After rescuing the pilot adjuster screw on my '83 rear carb I am now trying to get the accelerator pump set correctly. There are two settings I am wondering about. First, what is the correct length of the tie rod and what should the effect feel like for a properly adjusted rod? Second, what is the correct setting for the stop screw that limits the travel of the cam against the diaphragm in the bottom section of the accelerator pump? I find it sad that the maual provides no specification for such an extremely important component of the bike either except that the rod was set correctly at the factory.
Thank you.
working backwards:
i've never seen an 83 carb where the stop screw actually makes contact durring it's normal travel. i suspect it was used on other carbs besides this one.
the only spec given for the length of the rod is a service bullitin that said to increase the length by 5mm, total length from the bend to the end not to exceede 60mm. set it where it works best. if you can tell where it was previously set by discoloration on the threads, i'd start there, you'll be close & i've found unless it's severly off it's not as critical an adjustment as you'd think...
BTW, congrats on fixing the adjuster bolt, i'd REALLY, REALLY like to see pics....
--Lucky
You measure the injection quanity. Thats what you are dooing when you adjust the little rod. There is no accurate measurement for rod length.You have to measure the amount of fuel that comes out of the pump nozzle. That is 0.25cc per one compleat opening of the throttle, and you want to measure both front & rear cylinders. Make shure the float level is correct, and the carb is full of fuel. The little vile I use for measurement is a tool set I got many years ago to adjust Webber carburetors on cars. I have no idea if the stuff is still available. But the measurement device has to be small enough to fit down in the carb under the pump nozzle to get a accurate measurement. Several of the Vision carbs I have checked inject too much fuel, whitch makes them stumble right off idle. The 0.25cc measurement came from the Yamaha technical department in 1985.
Ken G.
Good info, a small syringe could be used to measure the output. i have a plastic one but is graduated in ml (so 2.5 ml = 25cc's? is that right?)
got any more tidbits? how did you come across that one?
2.5ml = 2.5cc. Used interchangeably. Being a healthcare worker, I can get a few syringes (clean of course) if you need. I can get anywhere from 1ml up to 50ml.
David
David, The syringe would have to be quite small to fit in the carb, and still open the throttle all the way. The little vile I use is 1cc total and is graduated in 10th's, the number I gave is 0.25cc, or 1/4cc. The original setting for the 82's was 0.50cc, or 1/2cc. Whitch later determined to be too much. The update kit for the 82's carb & air cleaner, service bulliton M84-019 had these settings. The 83's were supposed to have the lower volume. Every one I have checked has had to be ajdusted. I have seen almost no fuel, to way too much.
Ken.
Good advice Ken. Thanks.
David
This is awesome, I've been trying to figure out for forever how exactly to set up the accelerator pump. Who would have thought it could be so easy.
Thanks for the great info! i guess this measurement should be attempted with the carbs on the bike but I'm worried about dropping something into the engine. Is there a way to independently adjust each carb?
thank you.
There is only one pump assy for both carbs, but sometimes the check ball below the nozzle will stick, so one nozzle or the other will not squirt the correct amount. The little vile I use has a rolled top edge and I use a 6'' piece of small gauge safety wire around the vile then slide a small oring up from the bottom to hold the vile in place, now you can dangle the vile down in the carb under the nozzle and hold it in place. The vile is made from glass, some plastics don't like gasoline very much. You might try to find a small measuring device from a place that sells test tubes, graduated beekers and such. I have a 250cc and a 500cc glass beaker I measure fork oil with, that came from one of those places.
Ken.
I went to a pharmacy and bought a newborn feeding syringe...comes with a small tube extension too.....$3
Quote from: Lucky on September 24, 2006, 07:16:03 PM
the only spec given for the length of the rod is a service bullitin that said to increase the length by 5mm, total length from the bend to the end not to exceede 60mm.
I'm looking at handwritten notes from that bulletin that dpequip scanned into this post: http://ridersofvision.net/rovforum/index.php?topic=12390.0
I'm a little curious because the sketch doesn't show the entire accelerator rod, and Lucky's comment says "from the bend to the end"... When I lengthen the rod to this measurement (measurement A in my picture) I'm running out of threads and the rod falls out of the adjuster. Should I be measuring A or B in my picture?
Thanks guys, happy Sunday. Have a great holiday tomorrow, lots of beer and cookouts. Thanks Vets!
Jim
Don't believe everything you read. This is just my opinion but those comments by dpequip are bogus. I thought he had something until I started to do my own research and consulted with the carb guru here.
All the more reason to be accurate and accountable for your comments. Someone using the search feature later gets misinformation. :(
Anyone can think the setup instructions are bogus I really don't care. I'll keep using them because I know they work. If you find them helpful use them but if you want to reinvent the wheel feel free..... These are not my notes. The source of the hand written notes was our Yamaha Technical rep in 1984 "Back in the day" when these bikes were being sold brand new. I used those instructions to setup over 20 new bikes out of the crate and they worked. All I can say is the instructions had to be followed to the letter and everything had to be done or they would not work. Setting the Idle CO % is also a big deal in getting a Vision to run right. Unfortunately, most people don't have access to a Exhaust Gas Analyzer to correctly set CO %. This makes setting up a Vision to run right a difficult proposition at best. The bikes as setup per the instructions were right as I was the only one in the dealership that set these up. These setup notes ONLY apply to 1982 US Spec models that have the vacuum flapper door in the airbox mod kit installed. The instructions also assume the engine is in new condition, the YICS box works as it is suppose to, and all the passages in Carbs are clean and unplugged. Unfortunately many of those assumptions are not valid today since these bikes are almost 30 years old. Because of that, the settings may have to be adjusted to compensate but they should give you a good baseline to start from. One other major difference is the gasoline they sell today has no resemblance to the gasoline that was sold in early 1980's. In these small engines the current gasoline ( I call it weasel piss) sold especially that with ethanol blended in it make motorcycle engines in general run worse and hard to start. Ethanol free gas makes a difference in these engines but that is a different subject for a different post. Whether these settings work on other models or other world market models I have no idea or make no claims they do. They definitely don't apply to 1983 models (Which I think this thread asked about) which have carbs that are a whole different animal.
Jim, Your rod is FUBARed. it's not supposed to have that bend in it, it should be straight like the drawing. you need a new one. PM me an address & i'll drop one in an envelpe for you unless you already have a spare.
Rikigun, I think it's more likely tha the doccument Dpequip scanned is from a Yamaha Rep, I think that a lot some of the info on it is inaccurate, such as increasing the oraface size on the nozzle. More likely, that we know more after 30 years, than they did then... or the Rep got fed some bad info at a meeting.
Dpequip, we posted at the same time.. the section thats crossed out, that looks like it's saying to increase the nozzle, whats up with that?
Quote from: Lucky on May 28, 2012, 08:53:08 AM
Jim, Your rod is FUBARed. it's not supposed to have that bend in it, it should be straight like the drawing. you need a new one.
maybe that IS the correct rod for the rare 82 carb with the stop screw on the accelerator pump... no?
Anything is possable, i've never seen one bent up like that. Has anyone else?
My 2 sets of '82 carbs are different but neither has an accel rod bent like that. Also neither has the stop screw feature.
QuoteRikigun, I think it's more likely tha the doccument Dpequip scanned is from a Yamaha Rep, I think that a lot some of the info on it is inaccurate, such as increasing the oraface size on the nozzle. More likely, that we know more after 30 years, than they did then... or the Rep got fed some bad info at a meeting
Perhaps and maybe I could have used a little tact :-[ The PDF I recall was in a spreadsheet form but had similar info but no pictorial depiction of where the measurements were to be taken. As I recall the 50-60 mm rod length wouldn't work on my first set. It was suggested the rod had been cut by a PO but even with magnification I can't see evidence of that.
Kudos to whoever bent that bar up though, nice work! lol
I have your new one in hand.
QuoteKudos to whoever bent that bar up though, nice work
The more I magnify it the more grainy it gets but I can't see much in the way of tooling marks. Sorta' looks factory made.
Your replacement rod is on it's way, it went out in this mornings mail.
--Lucky
Thank you very much! Lemme know what I owe you.
nothing although.. (que Godfather music here) I may one day ask you to do me a favor... lol no we're good. :)
Here is a procedure that I discovered recently to be quite effective on the 82's. It should be helpful for setting up an 83 as well.
I usually use the 60mm measurement with the stock diaphram (but the Keyster kit necessitates shortening it, or the delay will cause a serious stumble).
You can start with the 60mm (assuming everything else is perfect on your carbs) and adjust the rod on the bike after a few test runs. There is a slight hesitation when the pump delay is too far behind the throttle plate opening. Yamaha had you set it visually to clear the throttle plates, but this only get you close and cannot realistically anticipate the venturi air flow effect.
I think I did about 7 turns (thread revolutions, shortening the rod) and it consistently improved in response. You can pull the rod out of the throttle actuator and while holding the shaft from turning rotate the bent end a full revolution each time. I started with four turns, then went to two turns and finally one more (for good measure and stopped).
I know Ken (motoracer) suggests the volume measurement, but I have not found that method particularly useful with any of my setups (with due respect here), because I find that timing is a more signficant issue than volume. My 82's don't have any bogging problems because of too much fuel, rather they tend to get too much air, too soon, and create lean conditions. Getting the fuel delivery into the venturi at the correct timing with the air flow has made the most difference in my tuning situations.
Cndlouie, that makes great sense. Thank you very much.
I sort of "stumbled" ::) upon that one when I was fitting a new keyster diaphragm that has a shorter actuator rod than the original, so I didn't have a clue what I should set it at. A bench test with fuel to see if the nozzles open up and cleared the throttle plates as early as possible is a good start, and what I usually did before coming upon this idea.
Everything was brand new in the carb set so I knew what I was dealing with, I started with 60mm and it still had a bog when first opening the throttle. I went right to the pump adjustment and started shortening the rod. Each time it improved the throttle response. I stopped when any hesitation vanished. I should have continued to see if further shortenings created any other issues, but hey, when you get things right you stop.
This makes for a good procedure for ensuring the rod adjustment is optimum under running conditions. Start at 60mm (from right bend to plunger arm) and if you have hesitation, shorten it until your hesitation goes away. This 82 procedure was done on the flapper controlled airbox. Now, this "assumes" that your carb set is perfectly set up in every other manner, because this will not compensate for clogged passages, or leaking throttle shaft seals and the like. This is like the last thing you would do to perhaps clear up anything less than fantastic throttle response.
Cheers
What are the symptoms of leaking throttle shaft seals?
same as other vacuume leaks. uneven idle, runs lean, hard to tune, hard to start, backfire on decel, etc
There are a few different methods and opinions for adjusting the linkage rod's length, but I've not read much about adjusting the stop screw... I've found that the general consensus is "don't touch it", but am a little too curious to stop there. One could control the timing of the pump by adjusting the linkage-rod's length and the overall volume that the jets squirt could be adjusted with the stop screw, right?. Obviously it's a sensitive balance and you would have to dance back and forth with both of these adjustments to get things just right, but it does sort of work that way, right?
Regarding your last two questions, that's definitely how I see it. If both variables are set perfectly, off idle flat spots should, at the very least, be greatly minimized.
As an aside, my '83 has/had a significant off idle flat spot. For many years I worked around it by coming off the line with a little bit of high idle and a little bit of clutch slippage. I'm convinced that this chronic minor clutch abuse resulted in shortened clutch life. The fact that the factory clutch lasted 72k miles is due in large part to many of those miles being rolled on the highway.
any adjustment that you can turn it with your fingers, a wrench, a screwdriver or heat and a hammer, you should play with!
Quote from: Night Vision on May 28, 2012, 11:44:56 AM
Quote from: Lucky on May 28, 2012, 08:53:08 AM
Jim, Your rod is FUBARed. it's not supposed to have that bend in it, it should be straight like the drawing. you need a new one.
maybe that IS the correct rod for the rare 82 carb with the stop screw on the accelerator pump... no?
Lucky sent me a replacement rod that arrived in the mail yesterday. After taking a closer look, perhaps I do have the rare '82 version... The rods are the exact same length. If a "stock" rod were bent up like mine, it would be shorter as a result. It's also evident that it was manufactured differently because the threads aren't the same length. I think that my rod was manufactured the way it is instead of being modified by a PO. I uploaded more pictures comparing the two.
Is there a VIN lookup or some other way to tell what I've got? Perhaps it holds more secrets :)
I also can't find "homemade" marks on it. The bends appear to be machine made.
Quote from: Rikugun on May 29, 2012, 05:45:24 PM
QuoteKudos to whoever bent that bar up though, nice work
The more I magnify it the more grainy it gets but I can't see much in the way of tooling marks. Sorta' looks factory made.
Very interesting. It seems theses bikes still have some surprises :)
If it's factory made then I have some other thoughts:
1)that it came out of something else because it would present quite an angle change from stock. I wouldn't be surprised that the end would pop out when the green plastic gromet wore out.
2) when you put the one i sent on, is the angle way off on that one? if not then the linkage is different, or... might not be vision carbs??..
A picture of the carbs may help clear up the mystery.
I considered the rod is from another set of carbs but can't think of any other Yamaha's that had accel pumps. Anyone know of any possible applications? Only two other Japanese bikes I'm aware of had accel pumps but the parts were different and they were from inline fours.
I have it too!
I recognized the bent rod immediately but wanted to check before posting, in case I had lost it (my mind). From a quick glance, I do not think the straight bar will fit as a replacement. I have a lot of other things to do at the garage but I will try to look into it a little deeper.
If you guys remember, I had accel pump problems, and with used guts from here, it works just fine. I haven't seen anything else to suggest I have anything other than original 82 carbs on an original 82.
Oh, and it has the stop screw adjustment, which IIRC works pretty much as described by jim
I'd say this qualifys as another carb varient now known...
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)...
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.
Yep, mine matches those pics. Mine is stamped 11H - 012683 , on the tag is JYA11H00 X CA012683
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.
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.
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.
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?)
Like you said, if there is an adjustment, play with it. ;)
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?
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!
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!
I have an '82 Australasian 16R, which has (I'm told) an '83 carb. The bike runs OK. Photos & lengths below, hope it helps.
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.
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.
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
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,