Fuel from needle jet at idle? WTH????

[1FK00]

Are all starter jet plungers seated fully?

 

[maleko89]

Are all starter jet plungers seated fully?

Choke fuel empties below the throttle plate.

Mark

Sent from my SM-G920P using Tapatalk

 

[dannymax]

Dan-o, does that engine start?

I still use my Motion Pro aux. fuel tank to check wet levels prior to putting them back on my bike. I also use a small level to make sure the carb brackets are all tight and were installed correctly.

I still turn the carbs upside down for dry levels and use a digital caliper to set at 1.125 inches. I found that the 1/2 moon on the jet block varies in position on some blocks.

Mark-o

You betcha Mark-o! :biglaugh:

I made a bracket with adjustable leveling feet to sit the rack on for wet levels....goes on top of the upper frame rails and the bikes fuel pump provides fuel volume & pressure, the 'usta-be' aux. fuel bottle is now the non-rusting fuel supply tank.

And it can be jacked up to the perfect working height so the 'technician' doesn't have to bend over to sync the carbs.

'Technician' = Dannymax :blink000:

 

[dannymax]

Danny is the fan just for light cruise speed or you got a 220 v hooked up to get the bike simulating v boost speeds hahah

Absolutely a 220V Rovic....I stand beside the engine & adjust and Heidi throws a bucket of bugs into the fan so I get the full effect!! :rocket bike:

 

[great white]

Well, no more fuel from the needle jets at idle. At least no visible fuel, certainly doesn't look like a pump shot from and accelerator pump on throttle blip!

Setting the float levels at 17mm and being very fussy seems to have fixed it.

The idle mixture screws seem to have no effect still, of at least any that I can discern by sound or rpm. But this bike can also run quiet happily as a triple and you'd almost not be able to tell.

I just set the screws at 1 1/2 out for now.

At least it doesn't smell pig rich at idle now.

Idles nice a smooth.

Funny thing now is I can block of carbs 1 and 3 and it starts to die immediately. Block off 2 and 4 and no effect other than it soaks my palm with fuel. All the pipes are hot, so they're all firing. I think I'll throw a clean set of plugs in it (as the ones in there now are surely black with carbon) and see if it makes any diff....

I might have to just go pop the money for a CO2 analyzer and be done with it....

 

[great white]

It can get confusing measuring the float position upside down and wet level checking them right side up......

I set floats with a gauge, and used to use a fuel bottle suspended over the carbs (on the bench) to approximate fuel pump pressure for wet level check.

Now I set with the same gauge and a longer line from the fuel pump with carbs leveled on top of test engine stand.

I had an old snowblower throw rod several years ago and I saved the fuel tank when we got rid of the dead carcass. I made some hooks for it and now I use it as my "aux tank" when working on bikes with fuel tanks removed. Even has it's own filter and fuel shut off valve.

I just hung the tank on the peg board on the wall above the workbench and used that to fill the bowls on the carb rack.

Made the process very easy. Dry measure dry, install bowls, open shut off valve, wet check, repeat as necessary.

Half moons on the jet block were not reliable references. I had to measure and wet check each one to get all four within spec.


I wish they had designed the needles like a holley carb where it's externally adjustable by a simple turn of the screw. Bending tabs sucks and they're so super sensitive to the slightest change (ie: bend) it's stupid....

 

[dannymax]

I had an old snowblower throw rod several years ago and I saved the fuel tank when we got rid of the dead carcass. I made some hooks for it and now I use it as my "aux tank" when working on bikes with fuel tanks removed. Even has it's own filter and fuel shut off valve.

I just hung the tank on the peg board above the bench and used that to fill the bowls on the carb rack.

Made the process very easy. Dry measure dry, install bowls, open shut off valve, wet check, repeat as necessary.

Half moons on the jet block were not reliable references. I had to measure and wet check each one to get all four within spec.


I wish they had designed the needles like a holley carb where it's externally adjustable by a simple turn of the screw. Bending tabs sucks and they're so super sensitive to the slightest change (ie: bend) it's stupid....

Wouldn't that be sweet!! unk:

 

[great white]

Sitting here thinking I'm going to do a carb synch too just in case one or more of the butterflies are too closed at idle.

Quick and easy check.

 

[maleko89]

Yeah, definitely. They always change at least a bit when carbs are removed.

Mark

 

[great white]

Went for a run, felt pretty good.

Step where the Vboost comes on isn't noticeable anymore. At least not like it was.

pretty sure I fouled a plug towards the end of the run an it laid down pretty flat.

I hadn't slapped clean plugs in before going and I'm thinking it might have been down a cylinder (or that little misfire before it goes away completely) and then I dropped a second plug on the way back.

When I think back to it, being down one cylinder before made the vboost behave like it did on the run.

I'm going to pull the plugs, see what the burn looks like, install fresh ones and try again later.

At least it pulls clean in each gear now. Not shuddering at all like before.

At least until I dropped a plug that is.....

 

[blaxmax]

Can you post a pic of the plugs?

 

[tugla]

Absolutely a 220V Rovic....I stand beside the engine & adjust and Heidi throws a bucket of bugs into the fan so I get the full effect!! :rocket bike:

unk:unk:

 

[great white]

Dropped the carb stix on ghe bike.

1&2 were good. 3&4 were good.

But 2&4 were right out to lunch.

After a fair bit of fiddling,got it all balanced up.

Now the engine will stumble when covering throats 3&4 and the mixture screws will make the engine stumble. Very slightly and they have to be closed right off, but at least they have an effect now.

I'm not sure what happened, but something got the balance way out of whack. Seriously out. Not just a little hump, but several full turns on the adjusters.

At least I'm now at the point where I can start zeroing in on final adjustments and jetting.

Doesn't seem to foul plugs now either.

One bummer was I found my pull throttle cable is fraying at the metal 90 degree fitting. Will have to call my friendly local neighborhood Yammy dealer Monday and see how horrible that is going to be.....

 

[great white]

Alright, I'm po'd at this thing now.

It seemed to be pretty good, except it has a bit of lean surge and mileage is 18 mpg!

Yes, you read that right:, 18 mpg. I didn't think it was possible either, but there it is. checked my math several times. Even of I'm generous on my numbers, its still only going to work out to around 20 mpg.

All I can figure is the lean misfire on the highway is just sucking back the fuel. Seems contradictory (lean= less mpg) but it wouldn't be the first time I've seen it happen.

Right now I'm lucky to crack 120 KMs on a tank. That's a Venture tank, not a VMax tank! 20 liter tank vs 15 liter. These things were rated with a range of approx 360kms when they were tested by the mag's back in the day. I can petty much watch the level drop on the fuel gauge as I ride. 25 minutes highway blast at 100kph (approx 62 mph) will fire nearly 1\2 tank out the pipes. Screw the Venture supposed 40 mpg, I'd be over the moon to get the VMax 34 mpg right now!

That tank full was also just riding, only adjustments were an occasional 1\8-1\2 turn tweak of the fuel screws to richen up any lean carb pops so no sitting at idle making adjustments and getting 0 mpg to skew the results. Idle fuel screws are all right around 2 to 2 1\2 turns out.

So I go through it all again and find all my float levels are somehow down around 20mm and a plug chop reveals the main jet is a bit lean too.

Lacks power on the highway too. Below 3500 rpm (1\4 to 1\2 throttle) the cruise control will drift down and kick off because it can't roll on enough throttle fast enough. Get it above 3500 rpm and it will hold. Engine feels like it's "soft" too.

A lean condition kinda makes sense with what is going on: lacks power, feels like a light lean misfire, low float levels, etc....

So I tear it all down and bench set my levels to 16-17mm. I build a graduated tube so I can get it bang on. I also swap my 140 mains for 145.

Put it all back together and fire it up. Raw fuel is once again pouring out around the needles! #1 is the worse, actually running down the sides of the venturi. 2-4 you can see it pulling fro. The needles at idle and throttle blip looks like an accelerator pump shot again. Fuel screws can again be turned in to closed and have no effect on idle speed. After 10-30 secs running and the garage reeks of rich exhaust.

I rip the carbs off again and confirm the levels. Not one less than 15mm.

I split the rack again and in maybe a bit of a "hail marry pass", I dry set the float levels to what Morely has recommended (1.115) on carbs 1and 2.

Level the bodies and wet check the levels shows 17-18 mm on carb 1 and nearly 28mm on carb 2.

WTF?

So I adjust carb 2 to get 18mm like carb 1 and the float is significantly higher. I haven't taken the bowl off to compare the dry height, but its significantly less than 1.115

That's where I left it last night. It was late and I was tired of sopping up fuel on the bench,.smelling like gas and just generally all around tired of f-ing with it.

I'll set 3 and 4 today, put it back together and see what I get.

These Yammy V4's have always been a pita for me. Great engines but nothing seems to adjust or react like any other engine I've worked on. Heck, drop a cylinder to a "V3" and you can't hardly tell at all. On my V4 interceptor there's no doubt at all you've lost fire in one of the holes. The FJ inline 4 let's you know right now you're not firing on all 4.....not so the Yammy V4.

Oh well, I'm just bitching now.I'll get it figured, it's just such a pita pulling carbs on a vmaxed Venture. So much plastic to pull off and I have to pull the front engine mounts to get enough clearance (frame tubes are lower over the carb compared to Max) to get the carbs out.

Not to mention, I'm getting tired of f'n working on this thing all the time. I want to puts some miles under the tires. I mean it's a frickin bike, its not a great mystery. It's just a machine, it shouldn't be this hard to get it sorted....

:bang head:

 

[Traumahawk]

Is this a Vmax engine with venture heads, or a venture block with Vmax heads?

You can sent the carbs out to get them sorted.

 

[great white]

Venture 1200 block. 31,000 kms on the rotating assembly.

All VMax from the head gaskets up to the carb boots.

Its the 34mm Venture carbs.

Pilot jet 42.5 (all stock for an 83 1200)
Main jet 145

Venture manual calls for 14mm +-0.5 for float levels. Too high for this combo so I'm using VMax spec for floats and dropping from there. Possibly the 1mm smaller venturi from the VMax is making for too high a signal over the stock float levels but Gary is\was running the same\similar combo and I've never heard of him mentioning float level\lean issues.

It's a bit of a frankenbike so I'm on my own with setup I think...

 

[dannymax]

I ran some Venture 34mm carbs on my '99 Vmax with stock VMax float levels and it ran great.

Not sure about the requirements of your 'Frankenbike' tho. :confused2:

 

[Traumahawk]

Venture 1200 block. 31,000 kms on the rotating assembly.

All VMax from the head gaskets up to the carb boots.

Its the 34mm Venture carbs.

Pilot jet 42.5 (all stock for an 83 1200)
Main jet 145

Venture manual calls for 14mm +-0.5 for float levels. Too high for this combo so I'm using VMax spec for floats and dropping from there. Possibly the 1mm smaller venturi from the VMax is making for too high a signal over the stock float levels but Gary is\was running the same\similar combo and I've never heard of him mentioning float level\lean issues.

It's a bit of a frankenbike so I'm on my own with setup I think...

I would start with the Vmax settings in the carbs, and go from there. PAJ#1 90, PAJ#2 170, mains 152.5's. The pilot jets on the stock Vmax are 37.5's and with the displacement being only 1200 CC's I would start there.

Float level on a vmax is 15-17 mm. Best hp is made at 17 mm. Ive known of people to run the 34 mm carbs on a Vmax with no issues......you just might lose a couple of hp on top, but it should still run very well.

Are you running Vboost as well?

 

[sdt354]

I break the rack in two's, then bench check them wet. Easy access to the bowls this way. And, in two's they stand level on a level table. 16.5 mm is my preferred level. A check on the bike is always a good idea when finished.
A/f screw sensitivity requires the carbs be in sync. And the idle be low, and the circuit clean of course, and everything else in the carbs ok. I don't think this is your issue because of the fuel spilling in around the needles, but thought I'd throw it out there because I hear this complaint often.
Steve-o

 

[caseyjones955]

Just throwing this out there, I recently read somewhere that the emulsion tubes can wear out with not to many miles on them and allow excessive fuel past the needles.

Sorry about the hassle, hope you nail the issue soon and get back on the road.

Not sure about this particular setup or how Ventures are normally jetted but I know a 145 might be a touch lean for a Vmax unless your at significant altitude.