Oh Boy, fighting the jetting fight......:(

[TourMax]

Spent yeterday tidying up the battery relocation and things like the vboost bracket, map sensor bracket, starter solenoid relocation, wire and cable routing, etc.

Once back together, I hooked up the carb stix and ega. The 40 pilot jet needs between 3-3.5 turns out. That gets me at about 2.40-2.50 CO and a nice stable idle of 980-1030 rpm (measured on ignitec software). Accepts throttle nicely after about 30-60 seconds of choke. Needs just a hint of choke to ease starting at 15C, so that seems good. 3-3.5 turns would seem to idicste the jets are a touch small, but at least they adjust normally, whereas the 42.5’s were in the 3/4-1 turn range and the 37.5’s were 3.4-4.5 out. I’ll see if that is fewer turns out with the 40’s when the stock vmax airbox goes on.

Lambda is in the .8-.9 range. A bit on the rich side for lambda, but good for a bike as CO and lambda put it around 13 afr. 14.7 may be considered “ideal”, but i dont like being that close to the lean side of lambda on a carb fed engine.

HC continues to be troublesome, same with CO2. 1 and 3 are pretty good with HC playing around 200-300 and CO2 at 11-12. But 2 and 4 have HC up around 800-1000 and CO2 down in the 7-8 range. That would indicate very poor combustion in 2 and 4, if CO was also high. But since CO is the same in 1,2,3 and 4 and compression checks reveal 160-170 across all 4, I'm leaning towards a problem with the front head. The front and rear heads came off different bikes and while the valve guides seemed to check out fine, I’m thinking the valve seals are bad (or going bad since there no blue smoke). Deteriorating valve seals letting too much oil past could explain the high HC and low CO2 readings on 2 and 4. Thats a reasonably easy fix if thats what it is. Cams out, pressurize cylinder, depress the spring, change the seal. Well, sounds easier than it is i guess... :icon_rolleyes:

By the tracking number, looks like the vmax airbox will be delivered tomorrow.

I won’t have a stock filter to install yet, but from what i understand it wont make a huge difference. Seems the main restriction is the box itself (i think it was “vmax guru” site i saw some testing data).

I’ll pull out the air correctors today and drop the max airbox on it tomorrow evening.

Fingers crossed. I’m getting pretty tired of chasing this thing...

 

[TourMax]

Grabbed this while I was at the shop yesterday

Thanks, thats great!

Looks like I’m going to have just enough room. Good thing too as the battery is as far forward as its going to go....

 

[TourMax]

Well SOB!

Started it up this morning and turned on the ega just because it was still hooked up.

#2 HC off the scale, CO2 stupid low and no response to the mixture screw.

Totally po’d, i shut it down n and pull the plug. Wet.

Test the spark with the ignitek test option and a nice fat blue/white spark.

Wtf?

So i yank the airbox to get ready for the vmax airbox and when i look down the throat of #2 theres liquid fuel pooled on the throttle blade. A closer look at the slide needle reveals fuel dribbling out.

So it looks like the float neddle is buggering up somehow, yet not enough to flow out the overfloas.

Jesus, it never ends.....

 

[Bill Seward]

If there was a reasonable way to modify these bikes to fuel injection, and not have to dump a boatload of money into them - I'd love to do it. One big *** throttle body, simple and reliable (and inexpensive!).

 

[TourMax]

If there was a reasonable way to modify these bikes to fuel injection, and not have to dump a boatload of money into them - I'd love to do it. One big *** throttle body, simple and reliable (and inexpensive!).

Agree.

I have looked at machining a replacement “plug” for the slides and popping an injector in each.

Always stopped at the management system.

Gets very pricey for components, very fast and its all custom built.

I seem to recall there was a system avsilable at one time from a guy who built vmax trikes or something like that.

On the upside; whatever was causing the #2 flooding issue seems to have cleared. Time to change out the fuel filter I guess, just in case.

Also pulled out the air correctors in prep for the vmax airbox.

Just for the hell of it, i turned the ega on once they were removed. Mixture screws went from 3-3.5 out to 2-3 out, HC/CO2 and lambda got better as well. That was without the airbox at all. Then i threw the airbox on just for giggles and it actually leaned the engine out on all 4 cyls.

Wtf?

Should be interesting to see what happens when i toss the vmax airbox on it.

One thing is for sure: I’m done messing with the intake side of this rig. It just doesnt respond “normally” like other cv carbs do to the same modifications.

 

[TourMax]

Ah, here it is. “Roadstercycle”:

http://roadstercycle.com/yamaha_vmax_fuel_injector_cv_car.htm

Ya know, I’ve got a bunch of older gm ecms, some obdii pcms and software to program them, as well as a couple gm tpi and ford 5.0 efi systems. Also, a couple spare racks of venture carbs...i wonder.....:hmmm:

 

[TourMax]

Airbox is installed. It fits, but it’s all very compact in that area now.

Dont have a filter yet, but i still popped it on and ran the ega.

Much better results.

#2 still has something funky going on by the readings and i need it 5-6 turns out to get the co to adjust. I’m now thinking some junk has found its way into #2 carb since it started flooding yesterday and now the mixture screw is not behaving normally while the other 3 carbs are. Would seem something.may have made its way into the pilot circuit. Maybe a foake of rust of something.

But i think the gmax airbox was a big missing element here. I havent ridden it yet, but things seem much smoother, a funky little idle rpm “wobble” is gone and things are adjusting as i would normally expect.

 

[Fire-medic]

Wild Bros. had a system for the VMax, Sean Morley had one. I think it was problematic.

Checking the Microsquirt link you posted, they mention the Wild Bros. system.

 

[TourMax]

Popped #2 mixture screw out and blasted the circuit with compressed air. Both forward and reverse direction a couple times. Just for good measure, i hit it with carb cleaner also and then finished up with a few more compressed air blasts.

To be doubly sure i was getting good readings, i blew out the ega lines going to the exhaust ports with compressed air. That needs to be done periodically anyways.

Now #2 carb will adjust, although still has low co2 readings and hc on the high side. That usually indicates a poor burn, but co is adjustable as is and lambda agrees with co readings. Plus, screw adjustment cant get the co2 to raise raise but has some effect on the hc. Pretty sure its just a hint of oil sneaking past the valve seals and skewing the co2 and hc readings. When get a chance, I’m going to do the valve seals on the front head.

Now to get the bike back together and take it for a burn to see how it behaves. Wont be far since I’m still waiting for the filter, but it should be good enough to show me if i may need to do a bit more work. Then, when the filter arrives, it should at least be close enough that a few “tweaks” will get it up to snuff.



Bizzare thing was when i popped the bodywork cover over the airbox it actually made the ega readings go lean. Something that should have made the intake tract more restrictive makes it go lean. Go figure....

This bike does everything weird. It’s like it exists outside the laws of physics sometimes...

 

[TourMax]

Ok. Took it for a burn today. Seems pretty good with some areas needing a little more work.

The vmax airbox is in place, but no filter yet. Air correctors are removed. It had just rained, so i was relatively confident the air is as clean as it gets, if not a little humid.

The airbox has cleaned up a lot of the ill behaviour it had. Idle is good. Cruise is good. Side bonus is intake honk is down and its a little more pleasurable to ride that way.

There is a noticeable “bog” if i get it into overdrive 5th at 100 kph and whack the throttle. That takes me out of 1/8 throttle and over the 1/4 throttle transition where the needles come into play. There was also two small “queefs” from the rh muffler on trailing hrottle overruns.

Float levels are a touch low and my needles are adjustable. I could start messing with those items, but I’m going to wait and get the air filter installed first.

At this point, im happy with the direction it is going with the vmax airbox so i’ll keep heading down this path and see where it goes.

Just for grins, i did the fuel calc for the last tank and it was 14 mpg! Lol! Of course, pretty much that whole tank was burnt off at idle trying to get things adjusted properly...

Looking for good drivability and mpg for now. Hp can come later after I’ve gotten a little “payback” (ie: seat time) for all the expense and work so far.

 

[TourMax]

Holy crap I’m ready to burn this thing to the ground!

Since the carbs were all low on fuel levels (20mm on a couple), i pulled them off and set them all to 17mm. Thats leveled on a bench, i use a raised fuel tank (approx 1-2 feet higher than bench) and a wet measurement of levels.

Put it back together and now it runs like crap!

Acting like its rich, starting without choke from dead cold. Except; now the fuel screws wont adjust the co over 2.5-ish and HC is though the roof everywhere!

You would think “rich” (and lamda indicates dead rich also), except that co stalling at 2.5 doesnt match up with any of it. Even 5 turns out makes no difference.

I’m thinking of going up to 42.5 pilots from the 40’s, but im just not sure now....this thing just makes no sense every time I adjust something to specs....and dropping the engine to pull the carbs (venture frame has less clearance than vmax frame due to no vboost on a venture) every time is getting pretty g-d old!

 

[one2dmax]

Float levels can alter jetting requirements to about one jet size per 1mm of float variation. You're detailed testing should validate this.

 

[caseyjones955]

Stories like this are why the Vmax heads/cams/intakes are still in a box next to my Venture. Ill get to it if my Venture does not sell. On the EFI, I recognize the system in the above link. All the tooling, plans, rights and parts were purchased by a fellow on the Venture forum who is machine savvy. 98% sure its the same one. Not sure what hes doing with it but if it may help I'm happy ask him if I can pass his contact info along. I cant get the idea out of my head, like the single carb setup that never quite made it to production. When the cost of the fuel injection is greater than the cost of a fuel injected bike there are some math problems. Ive never found info on TBI systems being tried but for a cost effective alt to carbs...

 

[TourMax]

Stories like this are why the Vmax heads/cams/intakes are still in a box next to my Venture. Ill get to it if my Venture does not sell. On the EFI, I recognize the system in the above link. All the tooling, plans, rights and parts were purchased by a fellow on the Venture forum who is machine savvy. 98% sure its the same one. Not sure what hes doing with it but if it may help I'm happy ask him if I can pass his contact info along. I cant get the idea out of my head, like the single carb setup that never quite made it to production. When the cost of the fuel injection is greater than the cost of a fuel injected bike there are some math problems. Ive never found info on TBI systems being tried but for a cost effective alt to carbs...

If i ever go efi, i’ll make it diy style.

Turning out the inserts on the lathe is a piece of cake. I’ve got a couple sets of the ford injectors lying around. The rest is just a megasquirt setup doing batch fire. Ignition is already handled by ignitek, as it the vboost.

 

[TourMax]

Float levels can alter jetting requirements to about one jet size per 1mm of float variation. You're detailed testing should validate this.

Yessir.

But you would think raising the level from 20 mm to 17mm (ie:richer) would require a smaller idle fuel jet, not a larger one.

Pretty sure I’m not, but maybe i’m thinking backwards here....:ummm:

 

[TourMax]

So, I’m going to take a stab in the dark here.

Fuel level comes up, should get richer.

Co wont adjust past 2.5, hc high, lambda shows dead rich.

Carbs are venture 1300 carbs. Jets are all vmax spec...EXCEPT....paj1. That’s the venture 80 jet.

Vmax 1200 uses a 90 jet.

So, my theory is the smaller paj1 is not passing sufficient air to allow the mix screw to adjust as it should. Less air, richer mix. Would explain the lambda and hc readings.

So, time to order a set of paj1’s i guess.

I do have a couple sets of 80’s lying around though. I might try opening a set up and see if it helps before ordering a set of 90’s. Cant hurt, easy to try and no cost to me.

Paj1 too small could possibly explain why a bigger pilot would give the readings (ie: co wont go past 2.5%) it currently does and sure as heck couod account for the hc and lambda readings. Not enough air for combustion, so tops out at 2.5%. Toying with the idea of swapping back to the 37.5 from the 40 pilot...

 

[one2dmax]

Rarely do we need a larger pilot. Even not needed on the big bore engines.

 

[maleko89]

I have 40’s in mine. I just wanted to try it. It was a waste of time. Tuning of the screws became more finicky and is way too easy to be overly rich at small throttle openings.

Mark


Sent from my iPhone using Tapatalk

 

[TourMax]

Alright. The weirdness just continues....

Drilled paj2 to a 90. Nada. Same behavior.

So i figured I’d blow out the passages, just in case. Pulled the slides out and just becuase i was in there, i looked at paj2.

150.

Ummm, what? That should be a 170 by the parts fish for my 86-92 carbs.

So i pop the cap off my spare 83 carbs to check. Should be a 180 by the parts fish.

150.

What?!?!?

Something screwy is going on here. Unless canadian carbs are different than the listing I’m looking at on parts fish.

So, maybe I’ll take one set of the 150’s and crank them out to 170’s. Nothing to loose at this point...

 

[TourMax]

Yep, seems i stepped on my own pecker somewhere along the way here.

Tossed the carb stix back on it. Sure enough, 1/2 are through the roof and 3/4 are down low.

Seems somewhere along the line here, the sync got out of whack. Probably me pulling the carbs off once and forgetting to recheck it.

So now all 4 are running again. They adjust normally...again.

Hc is still pretty high on all 4, but lambda now shows closer to a decent burn. It all gets better once i get each cylinder in the 3.5% co range, which makes sense...again. Even at 3.5 co, hc is still higher than it should be.

Fuel screws are all out in the 4-5 range. So it seems to be asking for a bigger pilot....again.

It makes sense, so off the carbs come again and in goes the 42.5’s for the 40’s.

Then, it all starts over from step one: synch, idle rpm, ega, back to sync, idle rpm, ega...etc.

I feel like I’ve almost got it, but this thing has “**** punched” me so many times I’m super wary of being “optimistic”...