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| jetting /carb choice for 1980 cr250R https://vintagedirtbikeforums.alp-sys.com/viewtopic.php?f=21&t=2400 |
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| Author: | jimr5321 [ Wed Jun 03, 2009 9:19 pm ] |
| Post subject: | jetting /carb choice for 1980 cr250R |
I am having difficulties with the jetting on my 1980 cr250 . I am using the stock keihin carb ,71 mm bore ,boyesen dual stage reeds, circle F pipe. I realize the reeds make the engine run a little rich on the main and lean on the pilot . I have dropped one main jet size and turned the air screw. However , it still seems really rich at high rpm and extremely lean at low rpm.Has anyone had the same difficulties ? I am at 615 feet above sea level and run maxima castor at 38 to 1 with 93 octane gas. Also has anyone dropped kicked the keihin and bought a mikuni form one the vintage suppliers . If so, what size of mikuni and what jetting . I see some places advertise prejetted carbs . Would this be a custom application for altitude , application etc? Sorry for the long winded question any input would be appreciative. Thanks |
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| Author: | redrocket190 [ Thu Jun 04, 2009 12:07 am ] |
| Post subject: | Re: jetting /carb choice for 1980 cr250R |
Jetting for 36mm Mikuni VM roundslide carb. This works in SoCal so sea level up to 1000' and 75-85 degrees F. Pilot 35 Air screw 1.75 out (could go in a turn and use a 30 pilot) Slide 2.5 Needle Jet 159-P8 Needle 6FJ6 Clip #2 Main 360-380 Float height 19mm |
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