Carb metering rod question..

[cowpuc]

Old Tweeks (our 83) is well over 200k on her, getting her ready for headin west - carbs synced up nice, new plugs yada dee yada.. Dont have access to an exhaust sniffer but using my built in one (nose) I KNOW she is running rich and MPG is suffering.. Pulled the diaphrams (again) and noticing more fuel gathering on the slides than I like.. Not spot of drippage on the float overflows..

Anyway, because of her mileage (yea, ok,, maybe even a little abuse) I am suspecting that the slide metering rod orvices may be oblonged a little.. I know I read on here recently about dropping the metering rods down 1 mm to lean down a little.. Have done many many carb adjustments like this through the years and was expecting a typical multinotched metering rod for the circlip on this 83.. Found out this is not so on these carbs - see pic..

So,, how do ya adjust the needle depth on these puppies (see pic).. Use washer/shim rings from differnent needle set up??

 

Thanks in advance ya bunch a lop eared gearheads!!

Puc

[Prairiehammer]

So,, how do ya adjust the needle depth on these puppies (see pic).. Use washer/shim rings from differnent needle set up??

 

Yeah, washer shims.

I think someone provided the proper washers on here. Maybe Skydoc or Dingy?

 

Apparently the Canadian market Ventures came with the adjustable needles (with notches).

But, 1983 needles (left in picture) are different in profile from the 1300 needles (right in picture). So be careful what year you get the Canadian needles from.

http://www.venturers.org/Forum/download/file.php?id=10581

Edited May 26, 2014 by Prairiehammer

[MiCarl]

Puc,

 

First thing you should do is check the fuel level in the bowls. If those are spot on you can look at the needle jets/jet needles.

 

Skydoc17 sells a kit to lower the needles. My 89 was getting mpg in the low 30s. After ruling everything else out I put in Skydoc's kit. Last ride I got 40mpg.

 

When I lowered the needles I needed to richen the idle mixtures some.

[GAWildKat]

Think you might be onto something with Mike's bike....depending on gas quality he avgs between 29-35mpg. I still think he needs to check the diaphragms, needles and floats now that he did a carbtune. But its been a crazy yr so far. This weekend is the 1st since Jan we haven't had to run somewhere or do something.

 

Sent from my SPH-L710 using Tapatalk

[cowpuc]

Thanks you guys!!

Carl, float levels were spot on end of last summer when I set them and currently no sign of sticky floats (over flows are bone dry).. I am really thinking with all these miles I am looking at tired main jet/needle jet orvices and wanted to try lowering the needles just to compensate some.. On another thread I read "lower the needles 1 mm".. That sounded suspiciously wide to me (just seems like maybe 1/2 millimeter increments would be closer.. Any idea how far you took your needles down to see that kinda change in mileage? You see any increase in running temps after leaning it down? And any idea how for out you took the pilot jets?

 

THANKS A GAZILLION!!

Puc

[MiCarl]

Thanks you guys!!

Carl, float levels were spot on end of last summer when I set them and currently no sign of sticky floats (over flows are bone dry).. I am really thinking with all these miles I am looking at tired main jet/needle jet orvices and wanted to try lowering the needles just to compensate some.. On another thread I read "lower the needles 1 mm".. That sounded suspiciously wide to me (just seems like maybe 1/2 millimeter increments would be closer.. Any idea how far you took your needles down to see that kinda change in mileage? You see any increase in running temps after leaning it down? And any idea how for out you took the pilot jets?

 

THANKS A GAZILLION!!

Puc

 

Now I'll have to dig into my memory (I did this early spring). Numbers not guaranteed....

 

I had guessed I might need to drop them 20 - 40/1000". I asked a machinist I know to make me a set at -0.060" from stock. I've got a box of 0.020" washers that I figured I could use to richen it back up from the -60.

 

Then I decided to order Skydoc's kit to see what he was doing. I believe his shims measured at -0.060" from stock so I put them in and asked the machinist to not bother. I like my results (plugs look good) at -0.060" so I've left it there.

 

I did a full sync and set the mixtures. Unfortunately I did not pay attention to how much I backed them out.

 

BTW, 0.060" ~ 1.5mm.

 

It is definitely lean just off idle. Until it's good and warmed up it's got a bit of a flat spot. The days of starting it up and immediately turning the choke off are gone.

 

Does it run hotter? No - the thermostat still keeps the temp where it belongs. If I get into traffic where I'm not moving a lot of air it does seem like the needle climbs faster. Can't say for sure though.

 

Going by the plug color it's not lean in normal operation - they look like perfect wheat toast. My guess is it's just off idle where it is lean at all.

[Prairiehammer]

Puc,

I found a recommendation of .020-.025" washer thickness in one of my 'archived' documents. One feller says to find brass or nylon washers at Radio Shack.

 

From unknown date or forum thread:

What is the proper amount to shim my carb needles?

Original question by Dom Ochoa....My understanding from the tech clinic is I can buy brass washers at Radio Shack, but I can't remember what the recommendation was about thickness. (By the way, I'm still running the stock exhaust)

 

Mario wrote: Between .023 and .027 thickness is what most people use.

 

Ted wrote: I have the covers off the carbs and plan to shim the needles about .020" to richen up the midrange.

 

Henry wrote: Mine measure .020 exactly!

 

Scott wrote: The washer thickness is .020. Radio Shack sells them in a little plastic bag of various O.D.'s and I.D.'s. The washer you want to use is obvious.

 

Dale wrote:I have found the stock needles work better or as good as an aftermarket. I would shim the needles with a brass #4 finishing washer found in most hardware stores. These are about .025 thick. I use these in my jet kit when a customer buys one of our exhaust systems. I would also suggest a K&N air filter to allow a bit more air flow.

[ReinyRooster]

"lop eared gearheads!!"........now thats funny! I have been called alot of things....manny of which I can't say here...but never been called that! Thanks for the laugh.

[Peder_y2k]

Hey Puc........ I think you are spot on about the jets being worn out-of-round due to high mileage. It would be a great investment to buy new replacement needles and jets. As long as you're buying carb parts, get new pilot circuit needles, emulsifier tubes, fuel inlet valves, along with all the o-rings for the carbs. My '83 with 50K miles delivered 42-46 mpg consistently riding two-up before I sold it, and my current '88 gets 45-49 mpg two-up, and neither bike has modified needle position.

-Pete, in Tacoma WA USA

[cowpuc]

"lop eared gearheads!!"........now thats funny! I have been called alot of things....manny of which I can't say here...but never been called that! Thanks for the laugh.

 

Your welcome Reiny,, glad you got a chuckle.

 

Thanks for all the info/input guys..

Pete, I really am trying to just suck the last little bit out of the old girl and trying to do it without spending the time ripping the carbs all apart (if I get started on it the whole bike needs to come apart, replace every bushing - bolt - electrical terminal and on and on,, better off to unscrew the rad cap and drive a new bike under it:rotf:).. Probably sounds crazy ut a real deal beater.. Its tired... THANK YOU for the input brother!! And by the way - I TOTALLY AGREE WITH YOU - YOU ARE 100 PERCENT ON TARGET!! That is the proper way to do it..

Prairie, Carl - between the two of you I gained some vital info.. What I was really looking for was an idea of shim size increments so I had a starting point in gaining control of fuel/air mix without taking the time to do it correctly like Pete mentioned,, a lazy mans fix so to speak..

Ok,, here is what I am in the process of trying.. No money, very little time, and fairly easy to do..

If you look at the pics below notice the stock plastic shim on the needle.. It has a round, what I am gonna call a locating pin that sticks out of the bottom of the shim.. On the opposite side of the shim from the locating dowl/pin is a small protruding edge the sits internally on the surface of the slide.. Measuring the protrusion yeilded .024 (24 thou) of protrusion.. I took a razor knife and nocked that protusion off, dropping the needle 24 thou on all of them.. Its been raining here so I havent had a chance to do a mileage check on it but I did run it around the block, noticed a small 200 rpm change in my idle - no starvation lag coming off idle.. I have lots of xtra carb parts - I plan to take another set of the same stock shims, nock the protrusion off and file off another 20 thou from the top of the shims and test those too just for comparison.. Creeping my way to the edge of where Carl had to rejet the pilot but staying on this side of the line so I dont have to,, I love experimenting. It would be pretty cool if just nocking off the protusions showed gain in MPG - will let everyone know..

Looking at the protustion itself makes one wonder exactly why the Yamaha engineers put it there in the first place.. First thing that popped into my mind was I wonder if it had to do with emissions - maybe the California bikes had to be run leaner to pass emissions and this little nub is not present on their bikes.. Anyone have any thoughts or ever heard anything about it?? I am not refering to the locating pin here,, there is a line up hole in the slide bottom that you have to make sure you locate the pin into for that - the pin has a definite reason for being there.. The smaller nub,, not so much, it just sets on the inside bottom of the slide raising the needle 24 thou..

If this works it would be a VERY easy lazy mans way for pulling out some fatness.. Hey,, even a couple mile per gallon and I will be SMILING!!

Thanks you guys for not pickin on me about this worn out old bike AND for NOT saying something along the line of,,, hey Puc - drop a compression tester on her and see if she is even capable of handling the close to the fuel it was designed to handle... Its to the point now that I dont even wanna know,,, as long as she's hitting on four we are headed for the West Coast in a week:cool10::cool10:

Syncing her back up and testing continues

Puc

[MiCarl]

The only possible reason I see for the pin is to orient the protrusion. They wanted that protrusion in a particular spot for some reason. The kit from Skydoc has neither the pin nor the protrusion.

 

Next time you pull them apart make sure the pin doesn't stick through the bottom of the slide. You don't want that guy stirring up the air flow.

[mega2500]

I removed the plastic shim and just built back with the correct shims -25thousands

and gained 10mpg with sidecar on . got shims at local hardware store .05 each

running today at 85deg it was about 1/2 to 3/4 on guage at 65mi per hr [35mpg]

[Peder_y2k]

It's been my understanding that the small 'post' was designed to cause the needle to be offset in the jet orofice...... 'kicking' the needle to the side of the jet so as to not run down the middle. Have no idea about the reasoning for this other than to prevent swirling of the fuel like water rushing down a drain.

-Pete, in Tacoma WA USA

[Venturous Randy]

I suspect that there really is a relationship between the pin and the locating tab on the diaphragms. I wonder if anyone has ever looked at this with an unmolested set of carbs and diaphragms. My suspicion is the pin would be on the bottom of the assembly to cause a slight lift on the end of the pin, maybe to center it a little and maybe reduce wear on the pin and jet. I have a set of carbs that appear to have the original diaphragms and if I can remember, I will check this out.

I did the shim thing on my carbs several years ago and played around with different thicknesses and worked through some hesitation and responsiveness until I got what I wanted. I used to be happy if I ever saw 40mpg and now I am wondering what is wrong. With being very careful with not lugging the bike, I have seen as good as 50mpg and this is without losing any power. This is also with not having the strong fuel smell with the bike idling in the garage for a few minutes.

RandyA

[cowpuc]

I removed the plastic shim and just built back with the correct shims -25thousands

and gained 10mpg with sidecar on . got shims at local hardware store .05 each

running today at 85deg it was about 1/2 to 3/4 on guage at 65mi per hr [35mpg]

 

Now THATS what I am talking about!! Its been fun screwing with this thing over Memorial Day weekend but now that the stores are open here locally again THAT is exactly what I am gonna do... Thanks Mega!

 

It's been my understanding that the small 'post' was designed to cause the needle to be offset in the jet orofice...... 'kicking' the needle to the side of the jet so as to not run down the middle. Have no idea about the reasoning for this other than to prevent swirling of the fuel like water rushing down a drain.

-Pete, in Tacoma WA USA

 

Pete it sure makes sense that the post could/would do exactly that and be for exactly what your talking about - good point!!

On the other hand,, it sure seems like if that were the case the extra side pressure from the needle setting at slight angle would cause excessive wear on orifice and needle doesnt it?

 

I suspect that there really is a relationship between the pin and the locating tab on the diaphragms. I wonder if anyone has ever looked at this with an unmolested set of carbs and diaphragms. My suspicion is the pin would be on the bottom of the assembly to cause a slight lift on the end of the pin, maybe to center it a little and maybe reduce wear on the pin and jet. I have a set of carbs that appear to have the original diaphragms and if I can remember, I will check this out.

I did the shim thing on my carbs several years ago and played around with different thicknesses and worked through some hesitation and responsiveness until I got what I wanted. I used to be happy if I ever saw 40mpg and now I am wondering what is wrong. With being very careful with not lugging the bike, I have seen as good as 50mpg and this is without losing any power. This is also with not having the strong fuel smell with the bike idling in the garage for a few minutes.

RandyA

 

May very well be right on that Randy.. This set of diaphrams are stock and never been off the slide - I will take a check on the locating post hole in the slide and see if thats correct - just to solve a mystery and out of curiosity.. Good point.. The only thing is it seems like .024 would create more than a slight lift,,,, hmmmm,, maybe the lift (or angle that Pete was talking about) is being controlled by the locating pin.. wierd little intreeeging design what ever its for.. It also still seems like any amount of side pressure created by that needle would produce extra wear - not eliminate it....

Hey, were you able to see the 50 mpg by working thru a shim stack without pulling it down and tossin new jets at the pilot circuit?

 

Thanks you guys!!!!

[Venturous Randy]

 

 

Hey, were you able to see the 50 mpg by working thru a shim stack without pulling it down and tossin new jets at the pilot circuit?

 

Thanks you guys!!!!

 

At the time I did the shim thing, I went to Lowes and got some small washers that fit over the needle and tried different thicknesses until I got what I wanted. My first try caused a noticeable hesitation and after another try or two, I worked it out. I did not change any other jets.

This particular run that got 50mpg was during the Asheville Rally a couple years ago. I filled the bike up and rode the Blue Ridge Parkway going across the highest part of the Parkway to Cherokee, NC. I made a point of running easy on the throttle and downshifted any time I felt like I was lugging the bike, going back to the theory of if you leave the throttle the same and downshift and the bike speeds up I wasn't running the most efficient. To maintain the same speed in a lower gear, I had to reduce throttle a little. It is a long pull to the top of the mountain, but it is also a long way down the other side.

On the run back to Asheville, I went through Maggie Valley back to Asheville. I then stopped at the same gas station and refilled the bike.

I don't always check the mileage, but several times lately I have gotten in the high 40's and that is with the V-Max rear.

RandyA

Edited February 20, 2015 by Venturous Randy

[cowpuc]

At the time I did the shim thing, I went to Lowes and got some small washers that fit over the needle and tried different thicknesses until I got what I wanted. My first try caused a noticeable hesitation and after another try or two, I worked it out. I did not change any other jets.

This particular run that got 50mpg was during the Asheville Rally a couple years ago. I filled the bike up and rode the Blue Ridge Parkway going across the highest part of the Parkway to Cherokee, NC. I made a point of running easy on the throttle and downshifted any time I felt like I was lugging the bike, going back to the theory of if you leave the throttle the same and downshift and the bike speeds up I wasn't running the most efficient. To maintain the same speed in a lower gear, I had to reduce throttle a little. It is a long pull to the top of the mountain, but it is also a long way down the other side.

On the run back to Asheville, I went through Maggie Valley back to Asheville. I then stopped at the same gas station and refilled the bike.

I don't always check the mileage, but several times lately I have gotten in the high 40's and that is with the V-Mar rear.

RandyA

 

Now we are talkin!!

Randy did you end up having to run high octane fuel to fight spark nock or are you able to stay at 87 octane even leaned down?

[Venturous Randy]

Now we are talkin!!

Randy did you end up having to run high octane fuel to fight spark nock or are you able to stay at 87 octane even leaned down?

 

I normally always run 87 octane, even when with pulling my 450 pound camper through the mountains. I have never had a problem with pinging that has been noticeable unless I absolutely lug the bike until it is bucking. I know that the V-Max rear will make a little difference, but on flat ground, I can take my bike down to about 15mph in 5th gear and slowly accelerate back out of it smoothly. I don't make a point of running non ethanol gas, but if it is convenient I will. I usually run what they sell at Walmart, which is Murphy around here.

RandyA

[cowpuc]

I normally always run 87 octane, even when with pulling my 450 pound camper through the mountains. I have never had a problem with pinging that has been noticeable unless I absolutely lug the bike until it is bucking. I know that the V-Max rear will make a little difference, but on flat ground, I can take my bike down to about 15mph in 5th gear and slowly accelerate back out of it smoothly. I don't make a point of running non ethanol gas, but if it is convenient I will. I usually run what they sell at Walmart, which is Murphy around here.

RandyA

 

OUTSTANDING!! I want to avoid painting myself into a corner with needing above 87.. For me, another one of the great things about these bikes is what they will run on.. I have ran a lot of 85 octane out west and never had a problem with ping either,, even loaded running mountains.. Have always been amazed at their torque capabilities in stock gearing - cant even imagine what tossing gearing at one with a Max rearend would be like!!

Thanks Randy!!

[skydoc_17]

Hey Scott,

The reason I use the single Nylon shim instead of S.S. washers is (believe it or not) the stack of S.S. washers weighs three times what the Nylon washer of the right thickness does. This extra weight slows the movement of the Slider and Carb. Diaphragm. After trying about 20 different thicknesses of Nylon shims, the current set I offer gives you the best blend of performance and gas mileage. YOUR wrist action will have a direct effect on the gas mileage part!

Here is a link to the Needle Shim Mod I offer in the Classifieds.

 

http://www.venturerider.org/classifieds/showproduct.php?product=3770&title=first-gen1983-to-1993-vr-needle-shim-mod-kit-21&cat=22

 

Here are some other things you might be interested in for the First and Second Gens.

 

http://www.venturerider.org/classifieds/showcat.php?cat=500&ppuser=4738

 

I hope this helps,

Earl

[cowpuc]

Hey Scott,

The reason I use the single Nylon shim instead of S.S. washers is (believe it or not) the stack of S.S. washers weighs three times what the Nylon washer of the right thickness does. This extra weight slows the movement of the Slider and Carb. Diaphragm. After trying about 20 different thicknesses of Nylon shims, the current set I offer gives you the best blend of performance and gas mileage. YOUR wrist action will have a direct effect on the gas mileage part!

Here is a link to the Needle Shim Mod I offer in the Classifieds.

 

http://www.venturerider.org/classifieds/showproduct.php?product=3770&title=first-gen1983-to-1993-vr-needle-shim-mod-kit-21&cat=22

 

Here are some other things you might be interested in for the First and Second Gens.

 

http://www.venturerider.org/classifieds/showcat.php?cat=500&ppuser=4738

 

I hope this helps,

Earl

 

Hi Earl

Thank you for the response!!

I totally understand what your saying about the xtra weight.. Did my test run on my 83 this morning and ended up with a 3 OR 4 mpg gain on just nocking off the little protrusion on the original shim - that was without a re-sync on the carbs - VERY IMPRESSIVE FROM MY PERSPECTIVE,, every little bit helps.. The removal of the little protrusion dropped the needle .024 and I am reluctant to go much farther as I am getting ready to head west and dont want to have to tear the carbs down and rejet my pilots or run into having to run high octane..

Depending on how the ol beater does in the real heat and mountain running with all the gear on her back I may be looking at a set of your shims!!

GOOD LOOKING BUNCH OF VENTURE PARTS YOUR OFFERING UP!!! THANK YOU FOR DOING YOUR PART IN KEEPING THESE GOOD OLD BIKES ON THE ROAD EARL!!!!

 

And Earl, you helped A LOT!!

 

Thanks

Scott

[BlueSky]

Cowpuc, I was in Jerome, AZ Saturday and I was looking around for an 83 Yamaha Venture with lots of stickers on it! I'm on vacation and not on my bike unfortunately. We flew to Phoenix, drove to Jerome and then to Monument Valley. Monument Valley is awesome! Now, we are in Las Vegas and plan to go to Sequoia National Park in CA next. I hope you have a safe and wonderful trip!

[cowpuc]

Cowpuc, I was in Jerome, AZ Saturday and I was looking around for an 83 Yamaha Venture with lots of stickers on it! I'm on vacation and not on my bike unfortunately. We flew to Phoenix, drove to Jerome and then to Monument Valley. Monument Valley is awesome! Now, we are in Las Vegas and plan to go to Sequoia National Park in CA next. I hope you have a safe and wonderful trip!

 

BUMMER Blue!! Way things are working out around here you were about a week and a half to early for us.... Wish we could have bumped into ya cause I would have asked if you would sign our bike (Aussie Annie would never have forgiven me if I didnt offer ) and would have loved to have met you!!

Soooo,,, sounds to me like I should put this "Monument Valley" place on my possible to see list?? We are trying to get out of here before it gets so stinking hot down near the border (Meheeeco) that the tires burn off our bike - WE ARE GONNA SEE DA ALAMO (history lovers). Been to Jerome a few times and cannot wait to show it to Tippy BUT,, I am allll about seeing things together neither of us have seen before,,, a together moment if you will - man I love that women,, she's my bestest friend ever!!

Anyway,, tell me about the Valley Blue (if ya gotta sec).. Also anything of real interest you may have bumped into that was extrodinair..

Any chance you found any Ghost Towns on your vacation?? I especially love those!!

 

Sounds like you are doing some AWESOME traveling,, even though ya aint sleepin on the ground and staring at the stars at night sounds like your getting to see some AWESOME country!! You gonna drive a car to Sequoia? GORGEOUS biking in there buddy!! If ya have time ya oughta do the big 3 (Yosemite/Kings Canyon) - if you do I tell ya where to find all the fools gold you want (at Kings Canyon) - still got some under shipping tape on the side of my bike ..

 

Thanks for the well wish on our summer touring,, right back at you on yours BlueSky

 

Puc

[BlueSky]

Would have been great meeting you too! If you drive north on highway 163 just after you cross the AZ UT border there is a road that crosses 163. Turn east and go a few miles. It cost $6 I think for a motorcycle to get in the Navaho controlled park. They have a gift shop and museum and you can go on a tour of Monument Valley. The road is unpaved and rough so we paid for a tour in an SUV ($120). High cost but worth it. This is where John Ford filmed many western movies starring John Wayne. Some people drove their cars on the road but I suspect they dragged the bottom in places. They don't recommend riding a motorcycle on those roads but i suspect a skilled rider would not have a problem and you would avoid the cost of having them give you the tour. We plan to drive to Sequoia National Park and then maybe to Yosemite. At the shop at Monument Valley, my wife recognized a tv and movie star, Justin Chatwin, who with two friends had been traveling all over the country on 3 flat black Harley Sportsters camping along the way. He was nice enough to allow me to take a photo of her with him. So now she is following his twitter comments and photos. When we got to Lake Powell, we saw him again after he got pulled over by the police! I am envious of those 3 riders traveling all over the country camping along the way!! One of the riders was a young lady.