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Post by Jimmy D on Jan 18, 2012 10:06:20 GMT
Going from a standard PK 19/19 to a PHBL 24mm, not quite sure where to start.
Would I use the same jets as I use in my 19/19, or would they need to be larger as I presume a larger carb takes in more air?
And what does the needle/atomiser do, and how do I get that bit right?
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Post by jonnysnatchsniffer on Jan 18, 2012 10:45:14 GMT
u will need larger jets, around 105 main 48 pilot, AQ264 atomiser and a D22 needle this will be a tad rich but not far off, you may find with the main that you will be around 100 but id start there and work down
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Post by Jimmy D on Jan 18, 2012 11:19:49 GMT
u will need larger jets, around 105 main 48 pilot, AQ264 atomiser and a D22 needle this will be a tad rich but not far off, you may find with the main that you will be around 100 but id start there and work down Cool... was about to say I have all those jets already but just seen PHBL uses 6mm not 5mm jets! Jonny can you explain in that special way only you can what the atomiser/needle do, and what changing them for smaller/bigger (i've heard people talk about moving the needle?) does? Is the needle the same as the float needle on a 19/19, just an adjustable version?
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Post by jonnysnatchsniffer on Jan 18, 2012 14:39:43 GMT
the atomiser does just that, it atomises the mixture, the little holes in it introduce air, there are richer ones and obviously leaner ones some are shorter than others and have different shroud lengths etc the atomiser controls fuel in the 1/3 - 3/4 range ish the needle is another kettle of fish and dellorto have quite a few and you will need a needle chart to even begin to not understand them but basicly the needle is tapered and along with the atomiser controls fuel from 1/4 to up to wot, as the needle is tapered and it can be moved up and down this makes it possible to richen or weakken certain areas in the 1/4 to wot so if you sre a tad lean in one area you can raise the needle to compensate the other alternative is to find a needle on the chart that is slightly thinner at that throttle opening. there is a lot more to it than that because the pilot, slide and main all effect these throttle positions and sometimes there is alot more overlap than it seems but for what you want most 24phbl set ups will be roughly the same so it will just be a bit of fine tuning
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Post by Jimmy D on Jan 26, 2012 22:31:41 GMT
Got an AQ264 right here... is it supposed to have no holes in it?? It's basically an open tube, not an atomiser...
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Post by Perkin on Jan 26, 2012 22:33:35 GMT
I think the atomisers with holes in are 4-stroke bits...
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Post by Jimmy D on Jan 26, 2012 22:50:19 GMT
I think the atomisers with holes in are 4-stroke bits... Aha, thanks. Next question... looking on side of PHBL there's one mixture screw (with thumb grip - so I presume this is air mix?) and then there's another one, this time only turnable with a screwdriver, like a smaller version of the other? What's that one for, and what is the default setting for each? This carb is so much more complex than the standard 19/19 but also seems to be far better designed...
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Post by nickj on Jan 26, 2012 23:10:46 GMT
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Post by jonnysnatchsniffer on Jan 27, 2012 23:36:11 GMT
the smaller screw in the body just above the float bowl is the mixture screw the one higher up screws into the slide raising or lowering it is the tickover screw, you can see the slide move turning the screw, the needle i suggested goes in the bottom of the slide, the float needle is inside the float bowl attached to the float and controls the fuel in set by the float height it is more complex than the 19 but has more scope for fine tuning throughout all throttle positions the aq atomiser has no holes apart from top and bottom, the air can be introduced thru the bottom hole whithe the top hole controls the final mixture the mikuni atomisers have holes in the side but work in a different way to some dellys, being that the phbl has the mixture screw at the front of the carb (manifold end) and the mikuni tmx and keihin pwk has an air screw at the rear of the carb just fit it with the mixture screw 1.5 turns out and the needle clip in the middle and fire it up and see how it goes
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Post by smallyshane on Jan 28, 2012 8:55:20 GMT
jim, i had set it for you to put on and fire up mate. The screw driver one was 2.5 turns out, the bigger one is tick over. Overall i would have thought she should run ok as is, but will need you to fine tune obviously. More turns out on the screw driver one will richen the mix, in will lean it off. Hope it goes well today mate, i will pop in to check so keep up updated. ;D
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Post by Jimmy D on Jan 28, 2012 9:24:55 GMT
jim, i had set it for you to put on and fire up mate. The screw driver one was 2.5 turns out, the bigger one is tick over. Overall i would have thought she should run ok as is, but will need you to fine tune obviously. More turns out on the screw driver one will richen the mix, in will lean it off. Hope it goes well today mate, i will pop in to check so keep up updated. ;D Thanks mate, appreciate you setting it up, just for my own knowledge (and a bit of cleaning) wanted to take it apart and put it back together again ;D Main thing I learned is that carb cleaner burns your skin!
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Post by jacques on Jan 28, 2012 10:26:52 GMT
I've read on a few pages now that Delly carbs should be 2.5 turns out, amal ones are 1.5 turns out. When I told my dad about my carb he immediately chirped "turn it 1.5 out"...So what is it?
I'm at 1.5 turns and it runs fine, maybe even a bit rich with a 45 pilot.
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Post by jonnysnatchsniffer on Jan 28, 2012 14:35:28 GMT
there is no set in or out, all motors will be different, however if you need to richen it and you go more that 1 turn in or 3 turns out then you will need to go up one on the pilot and vice versa if you need to lean it off as the pilot it set, the air or mixture screw (depending on carb) adjusts the fueling at tickover, so you get even tickover and clean pickup look at others tried and tested setups and work from that, just hoping that there not a complete cunt as ive said before most sizes of carbs will have roughly the same jetting no matter what the fuck they are off, and if you have to jet wildly different then there is something wrong
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Post by Jimmy D on Jan 29, 2012 16:50:16 GMT
Okay. Got the manifold on and fitted carb. First problem - RamAir filter doesn't fit in PK frame. I thought a PK would have more space than a V, I guess not? The filter is crushed almost flat by the frame, which means at WOT it's losing it as it struggles to breathe. I cut down and reglued the RamAir filter and it fits, but still can't breathe properly. Move from 100 to 96 jet and it's better but still not perfect. Take off the filter and use the CNC bell Shane sold me with it and the bell hits the frame. Take off all filters and from half throttle to WOT it absolutely roars. So I guess I'm just destined not to run a filter and to worry about shit getting in the engine. Or should I drop down to a 92-94 main jet? 2nd problem: Can't seem to get idle right. I miss the nice big plastic key screw of the 19/19 The engine behaves well in picking up/returning around 2 turns out. But the idle seems really irregular. I can pull up at lights and it'll be idling really high, then I pull over, engine off, wait 1 minute and it'll idle at a normal speed. Sometimes it'll wander a bit if I just leave it... if it's revving high and i leave it for 30 seconds, it'll slowly return to normal. Any ideas? Obviously sounds like air leak, but everything's done up tight and the cylinder etc has no leaks.
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Post by Juan on Jan 29, 2012 17:52:29 GMT
Cut a bit out of an old pair of tights and rubber band them over the bellmouth.
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Post by Jimmy D on Jan 29, 2012 17:55:59 GMT
Cut a bit out of an old pair of tights and rubber band them over the bellmouth. Yeah, sorry just to clarify the bellmouth doesn't quite fit... it hits the sticking-out seam on the PK I might try grinding one side of the bell down a bit, then doing the tights thing...
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Post by Jimmy D on Jan 30, 2012 11:23:42 GMT
I have a few jets kicking around for the phbl size so before your rush off ordering give me a bell/pm Thanks Nick. Have you got any 5mm pilot jets: 50, 52, 55? Shane gave me a 47 pilot, but I'm not sure if it's enough - I think I had a 50 in my 19/19!
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Post by jonnysnatchsniffer on Jan 30, 2012 18:46:57 GMT
are you adjusting the mixture screw with the motor running ? you need to do this
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Post by Jimmy D on Jan 30, 2012 23:23:15 GMT
are you adjusting the mixture screw with the motor running ? you need to do this Easier said than done... I can just about turn it with a ratchet driver if I take out the tank but it's clumsy. As i say the plastic 'key' screw of the 19/19 is a lot easier to adjust while running... Going to see if the local tool shop has an allen-key style 90 degree flathead driver, that'll help
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Post by nickj on Jan 30, 2012 23:35:37 GMT
are you adjusting the mixture screw with the motor running ? you need to do this how the hell do you do that with a phbl carb in the body Drill a hole thorugh the side or twist the carb sideways...or is there some other clever trick......
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