It's time to start a winter Project. The Red Bike

Runs on one cylinder. Swapped wires and it still runs on the one right cylinder. Changed the plug, same.Dropped the float bowl, seems proper. Main 185, Pilot 42.5. Switched over to SS Allen head cap screws. $1.90 each but I have a feeling they will pay for themselves as often as I may have to go in for jetting fine tune.
I know that the VMs are a different type than the BS but 185 on the main sounds large. Stock jetting on the bs 34 is 132.5 main and 42.5 for pilot. Looks like you're running stock air boxes and stock like exhaust. Maybee someone can chime in here with some better info.
 
I know that the VMs are a different type than the BS but 185 on the main sounds large. Stock jetting on the bs 34 is 132.5 main and 42.5 for pilot. Looks like you're running stock air boxes and stock like exhaust. Maybee someone can chime in here with some better info.
Carbs have small pods, seems the exhaust has sporty muffs on stock head pipes. A VM thread here had 190 or 200 mains. I will have to research the pilots and slides.
I did check the BS34s that came cleaned up in a box of parts. They had your 132.5 mains and 42.5 pilots. First up get both cylinders firing.:)
 
I know I'd be tempted to play around with the VMs if I got a set on a bike, but the BS34 is a really nice carb once jetted to get over it's factory lean settings.
 
I know I'd be tempted to play around with the VMs if I got a set on a bike, but the BS34 is a really nice carb once jetted to get over it's factory lean settings.
One pilot was stuck and the head was "ramped" ccw. :) A small easy-out removed it with out drama. The BS 34s are indeed tempting due largely to the body of knowledge here and they are "racked". The VMs are hanging out there by only the throat clamp. But, the VMs are mounted, have the proper throttle cable and are new. When I resolve the left cylinder not firing I will spend some time trying to get them right but I know I have a fall back to the BS34s and some nice VM kit to sell. The cylinder not firing may be weak spark, dull yellow not hot blue. I have to check with garage lights off. Lots of LEDs distorts perception.
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Confusion abounds. The carb manifolds have vacuum ports. Removing the left nipple causes the left cylinder to fire so the enricher seem to be too rich. But at least I know ot runs on both cylinders now. If I turn off the enrichers at 3000 ish rpm the motor continues to run and respond to throttle. If I let it down to lower RPM, 1200-1800 ish it gasps and dies. I will assume the pilot needs richening.
 
As an aside, the floats ride up and down on posts in the float bowl. The float valve arms ride freely on the float but are totally seperate.
 

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Seems these carbs came with a jet assortment. 160 - 185 main and 12.5, 15 and 17.5 pilots. These are all small for following http://www.amckayltd.com/vm34-36.pdf so I went with the 17.5 pilots and found one carb had a 175 and the other a 185 and now both have 185s. The bike starts and idles and doesn't make any funny noises. Now on to verify timing and cam chain adjustment.
 
Really good grab bar/taillight off for good. It and a padded back rest will hit the classifieds along with BS34s and stock KYB shocks. Some engine decreased and a pressure wash befor going up on the jack.View attachment 221929
It's hotter'n hell out there... and a long ways from Winter. Pace yourself. ;)
 
That butt ugly seat should go next, lol.
78 side covers. I will examine trimming the seat base to fit over/above 78 side covers only because the latch works but probably cut all of that stuff off and make a bolt down seat with room for a passenger. It already has 12.5 inch konis, an aluminium 18 inch rear is on the way, a 19 inch aluminium front rim is coming. Need to find 77/78 style head pipes and commando pipes.
 
Stock headpipes may look big but that's only on the outside. They're a "pipe-in-pipe" design with an air space between the two, so that makes the I.D. quite small, only like 1.25". They're pretty restrictive because of that. I think you're better off with the 1.5" single wall aftermarket headpipes. YamahaXS650.com even has them on sale, lol .....

https://yamahaxs650.com/product/xs-performance-chrome-1-5-od-headpipes/

They also carry the original Commando mufflers with the removable baffle bolt.
 
Stock headpipes may look big but that's only on the outside. They're a "pipe-in-pipe" design with an air space between the two, so that makes the I.D. quite small, only like 1.25". They're pretty restrictive because of that. I think you're better off with the 1.5" single wall aftermarket headpipes. YamahaXS650.com even has them on sale, lol .....

https://yamahaxs650.com/product/xs-performance-chrome-1-5-od-headpipes/

They also carry the original Commando mufflers with the removable baffle bolt.
Those are the ones. On sale now too.
 
The time you saved not having to touch that will be invested in more polishing to match it: XS Karma rule:wink2:
Karma... The pic doesn't do justice to the inside hub. A paint (Industrial grey?) with the ribs polished. The front hub I will need to work on before lacing a rim (that I will have to work on...) has a rather irregular shape.
 
Stock headpipes may look big but that's only on the outside. They're a "pipe-in-pipe" design with an air space between the two, so that makes the I.D. quite small, only like 1.25". They're pretty restrictive because of that. I think you're better off with the 1.5" single wall aftermarket headpipes. YamahaXS650.com even has them on sale, lol .....

https://yamahaxs650.com/product/xs-performance-chrome-1-5-od-headpipes/

They also carry the original Commando mufflers with the removable baffle bolt.
Ordered the head pipes. Note to self, "go 2 or 3 up on mains and pilots and work backwards" to avoid the blue...
 
Stock headpipes may look big but that's only on the outside. They're a "pipe-in-pipe" design with an air space between the two, so that makes the I.D. quite small, only like 1.25". They're pretty restrictive because of that. I think you're better off with the 1.5" single wall aftermarket headpipes. YamahaXS650.com even has them on sale, lol .....

https://yamahaxs650.com/product/xs-performance-chrome-1-5-od-headpipes/

They also carry the original Commando mufflers with the removable baffle bolt.
YAMAHAXS650.COM list 2 Cammando styles, one at 1.75 with reducers and one at 1.5in. Which has the baffle bolt? It is not listed in either description. The 1.75 mentions a plug.
 
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