1983 Venture in Dublin CA Need Trouble Shooting Help

[dabaker]

I am working on an 83 Venture that was stored 10 years. I have the compression up to 210 on all four holes, carbs are good, but it spits through carbs at idle, has an intermittent fast idle issue, and seems to miss on 3. I have a spare CDI, but it runs the same on both. Don't know if they are good, and the guy who tested them here has a dead email link. Would there be anyone in the E. SF Bay Area who could help me trouble shoot this bike? Greatly appreciated any help and can reciprocate. Thanks in advance, Please advise your contact, as I cannot post my email here. Dan

[RDawson]

Do you have the air box sealed and filter in place? They won't run correctly without it.

[videoarizona]

I am working on an 83 Venture that was stored 10 years. I have the compression up to 210 on all four holes, carbs are good, but it spits through carbs at idle, has an intermittent fast idle issue, and seems to miss on 3. I have a spare CDI, but it runs the same on both. Don't know if they are good, and the guy who tested them here has a dead email link. Would there be anyone in the E. SF Bay Area who could help me trouble shoot this bike? Greatly appreciated any help and can reciprocate. Thanks in advance, Please advise your contact, as I cannot post my email here. Dan

 

 

Vacuum leak???

[Condor]

And have you done Sea Foam and sync'd the carbs yet??

[Patch]

I am working on an 83 Venture that was stored 10 years. I have the compression up to 210 on all four holes, carbs are good, but it spits through carbs at idle, has an intermittent fast idle issue, and seems to miss on 3. I have a spare CDI, but it runs the same on both. Don't know if they are good, and the guy who tested them here has a dead email link. Would there be anyone in the E. SF Bay Area who could help me trouble shoot this bike? Greatly appreciated any help and can reciprocate. Thanks in advance, Please advise your contact, as I cannot post my email here. Dan

 

 

Listen,,,,,,,,,,,,, you are fortunate that the intake valve seats are leaking the pressure!

 

You are way over the max compression limit!

 

The bike has been run way too rich, for way too long!

 

What is the mileage?

 

You have too risk decarbonising, I haven't covered it but I can it in my fogging post but unless you want to pull the heads we can try it chemically.

Patch

[frankd]

When my 83 was new, I used to run leaded gas in it. When it got up in mileage, long after leaded fuel wasn't available any longer, after it sat for a while sometimes it'd be a bear to get started. You could tell by the way it cranked so fast that the compression was way low in some cylinders. After I got it started, it ran terribly for a while, spitting out of the carbs and also exhaust. Then after a couple of minutes, it'd get better and then it ran and started normal. One year after a long winter (I lived in northern Illinois then) it almost started the first time, and then it started the same ritual except it was worse then normal. I couldn't get it to start at all. Because it was spitting out of both the carbs and exhaust, I pulled the valve covers to check the clearance and found that the valves had excessive clearance, so I assumed that there was some garbage between the valve and the seats caused by crud breaking off the combustion chambers. I made a fitting that would adapt an air hose to the spark plug hole and applied air pressure to the cylinders and spun the engine over. After I did this, the bike started but barely ran for about 5 minutes and finally got better. I treated the bike with Yamaha Ring-Free and although one of the spark plugs had it's insulator ruined and I had to change the plugs, the bike ran great. I could tell by how it cranked on hot starts that the combustion chambers had been cleaned out. I never had that problem again. Now I see that Yamaha makes a combustion chamber cleaner and it'd probably be what I'd use if I needed to.

 

https://www.shopyamaha.com/product/details/yamaha-internal-engine-cleaner

 

If you trust your compression gauge's accuracy, it sounds like your on the same path.

[Patch]

Not sure if you're looking for help or suggestions? But the standard compression is only 142 lbs and the max is 156.. So, shouldn't be a hard engine to spin given a good battery.

 

Now tho you will be subject to preignition as well other destructive forces such as suddenly reversing crank rotation; best tend to it before it starts bending rods and crashing journals.

 

Don't know the mileage nor how much you value the bike, the ball is in your court.

 

I would guess there may also be a problem with the PCV, and should the rings be worn (likely) then the blow-by will cause excessive carbon buildup in the oil then on the valve seats thru the crankcase vent which will deform the ground/cut seat angles and surfaces; also wears the stems, scores the cylinders, journals, common oil flowing across the gearbox ... so... A tear down with that much carbon really is the best way forward..

Patch

[Venturezach]

Hi there neighbor! I’m just a hop over the hill in disco bay and I’ve experienced a similar issue to the one you’re having. My 83 sat for awhile also. I’d have to squirt starting fluid in the air box just to get it going and after I got it going it would run like crap, almost spot on as to what you’re describing with it spitting back at you and all. What I did to mine was after some pretty intense troubleshooting, found out it was the carbs causing my issue. Hopped on the eBay and the googler to try to hunt down a rebuild kit. Well no luck on that, but I did find the solex pict 3 carb conversion kit. I pondered and ran it through my mind a dozen times because it ain’t cheap(about $500) but if you were to take it to a shop that will touch a near 40 year old bike(good luck) then you’d be lookin at about double that. I am happy with the single carb. Great power, mileage is about 33 on average and it starts on a dime every time. Although I need to give some credit to Dano for helping me out with the starter clutch upgrade (highly recommend this upgrade). All that being said with what you’re experiencing and from what I’ve experienced I would recommend the solex carb. Would’ve hopped on here earlier to help you but life has been nuts here lately but looks like it’s startin to settle down(knock on wood). Let me know how it goes and maybe we can meet up to check out your bike and get her runnin right. These things are a blast to ride!

[Patch]

Hi there neighbor! I’m just a hop over the hill in disco bay and I’ve experienced a similar issue to the one you’re having. My 83 sat for awhile also. I’d have to squirt starting fluid in the air box just to get it going and after I got it going it would run like crap, almost spot on as to what you’re describing with it spitting back at you and all. What I did to mine was after some pretty intense troubleshooting, found out it was the carbs causing my issue. Hopped on the eBay and the googler to try to hunt down a rebuild kit. Well no luck on that, but I did find the solex pict 3 carb conversion kit. I pondered and ran it through my mind a dozen times because it ain’t cheap(about $500) but if you were to take it to a shop that will touch a near 40 year old bike(good luck) then you’d be lookin at about double that. I am happy with the single carb. Great power, mileage is about 33 on average and it starts on a dime every time. Although I need to give some credit to Dano for helping me out with the starter clutch upgrade (highly recommend this upgrade). All that being said with what you’re experiencing and from what I’ve experienced I would recommend the solex carb. Would’ve hopped on here earlier to help you but life has been nuts here lately but looks like it’s startin to settle down(knock on wood). Let me know how it goes and maybe we can meet up to check out your bike and get her runnin right. These things are a blast to ride!

 

 

And I would like somebody to put some real numbers down.

"plenty of power" compared to what? Seriously you couldn't find jets or clean them, replace some gaskets?

[Venturezach]

Steven G, I was referring to how it ran before the carb swap sorry I didn’t make that clear and to answer your question I seriously could not find a rebuild kit for these carbs, I’ve searched high and low but would you happen to know where rebuild kits are available? I’m sure it would help other members if they knew. I’d really like the opportunity to put my scoot on a dyno to see what it’s puttin out, if I ever do then I’ll be sure to post it on here as I’m sure many are curious.

[Patch]

Steven G, I was referring to how it ran before the carb swap sorry I didn’t make that clear and to answer your question I seriously could not find a rebuild kit for these carbs, I’ve searched high and low but would you happen to know where rebuild kits are available? I’m sure it would help other members if they knew. I’d really like the opportunity to put my scoot on a dyno to see what it’s puttin out, if I ever do then I’ll be sure to post it on here as I’m sure many are curious.

 

 

Its not about dyno numbers, it is about flow rates!

The more I read these days about cheap fast fixes the less thought and basic performance principles are actually being shared.

Everything about combustion engines is about air flows; how to manipulate air flowing in and out is the game, how much and how fast or where to speed or slow it is the aim.

Mixing fluids then delivering that metric to the chambers takes more thought then simply bending and cutting tubing and welding's that are so poor in quality at least in the examples we seen posted.

Understanding pressure differentials also seems to be lost. Knowing the filling potential of the available displacement is the first step always; then you move thru the rest.

Performance machines such as motorcycles have a long power range, knowing how changes will impact the range and at what rpms requires modeling then, those posted numbers are suppose to be the reasons we crack our wallets open, no numbers, no coin exchange.

 

A quick search brought up several supplies of kits and parts bee is just one

Patch

 

https://www.ebay.ca/itm/Motorcycle-Carburetor-Repair-Kit-Main-Jet-Sub-for-Yamaha-VMAX-V-Max-1200-VMX12/113753550982?_trkparms=aid%3D555018%26algo%3DPL.SIM%26ao%3D1%26asc%3D20131003132420%26meid%3De1d5d47c6b064ba88808147c48229185%26pid%3D100005%26rk%3D2%26rkt%3D12%26sd%3D142418886727%26itm%3D113753550982%26pg%3D2047675&_trksid=p2047675.c100005.m1851

[Venturezach]

Its not about dyno numbers, it is about flow rates!

The more I read these days about cheap fast fixes the less thought and basic performance principles are actually being shared.

Everything about combustion engines is about air flows; how to manipulate air flowing in and out is the game, how much and how fast or where to speed or slow it is the aim.

Mixing fluids then delivering that metric to the chambers takes more thought then simply bending and cutting tubing and welding's that are so poor in quality at least in the examples we seen posted.

Understanding pressure differentials also seems to be lost. Knowing the filling potential of the available displacement is the first step always; then you move thru the rest.

Performance machines such as motorcycles have a long power range, knowing how changes will impact the range and at what rpms requires modeling then, those posted numbers are suppose to be the reasons we crack our wallets open, no numbers, no coin exchange.

 

A quick search brought up several supplies of kits and parts bee is just one

Patch

 

https://www.ebay.ca/itm/Motorcycle-Carburetor-Repair-Kit-Main-Jet-Sub-for-Yamaha-VMAX-V-Max-1200-VMX12/113753550982?_trkparms=aid%3D555018%26algo%3DPL.SIM%26ao%3D1%26asc%3D20131003132420%26meid%3De1d5d47c6b064ba88808147c48229185%26pid%3D100005%26rk%3D2%26rkt%3D12%26sd%3D142418886727%26itm%3D113753550982%26pg%3D2047675&_trksid=p2047675.c100005.m1851

 

Thanks for posting this link, not sure why I was unable to find it before but I did find the flow rate for the solex 34 pict 3 carb I installed. 34 PICT w/ no mods & choke plate held fully open (as on all tests): 114.9CFM at 25".

[Patch]

Thanks for posting this link, not sure why I was unable to find it before but I did find the flow rate for the solex 34 pict 3 carb I installed. 34 PICT w/ no mods & choke plate held fully open (as on all tests): 114.9CFM at 25".

 

That tho is not the whole picture; you used an adapter to install the carb.

Patch

[Patch]

Before this goes any further let me mention a couple of points from my point of view:

You do not need to defend your decision!

Your bike your way, my motto and belief!

You did not claim ( that I read) this to be a more efficient metric for this or any bike!

 

Now that said the numbers you and others do post tell the experienced gear heads this is in fact an inefficient kit! Efficiency builds power whether its to be measured in torque or HP both of which are primary goals set by the builder or modifier!

 

Even tho I have not held or played with the setup mentioned, it has been very clear in the reacquiring issues we here have read. This adapter is so poor in design that in my opinion is not fit for a lawnmower! And at this point I do not care who does or does not agree with me on this opinion! It is a collection of a mess, period.

 

What is going on with that adapter is a cycle of lean to rich, caused by pooling and separation. If that was installed on a say barely broken in engine you could start the countdown to its premature end!

 

Mikuni while many perceive as arrogant to deal with, are not inexperienced, nor do they guess at the manufactures requirements when they set out to design a fuel delivery system! So, if we want to beat them at their bread and butter we need to at least flow the math.. Anything else is hearsay.

 

My final thoughts on the subject

Patch