Time for the dyno and I have questions

[cjmeg]

Greetings all.
Talked to my dyno guy today, who worked for Yamaha when the Max was introduced.
He has done only 3-4 Max's, usually they have been messed with (like mine).
The last one had flatsides, which he ended up with 135hp at the rear (I wish)

In order to make his work a little easier, I want to identify my bike's setup.

So....
Stock airbox and filter, y removed.

Jet under diaphragm (PAJ2?) Mikuni #051
Jet in "top" of carb (PAJ?) Mikuni #090
Main Jet large Mikuni style has RD 160 written on it
Needles taper to a fine point, are adjustable, and are 4th clip from the bottom. Also have a shim washer under them (between the clip and a plastic spacer that seats into the slide.)
Mixture screws 3.5 turns out.
Carbs balanced.
Vboost is removed, straight tubes installed.
Vboost controller still there (does it need to be?)

Kerker system, can is app 3" dia, has a spring-loaded insert, and a washer 2/3 down (inside the muffler) with an (approximately) 5/8" hole in it..

Is this a stage 7 kit?
By whom perhaps?

Bike idles like it's rich, soggy in the low/mid range
Plenty 5000rpm up, gives me 45mpg on the highway.
(The dyno guy told me when I told him the mileage that if I was concerned about economy, then I shouldn't have bought a VMax!! :rofl_200

I'm not looking for HP gain (much), just wanting to make sure it's doing the best it can do..

Any info that would help this tuning ledgend to make my toy go faster gratefully received..

 

[maleko89]

You'll have a torque dip in the midrange w/o the vboost. How did you sync the carbs with running vboost wide open?

The 160's under the slides aren't stock. Stock air jet there is 170's so you'll be a little rich off idle. 3.5 turns isn't too bad for mixture screws. You might be able to turn those in a tad to get rid of rich idle. I would see what you have for main jets. Stock mains work best for stage 7 and Kerker 4-1. Check float levels too. All should be the same at either 16 or 17 mm.

Dynojet is the only place selling stage 7 kit.

For needles are they 2nd groove down from blunt end? That should be close. In the Carbs section check the sticky's out. ONe of them explains how to test for lean or rich needle.

 

[cjmeg]

Just been wandering thru' da posts, know some more stuff (handy site this :eusa_dance
Needles are definitely stage 7 type
Main air correctors look like?.
Slides don't appear to be drilled: how do I tell?

 

[cjmeg]

"How did you sync the carbs with running vboost wide open?"

Using a weber-type sync tool as you suggested. :biglaugh:
Really easy once I used the correct carb as the base (non-adjustable) carb :bang head:
And my neighbors didn't complain: just as well.

Jet under the slide #051
Main jet RD #160 (inside the carb under the float)

Needle is 4th clip from the sharp end, seems to pass the rich/lean needle test
Am I reading these right Mark??:ummm:

 

[maleko89]

I'm suspect of the one under the slide. 051 is rich regardless if it's a Dynojet or Mikuni jet. Leave the mains for now. Make sure the dyno as an a/f monitor. If it's richer 13:1 then decrease the main jet size. Shoot for 12.75 - 13.25:1.

Ah, Weber. Great!

 

[cjmeg]

Thanks Mark!!
It is a Mikuni jet (small square embossed on it) Stock size should be?
Will continue to advise as it all unfolds :clapping::clapping:

 

[maleko89]

Stock are:
PFJ: 37.5
Main: 152.5
PAJ1: 90
PAJ2: 170

You're welcome!

 

[one2dmax]

sounds like a hybrid kit. Needles may be factory pro.

 

[cjmeg]

"sounds like a hybrid kit. Needles may be factory pro."
I did wonder.
Also thought that maybe " 051 " is in fact 150 :bang head::bang head:
They (the needles) look like Mark's post showing stage 7 needles..
The more I can give the dyno guy (i hope) the easier his job will be..

 

[cjmeg]

Feedback today from the dyno guy.
Means that I might get it back soon!

Apparently it is running seriously rich.
He has adjusted the needles, but will rejet tomorrow and run it again.
It has "RD" #160 main jets: he's thinking 140 ish will be more along the right lines.
Will keep ya posted.

 

[cjmeg]

I has a result! :clapping::clapping::eusa_dance:
And yes I'm happy! :biglaugh:
Before dyno, 101hp
After : a touch over 115hp

Main jets now 140

Still running stock air filter box and filter (no Y piece)
Will need to up the needles 1 clip when I put an K&N in.
He has it running a touch lean at low revs, but he is not concerned, and he is an expert, (with water cooled high performance bike engines) so I'll trust him.

(This guy can get 180hp plus out of a ZZR1100 engine without major surgery: very, very clever)

Evidently only rich above 8500rpm, so if I sit on 100mph, I'll use a s#$#load of fuel. Mmmm, not too worried about that one.:worthy:
It develops a death wobble at 110mph, better tyre selection will (evidently) fix the problem..
Will post complete setup as I know it!

 

[Shuriken]

It develops a death wobble at 110mph, better tyre selection will (evidently) fix the problem..
Will post complete setup as I know it!

My bike has the 110 death wobble..... NOT fun...

 

[naughtyG]

It develops a death wobble at 110mph, better tyre selection will (evidently) fix the problem..

Make sure to check out the state of your steering bearings and torque them properly first - mine also had the death wobble in a straight line above 115mph, and since doing the furbur fix and torquing the bearings properly, I've gone as fast as 135 without any wobble in a straight line!

That's with very worn Dunlop Qualifiers, and I can't do any turn above 85mph as that induces an instant death wobble too..

New Shinkos should be on my doorstep tomorrow - I'll give ya an update on how much they help!

You can see the current state of my '86 steering bearings here
http://www.vmaxforum.net/showthread.php?t=5094&highlight=bearing&page=4
the races are still smooth to the touch and the bearings felt fine, so I put them back in and will decide on replacing them after I find out how much the new tires help..