Tuning Woes - 2005 Zuma

[jack667]

Edit - problem solved.  See post #3.






Hi - I'm trying to get to a good place with my Red 2005 Zuma.  All the build info is in my sig and I'll paste it below as well.  It seemed to be running lean with the 90 main jet and I went to 100 and then that seemed too rich.  It's amazing how much difference 5-10 increment makes.

The 95 from my jet kit was in my other Zuma with a similar build (also in sig) so I decided to buy another jet kit.  While I was shopping for that, I also bought a kit with 7 1" holes for the airbox.  I knew this would lean it out but I didn't know how much.  

When the parts came in, I went for the dreaded 2-at-once mod approach. 

I drilled all 7 holes in the airbox, and added the circular inserts that had some foam/filter in each.  And then I tried the 95 (lean), 100 (lean), 105 (lean), 110 (lean), and 120 (lean).  I guess those holes make a big difference!  The best of these scenarios was the 110 main jet.  Speed was awesome and the temp was under my threshold of 350.  It's the only test I did where I didn't need to ease back on the throttle to keep temps in check.  

Since 4 of the holes are on one half of the airbox cover and 3 are on the other side, I figured I'd grab my spare airbox and swap the side with the 4 holes, back to stock.  This was with the 120 main jet in.  The idle shot up like crazy, 4500-5000 when I started it up.

So I put the airbox back to the was it was with the 7 holes and tried the 125 main jet.  It went so slow, I didn't even bother going out of my neighborhood.  

I really thought I was making progress with the 110 jet, and almost home, but then I took that step back and I'm now lost.I'm running out of plugs and tearing my hair out a bit on this project.  I figure I should see if you guys have any ideas, or maybe answer a couple of Q's:

1) The one curious / inconsistent thing in my test is where the temp went up when I increased the main jet from 110 to 120.  Any ideas on that one?  

2) I think my next step is to go back to stock airbox and try to get it dialed in with that.  Does anyone have a better idea of what to try next?

3) Am I missing something?  

Thanks in advance!



Set-up:  Red 2008 Zuma 50. Malossi Sport BBK, Uni filter in stock airbox, Dellorto 17.5, Malossi Reed Cage, Yasuni R unrestricted, Malossi MultiVar, 5g rollers, fan, belt, 107mm delta clutch and bell combo. TTO temp & tach,  Just added:  14/42 gears for ~11.0 final drive

[oldgeek]

I would go to the stock air box, snorkel removed, no extra vents. There is just no need for them. I would also refrain from adding vents to the non filtered side of the air box. I realize the vents you have are filtered, but those filters have a nasty habit of getting sucked into the motor.

It is amazing how easy it is to upset the airflow and completely ruin your tune.

And what do you mean by "UNI filter in the airbox" got a picture?

[jack667]

oldgeek - Thx for the response. I just got back from a ride with the stock airbox, that Uni filter, and the 95 jet.

The Uni filter is the same 'form factor' as the stock filter element, just with the UNI brand and all their awesome power advantage!!

The bike ran the full 5.5 mile test ride with really good speed, and max temp of 323.  Except for while in my neighborhood, I ran almost the whole ride at WOT.

Curious if I could be doing better from a tuning perspective? Any ideas?  It was wet and windy.  

I use the Strava app for checking speed and here are some photos:

[jack667]

See below for probably my best graph on speed, but it was running a bit lean here with high temp of 340. It was from earlier today. This was the one with all the holes and the 110 jet. Maybe I could just have the holes on the side of the filter box away from the engine, so the main filter element would protect things... Seems like there's some room for me to improve on the situation above
(btw - need to ignore average speed as there's some time sitting in my driveway with the clock ticking, before and after the ride.  Also, I stop halfway for a variable length of time before heading back home)
Also, I'll bet some of the variability is due to shortcomings of the app and GPS, maybe due to cloudy weather.  The smoothness of the speed graph above is probably a red flag - not enough data points.

[ryan_ott]

Just use the stock air box. The stock filter will add a slight amount of richness and the Uni filter will lean slightly. When using air boxes or tuning, more is not always better, less is more or so I’ve found.

I’m using a stock box with one 1/2” hole drilled and I’m only using a 88-92 depending on the temp and cylinder I’m using at that moment. I’ve also run some lower end hyper race cylinders with stock air boxes. They flow plenty.

[jack667]

Jan 13, 2019 17:54:26 GMT -5 ryan_ott said:

Just use the stock air box. The stock filter will add a slight amount of richness and the Uni filter will lean slightly. When using air boxes or tuning, more is not always better, less is more or so I’ve found.

I’m using a stock box with one 1/2” hole drilled and I’m only using a 88-92 depending on the temp and cylinder I’m using at that moment. I’ve also run some lower end hyper race cylinders with stock air boxes. They flow plenty.

Sounds good - thx. I should probably leave well enough alone at this point on this red scoot.
I need to get back into the black one. Primary gears, tweaking tuning possibly. And then I’m going to work on the throttles.