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| Fuel Starvation??or something else?? | |
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| Tweet Topic Started: May 27 2012, 06:35 PM (535 Views) | |
| neaty5000 | May 27 2012, 06:35 PM Post #1 |
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Knight
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Hi Guys Having a problem with my 644 DS, its holding back at higher revs intermittently - to me its like once ive accelerated hard once or twice and then i go for it again it holds back about 2/3rds of the rev range - as if fuel starved. its then ok again if i bimble - possibly float height is incorrect? and im using the fuel up before it has chance to be refed? Its done 4700 miles I have just checked TPS and adjusted - wasnt far off so no change K&N fitted - air box lid removed Sports exhaust 150 main jet 25 pilot Needle on second clip New fuel Cleaned out fuel filter - original type inside fuel hose new plugs Emissions items removed and blanked Any ideas?? |
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| Monty | May 27 2012, 08:07 PM Post #2 |
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Charlie Big Banana's
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You may have to drain the tank, there has been issues with the swarf from the drilling of the fuel taps blocking the filters(which you have checked) may be large particles blocking the internal pipe Shot in the dark, but you will changing the pilots I know. Tesco's fuel or shell, basicly what I mean is crap from supermarket pumps or the better stuff from a larger company 98 octane if your wallet will go for it, will run ok on 95 |
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If it aint sharp I can play with it My Utube Channel, lots of bike vids here. Subscribe if you likehttp://www.youtube.com/user/choppermark?feature=watch
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| neaty5000 | May 27 2012, 08:34 PM Post #3 |
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Knight
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Ok, ive just checked the fuel tap and tank breather - both are clear of blockages Fuel filter is spotless Tank was drained a couple of days ago as the filter had dirt in it Changed Main jets and cleaned out float bowls too so ruleing out those items It is on supermarket fuel 95 ron - but why intermittently? found an old thread on ccm riders with owners having the same problem but no resolve - talk of high flow fuel taps etc I am changing the pilot jets soon, so i thought it would be a good time to check float heights Cant find any guides to do this though? |
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| Marc | May 28 2012, 07:23 PM Post #4 |
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Marquess
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I would check the diaphragms atop the carbs,they could be ripped/nipped and make sure clips are both set in the same slots while you are at it... Edit : 2nd slot seems low from my feeble memory,are we talking from the top or bottom,I'd be tempted to aim more to the middle range |
CCM 644,Kent cam,Braking wavy disc and 4pot caliper,Brembo radial m/c etc etc
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| neaty5000 | May 29 2012, 09:45 PM Post #5 |
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Knight
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............ Continued Removed Carbs tonight Diaphrams are perfect Needle setting second from bottom on both Changed pilot jets and bowl screws Added Redex fuel cleaner to fuel Set mixture screw Took it for a ride - was better but it didnt seem to pull that strong, so i replaced the airbox lid and it was much better! Do i need a bigger main jet than 150? Tops out at 95mph on trail wheels is this normal with standard gearing? |
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| pickle3 | May 29 2012, 10:56 PM Post #6 |
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Earl
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I would of said bigger pilots too, I got twin air dualphase foam and I got 27.5 pilots and 150 mains arbox lid off. Not sure if for 710 with box removed completely but remember off riders with k &n with 157.5 and 162.5. Or get some more 150 and drill them out till you get desired performance
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| http://i864.photobucket.com/albums/ab205/p...13/SAM_0759.jpg | |
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| Monty | May 30 2012, 06:09 AM Post #7 |
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Charlie Big Banana's
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150's should be fine with lid off, if it runs better with lid on, is it low down or throttle wide open, pilots usually work from fully closed to about 1/3 throttle mains approx 1/2 to full. You may have a leak in the inlet manifold, hense having to refit lid 95 on trail wheels, scary, why? private road of course |
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If it aint sharp I can play with it My Utube Channel, lots of bike vids here. Subscribe if you likehttp://www.youtube.com/user/choppermark?feature=watch
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| neaty5000 | May 30 2012, 08:50 AM Post #8 |
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Knight
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Forgot to say that i had checked float setting using clear tube method - Both carbs where level with the top of the float bowl joint flange. Intake leak wise - the only thing i can see could make a slight difference is the aluminium pipe that fits between the manifold and air filter is not bonded into the rubber manifold - not sure if they are supposed to be? But it is a snug fit, so? What would be a good solvent to bond these? The private road test was me trying to establish if my bike is down on top end power |
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| Monty | May 30 2012, 10:34 AM Post #9 |
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Charlie Big Banana's
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The ring for the airfilter will not be an issue, its the rubbers fitted to the head that could cause your problem Try spraying carb cleaner at strategic points when the bike is running. The revs will rise if theres an air leak at that point as carb cleaner is drawn in. I have attached a diagram that will will explain what jets do what
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If it aint sharp I can play with it My Utube Channel, lots of bike vids here. Subscribe if you likehttp://www.youtube.com/user/choppermark?feature=watch
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| neaty5000 | May 30 2012, 11:06 AM Post #10 |
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Knight
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Thanks Monty Thats a great diagram and a handy tip with the carb cleaner i will give it a try |
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| pickle3 | Jun 5 2012, 05:52 PM Post #11 |
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Earl
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Silicone sealent. <..spelling Don't think that is std though just what I used. |
| http://i864.photobucket.com/albums/ab205/p...13/SAM_0759.jpg | |
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