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clark4131

Leak Jet Experience

14 posts in this topic

I've been slowly but surely getting my jetting dialed in...that last 10% is the hardest, but I'm a perfectionist. I did some experimentation with the Leak jet today and found out something interesting. I was running the #40 jet, as has been suggested over and over, with positive results. I also installed a Boyesen Quickshot. With the proper Main and Pilot jets, and the correct needle height, I was able to get to a "seat of the pants" 90% jetting efficiency. But, I still had the "throttle snap bog" (TSB) when the bike was in neutral or at extremely low RPM's. I've timed my Accelerator Pump correctly according to both the manual and the Boyesen instructions, which produce the same adjustment. I also have my airbox opened up with a Barnums kit. For all my specs, look for my entry in the Jetting Database on the first page.

Today, I decided to play with the Leak jet some more and installed a #35. The results were amazing as the TSB was virtually eliminated. I wish I could go smaller, but the #35 is it. I guess my next move would be to solder my #50 closed and try that, unless someone out there has a .30mm drill bit...SC

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I have been telling people to solder there stock leak jet and run it if it is cool out or if your bike still has a bog. The #40 or #35 are good for most bikes with richer pilots (48) and JD needles. People keep underestimating the throttle response provided by the leak jet/ ac pump diaphram. :)

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You are the jetting guru. But with great power, comes great responsibility. Then again, the genius of many great minds is never truly realized until it is gone...That said, I'm going to solder my stock leak jet closed. Did you use anything special to do it?...SC

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I just used silver solder on the stock leak jet since it is useless anyway and I plugged the hole from the back side. It has not worn out over a full winter of riding and it will not contaminate the fuel in any way. :)

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Does this effect the "just off idle" transition area? Mine runs good everywhere except the transition from idle to slight power. No bog really just an annoying little hesitation when crawling slowly at idle and adding slight power. It sometimes will fart and die here too. I can make the transition smoother by turning the screw out about 3+ turns. I changed from a 48 to a 50 low speed jet with no real change. It still needs to have the screw way out to prevent the slight stumble.

Is this what the "Power Now" is supposed to address? Or is the flywheel just to light for good slow speed running?

Thanks in advance for any responses.

Larry

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Does this effect the "just off idle" transition area?

Absolutely! I rode today and there's virtually no bog anywhere. I think you may be too rich on your pilot and would suggest going to back to a 48 once you change the leak jet. I run a 48 with a ginormous hole in my airbox and only 1.5 turns on the fuel screw. I'm also running a 165 Main with the JD Red in the 5th position. No farting, puking, snoring, wheezing or sneezing...SC

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Absolutely! I think you may be too rich on your pilot and would suggest going to back to a 48 once you change the leak jet.

OK, thanks, I'll try it. But if this is the case, why does it run better with the screw out 3+ turns? If I turn in the screw it also starts popping on decel.

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You must be running a lean needle taper and/or clip position. :D 48 pilot is perfect on the WR and you should be around 1.5 to 2 turns. :)

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Hey thanks guys. I'll go back to the 48 pilot and raise the needle a notch. I'll let ya know what happens.

Larry

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I just used silver solder on the stock leak jet since it is useless anyway and I plugged the hole from the back side. It has not worn out over a full winter of riding and it will not contaminate the fuel in any way. :)

Will regular solder (Tin Lead SN 62) contaminate the fuel?

Thnaks for your help, Jeff

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