|
Post by fletche36 on May 15, 2024 17:09:39 GMT 1
For no particular reason im going to try a set of PWK 28s on my lc 250. The bike runs good as is but you know how we all like a tinker ![:)](//storage.proboards.com/forum/images/smiley/smiley.png) Anyway for the princely sum of not very much i aquired a set of clones and set about making them useable. Firstly i care not where something is made as long as the quality is there and i must say that im quite impressed with the quality of the machining/ tolerances etc and i was an engineer in a former career.Anyway after a few searches i came up with what seems a reasonable baseline to start with that wont destroy the motor so i went with 40 pilots ( 38s were pre installed) 140 mains (up from 120) and jjh needles ( the fitted ones were unmarked but appear a leaner needle). i drilled and tapped out the boss on the cylinder side to accept an M4 angled oil spigot which hasnt arrived yet so i cant test this setup. I also fitted a set of angled carb tops so the cables should be fairly close to fitting. Now i know the jets should be genuine but in the past i have used Jitsie ones which will be accurate ( a belgian company well known in the trials world) and Jitsie also supplied the carb tops (£10.50) and needles(£7), so altogether im about £75 in and should this all be a useless exercise and i have to buy some genuine ones i will have all the necessary parts i need. Im going to use some ram air pods as i dont fancy trying to squeeze these carbs into std air boots and once again if i cant get it running right ill refit the air box and try again with some silicone tube homemade pipes . I havent yet removed it and im not looking forward to that as its supposed to be a nasty job. Anyway , ill let you all know how it goes when i get around to doing the swap over. IMG_0274 by peter fletcher, on Flickr IMG_0269 by peter fletcher, on Flickr IMG_0263 by peter fletcher, on Flickr IMG_0267 by peter fletcher, on Flickr
|
|
|
Post by fletche36 on May 15, 2024 17:12:38 GMT 1
The Jet that looks like a genuine keihin is the one that came out of the copy carb!!!! Just for info
|
|
|
Post by tony2stroke on May 15, 2024 17:44:53 GMT 1
I put some 30mm knock off pwk carbs on my last 250lc, they worked great, I did change the manifolds for ypvs, and used 2 x 125lc boost bottles instead of the balance pipe, some fibre reeds too, and ram air filters, so they are OK if you do your own quality control as you have.
The airbox will come out easily if you take the manifolds off, this gives enough room to wiggle it out.
|
|
|
Post by jon on May 15, 2024 18:09:48 GMT 1
People have said the fake Keihins do not run well out of the box and that they need genuine hardware to stand a chance to work.
Interested if this works.
The genuine carbs are well over £300 if you can get hold of them. I waited nearly a year for one of various dealers to get them in. The fakes seem readily available.
I too would love a 30mm set, but never see genuine 30mm. They do Polini ones, which I have experience of as a good make.
Jon
|
|
|
Post by jessy03 on May 15, 2024 19:16:10 GMT 1
These copies are getting hard to spot the difference, I got some for £14 each (so if they don’t work I don’t care) I plan to run them with genuine jets and may be genuine slides/needles just because I have some spare. Looking forward to see your results 👍 ![](https://uploads.tapatalk-cdn.com/20240515/b49865cf2322924b87ebe8209b1645a3.jpg) ![](https://uploads.tapatalk-cdn.com/20240515/b6cd891d1688ff8c8f442054f7b6dc04.jpg)
|
|
|
Post by fletche36 on May 15, 2024 19:21:04 GMT 1
I put some 30mm knock off pwk carbs on my last 250lc, they worked great, I did change the manifolds for ypvs, and used 2 x 125lc boost bottles instead of the balance pipe, some fibre reeds too, and ram air filters, so they are OK if you do your own quality control as you have. The airbox will come out easily if you take the manifolds off, this gives enough room to wiggle it out. Thanks. im on v force reeds at the moment so they will be staying in and i have some other carbon reeds in the std blocks too to play with if necessary. i do like tinkering with little jobs like this ![:)](//storage.proboards.com/forum/images/smiley/smiley.png) im confident i can get it very close and then hopefully dyno it to check if its as good as it can be whilst still being safe.
|
|
|
Post by jon on May 15, 2024 19:38:46 GMT 1
These copies are getting hard to spot the difference, I got some for £14 each (so if they don’t work I don’t care) I plan to run them with genuine jets and may be genuine slides/needles just because I have some spare. Looking forward to see your results 👍 ![](https://uploads.tapatalk-cdn.com/20240515/b49865cf2322924b87ebe8209b1645a3.jpg) ![](https://uploads.tapatalk-cdn.com/20240515/b6cd891d1688ff8c8f442054f7b6dc04.jpg) This post is really confusing me. I thought the way to tell the difference was posted here: www.sudco.com/genuine_vs_fake_carburetors.html#:~:text=The%20fake%20PWK%20carburetor%20has,Japan%20and%20NOT%20in%20China.&text=A%20copy%20of%20the%20PWK%20carburetor%20will%20have%20an%20unmarked%20light%20hose. This post seems like parts have been mixed up? Jon
|
|
|
Post by fletche36 on May 15, 2024 19:45:34 GMT 1
These copies are getting hard to spot the difference, I got some for £14 each (so if they don’t work I don’t care) I plan to run them with genuine jets and may be genuine slides/needles just because I have some spare. Looking forward to see your results 👍 ![](https://uploads.tapatalk-cdn.com/20240515/b49865cf2322924b87ebe8209b1645a3.jpg) ![](https://uploads.tapatalk-cdn.com/20240515/b6cd891d1688ff8c8f442054f7b6dc04.jpg) The machining is very high quality and there is no slop or play in anything, even the carb bowl and top bolts are decent stainless allens. i doubt you could tell the difference between gen and non gen jets when they are stamped up with the keihin star logo.At least the jitsie stuff is genuine .
|
|
|
Post by jon on May 15, 2024 20:09:46 GMT 1
I assume the carb with the bellows is a genuine carb? It’s got Norbo’s sticker instead of the Sudco sticker so assume it’s genuine. It’s also got a feint ID laser engraved on the body.
However the doesn’t seem like any lettering on the pink hoses, unlike the other one? Also my genuine ones came with straight cable guides rather than swan neck?
Petrol inlet is noticeably different. Anyone comment on real or fake dimension?
Jon
|
|
|
Post by fletche36 on May 15, 2024 21:13:13 GMT 1
i think its likely that the levels of copying get better as time goes on. My fakes came with straight cable guides as do genuines hence i bought some jitsie ones. If you didnt have a real one to compare against you would know no different, they certainly dont feel cheap. i cant wait to test these now and see whether they are good or bad but even if they were genuine there is still some faffing to do to get the fuelling right but im confident i can get it good. I know dynos are good and since having mine done at Daves i am a big advocate but being old school i dont mind listening to the motor and doing what i think it needs.
|
|
|
Post by fletche36 on May 21, 2024 18:25:55 GMT 1
IMG_0288 by peter fletcher, on Flickr Oil spigots arrived so i have bonded them in the position where they need to be with JB weld and tomorrow they are going on the bike. im looking forward to this now.
|
|
|
Post by fletche36 on May 22, 2024 17:23:12 GMT 1
Job done..... Removing the old air box was a pain but not impossible, however i wouldnt want to do it too often. I had a bit of an issue with the length of the throttle cables and no matter which combination of parts i used the cable was either too long or too short so out came the dremmel and i adjusted the tubes of the jitsie tops by cutting 5mm off the brass adjuster and 5 mm off the top tube, the idea being that should i put the bike to std i havent butchered anything ( well not much). Carbs go in fine but the rubber inlets have little locating lugs for lining the carbs up which get in the way with the PWKs, so they had to be trimmed and then i find that one of the oil lines is 20 mm too short and one of the fuel pipes wont reach. Necessity being the mother of invention i rooted around and found a piece of drinking tube from an old camelback which sorted the fuel pipe out and i pieced in a piece of oil pipe. Both these will obviously done correctly asap. Anyway. tank on, chokes on and it fires up instantly and seems to run fine but no way was i going testing as its done nothing but rain all day here in Bury, then i come across an issue...... fuel leak ! Its the right hand carb and im thinking its the float valve so off it comes and it gets the std test of blowing down the fuel pipe but its shutting off fine so back on the bike and its still leaking . Bit of investigation and it turns out the camel back pipe is the culprit and its ever so slightly too big so i use another piece of donor pipe( carb overflow pipe) and its all good. Tomorrow i shall source some proper pipes and all being well ill go testing and then i can tune the jets as required.Not a bad job really. IMG_0295 by peter fletcher, on Flickr IMG_0297 by peter fletcher, on Flickr IMG_0299 by peter fletcher, on Flickr
|
|
|
Post by scootjockey on May 24, 2024 23:05:37 GMT 1
I came across your post last week after looking for suitable carb top for a 30mm PWK I have for my TDR125/170. Bought a top from Jitsie and it arrived yesterday. Fitted the carb tonight, the cable mount is ideal but the top is out by about 0.5mm and didn't line up so I used 3 gaskets to raise it past the machined cut out and castings. Turned the airscrew all the way in then out 1-1/4 turns as per the standard carb. Set up the tickover then took it for a spin. I know little 2 strokes don't pull like a train but difference in bottom end power is really noticeable. The bike pulls really well in all gears now. Once warmed up I swapped the plug out for a new one and gave it a good blast through the gears for a plug chop. The plug looks good and throttle response is much better than with the standard carb.
I know we slag Chinese copy carbs off but so far, and 1st impressions are really good and the change from 28mm to 30mm is very noticeable. Id go bigger but im struggling for an inlet manifold that will accept the 32mm and 34mm I bought also for next to nowt. Thanks for the info id still be trawling the net for the carb top/cable mount now if I hadn't seen this.
Cheers Gaz
|
|
|
Post by tony2stroke on May 25, 2024 6:53:33 GMT 1
I came across your post last week after looking for suitable carb top for a 30mm PWK I have for my TDR125/170. Bought a top from Jitsie and it arrived yesterday. Fitted the carb tonight, the cable mount is ideal but the top is out by about 0.5mm and didn't line up so I used 3 gaskets to raise it past the machined cut out and castings. Turned the airscrew all the way in then out 1-1/4 turns as per the standard carb. Set up the tickover then took it for a spin. I know little 2 strokes don't pull like a train but difference in bottom end power is really noticeable. The bike pulls really well in all gears now. Once warmed up I swapped the plug out for a new one and gave it a good blast through the gears for a plug chop. The plug looks good and throttle response is much better than with the standard carb. I know we slag Chinese copy carbs off but so far, and 1st impressions are really good and the change from 28mm to 30mm is very noticeable. Id go bigger but im struggling for an inlet manifold that will accept the 32mm and 34mm I bought also for next to nowt. Thanks for the info id still be trawling the net for the carb top/cable mount now if I hadn't seen this. Cheers Gaz Look up billet Banshee manifolds on ebay Norbo has some in his shop too, in pairs, ebay may do a single, maybe worth asking Norbo if he will sell a single.
|
|
|
Post by fletche36 on May 30, 2024 14:55:14 GMT 1
Tested the PWK s today as it was the first dry day we have had in ages. Baseline settings were 40 pilots/ 140 mains jjh needles on the middle clip, air screws at 1.5 out and running ram airs. Ok , the bike stars well ( half a kick) which i knew from starting in the garage and i let it idle for a minute to get some oil flowing. i set off and within a couple of hundred metres i could tell it was a little lean as i had to be gentle with the throttle to get the revs up. i gave it a mile or so and hit an unrestricted road so i let it breath a bit and it was pleasantly good on anything over 4500 revs( now i have to do a bit of guessing with the revs as the rev counter is being a bit intermittent). At this point im going to say power is more than with original mikunis at higher revs but less at lower revs which i will work on. So, back to the garage and a tweek with the air screws to half a turn out from full in and back out testing... its better but its not perfect so im going to be getting a pair of 42 and 45 pilots and then i should be able to get decent bottom end with the air screws back in the right place and ill raise the needle one notch to richen the mid too. i made sure i gave it a good rev on the last fast straight before home and then checked the plugs ( not a true plug chop i know but close enough)and they were a lovely light brown colour so ill probably leave the mains as they are and i wont be changing the power jet as thats unfamiliar territory for me and im sort of ignoring it . I think the theory is that it pulls fuel direct from the float bowl at massive revs ( venturi principal) to richen the mixture so you can run a slightly smaller main but its not often i would be riding like that in real world conditions. Once i have got it to what i feel is close ill get it over to Mutts for a dyno health check ( if he will have me as i used forbidden chinky carbs:) ) but overall it seems a worthwhile exercise for someone who just loves fiddling .
|
|
|
Post by jessy03 on May 30, 2024 15:25:09 GMT 1
From my experience with PWK’s on an LC, the pilots were between 48-52 and the mains were 120-125 ( airbox lid off, not pods)
Sounds like you’re not far away 👍👍👍
|
|
|
Post by fletche36 on May 30, 2024 16:11:42 GMT 1
From my experience with PWK’s on an LC, the pilots were between 48-52 and the mains were 120-125 ( airbox lid off, not pods) Sounds like you’re not far away 👍👍👍 Cheers, probably a similar airflow there. i would be frightened going that low on the mains as the plug colour is good but yes i may end up in that pilot range. The smart thing to do would be to dyno it now but i love being able to do things myself and you kind of know when things are right. certainly never dynoed anything back in the day ![:)](//storage.proboards.com/forum/images/smiley/smiley.png) The good thing is that swapping jets etc is a 5 min job now that i dont have to deal with those rubber air boots . Just got to wait for some jets to come now.
|
|
|
Post by tony2stroke on May 30, 2024 19:42:46 GMT 1
Be interesting to see what the dyno says They do look like very good quality copies, I have some 34mm ones I am thinking of putting on my 350, they also look very good quality, I was pleasantly surprised when I received them, very hard to spot the difference between genuine and copy with these ones, there seems to have been some quality control. Keep up the good work and keep posting about them please.
|
|
|
Post by fletche36 on May 30, 2024 21:04:27 GMT 1
Be interesting to see what the dyno says They do look like very good quality copies, I have some 34mm ones I am thinking of putting on my 350, they also look very good quality, I was pleasantly surprised when I received them, very hard to spot the difference between genuine and copy with these ones, there seems to have been some quality control. Keep up the good work and keep posting about them please. Will do sir. Thanks
|
|
|
Post by fletche36 on Jun 3, 2024 19:24:12 GMT 1
OK, new jets arrived today, a pair of 42s and a pair of 45 pilots. Now i know from experience to just do one thing at a time so you can feel/ see/hear what changes and also to test in between.So 42s went in and its better from the bottom but a bit of a step in the transition to mid so back in the garage and the needles get lifted by 1 clip ( clips lowered, for clarity). Back out for a test and its good through the range but not quite perfect then i remember i havent altered the airscrews which were only a half turn out from running with the 40s, so screws are backed out another half a turn and its better still, indeed i could live with this as it is now but i feel that i can get more by backing the airscrews another half a turn which would put them in the perfect part of the correct range. i didnt do this today as i ran out of time so that will be on the next test, also i may try it with the 45s just to check if there is anything else to be gained but it honestly feels decent now. If dynos werent a thing then i would be happy as it is but since they are it would be wise of me to get it checked and fine tuned as necessary but its not urgent and something that can wait till i have some free time and probably later in the year when the weather starts to go rubbish again ![:)](//storage.proboards.com/forum/images/smiley/smiley.png) Ill post up again if i change anything that makes it either better or worse.
|
|
dex46
Thrash Merchant
![*](//storage.proboards.com/1564063/images/OArpjc3Z26Vu8ExORmaz.png) ![*](//storage.proboards.com/1564063/images/OArpjc3Z26Vu8ExORmaz.png)
Posts: 409
|
Post by dex46 on Jun 3, 2024 21:58:33 GMT 1
Excellent thread following 👍 sounds like you are fairly close to a good set up was they eBay carbs
|
|
|
Post by fletche36 on Jun 3, 2024 22:10:25 GMT 1
Excellent thread following 👍 sounds like you are fairly close to a good set up was they eBay carbs Yes, im pleasantly surprised and i cant see how genuines would be any better and they too would need the same set up routine as you would be very lucky for them to come perfectly ready jetted. when i have finished ill post up the exact cost ( not to upset those who buy genuine, but to show what can be achieved on a budget). It may be that i got lucky with the set i purchased but i think thats how they are now.
|
|
|
Post by Tobyjugs on Jun 5, 2024 3:49:32 GMT 1
A friend bought a set of copy 38 mm PWK Keihins. He really wanted for 80 pk from a VJ 23 engine. I think it make 76 pk.
Not satisfied he bought genuine carbs. The engine ended up making 78 pk.
You could say not so much difference, but the biggest difference was midrange performance which was superior using the genuine carbs and the tuner remarked that the copy carbs were jetted differently from each other to get the same performance out of each carb and with the genuine carbs it was not needed.
It sounds like copy carbs are not so bad now. Unless you are after flawless performance.
|
|
|
Post by tony2stroke on Jun 5, 2024 10:07:02 GMT 1
You could say not so much difference, but the biggest difference was midrange performance which was superior using the genuine carbs and the tuner remarked that the copy carbs were jetted differently from each other to get the same performance out of each carb and with the genuine carbs it was not needed. I wonder why the big difference, what is the cause and can it be rectified. I did wonder about the consistency too, be interesting to see dyno reading. So it would seem that they really are getting quite good. I have to say that the quality of the ones I have are spot on to look at, and I can see brass pressed in air jets, not just drilling through the alloy, these ones with the Keihin stamped on them are really good copies, there appears to be some quality control, no sharp edges or wisps of metal, everything looks good quality, we will see.
|
|
|
Post by Tobyjugs on Jun 5, 2024 12:24:53 GMT 1
You could say not so much difference, but the biggest difference was midrange performance which was superior using the genuine carbs and the tuner remarked that the copy carbs were jetted differently from each other to get the same performance out of each carb and with the genuine carbs it was not needed. I wonder why the big difference, what is the cause and can it be rectified. I did wonder about the consistency too, be interesting to see dyno reading. So it would seem that they really are getting quite good. I have to say that the quality of the ones I have are spot on to look at, and I can see brass pressed in air jets, not just drilling through the alloy, these ones with the Keihin stamped on them are really good copies, there appears to be some quality control, no sharp edges or wisps of metal, everything looks good quality, we will see. It's probably performance that is only easy to see on a dyno unless your really in tune with your bike. Most of us ride our LC's now and again and between other bikes as well. I made my ignitech switchable. So I could just switch plugs and use the standard ignition if I wanted. It was night and day between the two systems. The bike idled better and rode away from standstill better as well. Back to back on the dyno bank you could see the gains over a lot of the rev range and the power didn't fall off so quick. I was disappointed I only had 1 horsepower more with the digital system. The disappointed was probably due to lots of people saying how good they are and then me interpreting it as more horse power. Even the old ignition has its advantages now and again.
|
|
|
Post by fletche36 on Jun 6, 2024 15:19:54 GMT 1
|
|
|
Post by fletche36 on Jun 6, 2024 15:23:19 GMT 1
20 odd mile ride today with a bit of everything thrown in. No complaints and thats the colour of the plug on return.Ill call it right for the time being until it goes on a dyno.There is more to be had but its not in any danger zone so im happy with it for now.
|
|
|
Post by fletche36 on Jun 18, 2024 16:47:32 GMT 1
Ok, results are in after a trip up to see Dave today ( Also had the pleasure of meeting Jon, all the way from Oz too) to make sure i was close with how i had jetted the PWKs. Now i knew i had got it close just by what i know myself( and im no pro tuner or jetting expert, just someone who has learned through experience over the years)but for peace of mind it had to be a dyno check and its got to be Dave for me as its an hours drive so not too far and he really knows his LCs. Anyway, i explain that i want a health check and to improve any areas where it can be made better so on the dyno it goes , ear defenders are on and fingers are crossed!The bike gets given the beans in a sympathetic way and the results come in.... not too much wrong with what i have done and no brass changing is needed just a turn of the airscrews. Another run is done and a slight improvement is found and im happy to share the results. ( for the fecking life of me i cant put the dyno pics on here and trust me i have tried)Max power is up from 33 bhp ( a healthy 250) to 39 bhp and torque is up from 21ft/lbs to 24 ft/lbs !!! Thats a std unported engine running swarbrick pipes, chinky carbs and pod filters. I do have a squished and o ringed head to fit at some point in the future which will put it over 40 bhp but for now ill happily run it as is through summer. Thats probably all ill post on this thread now unless i manage to upload the dyno graphs so thanks for your interest guys.
|
|
|
Post by Tobyjugs on Jun 18, 2024 17:04:29 GMT 1
Ok, results are in after a trip up to see Dave today ( Also had the pleasure of meeting Jon, all the way from Oz too) to make sure i was close with how i had jetted the PWKs. Now i knew i had got it close just by what i know myself( and im no pro tuner or jetting expert, just someone who has learned through experience over the years)but for peace of mind it had to be a dyno check and its got to be Dave for me as its an hours drive so not too far and he really knows his LCs. Anyway, i explain that i want a health check and to improve any areas where it can be made better so on the dyno it goes , ear defenders are on and fingers are crossed!The bike gets given the beans in a sympathetic way and the results come in.... not too much wrong with what i have done and no brass changing is needed just a turn of the airscrews. Another run is done and a slight improvement is found and im happy to share the results. ( for the fecking life of me i cant put the dyno pics on here and trust me i have tried)Max power is up from 33 bhp ( a healthy 250) to 39 bhp and torque is up from 21ft/lbs to 24 ft/lbs !!! Thats a std unported engine running swarbrick pipes, chinky carbs and pod filters. I do have a squished and o ringed head to fit at some point in the future which will put it over 40 bhp but for now ill happily run it as is through summer. Thats probably all ill post on this thread now unless i manage to upload the dyno graphs so thanks for your interest guys. Nice Post. I also do all my own jetting and just like you I like to check the results on a dyno. Just out of interest did the airscrews go in or out?
|
|
|
Post by tony2stroke on Jun 18, 2024 19:34:10 GMT 1
Great information for everyone, well done, thanks for sharing.
|
|