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

[great white]

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.

Those numbers are very close to the stock venture numbers. I don't have them right at hand at the moment, but they're close. 83-84 ventures were 42.5 pilots and then they went to the 37.5 in 85, vmax followed suit in 85 with the 37.5's. Lots of venture riders actually swap 42.5 for the 37.5 in order to smooth throttle transition and report no troubles.

My venture is also not a straight across vmax transplant. It uses the Venture airbox (IE: smaller) and the stock venture head pipes and collector. It has a set of R1 mufflers instead of the stock venture boat anchor muffs. IOW, it doesn't breath quite as well as a max. It's stuffed up so smaller jets are appropriate, it's just a matter of fine tuning those numbers to final form. What those numbers are going to boil out to be exactly is a different story, but I'm already in the ball park.

Long story short, I'm not far off a vmax stock setup and pretty sure none of that will be wonking out my fuel levels.

Float level on a vmax is 15-17 mm. Best hp is made at 17 mm.

anything under 18-17 mm seems to pull fuel right out of the needle jet.

Ive known of people to run the 34 mm carbs on a Vmax with no issues......

Me too, that's why it's frustrating right now. I even know of 1 franken bike that has run this way with (relatively) few problems.

you just might lose a couple of hp on top, but it should still run very well.

No worries on a couple hp, it's a touring bike after all. Just looking to blow my hair back now and then. the vboost rush is plenty enough fun for me when it hits! It's hell for fast as it is right now. WOT chops were crazy enough. I can't imagine holding it WOT for very long....

Are you running Vboost as well?

Yep. Controlled by an Ignitech controller. Comes in at the stock 4750 rpm and is noticeable at 5500-6000 rpm. That also makes me think its lean and down on power. When it was pig rich, by 5000 rpm you knew damned well the butterflies had opened and it felt like it was trying to rip your arms out of their sockets. Now its like: " umm yeah, it's there and I can tell at 6000 rpm but it's pretty soft.....ho hum".

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.

Same thing I'm doing. I'm using piece of plate glass (also use it to get the carbs on the same plane when putting rack back together) and a level acros the bodies in two planes.

16.5 mm is my preferred level.

I'm at 17-18 mm for the next testing. Trying to avoid the fuel around the needles but still not go too lean. It's very odd behavior right now....definitely not typical. The jet block is OEM yamaha, but maybe being an early production piece (one of the 1st 83's built) has something just a tad off. that off in WAG territory though. Dunno, just going to follow the breadcrumbs until it runs right.

A check on the bike is always a good idea when finished.

Natch.

A/f screw sensitivity requires the carbs be in sync.

done, checked after every adjustment.

And the idle be low, and the circuit clean of course, and everything else in the carbs ok.

done. Been in the ultrasonic twice now. It's spanking clean.

I don't think this is your issue because of the fuel spilling in around the needles,

agree. something weird is going on for sure. All points to float levels in my mind.

but thought I'd throw it out there because I hear this complaint often.
Steve-o

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.

31,000 kms on them. That's 19,000 miles. No discernible wear on the emulsion tubes or the needles. Unlike my FJ which is damned near oval and still runs like a top.

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

I'm just frustrated and tired of looking at it, I'll nail it sooner of later

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.

See above for the bike config. I'm essentially at sea level. It's more stuffed up than a Vmax. 140 was pretty good on a throttle chop. I went 145 to fatten it up a touch just to brown the pug a touch more. Stock 83 venture is a 117.5, 86-93 venture 1300 is a 125 with 35 mm carbs.






I'll get it eventually guys, it just a major PITA when things don't respond to adjustments the way they are expected to and you gotta sit on your butt and scratch you head for a while to figure out where to go next.

Making it worse is the carbs seem to be responding atypically to established techniques and adjustments. If I was new at this sort of thing I would understand, but I've been doing carb work on bikes for the better part of 35 years. Both cars and bikes.....

In a perfect world, it would go together and work. Problem is, this is the real world and the manual is at best only a guide.....just gotta keep pluggin at it and following the logical path....

 

[caseyjones955]

I have done quite a bit with various carbs too and the Yamaha v4 seems to have it's own rule book for sure. Im planning a 1300 frankenbike over the winter so watching your progress with great interest.

 

[great white]

ok. got them all bench set at 18mm.

they're going back in now and fingers crossed....

 

[great white]

sunova......

runs fine for a while, then seems to swap which carb is going to spit fuel out of its needle.

then, #4 up and overflows while im fine tuning the synch!

im going to replace the damned float needles on spec.

they look in fine shape, except that theses all have a metal tip and not the usual rubber tip.

i feel like im chasing my tail here. it didnt do any of this foolishness when i had the venture heads on it....

edit*

hmmm, that gets me thinking......i wonder if maybe my fuel pump is overpowering the needles? that would be out there in possibilities but im open to any logical thoughts right now....

 

[blaxmax]

sunova......

runs fine for a while, then seems to swap which carb is going to spit fuel out of its needle.

then, #4 up and overflows while im fine tuning the synch!

im going to replace the damned float needles on spec.

they look in fine shape, except that theses all have a metal tip and not the usual rubber tip.

i feel like im chasing my tail here. it didnt do any of this foolishness when i had the venture heads on it....

edit*

hmmm, that gets me thinking......i wonder if maybe my fuel pump is overpowering the needles? that would be out there in possibilities but im open to any logical thoughts right now....

Metal tips?
I don't think so.

 

[great white]

Metal tips?
I don't think so.

yes,metal tips. this is an xvz12, not an xvz13 or vmx12. 83-85 is the same as the xv535.

part no. 22u-14190-15

tip material is irrelevant. its matched to the seat its used in.

 

[great white]

well, did a live "wet test".

holds at 17-18mm.

so its not the pump over powering the seats.

ii have to be missing something simple her and i just cant see it......

 

[caseyjones955]

Im reaching here, are the needles able to seat in the emulsion tubes? Like compatibility-wise, ie vmax needles in Venture carbs, different barrel dia = needles incorrect "reach".

Reaching even further, vmax heads/cams on venture block with venture exh and airbox. High flow top end fighting the low rpm calibrated bike bits. I have been looking into frankenbike configs and couldnt find that as a proble for anyone. Its to bad you dont know someone with a known good vmax carb rack to test fit.

Edit, I know you prolly covered thos but what about an actual vacuum reading from each intake tuning port or the LP vac leak proceedure. I had some funkyness over a tuning port plug with a split along the top, impossible to see but found with WD40.

 

[blaxmax]

yes,metal tips. this is an xvz12, not an xvz13 or vmx12. 83-85 is the same as the xv535.

part no. 22u-14190-15

http://www.ebay.it/itm/VALVOLA-A-SP...714511?hash=item3d1abec34f:g:PlcAAOSwXSJXOu0P

tip materal is irrelevant. its matched to the seat its used in.

No I know they exist I am saying I would not use them.

 

[great white]

No I know they exist I am saying I would not use them.

they work fine and they aren't subject to the wear rubber tips see.

They also don't take a set to the seat and stick (unless they corrode and then you have other more pressing problems).

I'm chasing down a problem here, not looking for personal preferences.

 

[great white]

Im reaching here, are the needles able to seat in the emulsion tubes? Like compatibility-wise, ie vmax needles in Venture carbs, different barrel dia = needles incorrect "reach".

reasonable thought, but the needles are oem for the carbs as are the emulsion tubes.

Reaching even further, vmax heads/cams on venture block with venture exh and airbox. High flow top end fighting the low rpm calibrated bike bits.

I'm testing without airbox at the moment and still the fueling problem. Another reasonable thought though.

I have been looking into frankenbike configs and couldnt find that as a proble for anyone. Its to bad you dont know someone with a known good vmax carb rack to test fit.

Puzzled me too. Nearest guy who woudl have a rack I could test with is at least an hour and a half away by highway.

Edit, I know you prolly covered thos but what about an actual vacuum reading from each intake tuning port or the LP vac leak proceedure. I had some funkyness over a tuning port plug with a split along the top, impossible to see but found with WD40.

Same with either the plugs or the synch tool. I've already chased the boots and other sources with spray to see if it's a vacuum leak problem. Nada.

My carb holders are old and cracked though. Ordered new ones a while ago and should show up this week just in case.

 

[great white]

Alrighty!

It's been all day again and now getting late.

I decided to throw all the specs and tests in the manual out the window and go for a hail mary pass.

I set the dry float levels to 1.125 (as mentioned in the carb sticky) buttoned it all back up and cranked it up.

All the carb needles are "dry", the idle screws are behaving as expected to adjustments, it's balanced and sync'd, idling smooth and responds to throttle well.

I haven't even attempted a wet level test.

I'm going to throw caution to the wind, put it back together and road test the sucker tomorrow.

If it responds normally and runs well I'm probably just going to leave it alone, other than a little tweaking to bring things like the idle mixture within acceptable operation....

 

[caseyjones955]

HELL YEA! Ill be optimistic for ya, It sounds promising.

I recently set mine to 1.125" exactly, never fussed with wet levels and I had to start over with jets & needles but its laying more usable smooth nasty power down than ever.

Are you able to adjust needles without pulling the rack every time?

 

[great white]

HELL YEA! Ill be optimistic for ya, It sounds promising.

I recently set mine to 1.125" exactly, never fussed with wet levels and I had to start over with jets & needles but its laying more usable smooth nasty power down than ever.

Are you able to adjust needles without pulling the rack every time?

Nope. pulled and split everytime.

not really something you can do on the bike.....

 

[caseyjones955]

Damn, you have to split the rack just for needle adjustment? Maybe you'll get lucky and get it really close first time out. Ive been lucky that way but I had a lot of guidance from others here.

If you get sick of all the hassle just PM me the address and ill come take it off your hands. Im a thoughtful guy that way.:clapping:

 

[great white]

Damn, you have to split the rack just for needle adjustment? Maybe you'll get lucky and get it really close first time out. Ive been lucky that way but I had a lot of guidance from others here.

If you get sick of all the hassle just PM me the address and ill come take it off your hands. Im a thoughtful guy that way.:clapping:

If you think that's bad, consider this: since its in a Venture frame and the top frame rails don't pop up as high over the carbs as a VMax, I have to pull the front engine mounts and lower the front of the engine in order to get enough clearance to pull the carbs out of thier rubber holders since the vboost make the carbs sit too high for the Venture frame.. I also have to other loosen the exhaust or remove it in order to to get the clearance to rotate the engine down in the front.

You have to pull the float out and bend a metal tang to adjust float height. You could do it in the bike, but it would be a major pita. Can't do dry float height either since the carbs have to be upside down to do the measurements....

 

[caseyjones955]

If you think that's bad, consider this: since its in a Venture frame and the top frame rails don't pop up as high over the carbs as a VMax, I have to pull the front engine mounts and lower the front of the engine in order to get enough clearance to pull the carbs out of thier rubber holders since the vboost make the carbs sit too high for the Venture frame.. I also have to other loosen the exhaust or remove it in order to to get the clearance to rotate the engine down in the front.

You have to pull the float out and bend a metal tang to adjust float height. You could do it in the bike, but it would be a major pita. Can't do dry float height either since the carbs have to be upside down to do the measurements....

I knew there was more to it for the Venture but had no idea it was that much. I had to pull and split the rack for dry floats on the max but its fairly quick. Ive had the rack out a dozen times and split a handful of times. Honestly sick of doing it but im probably a needle adjustment or two away from done but that can be done with carbs on the bike.

Hopefuly its close enough to finish dialing in without more rack removal. I guess I now have an idea what to get psyched up for.

 

[DMAN999]

^ This thread (and the Honda Magna guys that have to jump through hoops to do carb work too) is Exactly why I appreciate the ease of working on my Vmax.

 

[great white]

^ This thread (and the Honda Magna guys that have to jump through hoops to do carb work too) is Exactly why I appreciate the ease of working on my Vmax.

I've got a v45 interceptor too.

Only hard part is getting the carbs in and out of the carb holders.

The Yammy holders are at least all vertical and fairly easy to get the carbs in and out. The v45 has them all at an angle and getting those f-ers in and out is pure hell...

 

[great white]

I knew there was more to it for the Venture but had no idea it was that much. I had to pull and split the rack for dry floats on the max but its fairly quick. Ive had the rack out a dozen times and split a handful of times. Honestly sick of doing it but im probably a needle adjustment or two away from done but that can be done with carbs on the bike.

Hopefuly its close enough to finish dialing in without more rack removal. I guess I now have an idea what to get psyched up for.

A couple guys have gotten around it by "dinging" the frame rails right above the rear carbs to give them the inch or so needed to get the carbs out.

I refuse to sacrifice the rigidity of the tube so I have to drop the engine for clearance. Sure, its a PITA, but once the carbs are sorted I won't have to pull them very often. And I'm getting pretty good at the whole process (not by choice though).

It's literally less than and inch you need to get the carbs out. It's the added height of the vboost manifolds that does it. VMax frame is built a little higher in that area.

Lots of other little things have to be moved, shaved and tweaked to be get all to fit in a Venture frame, but it will fit.....barely.