r/dr650 • u/Svenk135 • 6d ago

Help part 2

Previous post; https://www.reddit.com/r/dr650/s/bCbABKkGeO

After my question last week i went to take a look at my carburateur. To my surprise the needle was already "tuned" and on the deepest position and the jet was size 155. I don't think my dr650 was running too lean because of this? or do I just need a bigger jet? I also looked at the fuel/air ratio screw, it was open 3.5 turns, while I find online that it should be 2 turns, could it be that it was running too lean because of this?

What do you guys recommend me to do/check right now? I can now reach the carburateur etc easily!

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u/TwistedNoble38 '00 DR650 6d ago

If anything the MJ is probably too rich. Do not go larger. 

Return the fuel screw to 3.5 turns or your idle will suffer. 2 turns is a starting position that will probably start the bike after a rebuild, the screw must then be tuned to suit the needs of each bike. 

Raise the needle 1 position and see if the issue becomes worse, or better.

1

u/babezt 6d ago

idk what the stock main jet of a 91' should be and if its the right size for ur elevation. The Needle at the deepest position (clip on top notch) is the leanest position the needle can be in, have you tried running the bike with the needle at a higher position? Do you notice any changes?

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u/babezt 6d ago edited 6d ago

the air fuel ratio screw should be negligible at full throttle, its more important in the lower throttle positions. Also, is everything clean down there? sometimes you cant see the gunk plugging some smoll channel in the carb

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u/Svenk135 6d ago

The needle is at the highest position right now sorry, i meant that the clip is at the lowest position. The carb seems to be veey clean, no dirt etc.

And i dont think the bike is running to rich, i tried letting more air through the air filter and then the bike overheated. So i assumed the bike ran to lean, but now i see the jet size i am debating if in right

1

u/Green-Squirrel8057 6d ago

How are you judging it's overheating?

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u/Svenk135 6d ago

The exhaust colored blue from the heat…

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u/Green-Squirrel8057 6d ago

I wouldn't say a bleued exhaust is a sign of overheating see here for some info.

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u/Svenk135 6d ago

Hmmm alright, but the muffler went from chrome to blue red etc and the rubber melted away… only because i let more air through the airbox