Auggie_1970
Well-Known Member
So I finally got the carbs on the bike this afternoon and had to fire her up. What a difference, nice idle, no backfiring issues as before, and numbe one carb diaphram is no longer fluttering back and forth as it was previously.
Just for informational purposes, I bought this bike with 4,800 miles on it. I'm the third owner. Previous owner suposedly bought the bike as it was sold to me. Has cobra exhaust and upon opening the carbs had a dyno jet stage 1 jet kit in it. When I test drove the bike it ran ok but I never rode another vmax so I didnt have anything to compare it to except for the bike I currently owned. It did howerver run like crap at idle and had a very strong gas smell at idle like it was very rich(blowing a good amount of black smoke)..Bike backfired pretty good several times a minute. I figured/hoped it was just a carb issue and bought the bike. Previous owner did not know much about the bike but indicated it sat with carbs full of gas since September of last year.
Was fortunate to find this forum which has all this information available , which I found extremely helpful in diagnosing and fixing the problem.
So heres what I found , not sure which one is the source of the issue but I would have to think its a combination of many of them.
1) All float heights were extremly rich, ranged from 13-14mm..Reset using the 1.115 measurement which gave me about 16.5mm on the one I wet tested.
2) Carb number one had a blocked pilot jet. Also had a sliver of somethign blocking the Paj1. All carbs were broken down 1 by one and all parts that were screwed in were removed and soaked in a solution of yamaha carb cleaner and gas. (had this stuff laying around from cleaning my quad's carb a while back). Also used an old tooth brush in which I was able to squeze a few bristles in the jet orifices to help free up the passages.
3) Carb 2 had what appeard to be a hard piece of plastic inside the area in which the diaphram sits. Still cant figure out what this was , it was the color of the slide but slide looked ok despite being drilled out.
4) Carb 4 the needle was not positioned correctly in the diapram. The little tit as they call it , was not seated in the hole in the diapram and it was crushed or bent down as the screw holding this all together was screwed in. This would have raised this needle up a little more that the other 3 carbs so I unbent it and made sure to properly align these when putting all back together.
5) Once backtogher (all four carbs back in the rack) I turrnd the idle adjuster enought so that there was a very small opening where the throttle plate is on number one, then ajdusted/sync'd number 2 to mimic this small opening, then 3 &4. Then put the carb rack on the bike and attached the throttle cables then the gas line and fired her up.
Bike runs so much better even before I syncd them with the carbtune. I cant wait to take her out for a ride to see how she pulls now...I'm guessing /hoping its going to be a night and day difference.
Here's stuff I found helpful.
1) Read all the stickies here about taring down the carbs...Familirize yourslef with all the parts that need to bee investigated and cleaned..Then re read them again.. Theres lots of parts in here.
2) Take digital pictures as you go along..Like I said, there's lots of parts here, and being my first time taring these apart, it can get confusing if your not familar with this set up. Now when I have to do this again, it wont be nearly as intimidating or confusing but for your first time, i would recomend the taking pictures to refer back to when you cant remmeber exactly which way something goes on..
3) Before you even break into the carbs, do yourself a favor and order allen head screws for the floats, the slide covers and the brakcets that hold it all together.. The button head screws on these are so soft that despite using the proper sized philips head, and even giving the screw driver a few good light hits on the screwdriver, I ended up messing up several of them. I even had to resort to pulling out the old reliable, safe me in the middle of a project, dremel tool and using a cut off wheel, notched a slot to use a flat screwdriver to extract 2 that ended up rounding off completely(tense momemt).
Here's whats deceiving..The parts diagram says you need 7 5x12mm and the one torx screw per carb..
When I pulled mine apart, the ones on the slide cover are longer than the ones on the foat cover. Not sure if this is from someone else prior to me or if this is how it came from the factory.. Anyhow, I orders the parts from McMasterCarr..Heres what you'll need Make sure they are stainless.
16 each of 5x12mm x.8 thread pitch, allen head screws-float covers.
16 each of 5x14mm x.8 thread pitch , allen head screws-slide covers.
16 each of 6x10mm x1 thread pitch , allen head srews-carb brackets.
You have to buy in bulk , I could not find these in any of my home depots, lowes or ace stores. Dealer wanted something like 2.35 per screw..I couldn't keep from laughing on the phone as the guy was telling me this.
Anyhow I think this came to 17 bucks in total , well worth it to me since it makes putting things on and opening them back up that much easier.
4) Your going to need a few different sized screwdrivers.. One for the paj''s 1&2, one for the jet pilot (its small), one for the main pipe bleed in the jet block(use this one also for adjusting the air mixture screws), and another to get the mains out. I took some old ones I had around the shop and used an grinder to narrow up some to get in the narrow passages of the jet block, and also ground the tips shorter to make them fatter to fit the slots in the jets just right. I tried to skip this when trying to get one of the paj's out and I stated to see I was going to buger up the thing if I didnt stop...Many of these were in pretty tight so having the right size screwdriver was very helpful.
5) Work in a clean area. Get a small container to toss the parts in as you disassemble the carbs, another to put the cleaned ones back in. I took the advice of other people on the forums and did one carb at a time.
6) Take your time this isnt going to be a 30 mintue exercise for all 4 carbs..Now that I've done this once, the second time will go much faster but still its going to take some time..
7) I used yamaha carb cleaner that you mix 1 parts to 3 parts gas. I also used a can of carb cleaner with the plastic straw that I always end of loosing and spend 30 minutes trying to find. I used a air compressor with an air attachement for blowing things out and dry after they sat in the cleaner for at least 30 minutes...
Following the advice on the other stickies, I used Wd40 to clean the diaphrams and used light air pressure to blow these off.
I also used 1500 gritt sandpaper to lightly , very lightly, clean off the plungers on the coasting enrichners, and the starters (the choke assemblies on each carb). Mann, is the choke lever action smooth now!
8) When I removed the carbs, I placed a piece of aluminum foil over each rubber boot on the bike to prevent crap from getting in there. did the same with each carb once they were cleaned and set aside while I cleaned the others. I'm anal what can I say
9) Mmm, should be listed higher up on the list but I used some blue painters tape to tape up the left side of the frame to prevent getting scratched up when you slide the carb out of the bike. Theres a good amount of room so if your carefull should not even be an issue but that Murphy's law guy show up everynow and then for me I'm not taking any chances.
I know I'll be back in these carbs shortly cause whoever jetted this bike put 170's in the main, and has the stage one needles on the richest clip on the needle. This may be ok for a full exhaust but I only have cobra slip ons and from what I've read they cause the bike to run rich. I think from what I read, 147 mains are the way to go but I didnt want to mess with too many settings until I ironed out what was going on with the bike to begin with.
Hope this helps anyone contemplating tearing open the carbs...Now that I've done it once, I can honesly say its not that bad but when I had everything off originally I was like what the heck did I just get myself into.
Just for informational purposes, I bought this bike with 4,800 miles on it. I'm the third owner. Previous owner suposedly bought the bike as it was sold to me. Has cobra exhaust and upon opening the carbs had a dyno jet stage 1 jet kit in it. When I test drove the bike it ran ok but I never rode another vmax so I didnt have anything to compare it to except for the bike I currently owned. It did howerver run like crap at idle and had a very strong gas smell at idle like it was very rich(blowing a good amount of black smoke)..Bike backfired pretty good several times a minute. I figured/hoped it was just a carb issue and bought the bike. Previous owner did not know much about the bike but indicated it sat with carbs full of gas since September of last year.
Was fortunate to find this forum which has all this information available , which I found extremely helpful in diagnosing and fixing the problem.
So heres what I found , not sure which one is the source of the issue but I would have to think its a combination of many of them.
1) All float heights were extremly rich, ranged from 13-14mm..Reset using the 1.115 measurement which gave me about 16.5mm on the one I wet tested.
2) Carb number one had a blocked pilot jet. Also had a sliver of somethign blocking the Paj1. All carbs were broken down 1 by one and all parts that were screwed in were removed and soaked in a solution of yamaha carb cleaner and gas. (had this stuff laying around from cleaning my quad's carb a while back). Also used an old tooth brush in which I was able to squeze a few bristles in the jet orifices to help free up the passages.
3) Carb 2 had what appeard to be a hard piece of plastic inside the area in which the diaphram sits. Still cant figure out what this was , it was the color of the slide but slide looked ok despite being drilled out.
4) Carb 4 the needle was not positioned correctly in the diapram. The little tit as they call it , was not seated in the hole in the diapram and it was crushed or bent down as the screw holding this all together was screwed in. This would have raised this needle up a little more that the other 3 carbs so I unbent it and made sure to properly align these when putting all back together.
5) Once backtogher (all four carbs back in the rack) I turrnd the idle adjuster enought so that there was a very small opening where the throttle plate is on number one, then ajdusted/sync'd number 2 to mimic this small opening, then 3 &4. Then put the carb rack on the bike and attached the throttle cables then the gas line and fired her up.
Bike runs so much better even before I syncd them with the carbtune. I cant wait to take her out for a ride to see how she pulls now...I'm guessing /hoping its going to be a night and day difference.
Here's stuff I found helpful.
1) Read all the stickies here about taring down the carbs...Familirize yourslef with all the parts that need to bee investigated and cleaned..Then re read them again.. Theres lots of parts in here.
2) Take digital pictures as you go along..Like I said, there's lots of parts here, and being my first time taring these apart, it can get confusing if your not familar with this set up. Now when I have to do this again, it wont be nearly as intimidating or confusing but for your first time, i would recomend the taking pictures to refer back to when you cant remmeber exactly which way something goes on..
3) Before you even break into the carbs, do yourself a favor and order allen head screws for the floats, the slide covers and the brakcets that hold it all together.. The button head screws on these are so soft that despite using the proper sized philips head, and even giving the screw driver a few good light hits on the screwdriver, I ended up messing up several of them. I even had to resort to pulling out the old reliable, safe me in the middle of a project, dremel tool and using a cut off wheel, notched a slot to use a flat screwdriver to extract 2 that ended up rounding off completely(tense momemt).
Here's whats deceiving..The parts diagram says you need 7 5x12mm and the one torx screw per carb..
When I pulled mine apart, the ones on the slide cover are longer than the ones on the foat cover. Not sure if this is from someone else prior to me or if this is how it came from the factory.. Anyhow, I orders the parts from McMasterCarr..Heres what you'll need Make sure they are stainless.
16 each of 5x12mm x.8 thread pitch, allen head screws-float covers.
16 each of 5x14mm x.8 thread pitch , allen head screws-slide covers.
16 each of 6x10mm x1 thread pitch , allen head srews-carb brackets.
You have to buy in bulk , I could not find these in any of my home depots, lowes or ace stores. Dealer wanted something like 2.35 per screw..I couldn't keep from laughing on the phone as the guy was telling me this.
Anyhow I think this came to 17 bucks in total , well worth it to me since it makes putting things on and opening them back up that much easier.
4) Your going to need a few different sized screwdrivers.. One for the paj''s 1&2, one for the jet pilot (its small), one for the main pipe bleed in the jet block(use this one also for adjusting the air mixture screws), and another to get the mains out. I took some old ones I had around the shop and used an grinder to narrow up some to get in the narrow passages of the jet block, and also ground the tips shorter to make them fatter to fit the slots in the jets just right. I tried to skip this when trying to get one of the paj's out and I stated to see I was going to buger up the thing if I didnt stop...Many of these were in pretty tight so having the right size screwdriver was very helpful.
5) Work in a clean area. Get a small container to toss the parts in as you disassemble the carbs, another to put the cleaned ones back in. I took the advice of other people on the forums and did one carb at a time.
6) Take your time this isnt going to be a 30 mintue exercise for all 4 carbs..Now that I've done this once, the second time will go much faster but still its going to take some time..
7) I used yamaha carb cleaner that you mix 1 parts to 3 parts gas. I also used a can of carb cleaner with the plastic straw that I always end of loosing and spend 30 minutes trying to find. I used a air compressor with an air attachement for blowing things out and dry after they sat in the cleaner for at least 30 minutes...
Following the advice on the other stickies, I used Wd40 to clean the diaphrams and used light air pressure to blow these off.
I also used 1500 gritt sandpaper to lightly , very lightly, clean off the plungers on the coasting enrichners, and the starters (the choke assemblies on each carb). Mann, is the choke lever action smooth now!
8) When I removed the carbs, I placed a piece of aluminum foil over each rubber boot on the bike to prevent crap from getting in there. did the same with each carb once they were cleaned and set aside while I cleaned the others. I'm anal what can I say
9) Mmm, should be listed higher up on the list but I used some blue painters tape to tape up the left side of the frame to prevent getting scratched up when you slide the carb out of the bike. Theres a good amount of room so if your carefull should not even be an issue but that Murphy's law guy show up everynow and then for me I'm not taking any chances.
I know I'll be back in these carbs shortly cause whoever jetted this bike put 170's in the main, and has the stage one needles on the richest clip on the needle. This may be ok for a full exhaust but I only have cobra slip ons and from what I've read they cause the bike to run rich. I think from what I read, 147 mains are the way to go but I didnt want to mess with too many settings until I ironed out what was going on with the bike to begin with.
Hope this helps anyone contemplating tearing open the carbs...Now that I've done it once, I can honesly say its not that bad but when I had everything off originally I was like what the heck did I just get myself into.
