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| 78 CR125M carburetor problems https://vintagedirtbikeforums.alp-sys.com/viewtopic.php?f=21&t=36 |
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| Author: | Doug [ Sun Jan 25, 2004 9:43 pm ] |
| Post subject: | 78 CR125M carburetor problems |
I have a 78 cr125m with a stock carb. The problem I'm having is when I try to rev it up, it bogs.Acts like it's not getting fuel. In fact, the fuel shoots into the airbox when I open the throttle. I've had this thing apart several times and don't see anything wrong. I put in a new size 135 main jet, with the stock pilot jet checked, thouroughly cleaned and reinstalled. It will rev up, sporatically, for the first 15 or 20 seconds or so, then it will only idle. I've adjusted the slide needle from the top notch down to the next to bottom and in the middle, but doesn't seem to make any difference. The bike always starts on the first kick, so I don't think it's a timing issue. Can anyone please offer any advise? Thanks, Doug |
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| Author: | Doug [ Sun Jan 25, 2004 9:44 pm ] |
| Post subject: | Re: 78 CR125M carburetor problems |
I for got to mention that I'm seeing oil seapage from around the plug. I pulled it out to find I had a wet black oily plug. The bike seems to smoke more than I think it should. Could this possibly mean I may have an oil seal leaking from trans? |
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| Author: | Barry [ Sun Jan 25, 2004 9:44 pm ] |
| Post subject: | Re: 78 CR125M carburetor problems |
Sounds reasonable, could be the center case gasket as well. |
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| Author: | Shawn [ Sun Jan 25, 2004 9:46 pm ] |
| Post subject: | Re: 78 CR125M carburetor problems |
Hi Doug, I had the same problem that you're having right now, and it was very frustrating for me had the carburetor at least 10 times. You could have few problems that causes the engine to boge, first, I would check. The excess amount of gas in the carburetor, open your fuel valve until your bowl gets full and then close the valve and run the engine and see if your problem is solved, my problem was bad crank seal, which the transmission oil went into the crank housing, You have to open the cylinder or you can open the plug and turned the bike upside down and see if you have any oil dripping out from the plug. My bike, would start an idle like Champ but as soon as I open the throttle gas, would shootout, I hope this helps |
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| Author: | John [ Sun Jan 25, 2004 9:46 pm ] |
| Post subject: | Re: 78 CR125M carburetor problems |
Check your reed valves. I'll bet one is broken, chipped or weak and not closing completely. Or your floats are set too high. |
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| Author: | Rick [ Sun Jan 25, 2004 9:47 pm ] |
| Post subject: | Re: 78 CR125M carburetor problems |
Replace the main jet with two sizes smaller and give it a whirl. I think it is running rich but you are reading it backwards. My 2000 CR250 just did this to me. Reeds will likely be fine. |
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