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DR650 Jetting with stock pipe

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I have a 2004 DR650. I still have the stock pipe which I plan on leaving on. The bike runs really clean except for at a steady throttle speed it seems to be starving a little for fuel. I have a Twin Air filter with airbox still stock. I remember reading a post from MXrob about jetting without using the DynoJet kit. I can't find the post though. My question is can I just shim the needle, install one of Jesse's fuel screws and call it good? Or should I swap out the stock main jet and remove the snorkel? I seem to find conflicting stories about the changing the main jet. I remeber reading about the Dynojet main jet being off by about 10. (ie: 160 dynojet main = 150 Mikuni main) I should quit being so cheap and just buy the Dynojet kit. Also is the snorkel the small piece on the top of the airbox?

Thanks!

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I have a 2004 DR650. I still have the stock pipe which I plan on leaving on. The bike runs really clean except for at a steady throttle speed it seems to be starving a little for fuel. I have a Twin Air filter with airbox still stock. I remember reading a post from MXrob about jetting without using the DynoJet kit. I can't find the post though. My question is can I just shim the needle, install one of Jesse's fuel screws and call it good? Or should I swap out the stock main jet and remove the snorkel? I seem to find conflicting stories about the changing the main jet. I remeber reading about the Dynojet main jet being off by about 10. (ie: 160 dynojet main = 150 Mikuni main) I should quit being so cheap and just buy the Dynojet kit. Also is the snorkel the small piece on the top of the airbox?

Thanks!

Yes! If you want to leave the air box stock just remove the snorkel and shim the needle 1mm (raising it to richen the mixture). Use a 3mm flat washer or two to add up to 1mm and put it/them between the stock needle's white plastic spacer and the needle clip. No other jetting changes are required unless you live up with the nose bleeders.🤣 Stock main is fine as is the stock pilot jet. Just install one of Jesse's fuel screws- set your pilot circuit and call it awesome.... OK maybe not awesome. 👍 You don't even need to remove the carb for any of this. You can just pivot the carb both directions still mounted in the manifold/air boot (just loosen the clamps obvously). Tilt the top of the carb to the left to remove the slide to access the needle. Tilt the top to the right to access the pilot screw easier. Just remove the screw holding the rear brake fluid well and remove the cables... in fact you don't have to remove the throttle cables... just loosen the cable ties holding them to the frame backbone to allow them to swing out away from the frame without tweaking them. The choke cable, however, should be removed. Easy, 12mm open end wrench and it unscrews from the side of the carb. If you don't the POS plastic cable guide will bust into several useless pieces. 🙂

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Thanks Rob, would the DynoJet kit be that much better than modifying the stock set-up? I remember your write up with the different needles. In your opinion is the KTM needle better than getting the DynoJet kit?

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Thanks Rob, would the DynoJet kit be that much better than modifying the stock set-up? I remember your write up with the different needles. In your opinion is the KTM needle better than getting the DynoJet kit?

Yes, that much better. The biggest restriction to increased performance on the DR650 is the stock air box. It's the number one hindrance to more get up and go. The next in line is the stock exhaust. But if I had to choose between a modded air box and DJ kit or a GSXR exhaust system for increased performance I'd pick the modded box and DJ kit. Now, once you let the intake side breathe a performance exhaust system makes a much larger difference... and the best is the GSXR sytem of course. 👍

Edited by mx_rob

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Alright Rob, I'll order up the DJ kit and quit fooling around. One last question. With the DJ kit, stock exhaust and modded airbox, do I still run the stock 140main jet? I assume that the kit is mainly for the needle. I'm in Northern, CA at sea level.

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Alright Rob, I'll order up the DJ kit and quit fooling around. One last question. With the DJ kit, stock exhaust and modded airbox, do I still run the stock 140main jet? I assume that the kit is mainly for the needle. I'm in Northern, CA at sea level.

No, the kit comes with it's own main jets. You'd want a DJ150 or DJ155 for the stock muffler at sea level. Remember the DJ main jets have a different numbering system than the stock Mikuni jets. MK jets are richer with the same number. There is a chart floating around for the match up between the two types of jets.....

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