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Post by pdxjim on Jun 3, 2019 19:17:26 GMT 1
Just getting back into my 4U0 rebuild after finally selling my KH400. Bottom end is now back together with new crank, bearings, seals, etc. Time to move on to the topend. Plan for now is head skim/o-ring/dowel, 'valve pistons, with lite porting/cleanup, Vforce3 reeds with 6mm spacers, etc. Looking towards the carbs, the obvious choices are PWK28 or VM30. They are about the same cost, and I can have the VM30 spigots turned down so they fit the standard manifolds. Which carbs would you choose for a fast roadbike, and why? Ease of fitment, throttle cable compatibility, bottom/mid throttle response, etc are all factors. I plan to keep the oil pump in use. TIA, I'll start a proper build thread here soonish like.
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Post by midlifecrisisrd on Jun 3, 2019 19:25:42 GMT 1
Cases look lovely
Pwk 28's are the weapon of choice for most
Easy to use a standard throttle cable with a tiny mod so no cable or oil pump issues
They are really good for midrange and throttle response
Don't know if the 30's would lose you some mid due to the size
Steve
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Post by dusty350 on Jun 3, 2019 19:32:43 GMT 1
I think you'll find 30's overkill. The 28's will be good into the mid 70's bhp I believe. I asked Mutts some time back as I've got some Pwk 28's , and that was his verdict. Dusty
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Post by pdxjim on Jun 3, 2019 19:46:35 GMT 1
That was the expected response.
Lotsa guys over here run 30-34mm carbs on AC's and Valves/Banshees. Seems waay too big to me but they all claim good results.
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Post by pdxjim on Jun 3, 2019 19:56:01 GMT 1
I assume the PWK28s fit the standard intake manifolds?
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Post by midlifecrisisrd on Jun 3, 2019 19:58:33 GMT 1
Yes they go in fine
Steve
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Post by midlifecrisisrd on Jun 3, 2019 20:07:00 GMT 1
The 30-34 mm on a standard motor is the equivalent of knob size bragging 🤣
Steve
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Post by muttsnuts on Jun 3, 2019 20:50:33 GMT 1
28mms will be fine, got plenty of YPVS motors running 28mms and pushing over 70bhp, so easily capable of delivering enough air and fuel to power a well tuned LC engine. You can also keep the original throttle cable with a small mod or change of the carb elbows, and slo fit oil injector spigots so can keep pump as well.
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Post by veg on Jun 3, 2019 21:06:05 GMT 1
The 30-34 mm on a standard motor is the equivalent of knob size bragging 🤣 Steve Mine are 34mm say no more 🥺
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Post by midlifecrisisrd on Jun 3, 2019 21:12:17 GMT 1
The 30-34 mm on a standard motor is the equivalent of knob size bragging 🤣 Steve Mine are 34mm say no more 🥺 You have been caught exaggerating already today 🤣🤣🤣 Steve
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Post by veg on Jun 3, 2019 21:15:37 GMT 1
😵🙌💪👌👃🐍🦍🐏🐃🥕🥖🦴🚇🗡
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Post by midlifecrisisrd on Jun 3, 2019 21:21:23 GMT 1
Any other euphemism emojis 😆
Steve
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Post by ianboom on Jun 3, 2019 21:29:45 GMT 1
I ran standard rejeted carbs and got over 70bhp, how much power are you expecting to make?
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Post by pdxjim on Jun 3, 2019 22:22:25 GMT 1
28mms will be fine, got plenty of YPVS motors running 28mms and pushing over 70bhp, so easily capable of delivering enough air and fuel to power a well tuned LC engine. You can also keep the original throttle cable with a small mod or change of the carb elbows, and slo fit oil injector spigots so can keep pump as well. Dave, while I've got your attention ... Which Vforce reeds to you recommend for tuned LC barrels running PWK28s? Choices are (of course) V382A (YZ85) which require opening up the cylinder reed boxes to fit, or V384A (RM100) which drop right in with 6mm spacers and the mounting holes opened to 9mm?
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Post by pdxjim on Jun 3, 2019 22:24:47 GMT 1
The 30-34 mm on a standard motor is the equivalent of knob size bragging 🤣 Steve Bigger is always better in America! ... and give our president (small p) a kick in the balls while he's over there please.
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Post by Tobyjugs on Jun 3, 2019 22:25:58 GMT 1
I have a set of 28mm PWK's and they work great. When i compare them to the standard Mikuni's the PWK's feel and look like inferior quality. Thats probably down to me though. Be careful as some of the older carbs have fixed needle jets and these can be worn out.
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Post by pdxjim on Jun 3, 2019 22:32:59 GMT 1
I have a set of 28mm PWK's and they work great. When i compare them to the standard Mikuni's the PWK's feel and look like inferior quality. Thats probably down to me though. Be careful as some of the older carbs have fixed needle jets and these can be worn out. I'll be using new genuine Keihin if I can find them for a reasonable price. Separating the real from fake is a bit of a gamble tho it seems.
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Post by rigga on Jun 4, 2019 22:46:49 GMT 1
Which Vforce reeds to you recommend for tuned LC barrels running PWK28s? Choices are (of course) V382A (YZ85) which require opening up the cylinder reed boxes to fit, or V384A (RM100) which drop right in with 6mm spacers and the mounting holes opened to 9mm? Interesting ....
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Post by pdxjim on Jun 4, 2019 23:51:28 GMT 1
Which Vforce reeds to you recommend for tuned LC barrels running PWK28s? Choices are (of course) V382A (YZ85) which require opening up the cylinder reed boxes to fit, or V384A (RM100) which drop right in with 6mm spacers and the mounting holes opened to 9mm? Interesting .... It’s true! Vforce3 V384A drop right in to LC (and AC) cylinders. Just need opening the mounting holes a bit to 9mm and using a 6mm (ish) reed spacer. That said, the tuners over here recommend opening the intake tract to accommodate the larger V382A's. Typical "bigger is better" as discussed above.
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Post by bare on Jun 5, 2019 4:22:41 GMT 1
I have a set of 28mm PWK's and they work great. When i compare them to the standard Mikuni's the PWK's feel and look like inferior quality. Thats probably down to me though. Be careful as some of the older carbs have fixed needle jets and these can be worn out. Surprised by that..I found Exactly the opposite Keihins are manufactured to a immediately apparent higher standard than my Collection of Mikunis. Which (beyond being 30+ yrs old :-) look quite poorly made. You have Genuine keihins? or one of the several low grade Clones being sold on as Keihins? Only asking as I'm not understanding this one at all.
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Post by Tobyjugs on Jun 5, 2019 15:15:21 GMT 1
I have a set of 28mm PWK's and they work great. When i compare them to the standard Mikuni's the PWK's feel and look like inferior quality. Thats probably down to me though. Be careful as some of the older carbs have fixed needle jets and these can be worn out. Surprised by that..I found Exactly the opposite Keihins are manufactured to a immediately apparent higher standard than my Collection of Mikunis. Which (beyond being 30+ yrs old :-) look quite poorly made. You have Genuine keihins? or one of the several low grade Clones being sold on as Keihins? Only asking as I'm not understanding this one at all. Yes Bare they are original Keihin. The Mikuni's have more parts you can adjust and feel heavier in the hand. Its that same feeling you get when you close a door in a cheap car or in an expensive luxury car. They both do their job, it's just that first impression.
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Post by bare on Jun 5, 2019 17:28:51 GMT 1
Ok thanx So weight is a quality criteria.. in a Moto part ? Geez I (we?) must be really well built then :-) Keihins require much Less work to adjust to give good result. Example; their (chicken hopper) float jet reservoir design alone is simply more advanced. Chromed slide is a quality touch as well. Very forgiving as to jettings, whereas Mikunis are far pickier, a PITA even to set up well.
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Post by pdxjim on Jun 5, 2019 18:07:59 GMT 1
Hardest part for me is finding proper genuine Keihins for a reasonable price.
Best I've found en ebay is $178usd or 143gbp. Chinese copies are of course MUCH less.
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Post by pdxjim on Jun 10, 2019 17:23:20 GMT 1
Found these in stock and on the shelf at a local scooter tuning shop less than a mile from my house. scooterswapshop.com/products/polini-carburetorThey look to be officially licensed Polini branded Taiwan version of the Keihin PWK. Anyone had and experience with the Polini branded version? I'm assuming the quality to be much better than the $30 Chinese garbage cluttering up ebay. Looks about a $70/56gbp difference in price per pair to the proper Keihins, so not a huge savings really in the end. At least I know they have all the jets and assorted brass I'll be needing.
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Post by Tobyjugs on Jun 10, 2019 19:02:36 GMT 1
Polini has a good name with the scooter boys here in Holland and i have seen then used on a YPVS flat tracker without problems which is used hard.
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Post by muttsnuts on Jun 10, 2019 20:37:07 GMT 1
Polini are good, those variants work fine, just avoid the cheap chinese copies
I have genuine Keihins on the shelf if you really want a set
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Post by pdxjim on Jun 11, 2019 18:32:22 GMT 1
Polini are good, those variants work fine, just avoid the cheap chinese copies I have genuine Keihins on the shelf if you really want a set Found these stock Kwak Kehins for just a few $$ more than the Polinis. www.bikebandit.com/oem-parts/detail/kawasaki/15003-1643/b778173That's only 190 GBP the set. Seems a good deal to me.
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Post by bare on Jun 11, 2019 19:29:53 GMT 1
Good .. used to be 85$ each for the Kawasaki Carbs. Increased demand I suppose. You Will however need; jjh needles.. 130 mains and 40 airs Suggest ONLY Genuine Keihin Parts... as there IS difference. Sudco sells 'em.
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Post by Tobyjugs on Jun 11, 2019 20:12:49 GMT 1
Are you using the original air box or pods? As this determines which type of needle to use.
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Post by bare on Jun 13, 2019 1:29:24 GMT 1
Airbox presumably... at least barring a damned good reason not to. It's been demonstrated.. repeatedly.. that unless a dedicated Track Only engine.. the airbox produces Mo' power.
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