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XR650L Jetting Size Opinions

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I've planned on doing Dave's mods for a long time now and am finally getting ready to start getting the parts together for it. I've held off on getting a new exhaust and changing out the air filter until I can do the carb mods. I plan on doing the uni air filter / removing the snorkel, as well as a getting a slip on exhaust. On the page it is recommended to start with 55/150 jets for sea level and stock exhaust. Were I live we are at about 1000 feet ASL. I'm wondering If that will cancel out the need to richen up for the separate exhaust or what size jets I should be looking at for my situation.

 

Here's to hoping I don't get railed too hard about searching being that it is a fairly individualized question!

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I ride at 1400' to 2400' altitude with Daves mods. 160 main, needle 3rd position, 2.25 mixture screw, uni, oem exhaust with baffle cut off to max and end cap on. I run 9 exi iridium plug and ride mostly back road twisties. Have about 25,000 miles on it mostly with those settings. Pipes end is dark but not black and plug looks similar color. Seems to run good with 89 and 93 octane with ethanol additive. I do know it won't run with the side cover off the air box for whatever reason i don't know other than too much air intake?

Edited by natey

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I'm at 1000 ft above and ride up to 2000 ft above sea level and run a 158/55 as recommended by Dave's Mods. I have a Uni filter, one shim/washer on the needle, snorkel removed, and two plates removed from the bottom of the stock exhaust. I also had the mixture screw out the recommended 2.5 turns but have since screwed it in to about 1.25 turns out. The pig runs good but I think I will try a 155/52 and 2.5 on the mixture screw next time I get some motivation.

 

+1 on NOT going with the DynoJet kit. It's expensive and confusing. Buy genuine jets at www.jetsrus.com for ~$4 a piece and you'll come out cheaper with less confusion. I'd buy both 158/55 and 155/52 since the shipping is what gets you.

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yep, plan on buying from jetsrus, but I know SQUAT about jetting so Im trying to figure out a baseline for this stuff.

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yep, plan on buying from jetsrus, but I know SQUAT about jetting so Im trying to figure out a baseline for this stuff.

55 pilot and 155 main with 2.25 turns out on the mixture screw is a good starting point.

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55 pilot and 155 main with 2.25 turns out on the mixture screw is a good starting point.

Sounds good. Should I get some others while I'm at it? 158 main?

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Two things.

Check with your local bike shops (brand doesn't matter) before you order jets. My local Honda and Yamaha shops both stock a range of kehin jets and they are both competitive with the on-line guys AND I walk out with what I need.

 

Many of the Dave's Modded XRLs are jetted way too rich. If you jet to the point of no decel popping, you are probably too rich. The engine will be more lively if you get your jetting right instead of simply throwing in the fattest pilot and main that your bike will tolerate. I used the standard "recipe" on mine when I still had the CV carb on it. I got about 42 mpg and the throttle was mushy. You can get closer to 50mpg with a carb jetted right. You may be closer to correct jetting right now than you think. Shim the needle and ride it... then go up one jet size at a time if need be...

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When I bought my L back in 2008 everyone was recommending that you re jet and remove the wings from the gas tank.  It seems like now more people are staying close to or at the original jetting.  I do know that I bought an oil temperature guage early on and with the stock jetting the bike would quickly reach 275 and go right up to 300 degrees if you were stopped say for a train.  Temps would be 225 to 275 with the wings when moving.  When I took off the wings it stayed at 275 once warmed up on a hot day.  With richer jetting temps stay at 220 to 240 most of the time and I have never seen over 260 and that is with an aftermarket tank.  I admit I don't ride hard but I know for sure that stock jetting runs measurable hotter.  It used to be that everyone was saying the L was jetted ridiculously lean from the factory.  But maybe we went to far the other way?

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Well, I do know that "Dave's Mods" are meant to be done in conjunction with a higher flow air filter and removal of the snorkel. If you are running the recommended dave's mod jetting without doing those two things you are going to be off.

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1230 above sea level

 

stock exhaust / stock jetting/ de smoged /Uni filter/ de snorkeled  

runs good plug has good color  so I have not messed with jetting at all  

Edited by Zimman

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Never-mind... started my own thread.

Edited by C6 DNA

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