What I learned today about intake manifolds

[Dragonslayer]

My 87VR always had carburation problems ever since I acquired her used at 40k miles. The last mechanic that worked on it before I gave up on other techs, and took over the full responsibility of being the only one to work on it told me that the intakes that were on the bike when i got it were the wrong intake manifolds. He said the ones on the bike were vmax manifolds that had a crossover port that the 87 xvz1300 did not have. He explained that the extra ports were sucking air that affected the air intake with the gas mixture to intake port causing the gas/air mixture feed to the spark plugs to be wrong. The end result was that the fuel burn was rich and the bike didn't idle properly and the fuel burn in the cylinder was not efficient causing poor ignition at the spark plug. It sounded reasonable to me so i gave him the OK to order the right intake manifolds.

 

It ran a little better for a while but the same poor performance quickly returned. Then the bike died altogether.

 

Note: The next few paragraphs are background describing my mental reference at the time If you not interested in my thought process and want to skip to the point scroll down to the paragraph heading "The Point".

 

 

It was at that point that I started believing that i was the proud owner of a dinosaur too old for reliable professional service and abandoned by Yamaha since a lot of the parts i needed were no longer available. And the parts that were available were so cost prohibitive that I couldn't justify the expenditure needed to keep her alive. I was almost ready to part her out.

In fact the Yamaha dealers wouldn't even talk to me about working on it since it was more than ten years old. Evidently Yamaha in their marketing strategy has decided to only stand behind their product for no longer than ten years. As much as that pisses me off I guess I can understand that they have to cater to the new money and twenty year old + bikes are past history, from their corporate point of view. But as a builder and contractor that has made my living built on my reputation of providing quality work and a man of character that stands behind his product, engineering, service and workmanship no matter how longs it been, I felt deserted and violated.

 

So anyway I had a decision to make. Do I give up on her, Part her out and and commit her usable organs to Ebay. Or do I stand by the old girl and fight for her life even though she was on Life support and could possible already be dead. I started looking at new Goldwings, BMW 1200's, Victory Visions. The ride on the Goldwings somehow felt like a park bench, the BMW's had a nice ride but the saddle didn't fit my crouch, the vision took my breath the first time I saw it. As I was considering it as a option the reoccurring thought that popped into my mind was about if George Jetson rode a motorcycle it would be the Victory Vision.

 

I was weighing out my options when I investigated ebay for the first time as marketing research to test the market for used 87 Venture Royal parts. My plan at that time was to generate the down payment on a new bike by parting out my 87VR. To my amazement I found out that ebay offered what Yamaha no longer did and what I needed could be won realitively cheaply on the internet ebay auction. The first Auction I won on ebay was a set of Carbs from Sean Hess (Hessforless ebay seller & member of VentureRiders.org) which I was sure was the root of my bike problems.

During that transaction I talked to Sean on the phone and he told me about Venturerider.org God Bless you Sean.

 

Well I BELIEVE THAT LIFE IS ABOUT TRIAL AND ERROR. Thomas Eidison was once asked about his failures in testing 300 and something different materials to use as the filament for the light bulb before he discovered that carbon tungsten worked. His response was, "None of those test were failures, in fact I succeed in all of those test by discovering what did not work". Dragonslayer philosopy: Failures are learning experiences you can profit by.

 

Am I rambling? The carbs didn't fix the problem so I timidly entered a tech thread that seemed to be related to the problems that I was experiencing and asked for help as a newby to VR.org. GeorgeS (my VR.org hero) responded offering his assistance. Typical of what I have since discovered is the nature of this club and it's members he selflessly committed his considerable time addressing and walking me through troubleshooting and fixing my bike. God Bless you GeorgeS, God Bless you VR.org each of you one and all. With his help and others we breathed new life into her.

 

With all of that said I'll get to the point. She ran better than she ever did. Well enough for me to feel good enough about her to break her down for a new paint job and going over which I completed just in time to make the Clay18 Bike presentation. Which was the first time I had met any of ya'll in person. Muffinman stepped up at that event to offer to sync my carbs in the parking lot. An offer I deeply appreciated and humbly accepted. Even though I felt that I had managed to get the sync fairly close judging by her improved performance. I was floored to discover from muffinmans carb sync that the intakes were still sucking outside air and as Muffinman explained it, meant that the current efficiency was equivalent of operating on 2 1/2 carbs instead of four. Evidently I still had some work to do.

 

I limped thru last summer diagnosing low compression problems on one cylinder, chasing Ohm demons through the electrical and electronic systems then finally starter clutch failure on top of the never resolved carb problems. So I committed to another ground up going over including a new to me, used 9000mile 1990 model engine. During that process i won a ebay auction for a November 1986 issue of Cycle Magazine which evaluated the 1987xvz1300 Venture Royal with technical changes from 1986 to 1987.

 

The Point

 

One of the technical points the article mentioned was larger carb bores from the 34 mm mikunis to 35 mm mikunis in 1987. And I quote, "These measurements come from the carb's mouths- at the venturis, the jump is even bigger: 30.3mm in 85, 31.6mm in 86. To even out the mixture, both pilot and main jets grow larger this year yet fuel consumption remains remarkably close to the numbers from our last test unit."

 

When I first read that information it didn't mean anything to me. During the history of my ownership and the foregoing background dialog I have ended up with three different sets of intake manifolds. All of which look exactly the same visually. But on the work bench they got mixed up. Then as I was preping carbs to mount on new motor I noticed that some seemed to fit tighter on carb mouths than others.:lightbulb:I Got out the ruler and guess what? There is a measurable difference in the opening (Where carb throat inserts in intake boot.) size between the three different sets of Intake manifolds/boots. is it possible that my problem all along was that the intake manifolds were not the same year as the carbs therefore the clamps did not fully constrict the boots around the carb throats and therefore not completely sealing or preventing air being sucked through that incomplete seal. I have no clue what year carbs I bought off ebay nor do I know what year each set of intake boots are. I figure that I will us the tightest fitting set to mount to this new (to me)1990 motor.

 

Then the next question occurred to me that I would welcome some input on...

 

I wonder how many internal carb changes might have occurred between whatever year carbs I have and the 1990 motor I'm getting ready to mount them to and to what degree will those changes adversely effect the performance of the 1990 motor potential performance.

 

These carbs just got brand new diaphragms and fuel enrichment/air cut off diaphragms if I'm gonna need to change jets to match 1990 engine I rather do it now while they're on the bench instead of putting it all back together and having to do it later.

[Yammer Dan]

Good info. I'm swapping carbs also and will check that. Swapped them on the "Blue Beast" and she ran a LOT better. Guess I just got lucky with that because I never checked it.

[Gearhead]

Just my thoughts: One, I think the diaphragms are the same for all years of VR, meaning your new ones can be put in different carbs if need be. Two, in the absense of other input I would install the jets that go with the carb.

 

Question: Did you find the old coasting enricher diaphrams to be cracked?

 

Jeremy

[mraf]

I have the same question about the coasting enricher diaphrams.

[Dragonslayer]

Just my thoughts: One, I think the diaphragms are the same for all years of VR, meaning your new ones can be put in different carbs if need be. Two, in the absense of other input I would install the jets that go with the carb.

 

Question: Did you find the old coasting enricher diaphrams to be cracked?

 

Jeremy

 

Yes, all of them where deformed with pin holes.

[Dragonslayer]

I have the same question about the coasting enricher diaphrams.

Yes

[Dragonslayer]

My 87VR always had carburation problems ever since I acquired her used at 40k miles. The last mechanic that worked on it before I gave up on other techs, and took over the full responsibility of being the only one to work on it told me that the intakes that were on the bike when i got it were the wrong intake manifolds. He said the ones on the bike were vmax manifolds that had a crossover port that the 87 xvz1300 did not have. He explained that the extra ports were sucking air that affected the air intake with the gas mixture to intake port causing the gas/air mixture feed to the spark plugs to be wrong. The end result was that the fuel burn was rich and the bike didn't idle properly and the fuel burn in the cylinder was not efficient causing poor ignition at the spark plug. It sounded reasonable to me so i gave him the OK to order the right intake manifolds.

 

It ran a little better for a while but the same poor performance quickly returned. Then the bike died altogether.

 

Note: The next few paragraphs are background describing my mental reference at the time If you not interested in my thought process and want to skip to the point scroll down to the paragraph heading "The Point".

 

 

It was at that point that I started believing that i was the proud owner of a dinosaur too old for reliable professional service and abandoned by Yamaha since a lot of the parts i needed were no longer available. And the parts that were available were so cost prohibitive that I couldn't justify the expenditure needed to keep her alive. I was almost ready to part her out.

In fact the Yamaha dealers wouldn't even talk to me about working on it since it was more than ten years old. Evidently Yamaha in their marketing strategy has decided to only stand behind their product for no longer than ten years. As much as that pisses me off I guess I can understand that they have to cater to the new money and twenty year old + bikes are past history, from their corporate point of view. But as a builder and contractor that has made my living built on my reputation of providing quality work and a man of character that stands behind his product, engineering, service and workmanship no matter how longs it been, I felt deserted and violated.

 

So anyway I had a decision to make. Do I give up on her, Part her out and and commit her usable organs to Ebay. Or do I stand by the old girl and fight for her life even though she was on Life support and could possible already be dead. I started looking at new Goldwings, BMW 1200's, Victory Visions. The ride on the Goldwings somehow felt like a park bench, the BMW's had a nice ride but the saddle didn't fit my crouch, the vision took my breath the first time I saw it. As I was considering it as a option the reoccurring thought that popped into my mind was about if George Jetson rode a motorcycle it would be the Victory Vision.

 

I was weighing out my options when I investigated ebay for the first time as marketing research to test the market for used 87 Venture Royal parts. My plan at that time was to generate the down payment on a new bike by parting out my 87VR. To my amazement I found out that ebay offered what Yamaha no longer did and what I needed could be won realitively cheaply on the internet ebay auction. The first Auction I won on ebay was a set of Carbs from Sean Hess (Hessforless ebay seller & member of VentureRiders.org) which I was sure was the root of my bike problems.

During that transaction I talked to Sean on the phone and he told me about Venturerider.org God Bless you Sean.

 

Well I BELIEVE THAT LIFE IS ABOUT TRIAL AND ERROR. Thomas Eidison was once asked about his failures in testing 300 and something different materials to use as the filament for the light bulb before he discovered that carbon tungsten worked. His response was, "None of those test were failures, in fact I succeed in all of those test by discovering what did not work". Dragonslayer philosopy: Failures are learning experiences you can profit by.

 

Am I rambling? The carbs didn't fix the problem so I timidly entered a tech thread that seemed to be related to the problems that I was experiencing and asked for help as a newby to VR.org. GeorgeS (my VR.org hero) responded offering his assistance. Typical of what I have since discovered is the nature of this club and it's members he selflessly committed his considerable time addressing and walking me through troubleshooting and fixing my bike. God Bless you GeorgeS, God Bless you VR.org each of you one and all. With his help and others we breathed new life into her.

 

With all of that said I'll get to the point. She ran better than she ever did. Well enough for me to feel good enough about her to break her down for a new paint job and going over which I completed just in time to make the Clay18 Bike presentation. Which was the first time I had met any of ya'll in person. Muffinman stepped up at that event to offer to sync my carbs in the parking lot. An offer I deeply appreciated and humbly accepted. Even though I felt that I had managed to get the sync fairly close judging by her improved performance. I was floored to discover from muffinmans carb sync that the intakes were still sucking outside air and as Muffinman explained it, meant that the current efficiency was equivalent of operating on 2 1/2 carbs instead of four. Evidently I still had some work to do.

 

I limped thru last summer diagnosing low compression problems on one cylinder, chasing Ohm demons through the electrical and electronic systems then finally starter clutch failure on top of the never resolved carb problems. So I committed to another ground up going over including a new to me, used 9000mile 1990 model engine. During that process i won a ebay auction for a November 1986 issue of Cycle Magazine which evaluated the 1987xvz1300 Venture Royal with technical changes from 1986 to 1987.

 

The Point

 

One of the technical points the article mentioned was larger carb bores from the 34 mm mikunis to 35 mm mikunis in 1987. And I quote, "These measurements come from the carb's mouths- at the venturis, the jump is even bigger: 30.3mm in 85, 31.6mm in 86. To even out the mixture, both pilot and main jets grow larger this year yet fuel consumption remains remarkably close to the numbers from our last test unit."

 

When I first read that information it didn't mean anything to me. During the history of my ownership and the foregoing background dialog I have ended up with three different sets of intake manifolds. All of which look exactly the same visually. But on the work bench they got mixed up. Then as I was preping carbs to mount on new motor I noticed that some seemed to fit tighter on carb mouths than others.:lightbulb:I Got out the ruler and guess what? There is a measurable difference in the opening (Where carb throat inserts in intake boot.) size between the three different sets of Intake manifolds/boots. is it possible that my problem all along was that the intake manifolds were not the same year as the carbs therefore the clamps did not fully constrict the boots around the carb throats and therefore not completely sealing or preventing air being sucked through that incomplete seal. I have no clue what year carbs I bought off ebay nor do I know what year each set of intake boots are. I figure that I will us the tightest fitting set to mount to this new (to me)1990 motor.

 

Then the next question occurred to me that I would welcome some input on...

 

I wonder how many internal carb changes might have occurred between whatever year carbs I have and the 1990 motor I'm getting ready to mount them to and to what degree will those changes adversely effect the performance of the 1990 motor potential performance.

 

These carbs just got brand new diaphragms and fuel enrichment/air cut off diaphragms if I'm gonna need to change jets to match 1990 engine I rather do it now while they're on the bench instead of putting it all back together and having to do it later.

 

I'm gonna repost my rephrashed question on a new thread title " need hel p on 1990 1300 carb specs" to get fresh input.

[Neil86]

Actually the 83-85 Venture and the 86-93 Venture used different diaphragms and springs.

[Bryon]

My 96 1300 RS has cracked manifold boots or rubber .they are leaking gas is it an easy job? What tools are needed? And can they be patched temporarily until I get it in the shop or I can do it myself in a couple weeks .

[scuff]

if you still have those v-max boots I could use them I have a 94 v-max???

[van avery]

Bryon

The boot cracks might not go all the way through the boots ( I believe they have metal inside the rubber). The problem I had was the Orings under the boots, Spray the boots with WD40 or starting fluid and the intersections of the boots to the cylinders with the bike running and if the idle increases in a certain area that were you look for the leak.

[dna9656]

I see a LOT of questions about the same/different part(s) used for such and such a year or that another year. So far as I know; and from what the wise heads here have taught me is that Yamaha changes the part number when the part changes. In other words if you need to find out if the kanutsenator for the thingamajig on the 1987 Zort fits the '85 or 96 model look it up in the parts catalog. So far as I know the whole fleet shares the same muffler bearings...

Edited March 13, 2015 by dna9656