gold on Black

JohnAMcG

Like you said, if there is an adjustment, play with it.   ;)
-JM

pinholenz

Hi Jim, I have been trawling through this post looking to set up my carb again. Its on its 4th strip and clean in 12 months so I am hoping I am getting close to OK by now!!

I too have a bent accelerator rod and a stop screw. (16R Australasian model) and like you have struggled to use the data available to set it up. Re-reading the posts, I will start with a 50mm rod length measuring from the first bend not the second. Is that what you did?

What was the consensus/your experience of the stop screw? Does it actually make any difference in practice? I went through the process of measuring the delivery volume and adjusting the stop to control it, only to find that with the link rod in place, the stop screw didn't travel to its stop position in any case.

Did you make a note of your final settings on your accelerator pump setup?
Only one '82.5  eXtreme Zen 550

Jimustanguitar

Quote from: pinholenz on April 07, 2013, 07:34:54 AM
Hi Jim, I have been trawling through this post looking to set up my carb again. Its on its 4th strip and clean in 12 months so I am hoping I am getting close to OK by now!!

I too have a bent accelerator rod and a stop screw. (16R Australasian model) and like you have struggled to use the data available to set it up. Re-reading the posts, I will start with a 50mm rod length measuring from the first bend not the second. Is that what you did?

What was the consensus/your experience of the stop screw? Does it actually make any difference in practice? I went through the process of measuring the delivery volume and adjusting the stop to control it, only to find that with the link rod in place, the stop screw didn't travel to its stop position in any case.

Did you make a note of your final settings on your accelerator pump setup?

The 50mm measurement should be to the end of the rod. Just measure it's overall dimension and don' t worry about the extra bend.

Note that this is just a starting point. You'll have to tune it by feel (like CDNLOUIE describes on page 2 of this thread). The engineer in you could also adjust it by spray volume like this thread describes: http://ridersofvision.net/rovforum/index.php?topic=14416.msg130896;topicseen#msg130896

The stop screw never makes contact on mine either... Can't say whether or not this works well, that's about as far as I made it into my carbs last year before discovering a corrosion hole in one of the little brass tubes that was causing a drip. I'm going to fix that now that the weather has turned and get back into the tuning process.

Good luck!

pinholenz

Thanks Jim, 50mm from the rod end looks much better than from the bend.

I think I am getting my head around how this pump works in practice - as you say its not just a matter of setting the length of the rod. There are too many other variables. The strength of the spring on the rod and the strength of the spring in the pump.

Initially I measured the fuel delivery load to the nozzle by adjusting the screw stop and activating the pump by hand. I am now convinced that the screw stop does nothing - as you say it doesn't seem to touch the pump body. From my tinkering and observation, my thinking is as follows:

Shortening the pump rod pre-loads the pump spring. When the accelerator is opened there is not much travel left in the pump and the quantity of fuel delivered is less. Lengthening the rod does the opposite.

The compressive strength of the rod end spring determines the delay between the throttle opening and the way the fuel shot is delivered. Strong spring gives a more instant shot. Soft spring gives a graduated shot.

I will keep fiddling and pretend I am tuning!
Only one '82.5  eXtreme Zen 550

cvincer

I have an '82 Australasian 16R,  which has (I'm told)  an '83 carb.  The bike runs OK.  Photos & lengths below, hope it helps.

pinholenz

As I mentioned earlier, my 82.5  XZ550 16R Australasian has a bent accelerator rod.  I just acquired a XZ400 of dubious heritage and it has a bent rod as well. The adjuster is so rusted up, I doubt that it has ever been altered. The length of the rod from the inside face of the connection to the spring is 60mm. The pump action brings the pump travel adjustment stopper all the way to the pump body. It looks much more positive than my XZ550 action. After it has been cleaned, I will try it in the XZ550.
Only one '82.5  eXtreme Zen 550

hoverhead47

Hi,
My 16R XZ550's (ADR compliance date April 82) accelerator rod has the double bend in it.    It also has the dab of yellow paint from it's original adjustment.
The measured length from the bush in the lever to the first bend is 42mm.
The stop screw effective length is 3mm.
I offer these observations for comparison.

pinholenz

Out of curiosity, and while it is on the bench, what is the length from the spring face down to the inside face of the arm where it joins in to the butterfly plate. (I.e from the bottom bend to the spring)?

Cheers
Only one '82.5  eXtreme Zen 550

hoverhead47

Quote from: pinholenz on October 04, 2014, 12:15:18 AM
Out of curiosity, and while it is on the bench, what is the length from the spring face down to the inside face of the arm where it joins in to the butterfly plate. (I.e from the bottom bend to the spring)?

Cheers
G'day pinhole,
The distance from the inside of the first bend to the facing bush side is 55mm. You'll had to add bush thickness if you want the distance to the spring.
bfn,