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

[TourMax]

Well, second test ride complete.

Bike is definitely running better. Smooth and strong.

Burned off a half tank. Small sample size, but it's the same as the last so it's relevant. Got 100 Kms when gauge hit 1/2 tank.

That calculates out to 29 mpg. That's up 2 from 27. Not even sure I'm going to call that an improvement as 2 mpg can be a difference in how much it was topped off.

There's at least another 5-10 mpg hiding in that engine somewhere and I'm gonna find it. Also need to go through the other possible culprits again: brakes drag, etc.

What a PITA this thing is turning out to be. Money, time, effort, sanity, etc......


This is turning into a knock down slug fest right to the very end and I'm just too stupid to give up.....

 

[VMAXXIMUM]

Small business owners across the land tell themselves that every day.

 

[Redbone]

Stick with it you're close to having it worked out, besides testing is fun!

Well, second test ride complete.

Bike is definitely running better. Smooth and strong.

Burned off a half tank. Small sample size, but it's the same as the last so it's relevant. Got 100 Kms when gauge hit 1/2 tank.

That calculates out to 29 mpg. That's up 2 from 27. Not even sure I'm going to call that an improvement as 2 mpg can be a difference in how much it was topped off.

There's at least another 5-10 mpg hiding in that engine somewhere and I'm gonna find it. Also need to go through the other possible culprits again: brakes drag, etc.

What a PITA this thing is turning out to be. Money, time, effort, sanity, etc......


This is turning into a knock down slug fest right to the very end and I'm just too stupid to give up.....

 

[TourMax]

Stick with it you're close to having it worked out, besides testing is fun!

Not completely sure where to go now though.



Dropping the needle another notch will make it full lean on the needle. Seems a bit extreme considering this is essentially a stock Vmax engine.



Specs:


pilot: 42.5, screws 3-3.5 out.
PAJ1 : 90
PAJ2: 180

Main: 145


Have to go pull the plugs now that it's cooled and see what they look like.



I've toyed with dropping the main a size and see what that does. Mains shouldn't be in the mix at the throttle settings I'm running at, but there is always "cross talk" over the circuits. The main is so big though (comparatively), it shouldn't have any appreciable effect on the midrange....

 

[TourMax]

So, plugs:

#1

#2

#3

#4

Perfect?
Well, no.
But certainly close enough to NOT explain the crappy mpg.

So lets look at general things that can cause poor mpg. Brakes top the list of possible culprits to cutting mpg by drastic amounts.

Rear wheel: spins fairly freely. Considering its got a differential attached to it that is.

And then, checking the front wheel.....squeeeeaaaak!

Aha! Brake drag on the front wheel! Wont even spin a 1/4 turn after you give it a spin.

Seems one of my r6 calipers has a piston somewhere that tightened up while it was sitting all these months. That will kill mpg faster than you can say “damnit”!

So now I’m wondering if i am going to take them off and clean them, or just swap on a set of gold dot R1’s i have waiting for my FJ1200....

 

[TourMax]

I decided I didn't want to mess with rebuilding calipers right now so I tossed the gold R1 calipers on, bled them and went for a ride.


Bike is definitely "zippier". Hits 75 mph (approx 120 kph) before I know it now.


The Mpg is significantly better, although I haven't filled and calculated yet.

The fill before the caliper change I would barely hit 50-55 kms before the gas gauge would come off the full mark. This time, it hit 75 kms before it started dropping off the full mark.

Before the caliper swap, the gauge would dip below half tank at or just before 100kms. After the swap, I'm sitting at 97 kms and I'm still one-two bars above the half mark.

For reference, the venture fuel gauge is a set of "bars" that drop as fuel is used. There are 6 bars on the gauge, with the full mark including the long neck part of the venture tank. Like so:

So it's better. how much better I don't know yet. Tomorrow, I'll run off a good chunk of the remaining tank, refill and then calculate.



It's over 30 mpg for sure. It's just a matter of how much over.


I'm in the home stretch now with it running right and mpg at least half decent. Now it's just a matter of tweaking and dialing it in to it's optimum...

 

[one2dmax]

That's an interesting find for sure! The gold special edition calipers work far smoother then the blue ones since they have an antistick coating on the aluminum pistons (vs plain polished steel).

 

[TourMax]

Alrighty.


Admittedly, these are small mpg samples, but they are all on the same loop, same speeds, etc so it's a relevant comparison.

Burned off 114 kms. Filled up.

Calculated: couple decimals over 34 Mpg.

That's a decent improvement considering I started at 27 mpg. it was down around 20-25 last year.

34mpg works out to just a bit over 270 kms (170 miles) on a 5 gal tank. Before the “vmax-ification”, i used to start looking for fuel around 225-250 kms (approx 140-150 miles). So its pretty much back to what it used to be.



Drive-ability is pretty good too. Chugs along happy as a clam at 3-3500 rpm, pulls cleanly from 1500-2000 in any gear (except od 5th, too sluggish) and rips from 6grang to redline lickety split! Nothing to complain about anywhere there for sure.


So it's decent "as is" now. Certainly perfectly usable. Most 83-92 Venture's regularly run in the mid 30's for mpg so even with the VMax engine, it's in the ballpark.



But there's more mpg hiding in there, I know it. Should be about 5 more mpg in it. It's just a matter of fine tuning it out of it....

 

[TourMax]

Burnt off another tank.

29 mpg.

But: pretty sure i got more fuel in it than last time, so its suspect.

But i’m also nowhere near what a stock venture should get on a tankfull. I should be out around 300kms on a tank and right now it wont crack 200.

One thing that makes it difficult is the venture tank has a long internal “neck” meant to allow for space at the top for expansion. But it has a tiny hole to allow for filling to the highest possible level and still leave some expansion space. What it really ends up doing is make it impossible to fill to the same level every time. Making it worse is that part of the tank is lager than the rest of the tsnk, meaning it can hold a significant amount of fuel.

So this weekend, I’m getting out the grease and the deill and opening up that stupidly tiny hole to something like 5/16 or 3/8. Small enough to still do its job, but large enough to make filling faster and repeatable levels possible.

Mpg is still off, but have to eliminate that possible calculation error point so i get an accurate idea of where I am before messing with stuff again.

Riding is still fun though. Yesterday i popped on the cruise control, turned on ELO in my BT headset and was able to actually stand on the pegs and just enjoy the wind....might have looked a little odd as I rode by though...

 

[TourMax]

Bike has been languishing in the back of the garage for a while now. I honestly just got tired of working on it.



But back to it, I tore it down and went with 135 main jets, put the needles back to center clip and then set up the idle on the 4 gas.



Runs pretty good. Maybe a little fat in the midrange as it is a little soft on heavy throttle.



I'll get some km's on it and see what the mpg is like.


I also still have the "drilled" PAJ1 and 2 in there. I ordered up a set of new jets and I'll pull out the drilled ones for the (hopefully) more precise mikuni jets. I also ordered one size up and one size down for each.


I'll leave the adjustments "as is" until the new PAJ's get here. No sense adjusting for the drilled jets and then have it go all "cattywhompass" on me with the Mikuni's.