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Rich or lean???

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Bike: 1990 DR650

Mods: Slip on exhaust, Dynojet kit with 160 main(147.5 stock), needle set 4th clip position down, snorkle removed, K&N filter, air pilot adjusted 2.5 turns out. All carb mods done per dynojet instructions.

Symptoms: Bike starts perfect, comes on strong, but between 4.5-5K rpms, it hits a bog, then rolls past the initial missing after 5K. This is worsened when the throttle is opened fast. So is it rich or lean?

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ThanX! I'll throw in the 155 and see what happens. Curious as to how you can tell between the two conditions. I couldn't tell if it was fuel starvation, or gorging? :thumbsup:

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Just did some test runs with the 155 and it now kicks ass! No bog. Thanx for the fast advice. Nicest part is the main takes less than 5 minutes to change. :thumbsup:

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hello Neville1,

I had also almost the same problem with you. You can have a look at my recent posts. I ride also with a K&N filter, airbox open top and an fcr 39. The bike was running fine except a small part of throttle opening (somewhere above the 1/2) where i couldnt understant if the bike was rich or lean. It was more like a "blrrr" and then the bike was coming to top end almost fine.

It was rich. I managed to make this rich condition dissappeared with the FS at 2.5 turns out. I believe that i can also go down to a 155 main (at the moment 160) but i should have to buy it.

What carb are you using? Needle? Clip?

Did you chech your plug with the 160 main and then with the 155?

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I believe the carb is a cv 40. The needle is whatever came in the Dynojet kit. The clip is 4th position down. It ran so good with the 155 that I didn't bother checking the plugs. I don't know about the new DR's, but my old one has 2 spark plugs.

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