28mm Keihin - Need a starting point

[Baketown Scotty]

Replaced my 26mm Mikuni carbs with 28mm Keihin carbs and would like some help with a starting point for jetting.  95% of all riding is in sand dunes, Pismo, Dumont and Glamis.  I believe the Mikuni's have 380 main jets and 50 or 60 pilot jets.  Going by memory since I'm working out of town.  Below is what I have.

 

 

1) What type of aftermarket exhaust do you have?  Toomey T5

2) What type of airfilter do you have?  K & N, one for each carb

3) Are you a)running a stock airbox with lid stock airbox with NO lid c) Stock airbox with vents d) no airbox at all

4) What is your elevation?      0 - 350 FT

5) What size pilot jets are you using?        That's my question

6) What size main jets are you using?       Thats my question

7) What temperature is your Banshee jetted for?    It needs to be 70 - 100

8) Do you have a port job?    Yes, I'm told it was a mild dune port job.

9) What kind of carbs?      Keihin

10) What size carbs?        28mm

 

 

Thank you
 

[lastnline75]

45's an 150's get you in the ballpark.

 

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[ATVridinMaNiAc]

45-48 pilot and 150-158 main Is my guess

[Baketown Scotty]

Thank you very much for the help. 

[RadarRacing]

Exactly as stated above. Start about 158 and work down if needed.

[ATVridinMaNiAc]

Yea its better to start off rich.

 

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[sleeper06]

My duneports run 165-168main,50-52 pilot jjh needle 4th clip

[Baketown Scotty]

I started with the pilots at 42, then 45 and ended at 50. Starts easy, idles and no hesitation from 0 up. 

With the mains I started at 158, then 160, 162 and 168 today.  Ran great through all gears, even pulling good in 6th.  Pulled the new plugs after WOT and they are looking pretty shiny.  Should I continue going larger with the mains until I get it too rich?  Or should I be looking elsewhere?

[Strm Trpr]

Have you done a proper Plug Chop?

[Baketown Scotty]

I have not done a plug chop. I will be home this weekend and will do one. Thanks for the help.

[Baketown Scotty]

I did a plug chop after running the 168 mains and everything was still clean and shiny.  Installed 178's last weekend and ran good with a very slight hesitation in the middle.  Looked at the plugs, still looking shiny and new.  I will chop them when I get back home this weekend.  Also going to go bigger on the main jets and try that.  It was 95-100 degrees last weekend so the added heat may have had some effect.  I'll keep going bigger until I start fouling the plugs?

[dave5.0]

If its a play bike that's what I do. Run up till it starts to sputter. Then back down till it runs clean. Then check plugs. Same with needle.

[Baketown Scotty]

It is just for me playing in the sand. I'll get the mains then start fooling with the needle to get mid range dialed in. Thanks for the comments and all the help.

[Ronshee238]

I have similar scenario. I just changed from stock 26. To kehin 28mm .I had 360 mains 27.5 pilots and now I need a starting point as well.i got in frame cpi 19cc domes +7 timing lightened flywheel vforce 2 billet intakes 100 av gas 32to1 klotz individual 2 stage unis I'm at 1400 ft. I need glamis set up tho? Any help?

Edited June 2, 2014 by Ronshee238

[Baketown Scotty]

Installed 190 main jets.  It ran fine and continued to run fine with choke pulled too.  I'll keep going up.