‘83 venture single carb conversion

[Venturezach]

Hello everyone, I am the proud owner of a 1983 Yamaha Venture xvz1200. I have decided to go with a single carb conversion kit off eBay for simplicity and ease of Maintenence. So I have it installed and performed the initial setup per instructions that came with the kit. The problem I am having is that sometimes it will fire right up and other times it will not. When it doesn’t it spits smoke up out of the carb a few seconds into cranking. I am mechanically inclined and have performed many repairs and modifications on my venture, I just need some help with this one. Maybe I’m missing/overlooking something? Thanks in advance.

[CaseyJ955]

Did you get the Solex kit, it's the only one I see on Ebay ATM?

 

I'm not wrapping my brain around how a single Solex could work properly on one of these beasts. Is the carb in the kit an authentic Solex or an off brand?

[Venturezach]

Yes, it is the solex carb kit. There is a YouTube video of a guy running the solex single carb, although he doesn’t talk at all during the videos, at least there is some verification there that proves it works. I’m going to put the link here.

 

[Marcarl]

That video doesn't prove much, other than it wasn't running well. He had stalling and starting issues as well and needed the choke to start it properly. He also had problems getting it to idle. Watching the video, I would suggest that the primary circuit was running a bit lean. Don't have any idea what your problem might be though, although it could be traced to the same issue. Try using a bit of restriction on the breather by taping off half of it and see what develops. Maybe post a video of your problem as well.

[videoarizona]

[Venturezach]

Thanks for the advice marcarl! Today when I got home from work and after replacing a part on my wife’s car(that always comes first) I had some daylight left so I figured why not try to start it and see what happens. Taped off half the intake and it started after a few revolutions. There are 2 vacuum ports on the carb, one at the rear and one on the left side near the large adjustment screw. Connected the port on the back to one of the vacuum ports on the lower intake manifold(plastic part) and it seemed to run noticeably better, still going to make some tweaks/adjustments until it is fully dialed in. Perhaps tomorrow if fate allows I will be able to take her on her maiden voyage with the single carb setup.🤩 I’m pretty excited to see how she’ll do out on the street and of course I’ll be sure to keep y’all updated. Hopefully I’ll get some videos up on here soon, tried to take one today but it came out too dark 😑

[cowpuc]

Hi Zach,,, and !!! LOVE what ya got going on there!!

 

Soo,,, just thinking out loud here,,,, all of my 83's got their spark advance set up from a vacuum line pulling vacuum from the carb.. My first Venture (and only non 83 I ever owned/rode out to terminal) was an 84 and it pulled it's advance vacuum from the #2 intake manifold. It would be interesting to know where/how you are setting up the spark advance on yours with it set up with that carb?? ing

[Marcarl]

You mentioned that you had 2 vacuum ports, but you didn't say what you did with them. Did you plug them? They can't remain open, or be connected to an open source. As Cowpuc mentioned, you also need some sort of vacuum to the ignition advance. Any of these issues will have it running crappy and make for hard starting.

[Venturezach]

Good points cowpuc and mercarl, sorry I forgot to mention how I did that. I left the vacuum line for spark advance connected to vacuum port 2 just as it was originally. Did away Witt the cruise control vacuum line and routed a vacuum line from the back of the carb to the port the cruise control vacuum line was attached to. I plugged the smaller port on side of carb.

[Prairiehammer]

Did away Witt the cruise control vacuum line and routed a vacuum line from the back of the carb to the port the cruise control vacuum line was attached to.

 

The 1983 Venture did not come with cruise control. On the subsequent years of the Venture, the cruise control utilized a vacuum pump, not manifold vacuum. What brand cruise control did you have?

 

I left the vacuum line for spark advance connected to vacuum port 2 just as it was originally.

 

The 1983 TCI requires the vacuum source be ABOVE the carburetor butterfly. The TCI will not function correctly if the vacuum source is from the intake boot.

Edited October 16, 2018 by Prairiehammer

[Venturezach]

It’s a markland cruise control, the component that I thought was part of the cruise control system is a black plastic canister type thing just behind the front left blinker. And as for the TCI, I will have to figure out how to route it to pull vacuum above the butterfly. Tried starting it again today, had to turn it a bunch of times and wouldn’t idle. I’m starting to suspect that the intake manifold is not fully seated in the intake boots🧐, have it back on the charger tonight and will try again tomorrow. Thanks for all the help guys I really appreciate it! 😎

[uhfradarwill]

I wish you luck on this modification but to me it like removing three chambers of your heart and then trying to tune your body for "original" performance.

[Venturezach]

Had more success today. Figured out my problem was a bad ground on carb, got it all hooked up with a better ground and was able to get her to idle and make some adjustments. Has much more power than before probably because my original carbs were all gummed up and out of sync. I also removed the yics as well and made sure to plug the ports on the motor. And I also put a little breather filter on the port where it went to the air box. ThatÂ’s all I have for now, will continue to ride and adjust as needed

[BlueSky]

Based on knowledge gained from my auto hot rodder days, many hot rodders just used mechanical (centrifugal) advance with a total advance of around 36 degrees combining the idle setting and the centrifugal advance. But for road use when an engine is running at low throttle at a steady speed the fuel mixture is lean and the engine could use more advance for optimum fuel economy. So, hooking the vacuum advance to the manifold vacuum would give you max advance at low throttle and lose it for full throtte which is ideal. I never understood why the vacuum advance would be hooked up to ported vacuum (above the throtte plates).

[CaseyJ955]

Glad the issue was sorted and shes running. After you have had some time to ride it and feel it out please follow up as sort of a product review. I'm really interested in how she performs in the upper revs and what sort of MPG you end up with. Very cool!

[uhfradarwill]

Had more success today. Figured out my problem was a bad ground on carb, got it all hooked up with a better ground and was able to get her to idle and make some adjustments. Has much more power than before probably because my original carbs were all gummed up and out of sync. I also removed the yics as well and made sure to plug the ports on the motor. And I also put a little breather filter on the port where it went to the air box. ThatÂ’s all I have for now, will continue to ride and adjust as needed

 

"A better ground"?? Are we talking an electrical issue or a fuel/air/delivery issue???????????

[Venturezach]

It was an electrical issue that led to an air/fuel delivery issue. Basically what I did was retraced what I did when I installed it and during that process checked for continuity at my connections. Positive connections were good, but when I checked for negative continuity it wasnÂ’t there. Relocated my ground and problem solved. DidnÂ’t get a chance to ride it today but hopefully I will tomorrow. ItÂ’s the perfect weather for riding too 😎 I will be sure to post updates about performance and mpgÂ’s. The main piece of advice I can give so far about this conversion is be prepared to spend some time tuning and adjusting. And of course check all connections and make sure they are good and have continuity. Thank you everyone for your advice and support. 👍

[uhfradarwill]

It was an electrical issue that led to an air/fuel delivery issue. Basically what I did was retraced what I did when I installed it and during that process checked for continuity at my connections. Positive connections were good, but when I checked for negative continuity it wasnÂ’t there. Relocated my ground and problem solved. DidnÂ’t get a chance to ride it today but hopefully I will tomorrow. ItÂ’s the perfect weather for riding too 😎 I will be sure to post updates about performance and mpgÂ’s. The main piece of advice I can give so far about this conversion is be prepared to spend some time tuning and adjusting. And of course check all connections and make sure they are good and have continuity. Thank you everyone for your advice and support. 👍

 

Being unfamiliar with your particular kit, I didn't realize it consumed electrical current to work properly.

I do have a fair amount of electrical engineering experience and I have learned many times that what appears to be ground is not always ground.

 

Continued good luck to you!!

[Venturezach]

Okay guys, got her fired up and running. Took her out for a quick ride around town and a bit on the highway. A bit “cold blooded” at first, but when warmed up runs great! Good throttle response and good power in my opinion. I’m not going to push it to get more power because it’s almost a 40 year old bike and I’m just trying to get it to run right so I can enjoy it. That being said, when I was out cruising around I noticed it was running warmer than usual. About a year ago I replaced the starter and when I did that I had to remove the radiator and the thermostat cover to get the starter out. When I had everything out, I replaced the thermostat and the thermostat cover because it’s plastic and they’re prone to warping. Also replaced all the little rubber hoses that attached to the radiator. And I replaced the radiator cap as well. Cooling system is fine, no leaks just runs a bit on the hot side. The needle gets just above the line into the red area which worries me. The fan is operational as I can hear it come on when the needle is at the top of the green zone on the temp gauge. Any suggestions on how I can make it run cooler? And it was about 80 degrees when I rode it.

[Freebird]

What you are seeing may be perfectly normal. The '83s always indicated that they were running a bit hot. Yamaha recalibrated the gauge after the first or second year.

[cowpuc]

Okay guys, got her fired up and running. Took her out for a quick ride around town and a bit on the highway. A bit “cold blooded” at first, but when warmed up runs great! Good throttle response and good power in my opinion. I’m not going to push it to get more power because it’s almost a 40 year old bike and I’m just trying to get it to run right so I can enjoy it. That being said, when I was out cruising around I noticed it was running warmer than usual. About a year ago I replaced the starter and when I did that I had to remove the radiator and the thermostat cover to get the starter out. When I had everything out, I replaced the thermostat and the thermostat cover because it’s plastic and they’re prone to warping. Also replaced all the little rubber hoses that attached to the radiator. And I replaced the radiator cap as well. Cooling system is fine, no leaks just runs a bit on the hot side. The needle gets just above the line into the red area which worries me. The fan is operational as I can hear it come on when the needle is at the top of the green zone on the temp gauge. Any suggestions on how I can make it run cooler? And it was about 80 degrees when I rode it.

 

What you are seeing may be perfectly normal. The '83s always indicated that they were running a bit hot. Yamaha recalibrated the gauge after the first or second year.

 

That Bossman around this joint is quicker than a 1st Gen tach and more accurate than the same IMHO. Running in the red zone is not normal in my experience though as all of my 1st Gen's have ran 1 or 2 needle width shy of the zone as their normal op temps. I think if it were my scoot I would double check the position of the bypass/drain valve down where the hoses come together below the rad and in front of the oil filter. If that valve is in the wrong position you could be starving the system of coolant and causing a run hot situation - an opinion of course..

I would also consider checking the condition of the water pump impellar as all but 2 of my bikes still had the plastic 83 OEM impeller in them.. Those would be the early ones that like to dissolve over time leaving nothing to move coolant but a spinning hub,, DEFINITELY an overheat waiting to happen.

I think I may have a video showing the valve I am talking about. Be right back if I can find one...

[cowpuc]

By the way Zach,, being from Stockton, you ever do that Sonora Pass ride thru the mountains just east of you? WOWZY WOW WOW WOW = GORGEOUS!! Or the one thru the mountains that Twin Cities Road (I think Twin Cities turns into 104 or something) that leads out thru that mountain town of Jackson and across to 89? We take that one a LOT to avoid those 4 hour jam ups coming out of Tahoe when going to Wilton/Sacramento to see the kids.. Both DEFINITELY rides pretty enough to make your eyes bleed!!!

[cowpuc]

Here ya go Zack,, go to 1:10 on the time line and you can see the valve control I am talking about. I dont have a video showing the exact position the valve is suppose to be for "RUN" but I do know that its not what a normal person would think would be a normal position... Almost like Mom Yam was trying to trick us or something. Hope I am making sense here cause this is something that could be an issue in your case (having messed with the coolant system)..

[Venturezach]

Okay, thanks for the info, I don’t believe the impeller is wearing as the color of the coolant is still bright green as it was when I put coolant in when I did the starter. I remember hearing about a coolant switch that turns the fan on on at a lower temperature, anyone have any info on that? Think that’s my issue because it stays right in the middle on the highway but in town is when it gets hot. And the only trip me and my wife have been on is up to Murphy’s during the springtime. Once everything is worked out we’ll have to check out those spots. Also riding up the 160 up to Sacramento along the river is a nice ride

[mantree91]

i am getting ready to install a webber 32/36 on my bike with a custom m intake. how are you liking the conversion?