the_moggster Posted March 25, 2009 Report Share Posted March 25, 2009 I have a Monty 315 fitted with a Keihin PWK 28 carb. This Bike is new to me. Ok guys this is what happens, Bike starts and runs fine, length of time running does seem to make a difference but eveytime i go out it fouls the plug, at first tick over starts to get uneven and its gets a bit smokey and you have to wind tick over thumb screw in. Then you can be pulling up a climb in 3rd, get to the top and then it loses power, and eventually dies, and wont kick over. Take plug out its black and sooty, put in new plug and away it goes first kick fine. At first i thought the plug was faulty BR6 IX (irriduim), fitted new one and off i went again. Next time out almost exactly the same place, died! Was out longer this time. But most had been me riding out across the moor so engine revs where higher, once i got back in to streams and wooden climbs it stopped, again sooty plug. Ok so first thing I did was to strip and Clean Carb and fit new Jitsie air filter, and check air screw setting, which was 1 1/2 turns, I upped this to 2 turns, then on advice of Sandifords I took ignition cover off and cleaned stator, which had obviously got wet and been left to stand at sometime. Ordered new spark plug, original one. BR6ES and fitted. Ok So out again short ride in woods, then blast out across moors, some technical stuff in the rivers and rocks, stop in farm for cup of tea, out back up through valley in and out of rock and trees, 3rd gear climb up out of valley shut of throttle to approach a hedge blipped throttle to hop up the wall, and flat dieing engine! full throttle in neutral bearly keep it running, smoked, but died! Original plug (first irriduim one that failed) brushed clean and back in, ran on tick over for about 4 mins, then died. Spare BR5ES got me back to truck. Called Geoff at Sandifords, suggested Stator rewind, ordered a new one instead, and new plug. Fitted New stator, check all connections, Took exhaust off and cleaned front pipe, Repacked and sealed silencer, Fitted Old Irridium plug to see if it worked with new stator, tick over was poor and it died, so fitted new plug and set out. 2 Mile across moors, down into valley in and out of rocks trees and streams about 30-45 mins, then stopped in farm to check out my old beta zero outfit, which never needed or fouled a plug until they were worn out. Started up rode off up track out across field into a little heavy mud 3rd gear lots of throttle, 4th across field slowed in gate way to hop up stone wall, wooly throttle then died!!! argggggggg Ok so BR5ES back in and back to truck!! Carb is PWK 28 118 main 40 idle Air Screw 2 1/2 turns. Jitsie Air Filter 80:1 premix (silkolene) I am guessing now that I have cleaned up the original spark plugs and they run ok until sooted up that it must be a fuel side problem and not an electrical side problem and as such it is seeming running to rich. QUESTIONS:- What should the Air screw be set at and are the jets the right size? Would fitting a hotter Running plug be a wise move? What else should I take a look at? Any suggestion would be helpfull. Cheers Simon Quote Link to comment Share on other sites More sharing options...
tt5th Posted March 26, 2009 Report Share Posted March 26, 2009 Have you checked the spark with the spark plug out of the cylinder? I was wondering about the coil. I can't remember the jet sizes in mine at the moment I'm afraid, but have you checked the float height as well? I'd agree it sounds like a carb problem but you seem to know what you're talking about and carbs are reasonably simple so I don't know what else to suggest! You haven't changed the front pipe recently have you? I put the later (2000 onwards?) chrome front pipe on my older bike to replace the black one and it had baffles in it that I had to grind out. Are there any air leaks in the rubber bits going to and from the carb? And (don't hate me I have to ask!) 80:1 is about 63ml of oil to 5L of fuel? Quote Link to comment Share on other sites More sharing options...
garethr Posted March 26, 2009 Report Share Posted March 26, 2009 Have you checked the needle clip position? Is it in the middle? If so, you may want to try and lift the clip up one notch, thus dropping the needle down making the 1/4 to 1/2 throttle opening leaner. Quote Link to comment Share on other sites More sharing options...
wherry Posted March 26, 2009 Report Share Posted March 26, 2009 Here's what JSE and Subira reckoned last year on 315/PWK jetting matters:- 'Here's the jetting for a Keihin on a 300 Pro, and I'm guessing you should probably start with a 118/120 main on the 250: MAIN: 122 PILOT: 45 (48 OK) NEEDLE: JJH (CENTER OF FIVE POSITIONS) SLIDE: 3.5 AIRSCREW: 2.5 TURNS OUT FLOAT HEIGHT: ARMS IN LEVEL PLANE WITH FLOAT BOWL BASE (PARALLEL) Jon' 'SubiraSep 24 2008, 07:39 PM I had one fitted, this is what I have in my black book! Pilot 42, main 118, needle GFH, slide 3.5' You won't be far out with Subira's settings. You'll need an inline fuel filter as well if you haven't got one as the PWK hasn't got an integral one like the Dellorto. Quote Link to comment Share on other sites More sharing options...
ticket2ride Posted March 26, 2009 Report Share Posted March 26, 2009 Hello! Well, sounds like somebody with exactly the same issue that I have....!!....do you get a dry or wet plug foul? I've had the stator re-done on the advice of Sandifords, tried running it with no air filter or rear mudguard....etc etc.....did find that it ran a bit longer on the Iridium plug though!!...looked at air leaks, jets, mixture etc etc.......the only other item maybe could be the coil....BUT, I'm getting a great spark!!....and , no mis-firing until the plug fouls and the engine dies... The bad news is that short of taking it in to Geoff I still can't the damned thing to run for more than about 15 - 20 mins!! In fact, I haven't had a chance to touch the blinkin thing in about 6 months but did plan to have another shot at it over this w'end!! Perhaps, the only difference we have is that I'm running the standard carb (whatever comes on a 2004 315?) but with the competition jetting....? Be really useful to stay in contact on this one and see if we can sort it between us!!...... Needle position is currently in the middle position - but, not sure how to measure float heights though!! Help is the word that springs to mind!! Quote Link to comment Share on other sites More sharing options...
the_moggster Posted March 26, 2009 Author Report Share Posted March 26, 2009 Hi guys, Whipped the slide out, its a GFH 3.5 Clip was in middle so have lifted it one place further up so dropping needle lower in slide. While slide was out I checked it over again and it looks to be to have a "step" or grove acoss it in and arc where it shuts over the Carb outlet. Should it be like this? Or should it be smooth, not looked inside a PWK before, and so im not sure, but it doesn't look right! If it is worn that could be a cause of the rich running! I have taken some pics and will post later. I have looked around the net for pics of a PWK slide but as usual if you want to find something specific the web is virtually useless!!! Anyone got a pic of a PWK slide?? Cheers Simon Quote Link to comment Share on other sites More sharing options...
robbo Posted March 26, 2009 Report Share Posted March 26, 2009 Hi, Have you considered the CDI as being the potential problem? possibility - worth trying to borrow one off someone else's 315R to try it - save you the expense if it's not that! Have you replaced the plug cap yet? Good luck! Quote Link to comment Share on other sites More sharing options...
robbo Posted March 26, 2009 Report Share Posted March 26, 2009 Also, the keihin carb slider is chrome plated all over and smooth with no gooves on the arc section. I can't see minor scoring causing an issue though. Good luck, Mark Quote Link to comment Share on other sites More sharing options...
stork955 Posted March 26, 2009 Report Share Posted March 26, 2009 Gday, is that carb the original one for the bike? Cheers Stork Quote Link to comment Share on other sites More sharing options...
the_moggster Posted March 27, 2009 Author Report Share Posted March 27, 2009 Hi all Sorry to hear you have some prob Tickettoride but good to know im not the only one, and yes keeping in touch would be a good plan.!! BTW plug is dry and sooty. Wet Plug would certainly bring the piston rings into question. Ok Pictures first. TT5th, Yeah spot on with the oil, although I did try it a little leaner to see if that made any difference, but it didn't. Air leaks I will check the rubbers i'm thinking one on the Airbox side might not make to much different but certainly on other side might. If I do end up taking that side of then ill do the reeds at the same time, and rebuild the carb as its a pain to get the PWK back on Airbox side, had to take airbox out and fit carb to airbox and then slide it all back through frame. Which was easy in itself just would be easier if you didn't have to do it that way. Tried warming the rubber etc but wouldn't go on easy. Robbo, Haven't considered DI as the bike runs fine in the timing sense and spark is strong on clean plugs. Stork, The PWK is an "upgrade" (lol) over the original carb! Spoke to Steve at Allens Performance, who supplied the carb and he has given me some ideas, and i have sent him links to pics etc and will chat with him later. Update later! Slide 3.5 Main 118 Idle 40 Needle GFH Airscrew Variable!! Quote Link to comment Share on other sites More sharing options...
the_moggster Posted March 29, 2009 Author Report Share Posted March 29, 2009 Definately think that lip on the slide isn't correct, and does anyone else think that this wear is likely to have been casused by running the bike without an airfilter, at sometime in its past. Don't think that this wear on the slide is responsible for the running rich as it is more likely to leak air passed the slide with this wear. Anyway I have ordered a new needle and jet to see if that helps and they look a bit worn and going by the damage to the slide it is possible that the worn needle could be the culprit for the rich running, also going to check the float level. I will keep you posted ticket2ride Lovely Day for a ride, shame!!!! Happy Riding Quote Link to comment Share on other sites More sharing options...
stork955 Posted March 29, 2009 Report Share Posted March 29, 2009 Gday, I reckon you are on to it there. The slide is definitely knackered, but the big issue is the needle. The polished end is a dead giveaway, and likely the needle jet is worn oval. You can check this by finding a drill bit just a bit smaller than the hole the needle fits through and slipping it into the jet. Have a good look, maybe with a magnifying glass and you may well see an oval hole in the fore and aft direction. Carbs need only the very slightest amount of wear to alter the mixture radically, this is common on road bikes with a bit of work under their belts, some more than others. Replace the pair first before altering anything else (I reckon the slide also, it wont make it run rich but it can make it stick) and see how it goes. It would pay to check float needle while you are there and set float levels as well. Cheers, Stork Quote Link to comment Share on other sites More sharing options...
the_moggster Posted March 29, 2009 Author Report Share Posted March 29, 2009 Hi Stork, Slide is Shocking!! not see one worn like that before, run with out an Air filter i think, well thats only thing I can think of! I hope we are both right on the needle and jets being the cause of the rich running, will find out tuesday I hope, if they arrive, if not i will be out riding with some spare plugs!! Cheers Simon Quote Link to comment Share on other sites More sharing options...
dad- Posted April 8, 2009 Report Share Posted April 8, 2009 what was the outcome ?? did the needle and slide cure the problem ? had a similar fault with my 315 but it had delorto carb fitted and was worse in the cold weather never had a problem when hot Quote Link to comment Share on other sites More sharing options...
ticket2ride Posted April 9, 2009 Report Share Posted April 9, 2009 Hi Dad! How did you cure the issue with the Dellorto? I've got the same fault and can't solve it for love'nor'money!! Moggster - how's progress?? Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.