Keihin PWK

[Rare Scottish Tree Badger]

I've just recently acquired my Banshee which has been prepared and proven in MX racing here in Scotland.

 

My dilemma:

 

The engine has had the standard head skimmed and a "Full Race Tune" port job for MX, but the carbs are still standard Mikuni 26's. Although I'm pulling great power in all areas, I'm sure the motor would benefit from a larger carb setup. ... I just don't know how big to go.

 

All mods in my profile, but the important ones are as follows: Doma Racing Exhaust, K&N filter with lid removed. .... Jetting: 270 mains, 25 pilots, Needle on #5. (Never above 1000ft and our pump gas is 97 Octane).

 

I'm looking at the Keihin PWK 28's, but should I really be looking at 30's or 33's.

 

Any opinions would be much appreciated.

 

Rare

[cbryant_2]

LRD has the 28PWKs that are taper bored to 30mm. They have great accelleration when used with v-force reeds.

[Duninshee]

LRD has the 28PWKs that are taper bored to 30mm. They have great accelleration when used with v-force reeds.

 

What he said. The 28PWK bored out to 30mm would be a great additon to your bike. I am putting them on my bike as we speak.

[locogato11283]

i wouldnt go any bigger than 30mm for a bike thats only used for mx. sounds like that carb would work good for you.

[Rare Scottish Tree Badger]

What he said. The 28PWK bored out to 30mm would be a great additon to your bike. I am putting them on my bike as we speak.

339765[/snapback]

 

So why not put 30's on in the first place? Or is it a benefit to have this taper boring? Or perhaps the characteristics of the 28's are better for our applications than the 30's. ..... ??

 

Rare.

[Duninshee]

Keihin doesn't make a 30mm carb. So inorder to get this you have to get the 28mm bored out to a 30mm.

[Rare Scottish Tree Badger]

Keihin doesn't make a 30mm carb. So inorder to get this you have to get the 28mm bored out to a 30mm.

339782[/snapback]

 

Ah, I see!

 

It makes sense now about boring to 30mm.

 

So is "taper boring" just a term for a straight bore, it's not actually tapered?

 

I'm not a machinist, and our meanings of words can be a little different this side of 'The Pond'. ....... You've got 'hoods', we've got 'bonnets'. You've got 'trunks', we've got 'boots'. You 'ship' and we 'post'. 'Zip Codes'/'Post Codes', etc., etc.

 

Rare.

[Duninshee]

I am fairly sure that they are actually tapered. I just told the machine shop that I wanted them taper bored and they said no problem $80 please.

[FORMULASPEED]

Is taper the same as ovaling? Cause then If its ovaled the velocitys would change

at different throttle positions if you know what I mean. Kind of like having small an big carbs in one.

[rocketboy]

theyre oval bored to 30 mm i have em. they remove stock from the tops of the carb bodys for topend performance with the bottom end grunt ,just buy em theyre kickass and will work great on a agressivley ported bike as well as mild mx bike too

[Rare Scottish Tree Badger]

Thanks for all your help, guys.

 

Pretty much decided to go for the 28's and a set of V-Force 3 Reeds.

 

I'll run the 28's the way they are at 1st and then have them bored to 30mm. I'll get more info. at the time when it comes to getting them bored.

 

 

Rare.