Thanks man and glad the video helped some. All the best to you and yours ! Steve

Thanks man…glad the video helped some 👍. Yep, it’s amazing the difference it makes to how these start up, idle, and pull up through the rpms when synch’ed up good. It also seems to help with plug fouling for the lagging cylinder since the cylinder with the butterfly more open wants to run at a slightly higher rpm and is having to drag the other one along with all the time throwing the combustion off. Thanks again and all the best ! Steve

Hey man ! Thanks 👍. Yep, it’s getting harder to find much on these for sure...people just don’t like working on these old carb’d bikes anymore it seems. I’ve got three of these 1st Gens since people almost give them away when they can’t get them running after they sat for so many years. There’s several videos out on the channel that cover quite a few things on the motor if you haven’t found them 👍. All the best and glad the videos help some 👍, Steve

Thanks man 👍. All the best ! Steve

Thanks man and glad the other videos are helpful as well 👍. Yes, having them sync’d good makes a huge difference in how the cylinders adjust and run. The bench sync does a pretty good job of getting them close, but since the carbs typically have so many years on them now and each wears a little differently (the slides mainly), doing the final sync on the motor keeps the cylinders from fighting each other when at idle and then throttling up when it goes from the idle circuit to the run circuit. Let me know how it goes once you get them all sync’d up 👍. All the best ! Steve

Thanks man ! Hope the video helps some. I can usually get very close to the proper Sync in the bench and then do a final sync in the bike just to be sure. There’s another video on the channel for the final sync in the bike as well to really dial them in perfectly. All the best ! Steve

Hey man ! I watched your video...I does sound a ton better 👍. Hopefully you are past the tough issues and it will be smooth sailing from here. All the best !

@@StevesDIYs i ve been working on the bike and i ve got issues with the rear cylinder (cylinder 1) when i start the bike it runs cold and takes ages to warm up. Bike has spark but not sure where else to look have you ever come across this issue?

@@adamc457 , hey man ! Yep, I’ve run into a few that were grumpy on one of the cylinders (my Cafe build was giving me trouble when I first got it to fire). For me, I’ll always start at the beginning again and check the compression and timing then the spark. If all of those look good I’ll then pull the carbs one more time and make sure I didn’t miss something (the breather tubes above the diaphragm sometimes pull crap in from the frame if the bike has been sitting for a long time). I check the diaphragm for holes that might have developed and clean out all of the jets and ports again, check the fuel levels again, and then re-sync. I’ve had them take two or three removals and cleanings till all if the tiny stuff in the frames finally gets pulled through. Aggravating for sure, but I’m really good at taking the carbs off now, lol.

Thanks man 👍. It’s not too bad once you’ve done a time or two. A lot of people use small drill bits vs. paper, but I’ve always used paper since it can only be pulled and not pushed so it’s easy to tell when you get them the same. Plus I never liked the butterflies hitting on something hard just to be sure it didn’t dent them.

J C , thanks 👍. There’s another video on my channel that shows the reassembly of the carbs and where the different jets go (there are different size jets, on top and bottom that can easily be mixed up if someone had them apart before you got it). Might be worth while to check them while you have them off to sync them since it is so painful to remove the carbs from the bike. Not sure if I mentioned it in the other video, but be sure the deep hole in the bowls where the brass tube goes into is not clogged. It has a very small cross drilling at the bottom that gets clogged easily...if you squirt carb cleaned in the top of the hole, you should see a tiny spray come out in the bottom of the bowl if it is clean

have you check the vacuum petcocks? change the gaskets

Thanks 👍. Yep, eventually it seems the center linkage gets too worn to be able to adjust it out. Sometimes you can find a set of carbs relatively cheap, but usually you can get a whole parts bike for just the cost of a set of carbs. Someone mentioned on one of the video’s the comments that they were going to try to replace the roller in the linkage, but I never heard back if they were successful.

. @StevesDIYs I posted on Virago Owners pic of my low budget/ skill fix. A 157 feeler gauge cut in half, hole drilled, slit and pulled over the two riveted pivots, folded over and soldered. Work like new and think it will last a long time. Seen you on Virago Nation but admin doesn't let me post

@@mestep511 👍. Yep, just saw the post…looks like that will keep it tight for many years to come 👍

Hey man ! For the air/fuel mix screw (needle), the motor needs to be running to set it correctly, but for a starting point, I usually start at 1.5 turns out from a soft seat for a stock setup (a soft seat is when you turn the needle in all the way until you feel it bottom out in the carb very lightly, but you may have already known that 👍). If I changed the air filter to the pod type or opened up the exhaust I’ll start a 2 turns out. After everything is back in the bike except for the big rubber elbows that go to the carb, I’ll try to fire the bike up with no choke to see if it will fire up and at least run on one cylinder. If it doesn’t want to fire up on either cylinder, a trick I learned is to put my hand over the end of the carb where the big rubber elbow connects and crank it to see if I can regulate the air fuel mix by hand to get it to fire. If it fires up, I’ll then keep it running by separating my fingers to control how much air comes in while adjusting the air/fuel mix screw in or out until the cylinder continues to run without my hand. Then do the same for the other cylinder. Once it’s close on the air/fuel mix adjustment and will fire up on its own, I put the rubber boots on and then do the final air/fuel screw adjustment by listening to when the rpms increase as the screw is adjusted. The closer the setting is to optimum, the higher the motor’s rpms will get by adjusting the screw (sometimes you’ll have to adjust the idle back down with the idle adjustment knob as it needs to be around 800 to 1000 rpms to adjust the screw). When each cylinder is adjusted to where the rpms are the highest at idle, I then turn each screw out about 1/8 turn just to be sure I’m on the rich side of the adjustment vs. being too lean and turning my exhaust pipes purple, lol. After they are adjusted and the motor idles decent and will rev up somewhat, I then do the final carb sync on the bike with oil filled clear tubes connected to the carbs (another video in the channel), then do a final adjustment on the air/fuel mix screw to find the optimum number of turns they should be that gives the highest rpms and best throttle up. Then turn each screw out the additional 1/8 turn just to be sure they are not too lean. Sorry for the long reply, but it is a bit tricky to set the carbs for the first time so I added a bunch of detail. Hope this helps though and all the best ! Steve

Thanks...glad the video was helpful 👍. Yep, doing the bench sync should get them very close on the adjustments and both cylinders will be pulling equally so the bikes power should go way up compared to them being out of sync. I usually do a final sync once the carbs are back on the bike to get them perfect, but just the bench sync has always gotten them very very close. If you wanted to do the final sync once the carbs are back on (after the bench sync), here’s another video on the channel on how to do that: kzfaq.info/get/bejne/grZxZLGbnZbDZn0.html . Thanks again and all the best ! Steve

@@StevesDIYs that ones helpfull aswell, also just watched the video where you show how quickly your Xv starts, Very impressive! Gonna get back to my xv920 this weekend. Tried starting it again yesterday since your video gave me motivation to start putting some effort in this old Bike again but I couldn’t get it to start anymore. I’ll keep you posted if you’d like that.

@@OpaSann0 thanks man ! Yep, keep me posted on how it progresses 👍. I like hearing about it when folks get another one back on the road and enjoyed again. I’d say you’ll have it up and running in no time 👍

Thanks and glad the videos help some 👍. For the paper thickness, yes, it is just normal copy paper thickness. Since it is so thin, it is easy to feel when the carbs are very close for the gaps as the paper will bow up instead of push back in when it’s just slightly tight. Once you have the bench sync’d set, you might have to adjust the idle up a little before doing the final sync with the carbs on the bike and motor running. Hope this helps and all the best ! Steve

Hey man ! I took a pic of mine to show the approximate height the screw goes up to touch the arm (the rear cylinder’s carb)...here’s a link to it on my Facebook page as KZfaq doesn’t allow pics in the comments: facebook.com/stevesdiys/photos/a.155473795999070/402003588012755/?type=3 . I checked all three of my bikes and they show about 5 threads in between the top of the tab the screw is in and the bottom of the arm. If your adjustment arm is much higher than this, it may be that the rod that the butterflies screw to is possibly bent or the arm’s connection to the rod is worn. It might be that the butterfly was accidentally put in backwards, but that would be easy to spot as they have an angled edge that allows it to close tightly into the carb throat. Hope this helps and if you need another picture or something for reference just let me know 👍. Oh, it might also be that the screw is not the original one and is too short (I had that issue on a parts bike’s carbs once. All the best ! Steve.

@@StevesDIYs I did have to give the arm on the Rear carb side a tiny tap as it was slightly bent and was wide of the set screw, so it could've been bent the other direction as well. I just reset everything, loosened everything on both carbs and started over, and I was able to get the set screw snug( with a hair left so it's snug to the piece of paper as shown in the video) this time with the bench sync. Not much wiggle room but I will just have to cross that bridge when I get to it if I end up having to open it up more and extend the set screw beyond a turn or so. Thanks Steve, your videos are great and your fast replies are even better!

@@kodymorland3678 , thanks man ! No problem...glad to help 👍. Hopefully it will sync up fine when you do the final sync on the motor with it running 👍. All the best ! Steve

I know this was a while ago but working on mine now I used a 10-32 nut and 10-32 size screw although the screw doesn’t fit the thread perfect I used the nut to lock it in place. I found a 1” screw fit perfect for me

Good deal 👍. Glad you got it sorted out. The Cafe I did a bit ago was almost at the end of the screw for it’s adjustment…I think the linkage is really worn on it so it is probably gonna have to get a longer screw if it starts getting out of balance as well

kingdom Nate , hey man ! I looked at the video at the time stamp...do you mean the black small plastic cylinder looking thing that’s attached with the black rubber tubes? If so, it’s actually a little filter that clips into the rubber tube. It allows filtered air to come in above the diaphragms so they can lift (which lifts the needle) to allow fuel to be pulled up from the fuel bowl. They should be unrestricted or the air coming into the carb won’t lift the needle. The foam filter material that’s inside had disintegrated over the years on all of my bikes and the particles stopped up the two air jets that are on top of the carb (under the fuel flow pipe for the choke that crosses inside the carb) so they wouldn’t pull fuel till I cleaned the upper jets out. The top jets are what control the air that goes to the fuel bowl to atomize the fuel (air comes into the small holes in the sides of the emulsion tubes from these jets from one of them). I just blew the rotten foam out of the little black filters and put them back into the rubber tubes. An option would be to replace the foam in them, but if they are restricted by too much foam (or if someone puts a little filter on the rubber pipes that’s too restrictive), the diaphragms won’t lift correctly and the bike will run lean as well.

@@StevesDIYs wow! Thanks for the info! Would have never have thought that they had little filters in them? I thought they were just air vent hoses. I purchased a 1982 yamaha and it looked like someone cut it out for what ever reason. My bike would idle high and be all over the place until I taped it off. Was also back firing real bad. Bike runs normal now. I found an oem part that I just bought so hopefully after putting that back on I won't have to worry about the tape anymore.

kingdom Nate , no problem 👍. If it runs better with the tube blocked off, I’d probably pull the carbs and check to see if the diaphragms were seated around the edges good (not pinched ) and also check for pin holes in them. These carbs are very sensitive from my experience and any little air leak can throw them off big time. Hopefully you’ll get it sorted out and running like a top 👍. All the best ! Steve

Hey ! It sounds like the linkage between the carbs may be worn or the roller that goes up and down between the carbs is damaged or worn if you cannot get any adjustment when turning the sync screw in or out…or possibly the carbs were separated in the past and the linkage was not put back together correctly or something. When I sync ones that have had everything taken off and I want to check the linkage, I back the left side stopper screw all the way down so that the right side idle thumb screw is only holding the front butterfly up the thickness of a piece of paper and the rear carb butterfly is fully closed. Then I pull up on the arm where the throttle cable connects on the right side to see how much movement the linkage makes before it starts lifting the rear cylinder’s butterfly. If turning the sync screw in the middle won’t allow it to start picking up the rear cylinders butterfly, then something’s wrong with the linkage (or it may be missing a washer on the screw or something. One other thing, the carbs have to have the top bracket to that connects them together (the metal bracket that uses the 4 screws that hold the chrome diaphragm cover on) and the two posts between the carbs up top must be aligned and their alignment pins in each others holes. If the bracket is missing, the carbs will not stay together up top and it will throw the linkage adjustment off and make them not adjustable. Hope this helps a bit and Al the best ! Steve

Thanks for the reply! This clears things up a lot. Yes I the top bracket is still there but there is a lot of play in the linkage, particularly in the roller like you said. And yes the right butterfly opens up lightly before the left butterfly opens no matter how much I mess with the synchronizer screw, so it must be the roller in the linkage or a washer that is missing. Is there anyway to fix the roller, or do you just need to buy a whole new part? Thanks!

@alexchapple7250 hey again, unfortunately, unless you have a way to make a new roller, they don’t make them as a spare part. Sometimes you can find a set of carbs that someone messed up the mix needle on and can swap out the linkage in the middle though.

Hello, it does seem like it’s undoing the bench sync done with the pieces of paper, but most of the time the final sync shows that the bench sync was very close so only slight adjustments are needed. It’s hard to tell where the idle is supposed to be by just the bench sync so the final sync sets the rear cylinder idle stop lever if the throttle side had to be adjusted to get the idle rpms correct. For me, without doing the bench sync, it’s hard to dial the air/fuel mix in when it’s first restarted as there’s no way to know if it’s the air/fuel mix that’s off or the sync. Even for the final sync on engine video, it was almost spot on just from the prior bench sync, but I took it out of sync on purpose just to show how to sync it back for the video. Also, if the bench sync is done, but then a lot of adjustment has to be made when doing the final sync, it is a good indication that something may be clogged in the carbs or a seal is leaking since the bench sync is done by matching the gap, but the final sync is using the actual vacuum being pulled through the carb. All the best and happy holidays ! Steve

Hey ! Yep for the first Gens, the linkage gets a bit sloppy so the best you can do with the bench sync is to set your base idle (which is the process you listed). But…since the linkage is sloppy, you’ll also need to do a final sync on engine where you check this idle sync, but then raise the rpms up to about 2000 to 2500 rpm and adjust just the screw in the middle to set the running sync. The reason for setting the left side carb just slightly off if the stop screw initially is because, once you adjust your running at higher rpm sync, this screw will not allow the left carb to go any lower so it will still be sync’d at idle as well. This way you can accommodate the slip in the linkage 👍

Hello, if there are little pin holes in the diaphragms, I’ve used a two part rubber adhesive (like what is used to fix a crack in a flexible bumper on a car) and a toothpick to seal up the pin hole. If it it torn I’d say that it probably needs to be replaced with a new one or a used one that is in good shape.

Hello, are you referring to the idle stop adjustment on the left side carb (the one for the rear cylinder) that has the small screw and nut that locks it in place? If so, it would need to be adjusted to compensate for the many years of wear on the carb linkage that connects the two carbs. After so many years of operation, the linkage gets worn so the carbs won’t sync up for both the idle circuit as well as the running circuit…the 1st Gen Hitachi carbs have this adjustment so the idle sync can be set with it, then the running sync is set with the screw between the carbs to help with the linkage wear. The 2nd Gen Mikuni carbs don’t have this adjustment, but the linkage was designed much better so it’s not really needed. Hope this helps a bit, and if this adjustment wasn’t the one you were referring to, just let me know and I’ll look to see which one to try to explain that one. All the best ! Steve

Hi Steve, I just Double checked, yes im refering to the idle Stop Screw in the left carb (connected to rear cyl). So ig I get you Right, due to the more than 40 years the bike has on its back now, you recommend ignoring the notice in the Yamaha Manuals and basically Perform a setup Oberhaul as described in your videos. In my case: Float adjust, Bench sync, maybe adjusting idlemixscrews (the ones at the bottom of the Carbs) and perhaps Leaving out the Gas Mixture Control valve? Kind regards, Valentin

@@FoxD13 , hey again, you may not need to adjust the idle stop screw on the left side carb (the rear carb) unless you can’t get the carbs to sync at the idle you are wanting. If your bike is still all stock for the air filter and exhaust I’d say it is probably ok, but can easily be adjusted if needed. The important things are to sync the carbs (both at idle and at higher rpms), get the float levels right, and adjust the air/fuel mix needle so you have a good air/fuel ratio. The problem comes in that in 40 years, a lot of air and fuel has gone through the carbs so it has eroded the surfaces some so it changes things. I’ve removed air/fuel mix needles in the past that were eroded and shaped like a C before lol. The good news it that these motor are very forgiving and will either run and sound really good when adjusted correct, foul plugs pretty quick if a cylinder is getting too much fuel (float too high, sync way off, or mix needle not adjusted right), or they will just flat refuse to start or accelerate if not getting enough fuel (settings too lean). You’ll know for sure when it is all dialed in…they will start on just two or three rotations, idle steady, and have a quick throttle response. Hope this helps a bit and all the best ! Steve

Hey man ! I believe there’s a guy out on the “Virago Nation - all things Yamaha Virago” Facebook forum named William Stack that rebuilds many of the Yamaha carbs. He has all of the spare parts and hard to find seals (like the butterfly shaft seals) so he might be a good option if your looking to have them rebuilt. I think he has a Facebook page as well called “Yamaha Carburetors”or something like that if you wanted to check.