Thanks man ! Yep, it gets very interesting with the equal and unequal runner trials for parts 2 and 3 of the video 👍. I should have part 2 ready for upload this evening. I’ll add a link at the end of part 1 so folks can find it if they don’t have their notifications turned on. Part 2 busts some myths about whether or not the single carb can do the job of two since the cylinders don’t fire at the same time and also where the extra torque comes from when switching to a single carb manifold.
Great work , and to die hard XV fans , very interesting , as mentioned before i have bone stock and rigid chopper XV first gen ( and TR1) i always thought like DNA testing that one day tech would allow us to finally figure out and tune this bike correctly .........all of mine run pretty good but cant really tell what they are doing ,,, short of reading the plugs , swapping silencers etc thats all i had for decades .... your best mod for me so far was the starter modifications ( did them all ) am now able to park near the shop or friends with out starter failure noise embarrassment . please dont give up working on these bikes ,,,,,, we still love them .
Thanks man ! Yep, I’ve always tuned them by ear and trial and error as well over the years so it was really interesting to finally put the AFR gages on one and see what the numbers were doing. It’s too bad that the bungs have to be welded in to the exhaust pipes for the O2 sensors as it would be nice to put the gages on the bikes for tuning when setting them up. Yep, the starter mods did help all of mine as well and sure takes the “cringe” moments out of starting them when other folks are around lol. Thanks again and all the best !
Steve this is a great comparison thank you, and hopefully this will settle a few "discussions". I would love to see a comparison with aftermarket and stock carbs as I'm thinking of going down the Mikuni route, be round or flat slide.
Thanks man ! Hopefully parts 2 and 3 will be interesting as well 👍. Now that I have the test rig complete, I figured I would do some more testing for different carbs and other manifolds as well to see what combinations work better. Gotta save up some money though as I spent too much of my “fun money” on this crazy test rig LOL !
Thanks man 👍. It’s actually a stock 1981 xv750 with the only differences being that: There are individual air pod filters on it vs. using the stock intake that pulls from the frame, and it has some Jardine separated pipes on it so I can isolate the exhaust for the temps and AFR readings. I needed to go with individual air pods anyway so I could use one of them for the single carb setup and keep everything consistent. Normally it’s not possible to keep the stock jetting with more open air intakes and pipes with less back pressure, but I put restrictor plates in the air pod intakes to balance the air back more like the stock setup and make the flow more laminar like the stock setup as well.
Sorry, I meant to ask about modification to the starter. I sounds so smooth. I have the clip clamp, cut the spring in half and the voltage regulator to the TCI on my 1982 xv920, works really good, but its not as smooth as this engine.
@@russellburns9480 ah, sorry…I misread your comment lol ! For the starter, I did add the clip clamp to the bendix on this one as well, but didn’t do any other modifications to the actual starting system. One other change that helps this motor though is that I put a bigger gage power wire from the battery to the starter solenoid as well as from it to the starter. I also grounded the battery directly to the frame that the motor is bolted to. Then finally, I swapped the regular starter solenoid for a bigger one (it’s one for a tractor from TSC farm supply). I figured I would be doing a lot of cranking on this motor dialing things in so going with bigger power wires and a bigger solenoid would keep the wires from getting too hot. These things help with the cranking speed as well so that may be what you are hearing in the video 👍
@@StevesDIYsHeads up Steve, I found a Solenoid that also works a lot better than the stock one, I believe the part number is BK #S66949 figured you might want to check it out
Hey ! It came with a non running parts bike I got a few years ago so I’m not sure who might have made it. I did just receive a different design from another Virago owner that makes them to trial so in a couple of weeks I’ll be putting that one on to see how it does. I’ll be posting a video up on the channel for the results of that one in a few weeks once I can get the testing done and will provide the details on it.
![How to CONVERT your XV750 [Virago] to single CARBURETTOR | Mikuni TM38 Flatslide |](/img/n.gif)
This is great Steve, thanks for sharing. I'm very interested in all of this data.
Thanks man ! Yep, it gets very interesting with the equal and unequal runner trials for parts 2 and 3 of the video 👍. I should have part 2 ready for upload this evening. I’ll add a link at the end of part 1 so folks can find it if they don’t have their notifications turned on. Part 2 busts some myths about whether or not the single carb can do the job of two since the cylinders don’t fire at the same time and also where the extra torque comes from when switching to a single carb manifold.
Great work , and to die hard XV fans , very interesting , as mentioned before i have bone stock and rigid chopper XV first gen ( and TR1) i always thought like DNA testing that one day tech would allow us to finally figure out and tune this bike correctly .........all of mine run pretty good but cant really tell what they are doing ,,, short of reading the plugs , swapping silencers etc thats all i had for decades .... your best mod for me so far was the starter modifications ( did them all ) am now able to park near the shop or friends with out starter failure noise embarrassment . please dont give up working on these bikes ,,,,,, we still love them .
Thanks man ! Yep, I’ve always tuned them by ear and trial and error as well over the years so it was really interesting to finally put the AFR gages on one and see what the numbers were doing. It’s too bad that the bungs have to be welded in to the exhaust pipes for the O2 sensors as it would be nice to put the gages on the bikes for tuning when setting them up.
Yep, the starter mods did help all of mine as well and sure takes the “cringe” moments out of starting them when other folks are around lol. Thanks again and all the best !
Steve this is a great comparison thank you, and hopefully this will settle a few "discussions". I would love to see a comparison with aftermarket and stock carbs as I'm thinking of going down the Mikuni route, be round or flat slide.
Thanks man ! Hopefully parts 2 and 3 will be interesting as well 👍. Now that I have the test rig complete, I figured I would do some more testing for different carbs and other manifolds as well to see what combinations work better. Gotta save up some money though as I spent too much of my “fun money” on this crazy test rig LOL !
@@StevesDIYs yeah I certainly know about the fun money or lack there of with an Xv cafe and an older BMW.
Great video. What modification, if any, do you have on the start on that engine?
Thanks man 👍. It’s actually a stock 1981 xv750 with the only differences being that: There are individual air pod filters on it vs. using the stock intake that pulls from the frame, and it has some Jardine separated pipes on it so I can isolate the exhaust for the temps and AFR readings. I needed to go with individual air pods anyway so I could use one of them for the single carb setup and keep everything consistent.
Normally it’s not possible to keep the stock jetting with more open air intakes and pipes with less back pressure, but I put restrictor plates in the air pod intakes to balance the air back more like the stock setup and make the flow more laminar like the stock setup as well.
Sorry, I meant to ask about modification to the starter. I sounds so smooth. I have the clip clamp, cut the spring in half and the voltage regulator to the TCI on my 1982 xv920, works really good, but its not as smooth as this engine.
@@russellburns9480 ah, sorry…I misread your comment lol ! For the starter, I did add the clip clamp to the bendix on this one as well, but didn’t do any other modifications to the actual starting system. One other change that helps this motor though is that I put a bigger gage power wire from the battery to the starter solenoid as well as from it to the starter. I also grounded the battery directly to the frame that the motor is bolted to. Then finally, I swapped the regular starter solenoid for a bigger one (it’s one for a tractor from TSC farm supply). I figured I would be doing a lot of cranking on this motor dialing things in so going with bigger power wires and a bigger solenoid would keep the wires from getting too hot. These things help with the cranking speed as well so that may be what you are hearing in the video 👍
@@StevesDIYsHeads up Steve, I found a Solenoid that also works a lot better than the stock one, I believe the part number is BK #S66949 figured you might want to check it out
Thanks man 👍. I’ll check it out !
Where did you pick up the intake with the unequal runners?
Hey ! It came with a non running parts bike I got a few years ago so I’m not sure who might have made it. I did just receive a different design from another Virago owner that makes them to trial so in a couple of weeks I’ll be putting that one on to see how it does. I’ll be posting a video up on the channel for the results of that one in a few weeks once I can get the testing done and will provide the details on it.