thedktor Posted May 6, 2008 Report Share Posted May 6, 2008 On a 2004 300 Raga Rep. When I test rode the bike before buying I noticed a tinkling rattle coming from the carb at low revs. Once home discovered it was the slide rattling in the carb bore. Reassembled and rode it several times a few hours each time and the noise had gone strangely. Stripped the carb again recently, rode it after and and the noise is now returned worse than ever! It basically "tinkles" away continually at low revs - rather annoying. I hadn't touched the slide and left it attached to the throttle cable, so its a bit odd why things have changed, any ideas?? I took the carb off again and cannot find anything wrong at all.... Steve Quote Link to comment Share on other sites More sharing options...
baldilocks Posted May 6, 2008 Report Share Posted May 6, 2008 On a 2004 300 Raga Rep. When I test rode the bike before buying I noticed a tinkling rattle coming from the carb at low revs.Once home discovered it was the slide rattling in the carb bore. Reassembled and rode it several times a few hours each time and the noise had gone strangely. Stripped the carb again recently, rode it after and and the noise is now returned worse than ever! It basically "tinkles" away continually at low revs - rather annoying. I hadn't touched the slide and left it attached to the throttle cable, so its a bit odd why things have changed, any ideas?? I took the carb off again and cannot find anything wrong at all.... Steve Is the carb touching the crankcase or the support that bolts onto the barrel ? Your carb is rubber mounted so it shouldnt rattle unless its touching somewhere. Quote Link to comment Share on other sites More sharing options...
jse Posted May 6, 2008 Report Share Posted May 6, 2008 Is the carb touching the crankcase or the support that bolts onto the barrel ? Your carb is rubber mounted so it shouldnt rattle unless its touching somewhere. That's my first guess too. As yet, I havent heard of a Keihin slide rattling, other than in an engine that's sucked a lot of grit and then, you wouldn't notice the slide over all the other noise the engine will make under those conditions (you might want to check the bell of the carb for accumulated dirt just to be sure). The Keihin hangs lower than Dellorto (and is longer, end-to-end, which is why I think the airbox boot, made to fit the large mouth Keihin and 03' VHST Dellorto, is a little too short for the standard PHBL Dellorto that has to use the rubber donut to adapt) and it's a tight fit. You might try a small thin piece of rubber or other insulating material between the carb body and the top of the case. I had to do the same thing when I put a Keihin on my old JTR370. Jon Quote Link to comment Share on other sites More sharing options...
hrc1 Posted May 6, 2008 Report Share Posted May 6, 2008 The Keihin on my pamp has a rattly slide too. However this goes away when throttle is opened. So - the cure: keep it pinned. Quote Link to comment Share on other sites More sharing options...
jse Posted May 6, 2008 Report Share Posted May 6, 2008 The Keihin on my pamp has a rattly slide too.However this goes away when throttle is opened. So - the cure: keep it pinned. Cool. That is one way to fix the problem Kinda like a buddy told me when I was flat tracking: "If you don't fall down once in a while, you're not going fast enough!". My problem was, I was going "fast enough" waaaaay too many times......... Jon Quote Link to comment Share on other sites More sharing options...
thedktor Posted May 7, 2008 Author Report Share Posted May 7, 2008 Yes the carb touching the engine cases was the first thing I checked but I always makes sure there is clearance anyway when fitting. I did notice that the carb vibrated a lot which has triggered a little light-bulb in my head - I was originally thinking it was intake pulses making the slide rattle, but I'm thinking now it is actually due to the carb vibration. I need to fiddle around with the boots and carb position to see if this can be reduced - when I take the carb off I remove the airbox/mudguard first so this could affect things as well presumably. Steve Quote Link to comment Share on other sites More sharing options...
peterb Posted May 10, 2008 Report Share Posted May 10, 2008 Hi Steve, I wouldn't worry too much about the carb rattle. I have used Keihins on Gas Gas since 2001 and after a while the rattle does develop, at low rpm just on tick over. It was evident on my friends bikes too and certainly not caused by a lack of airbox maintenance. I think there is little surface bearing area in the first few mm of the throttle body venturi of the flat slide Keihin when compared to (the force!) a circular throttle body type which may accentuate any slight wear in the area creating the rattle. If you have a close look, you can move the slide around rather easily back and forth in the throttle body in the almost closed position. Ta ta, PeterB. Quote Link to comment Share on other sites More sharing options...
toofasttim Posted May 10, 2008 Report Share Posted May 10, 2008 and certainly not caused by a lack of airbox maintenance. I think PeterB might be having a dig at me here Quote Link to comment Share on other sites More sharing options...
thedktor Posted May 12, 2008 Author Report Share Posted May 12, 2008 Yes I can easily move the slide back and forth and there is no sign of any grit intake so normal wear it seems. I am thinking that when I last fitted it I had twisted it against the slide spring so there was a bit of rotational tension and hence no rattle. As an experiment I tried fitting it with 1/4 turn twist compared to its natural position and the noise did reduce a little. Wont be buying a new carb in the near future so guess I will have to live with it! Steve Quote Link to comment Share on other sites More sharing options...
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