DR350 Thread

Discussion in 'Thumpers' started by leonphelps, May 16, 2007.

  1. ShaneInDenver

    ShaneInDenver n00b

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    So I am going through this new to me DR350 dirt model I just got. I emailed Jesse about some carburetor settings. The bike has stock exhaust, with the Jesse airbox mod and a K&N filter.

    I live in Denver, CO 5,000' and plan on being up in the mountains with this bike as high as 12,000', but I would like to do some passes above 14,000' too.

    The bike has a 122.5 main jet in it and Jesse recommended going up to 140 main jet. Will this be too rich for my altitude? I am new to this, but have read you want roughly 8-12% less fuel here in Denver. 8% less would be a 128.8 main jet, but we could probably round up to 130.

    Also he recommended making sure my needle is in the 3rd groove. I'm afraid I don't really know what he is talking about here.

    Thanks
  2. slartidbartfast

    slartidbartfast Love those blue pipes

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    Nope! There's your answer right there. In a one mile ride the bike does not get hot enough to drive off the moisture in the oil. It forms that white emulsion which collects in the high spots in the crank case. It won't really do much harm and one long hard run will most likely get rid of it. If you never or only very rearely do such a long run, consider changing the oil at less than the recommended interval.
  3. Greg Bender

    Greg Bender Long timer

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    Hi Shane,

    Welcome! I live at 2000 feet and generally ride up higher from here. I have a 1993 DR350 dirt model that originally came with a pumper carburetor (I've since switched to the CV carburetor). When I had the pumper installed, I also had the airbox cut (came that way from the previous owner). I have one of the original stock mufflers that Jesse has modified. I ran the stock idle jet and needed to increase the main jet to 132.5 (stock size was 127.5 for my model). I would have been wallowing in fuel at 140.

    Now that I run a CV carburetor, I use the stock settings for my model year and I am very happy with it (I'm using an uncut airbox with the snorkel installed).

    Personally, I would only ever fit a K&N filter for pavement use only. Riding in the dirt, I would fit a foam filter such as the UNI. Much better filtration and they flow great.

    As for aftermarket mufflers and cutting the airbox: My *opinion* is that they make a lot more noise with negligible (if any) performance benefits. I've yet to see anyone do back-to-back dyno runs showing differences.

    Disclaimer: my experience is limited to my DR350 riding almost exclusively at 2000 feet and much higher elevations (over 12,000 feet). Other locations/elevations may be very different.

    I hope this helps!

    Regards,

    Gregory Bender
  4. 2old2Bbold

    2old2Bbold was 2bold2getold

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    My book says stock is 132.5 and 3rd groove. If this is correct, that 140 may be a little rich at 6k to 13k ft. Not many passes much higher than that. So 122.5 might be close. How does it run. Most of us will not have a dyno or exhaust gas analyzer. You're gonna have to try it. How does it: sound... deep/throaty or tinny/pinging. smell...lots of gas smell or not. respond....quick or sluggish. Run hot or not. Plug color...white or black. Every bike is a little different depending on condition and set up. Get some jets and a manual and some help if you need it.
  5. thump!

    thump! Adventurer

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    Mr DR350 is running a stock muffler and airbox with the TM33 pumper carb. I'm also running the TM33 snorkel which is substantially larger than the CV carb snorkel. Air filter is a Uni. Except for the filter (and I agree that K&Ns aren't for me off pavement) it's probably just like yours. This bike runs well at 2000 feet with a 132.5 main and the needle in the center notch (that's the 3rd from the bottom as I recall) A couple of years ago I spent a week riding out of Silverton doing all the high passes into Ourey, Telluride, Lake City. My bike ran poorly when I took it off the trailer and simply would NOT run above 12000 feet. I don't mean it ran bad above 12K, I mean it quit! I had to rejet to a 130 main, needle in the 4th (from bottom) notch AND disable the accelerator pump in order to ride up there. It was still a bit rich and if we hadn't been planning on going on to Moab after Silverton, I would have gone even leaner. FWIW, my friends with CV carbs and low altitude jetting were little down on power at altitude but their bikes continued to run without problems. Hence, the next time I take the DR350 up there it will have the CV carb on it. (I have both) The pumper works well when jetted correctly but it doesn't like big changes in altitude!

    [​IMG]

    Trust me when I tell you Imogene Pass is NOT a good place to disassemble a carburetor!
  6. Greg Bender

    Greg Bender Long timer

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    Yep! That is where I am at, too. I can leave for a 10 day trip that spans 2,000 - 12,000 feet and the CV carb handles it better than the pumper carb (and no fiddling with jets). The CV returns better fuel economy (range), too.

    Great photo, BTW :>

    Regards,

    Gregory Bender
  7. e28rusty

    e28rusty Fool

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    So does anyone want to trade an almost new pumper carb for a cv?
  8. boardforever

    boardforever Been here awhile

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    You have a pumper you are looking to get rid of? Is there something wrong with it? :ear
  9. 2old2Bbold

    2old2Bbold was 2bold2getold

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    I agree. That Lake City, Silverton, Ouray, Teluride area is some of the best riding there is. Imogene has collected a lot of bikes and for that matter jeeps. A few years ago we came up on an old guy and is wife in a rented jeep near the top, where that step used to be on the Camp Bird side. He hit it kinda hard and jumped up in the air and almost went off the side. Must be at least 1500 ft straight down. Every body was standing around scratching their heads about how to get it back on the trail, It had two wheels on the edge. Finally I suggested we just pick it up and move it. So about 10 of us kinda scootted it 4 or 5 ft back on the trail. He got back in and gunned it again and did the same thing, but this time it landed on the trail and made it on up. His wife, though, had already walked on up to the top. Not sure she ever got back in. :evil The CV carb on the DR350 seems to work better than any carb on any other bike I've had for altitude compensation. Most are down on power about 1 gear even jetted properly, ( less air....less power) but I couldn't tell much difference on the DR at altitude. :clap
  10. MrPulldown

    MrPulldown Long timer

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    Not to talk Shit about Jesse as he knows WAY more about DR's than I EVER will. But he ALWAYS reccomends a 140 main with a cut air box. I do not think that you can go from a 122 to a 140 by jsut cutting the airbox and run well. I am sure it will run pig rich at 5K. I think he is slightly hard of hearing and did not hear 5k.

    As far as what is stock jetting on a DR. They changed in 94. The early years ran a 135 main (CV) and the 94+ (SE) went to a 127.5. Some say it was because of emmision regs. I think a kick start would be hard to start with such lean jetting.

    Greg do you run the modified Exhuast wiih the 93 stock jetting?

    Thump. Another way to get around elavation change is to mess with the air box opening. Before changing jets I would have removed the snorkle, the either crack or remove the air filter hatch. This often is enough to cheat your way to a running bike. Even losening and pulling the air filter slightly off the sealing base if you jsut need it for a short period.

    I had a little chinese 150cc scooter for my wife. I live at 6k'. The airbox had all these foam insterts covering intake hole in several different locations. Scoot ran rich stock. Kept pulling foam till it ran right. It acutally ran a little lean with all of them removed so I put one back.
  11. MrPulldown

    MrPulldown Long timer

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    Because it has SOOOO much extra power to spare.:evil
  12. Greg Bender

    Greg Bender Long timer

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    Hi MrPulldown,

    When I bought my DR350, it had a SuperTrapp muffler on it. I hated that thing. Really loud, always popping on deceleration, I couldn't get it tuned right even throwing jets in it and fiddling with the "tuning" discs. At the time I was looking for a stock muffler and there weren't any on eBay. I called Jesse and he sold me one he had modified. I don't know what a truly stock muffler is like. I've been using Jesse's modified stock muffler ever since: both with the pumper and the CV carb. Yes, I run the stock jetting (for my model year) with the CV carb, uncut airbox, CV snorkel in place, and Jesse's modified muffler. This combo works great for me.

    It has been mentioned previously that Jesse *may* recommend the 140 jet because it is very safe to go too rich rather than too lean. If this is the case, then I don't blame him one bit. It is a whole lot better to have a reputation for running too rich, than for recommending jets that are too small and holing pistons, etc. Alternatively, the way he tunes his carburetors for where he rides may justify 140 main jets. Honestly, this is all conjecture and I really don't know.

    Regards,

    Gregory Bender
  13. e28rusty

    e28rusty Fool

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    I've been fighting jetting since adding bigger exhaust, I'm ready to try something different. I don't know what else to try. I may go back to stock exhaust
  14. MrPulldown

    MrPulldown Long timer

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    This^ Makes sense. It jsut seems that there have been several mentions of speaking with Jesse and him reccomemding a 140, and the set up are all slightly differents with the only commonality being the cut airbox. And he is proably tired off listening to everyones what jetting should I use and this is a SAFE jetting he knows will work.

    Friend of mine runs a CV with a 140 and cut airbox. HE lives at sea level and says he is a bit rich. When he comes up here to ride, I have to lead cuase his bike is a choking fume machine.
  15. slartidbartfast

    slartidbartfast Love those blue pipes

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    Did you follow conventional wisdom and go for a bigger and bigger jet with every modification? If this is the case, you probably went too big (see previous post RE Jesse)
  16. Frankdozer

    Frankdozer Adventurer

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    OK, since my 1990 Suzuki DR350S has the factory stock tires on it, I want to replace them. They only have 1659 miles on them. Look great, no cracks have always been stored inside but I'm concerned that being almost 23 years old, I don't want a blow out while miles in the Maine woods or miles away from home in Maine. What tires do you recommend for 75% on road 25% off road? Thanks, Frank
  17. e28rusty

    e28rusty Fool

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    I have tried from 127.5-142.5 and needle clip at 2, 3 and 4 and it runs slightly better with the 127.5 but it still won't rev more than 3/4 of the way in neutral or under load
    Cut airbox and jesses header with fmf muffler at sea level
  18. thump!

    thump! Adventurer

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    Yep, that's how I got back to the hotel the first day. But I didn't want to run like that for two weeks. I had packed jets just in case. It's a good thing I did.
  19. FireDog45

    FireDog45 Mid-life crisis sufferer

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    I'd suggest swapping them out. At the very least change the tubes and if you're going to go to that trouble you may as well put on new tires.

    I really liked the Shinko 244's on my KLR. Very predictable on the pavement and did well for my style of riding off the pavement (motoring along quietly). I never had them in really muddy conditions but my understanding is since the knobs are relatively close together they don't clear as well as true knobbies.

    I'm planning on spooning a set on my DR in the near future.

    Another bonus is you can get a set for under $100!
  20. _CJ

    _CJ Retrogrouch

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    Anyone have any idea of average life for wheel bearings? I realize location and riding conditions play a big role, but....2,000 miles? 10,000 miles? 20,000 miles?