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PostPosted: Thu Aug 31, 2017 6:23 pm 

Joined: Mon Aug 01, 2011 8:24 am
Posts: 175
Location: Waterloo, IA
I installed UFO's on some stock vm30's a couple of weeks ago. I cut the slides and inserts to have a 3.5 cutaway and I installed a 15 pilot jet. I couldn't get it to be lean enough (mix screws at 2.75 turns out) so I drilled a small hole in the main jet choke. I still couldn't get it to lean out so I tried soldering my pilots shut. I think it leaned out but then I couldn't get it to idle down lower than 1800 rpm and it surged like crazy when I took it for a test ride.

So, I think I am going to give up on the ufo's and add some jb weld to my slides to get back to the 2.5 cutaway unless someone has some insight

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ride hard, ride long, ride safe!
Jason
72 h2 in a 93 Katana
03 cbr600rr
80 kz750 ltd
94 pw50


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PostPosted: Thu Aug 31, 2017 6:36 pm 

Joined: Tue Jul 24, 2012 6:06 pm
Posts: 822
Location: Honolulu
Surging is an indication of lean jetting. My VM30's were rich before and after UFO's. I went to O-4 needle jets and it fixed the problem.

You can read more here: viewtopic.php?f=14&t=11141=h2+needle+jets&start=20#p125345


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PostPosted: Thu Aug 31, 2017 6:42 pm 
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Joined: Wed Jun 13, 2012 9:00 pm
Posts: 790
Location: Eagle Wisconsin
Needle jet and needle play a big part even at idle and take off with those UFOs
Surging is way too lean.
Don't go for high idle adjusting the screws go for good takeoff and good idle rpm richen up the screws a bit and see what happens
On the resource site is a good description of tuning with UFO they realy do change the rules of jetting

How does it run in the needle?
I would try a smaller needle jet those draw a lot of fuel between the needle and the needle jet

Good luck. Running back to safe ground is a good choice too!


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PostPosted: Thu Aug 31, 2017 6:58 pm 

Joined: Mon Aug 01, 2011 8:24 am
Posts: 175
Location: Waterloo, IA
so I should explain why I don't think I could get it lean enough with the UFO's: the bike would fire right up and idle high when it was cold, no choke needed at all. If i let it sit there for a minute or two idling it would slowly drop rpm, to the point that I had to turn the idle screw in to get it to stay running. Same results if i took it out for a ride right away: when I got back to the shop the idle would be way too low to stay running.
Also, the plugs were very black and sooty, way too rich. So, the answer is probably somewhere between the #10 jets (I think I said they were #15's in my original post) and the closed pilots. I'm just not not committed to buying needles and more main jets.

Thanks for the observations, I appreciate it

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ride hard, ride long, ride safe!
Jason
72 h2 in a 93 Katana
03 cbr600rr
80 kz750 ltd
94 pw50


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PostPosted: Thu Oct 05, 2017 3:22 pm 

Joined: Mon Aug 01, 2011 8:24 am
Posts: 175
Location: Waterloo, IA
I un-converted my slides a few weeks ago, changing my cutaway back to a 2.5 from the 3.5 I had when the UFOs were installed. Here's what I did:
I cut a piece out of a soda can, applied some spray-lube to one surface, then wrapped it around my slide using a hose clamp. I made sure to get the piece of soda can flush with the bottom of my slide
Attachment:
IMG_20170907_142722947.jpg


I then mixed up some jb weld and filled in the cutout, using the soda can to mold the jb weld
Attachment:
IMG_20170907_142807481.jpg


Attachment:
IMG_20170907_142640320.jpg


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ride hard, ride long, ride safe!
Jason
72 h2 in a 93 Katana
03 cbr600rr
80 kz750 ltd
94 pw50


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PostPosted: Thu Oct 05, 2017 3:25 pm 

Joined: Mon Aug 01, 2011 8:24 am
Posts: 175
Location: Waterloo, IA
I then made a template using CAD that showed me where to cut to get back to my 2.5 cutaway. I taped that to my slide
Attachment:
IMG_20170907_152158361.jpg


Attachment:
IMG_20170907_152202092.jpg


Then I cut the angle using a dremel.
Attachment:
IMG_20170907_154032797.jpg


It turned out pretty well and the bike seems to relatively run well. I also ended up using #20 pilot jets also. Still trying to get rid of some of the surging on small throttle openings, mainly during decel.


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ride hard, ride long, ride safe!
Jason
72 h2 in a 93 Katana
03 cbr600rr
80 kz750 ltd
94 pw50


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PostPosted: Thu Oct 05, 2017 3:37 pm 
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Joined: Wed Jun 08, 2011 11:34 pm
Posts: 8015
Location: North Central NC
You didn't specify the throttle opening when you're having surging trouble, but you could try raising your needles a notch. I prefer getting good gas mileage to worrying about surging though. My H2 surged when I bought it, and shortly after that I learned how to avoid it with throttle technique and gear selection. Raising my needles a notch eliminates the surging I have, but it also drops it from 30 mpg to less than 25.

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If it surges, that's normal, upshift.


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PostPosted: Fri Oct 06, 2017 12:08 am 
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Joined: Tue Jun 07, 2011 6:37 am
Posts: 9809
Location: Rio Rancho, New Mexico
Get new pilots, you can't solder them and have them work correctly. Do't ask how I know.

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I can teach your triple how to "reed"........
http://kawatriple.com/aylor


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PostPosted: Mon Oct 09, 2017 10:55 am 

Joined: Mon Aug 01, 2011 8:24 am
Posts: 175
Location: Waterloo, IA
Jim
I had been getting less than 25 mpg out of my bike before/during my ufo experiement. If I raise my needles I get really bad bogging at cruising speeds on the highway. It essentially feels like it is dropping a cylinder randomly. If I lower my needles the bike feels really 'dry' and buzzy. I haven't put enough miles on it since taking the UFO's out to get an mpg reading so I am not sure if my current combination is helping in that department or not.

Ja-Moo
Not sure if your post was intended to be funny, I will take it that way though!

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ride hard, ride long, ride safe!
Jason
72 h2 in a 93 Katana
03 cbr600rr
80 kz750 ltd
94 pw50


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PostPosted: Mon Oct 09, 2017 12:18 pm 
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Joined: Wed Jun 08, 2011 11:34 pm
Posts: 8015
Location: North Central NC
You can move the needles in 1/2 steps (1/2mm) with shim washers under the clips.

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If it surges, that's normal, upshift.


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