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Jetting After Installing MRD Pipe Doing My Head In!

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This has been an ongoing problem since last year...

434BB/FCR39/"E" cams, airbox, cdi. Carb has had Eddie mod since 2010. E model carb.

Sea level.

I changed to the MRD last year. Before that I had an E header and an aftermarket muffler. As soon as the MRD was on the bike it started running really poorly, juddering under steady throttle and not smooth. Under load or winding the throttle it was fine but under steady throttle it was bad. Jud jud jud.

Settings last year and up to last week were PAJ at 38 and EMR needle middle clip. A/f screw 3 turns out. Turning it in all the way changed nothing. Turning out to the point of the screw almost falling out would make it stall. This is where it ended up after weeks of messing around with first a 42 PAJ from a 45, then a 40 then a 38. EMN needle wasn't working well either so the EMR went in.

Then about 3 weeks ago it started running really rich... I could even smell gas. I pulled the carb and checked if it was clean. Yes. Changed the Keihin a/f screw to an RD Flexjet. Dropped the needle down one clip, threw in a 35 PAJ and installed a 148 main from 150. Yes I have the baffle in the SSW pipe.

Now it runs quite well but the a/f screw needs to be 4 turns out. If I turn it IN more it stalls. I can turn it out all the way and nothing changes. THIS IS THE OPPOSITE of before with the previous settings. Still running a bit jud jud jud but less. With the 35 PAJ it is almost gone. Runs well if I wind the throttle.

Could this be a different problem than jetting? Like maybe the AC pump diaphram is torn or something else? I have no idea what I am talking about but the jetting is just so waaay off the recommended settings of 45 PAJ/EMN needle 3rd clip/ af screw 1.5 turns.

Any suggestions where to check would be much appreciated. Any link to how one sets the ac pump timing or aim or duration of squirte would be helpful too.

Thanks!

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Starts easy.

Idles smoothly.

Haven't tried pulling the insert BUT did try riding with the filter door off then tape over the air box opening. Ran worse in both cases.

Coast enricher was off when I bought the bike. Ports are capped, not joined.

Current settings...

148 main jet. Cork in pipe and not coming out.

200 main air jet

60 pilot air jet... MAYBE this is a problem...?

EMP needle 4th clip. Bike came to me with EMN on 3rd clip. Ran poorly with MRD until EMP installed.

35 pilot jet. Came with 45. Ran poorly with MRD until 35 installed.

Fuel screw 4 turns out.

I have the previous owner's tech sheet saying there's a 65 starter jet in the carb?

I also don't know how to check if my AC pump is OK. Will continue searching on here.

Edited by Flywalker

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GreenHornet450... thanks for your post. Would you happen to have a part number for the AP rod seal? Can't seem to find anything under that name. My carb is the E model not MX.

Craigo as always thank you! Any advantage to joined ports and 60 pilot air over capped ports and a 100 pilot air jet?

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GreenHornet450... thanks for your post. Would you happen to have a part number for the AP rod seal? Can't seem to find anything under that name. My carb is the E model not MX.

Craigo as always thank you! Any advantage to joined ports and 60 pilot air over capped ports and a 100 pilot air jet?

 

Either way achieves the same outcome...

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