waynerobshaw Posted October 14, 2011 Report Share Posted October 14, 2011 (edited) Hi All, I'm guessing that I may already have the answer to this question, but just as a second opinion... I've had my 06 300 Raga for about 6 months all all was well up to the last few months. I noticed that when shutting off the throttle the engine seemed to make a pinking type knocking sound. I played around with the mixture settings, new spark plug and super unleaded without much success. Today, I've just noticed that when the bikes warm and pinking (only when the throttle is closed), if I put the choke back on, it seems to run better and without and noticable knock/pink. I would guess this is pointing to the jets in the carb being blocked? Strip down and blast out? Also, I've noticed recently, that when starting from cold with the choke on, I have to quick close the choke when the bike fires otherwise it revs its nuts off. Does this tie in with the carb needing a clean out? Your wisdom is much appreciated! Cheers, Wayne. Update: 20/10/11 AAAARRRGGHH! Help! Tonight, stripped the carb and cleans all the needles etc. All looked well, so I reassembled and it kicked it life. It sounded better straight away. So I took it for a gentle ride and let it warm up....the pinking seems to have gone...great! After about 5 mins, I was just about to put the bike away feeling chuffed with myself, there was a clunking sound and the bike cut out. I kicked it up again only for it to cough, fart and backfire! It now runs like a dog and it not very happy It back fires, sounds to knock (pink) and sounds terrible! Help! The strange thing is, it was sweet as a nut for 5 minutes and then caput! What went wrong? Could by complete coincidence could the woodruff key have sheered and put the timing out or has the motor given in? I have no flywheel puller to check the state of the woodruff. I'm very worried... Your help is greatfully appreciated! Cheers, Wayne. Edited November 26, 2011 by waynerobshaw Quote Link to comment Share on other sites More sharing options...
lowbrow Posted October 14, 2011 Report Share Posted October 14, 2011 I guess you mean an 06 Raga? Yes, give the carb a good clean and blow through, but also check the rubber the carb' fits into for wear and splitting. The symptoms you describe hint at an air leak between the carb and the motor. Quote Link to comment Share on other sites More sharing options...
toofasttim Posted October 15, 2011 Report Share Posted October 15, 2011 Go up a size or two on the main. My 06 Raga 300 did the same. Quote Link to comment Share on other sites More sharing options...
waynerobshaw Posted October 17, 2011 Author Report Share Posted October 17, 2011 DOH! Yes, 06 (now edited) Ok doke, I give it a go and check for splitting too.... Thanks for the pointer... I guess you mean an 06 Raga? Yes, give the carb a good clean and blow through, but also check the rubber the carb' fits into for wear and splitting. The symptoms you describe hint at an air leak between the carb and the motor. Quote Link to comment Share on other sites More sharing options...
waynerobshaw Posted October 17, 2011 Author Report Share Posted October 17, 2011 Go up a size or two on the main. My 06 Raga 300 did the same. I might do that. Do the jet have a size stamp on them? Ie, would I know what I've got in at the moment? Cheers, Wayne. Quote Link to comment Share on other sites More sharing options...
jse Posted October 17, 2011 Report Share Posted October 17, 2011 I might do that. Do the jet have a size stamp on them? Ie, would I know what I've got in at the moment? Cheers, Wayne. Wayne, If the problem persists, you may want to go up a step or two on the pilot as the pinking occurs upon shut-off, rather than mid-range or open throttle. Jon Quote Link to comment Share on other sites More sharing options...
biffsgasgas Posted October 18, 2011 Report Share Posted October 18, 2011 Had the same problem this summer. As it turned out my base gasket was shot. Look around the bottom of cylinder for any oil or combustion residue. It progressively got worse as the gasket was dieing. Here is a pic --Biff Quote Link to comment Share on other sites More sharing options...
waynerobshaw Posted October 18, 2011 Author Report Share Posted October 18, 2011 Had the same problem this summer. As it turned out my base gasket was shot. Look around the bottom of cylinder for any oil or combustion residue. It progressively got worse as the gasket was dieing. Here is a pic --Biff Interesting! Was there any signs of this before you stripped the engine? Was there any residue visble externally at the bottom of cylinder? Cheers, Wayne. Quote Link to comment Share on other sites More sharing options...
hrc1 Posted October 18, 2011 Report Share Posted October 18, 2011 More than one GG pro has sucked it's base gasket in. On a dry dusty day you'll see oil/fuel stains at barrel base, on a wet muddy one, you won't. Cured with thicker gasket - and bike runs smoother too.. Pinking, if engine has tight squish - high compression - carbon build up can be enough for pinking. A decoke can cure. Quote Link to comment Share on other sites More sharing options...
waynerobshaw Posted October 20, 2011 Author Report Share Posted October 20, 2011 AAAARRRGGHH! Help! Tonight, stripped the carb and cleans all the needles etc. All looked well, so I reassembled and it kicked it life. It sounded better straight away. So I took it for a gentle ride and let it warm up....the pinking seems to have gone...great! After about 5 mins, I was just about to put the bike away feeling chuffed with myself, there was a clunking sound and the bike cut out. I kicked it up again only for it to cough, fart and backfire! It now runs like a dog and it not very happy It back fires, sounds to knock (pink) and sounds terrible! Help! The strange thing is, it was sweet as a nut for 5 minutes and then caput! What went wrong? Could by complete coincidence could the woodruff key have sheered and put the timing out or has the motor given in? I have no flywheel puller to check the state of the woodruff. I'm very worried... Your help is greatfully appreciated! Cheers, Wayne. More than one GG pro has sucked it's base gasket in. On a dry dusty day you'll see oil/fuel stains at barrel base, on a wet muddy one, you won't. Cured with thicker gasket - and bike runs smoother too.. Pinking, if engine has tight squish - high compression - carbon build up can be enough for pinking. A decoke can cure. Quote Link to comment Share on other sites More sharing options...
toofasttim Posted October 20, 2011 Report Share Posted October 20, 2011 Could by complete coincidence could the woodruff key have sheered and put the timing out Sounds very much like it. Quote Link to comment Share on other sites More sharing options...
waynerobshaw Posted October 21, 2011 Author Report Share Posted October 21, 2011 (edited) Sounds very much like it. ARRRRGH AGAIN! I got up this morning and kicked it back up....Its ran quite normally for at least 20 mins, no rough running, not backfiring...mental! This bike has a mind of its own! Unfortunately, it still pinks now and again when closing the throttle and sounds much nicer when the choke is engaged. I also sprayed some WD40 around the cylinder gasket/rubber carb inlet to see if the engine sound changed due to it sucking in the WD40....no difference. Is this a good way for checking gasket/rubber leaks? When I stripped the carb, I had the following jets/needles: 33 270k 300 118 60 Not sure which jets/needles they are though??? I might strip again and take a photo so someone can point me to which one is which. I'll also ring GG today and see what they think. Thanks all for all the replies so far. Cheers, Wayne (very confused) Edited October 21, 2011 by waynerobshaw Quote Link to comment Share on other sites More sharing options...
lowbrow Posted October 21, 2011 Report Share Posted October 21, 2011 Next time it starts farting around see if it behaves when you take the fuel tank cap off. Could be a blocked one way valve on tank cap breather pipe, or its on the wrong way round or the pipe itself could be blocked. Worth a try; costs nowt! Quote Link to comment Share on other sites More sharing options...
copemech Posted October 22, 2011 Report Share Posted October 22, 2011 Yes, you are confusing us! Depending upon which condition you are referring to with your symptoms. Basics #1= Throttle chop ping is something of a normal condition, as you have just cut off the fuel to the motor(goes lean). I presume this is a dellorto carb? Increasing pilot jet size can help minimize this(33 to 35/36) range, as the carb is then able to provide more fuel through tht transition circuit on throttle chop. Will likely require you decrease the fuel screw setting a bit for best idle.(2turn range rather than three) Is it still running ok otherwise now? Quote Link to comment Share on other sites More sharing options...
jse Posted October 22, 2011 Report Share Posted October 22, 2011 (edited) Yes, you are confusing us! Depending upon which condition you are referring to with your symptoms. Basics #1= Throttle chop ping is something of a normal condition, as you have just cut off the fuel to the motor(goes lean). I presume this is a dellorto carb? Increasing pilot jet size can help minimize this(33 to 35/36) range, as the carb is then able to provide more fuel through tht transition circuit on throttle chop. Will likely require you decrease the fuel screw setting a bit for best idle.(2turn range rather than three) Is it still running ok otherwise now? I'm assuming the "33" is the pilot and this is a standard Keihin PWK28 on a 300 Raga (usually mid-40's works well). That seems way lean for a pilot on this configuration. That would be way lean for a Dellorto in fact (usually #36-38) and may be the cause of the chop/pink problem. Air screw adjustment should be done according to ambient conditions (blip throttle and in/out to get best reponse). The backfiring problem is somewhat of a puzzle and could be flywheel alignment related, as well as an air leak (usually manifold). The shock loads on the flywheel/crank taper for a Trials bike are huge in comparison to most bikes and the flywheel bolt needs to be checked now and then. Jon Edited October 22, 2011 by JSE Quote Link to comment Share on other sites More sharing options...
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