Bored out carb jetting

Hey all,
just finished boring a set of VM26 carbs to 29mm. Bore job turned out great. Got them all cleaned and put back together 17.5 pilots,122.5 Mains and 5DL31 needles with 0-6 needle jets.
Bike is a 77 Kz1000 with a Wisco 1015cc 10.25:1 kit And K&N Pods, Dyna S ign., green Coils and Kerker 4-1 Header.
Put carbs on yesterday, bike starts ok with choke on but once its warm and you shut the choke off it wants to pop on a couple carbs. Seems to idle ok once it's warmed up but it's hard to get started again without the choke.
Used a small propane tank around the boots to check for leaks,but didn't find any. Does,WD40 work better for this? Thought the propane would make less of a mess.

So I was wondering, do you guys think a set of #20 pilots would help the hard starting? Also my carb boots a a little aged. Maybe new ones of those too?

"boring a set of VM26 carbs to 29mm"..... ewwwwwwwwwwwwwwwww..... sweet!

Please inform us you did a write up/tutorial/images on this....

OMR

boring the venturi isn't that difficult if you have access to a lathe and bridgeport type mill. it's cutting the seat deeper for the slide that's the tricky part. I'll post a couple pics later.

"lathe and bridgeport type mill"... Wonder if Harbor Freight Tools has these.... :S :laugh: :laugh: :laugh:

Well I'm confident this post will generate a few interested members in how you accomplished just the same...

OEM 26mm carbs, easily and cheaply available. Hell, I have 2 sets for the KZ1000...

And with prices of the Keihins and Miks going up daily, this would be cool...

dshelly wrote:
Used a small propane tank around the boots to check for leaks,but didn't find any. Does,WD40 work better for this? Thought the propane would make less of a mess.

Carb cleaner works great for checking for vacuum leaks, and no mess when done. Be sure to adjust the idle low as possible during test, makes it easier to tell if there are leaks. Ed

omr,actually harbor freight does sell chinese made lathes and mills.

dshelly,i for one would be very interested in any pics or tips that you used for setup and machining.i do have a mill and lathe and have always been interested in the particulars of boring carbs.
not being familiar with your elevation i can't add anything to help you dial them in,sorry.
leon

Hello, you don't say where your air screws are adjusted(how many turns in/out). I would suggest turning them more to the rich and see if it runs better, if you go all the way rich and it still doesn't help you need bigger pilot jets. also setting your valves to tight will make a bike hard to start when warm(just think outside the box).

Just a thought, but from my (limited) understanding of the Venturi/Bernneli principals, increasing carb bore diameter should reduce vaccum at mixture ports & needle throat... Probly more critical at the needle than mixture as the slide cutout would be a larger factor at nearly closed throttle. Less vac. should require larger jets for same fuel mix volumne. Just my opinion & I could be wrong...G

I think I'll try some larger pilots , check my valve clearances and see what that does. Just wanted some other insight before I order some. Thanks everyone.

dshelly