DR350 Thread

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

  1. MrPulldown

    MrPulldown Long timer

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    I just got some new rubber and need to do a couple of rear wheel swaps. It is always like wrestling a bear. Any one have any tips for getting the rear wheel back on the swinger. I already do most of the basics. Thinking of trying to support the rear wheel with a floor jack. I hope this tire comes in time for the weekend. Got a 120/18.
    [​IMG]
    Tusk DSport Tires | Adventure Rider (advrider.com)
  2. Ibraz

    Ibraz Been here awhile

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    Are your swing arm, axle, spacers, mating surfaces clean and greased? Gunk can cause clearance issues. Always slips in place nicely for me when clean and grease helps keeping the spacers in place. I use a floor jack that lifts the rear wheel just 1 inch above the ground so pushing upwards makes the bike stop tilting forward when the front contacts the ground.
    Usually sitting on the floor behind the bike and supporting the rear wheel with my foot.
  3. cwc

    cwc . Supporter

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    One thing I've done is to countersink the holes in part 3 (below) and use flat head screws for part 4. Probably not as big a deal in the shop, but on the trail it's just one thing less to contend with.

    upload_2021-7-21_6-58-4.png
  4. plugeye

    plugeye MC rescue

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    2x4 under the tire helps getting all lined up for axle penetration
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  5. markk900

    markk900 Long timer

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    I'm sure you do but just in case....do you pull the clips and pins from the end of the swingarm?
  6. plugeye

    plugeye MC rescue

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    i never have
  7. plugeye

    plugeye MC rescue

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    cleaned up a little
  8. Woodland_Johnny

    Woodland_Johnny Adventurer

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    IMG_7418.jpg
    Hey, DR350 lovers!

    Just got done with a big slew of work on my '96 SE (the copper one on the right) and the bike is running pretty dang good! I did the 440 big bore job a couple summers ago after my piston blew up. Other than a small leak at the base gasket (reared it's head right away) that I sealed with high temp rtv, it's been holding strong.

    I recently put a 16t front sprocket on the bike and now I can cruise at 60 mph at a smidge over 5k rpm and 70 mph right at 6k rpm! Very happy with that as I do mostly road and dirt road miles. It goes a long way toward getting this thing to be the lightweight ADV bike I've been dreaming about. I'm 5'5 tall and 150 lbs.

    I had a couple of questions, one related to jetting/fuel and the other motor oil.

    Can anyone with the 440cc bore done on their bikes enlighten me to their carb settings? I'm at sea level. There's also an aftermarket exhaust and airbox is opened all the way up.
    The previous owner did the Dynajet kit... I think he just put the new needle in but I haven't looked in awhile to what it was shimmed to. I am running the stock pilot and a newly added 145 main. It's a big improvement from 137.5 but I almost wonder if she wants more on the top end. I get a little backfiring on deceleration but nothing crazy.

    However! My gas mileage is abhorrent, clocking in at around 35 mpg. While my partners bike (open airbox and aftermarket camshaft I think?) is getting 55-60 mpg. Now, I would have thought the big bore would be the culprit, BUT this has been the case since I got the bike, before I did the big bore. It's always been a hog on gas. Another clue I can't fit together is when the bike sits with the pet cocks open, it floods the carb in short order. Where as my partners bike (same acerbis tank) can sit with the petcocks on for a couple hours (oops) and not be flooded. Do I need to reshim the needle, adjust the float? Should I look for a pumper carb or rebuild kit for mine? I'd really like to get more than 35 mpg.

    I'm pretty impressed with how well the bike pulls from 60-70. I have yet to actually go out and try to get a top speed clocked in but I will soon. I get some wobbles at high speed and think my front tire may be unbalanced so maybe I should take that in before breaking any land speed records.

    IMG_7602 (1).jpg

    My other concern is engine oil. It's a very unintuitive set up for monitoring oil levels and it scares me. Especially because it is probably the reason my piston blew up last time, as the bike only had 3k miles on it when I got it. I was on a long trip through British Columbia at the end of a long riding day. I honestly don't know if I was overfilling or underfilling. It's frustrating that I can check the bike after a ride, and the level will be different depending on whether I waited one minute or three to cool down. I've been doing the procedure specified in the manual, but that doesn't seem to warm the bike up enough and causes me to overfill, which I notice after I check it on a real ride....

    So, we know these bikes burn oil, and it seems to be more so at high rpm (duh). So what is YOUR personal procedure for checking the oil and getting an accurate measurement? I really don't to overfill the bike regularly.

    Oil Temps. When I ride there are times when the engine feels pretty hot through my right boot, not hot other times. I assume this is normal. However, I am concerned with keeping the oil cool, especially since I have the big bore now. I do live in the PNW so it rarely gets insanely hot and I almost always have cool air rolling through the fins. I'm wondering though if getting and oil cooler would be good insurance? Anyone with the BB run one?

    Last thing for now, sorry for the novel, but I want to be realistic about the 440 kit for other people considering it. I'm wondering if anyone else that has done it has noticed a real performance difference? My partner has a lightly modded bike but it seems to pull just as well as mine and go just as fast... I have to do some more accurately measured comparisons. But part of me is worried that I had the cylinder enlarged, compromising the strength of the engine, for not much gain. That could also be that it's not tuned properly as I mentioned above, but I'm a newby at a lot of this stuff and the carb specifically is confusing.

    Thanks a lot for reading, any responses are appreciated. Even just to the parts you're interested in!

    Johnny
    Hamburgerhotdog likes this.
  9. slartidbartfast

    slartidbartfast Life is for good friends and great adventures Supporter

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    Oil cooler not necessary unless you are doing a lot of slow, digging through mud, 1st gear slipping-the-clutch, type of riding.

    If you are doing something even close to the factory suggested procedure or checking the bike shortly after a run, you should be seeing oil somewhere within the acceptable range marked on the dipstick. If above - well you clearly over-filled; If below - add some! It's not exactly a big deal until you overfill by a lot or let it run very low.

    I've been fortunate neither of my DRs used much oil. The 93 435 big bore would weep and burn a little when run hard but it was more of an irritation than a real problem. The 96 SE is still pretty low mileage, has never been abused and uses zero oil.
  10. rockt

    rockt Long timer

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    Stupid question but is the dipstick screwed all the way in or out when you check it?
  11. Woodland_Johnny

    Woodland_Johnny Adventurer

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    I just rest it on the threads. I don't screw it in!
  12. Woodland_Johnny

    Woodland_Johnny Adventurer

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    Thanks for the response! Good to hear about the cooler.

    I was under the impression that with the cam journal situation that it was pretty imperative to have the oil where it's supposed to be. And now having a piston blow up on me and leave me stranded I'm extra cautious. I'll just make sure I let it cool down a minute or two after a real ride. I just don't know what else would have caused my piston to explode like that. It was gnarly looking. IMG_4920.JPG IMG_5260.JPG
  13. markk900

    markk900 Long timer

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    Makes the job way easier.....
  14. MrPulldown

    MrPulldown Long timer

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    SO the screw head does not protrude as far out into the swing arm opening. Like you can see in Plugeye's Scotts swinger pic above, it could really get in the way. Good idea

    I think this is where my struggle comes from. I am sitting on the ground trying to lift the tire with one hand and inserting the axel with the other, using my foot or knee as a lif. One of the spacers is bound to slip out of place. I was thinking of using a floor jack to help lift the rear wheel. Maybe I am over thinking this and all I need is a 2x4.

    Not typically. I looped the chain over the side of sprocket before I attempt to slide the hub into the swinger. Not enough length in the chain to come in from the opening. If I do not have to contend with the chain I would insert the axle first and push it in from the rear (with pins removed). Half the time mid struggle I pull the pins just to have one less thing in the way but it doesn't usually do me much good.

    Oh yehh. I don't grease the axle. Clean, buff and lightly oil. I find that grease on the axle can get sticky, and make it hard to insert. Grease on all of the spacers to help hold it in place. I also use a cush drive so the assembly is left spacer, hub, cush spacer, cush, right spacer. Many times I have finished the job only to find the cush spacer on the floor. DUUUHHHooo.
  15. slartidbartfast

    slartidbartfast Life is for good friends and great adventures Supporter

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    Breaking pieces off the side of the piston, above the rings like that, is usually a symptom of detonation. Causes could be related to mixture, fuel choice, incorrect spark plug, or ignition timing (only really a problem with big bore and not easily changed.) While an overheated engine is more prone to detonation and there may be an element of localized overheating, extra cooling for the oil would be unlikely to help much.
  16. MrPulldown

    MrPulldown Long timer

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    Need to check the float needle. It should not flood at all, even with the petcock left open all the time. Make sure the float needle is not worn and the o-ring on the seat is in good shape. Get o-rings rom Greg.
    O-rings for the Suzuki DR350 - Moto Guzzi Parts - Products - Gregory Bender (thisoldtractor.com)

    Most will tell you to only use Mikuni parts. This is especially true for the jets. You mentioned that you are running a 145 MJ. Is that a dyno jet # or a Mikuni. DJ uses its own # designation and can be hard to tell what you are actually using. A 145 MJ sounds large even for a 440 BBK. But if it is a 145 DJ jet then who knows. THere are conversion charts on the web that relates a DJ jet # to a Mukini. I was reading Pablo's DR350 build thread and learned that bigger bore doesn't = bigger main jet. Was learned that the larger amount of air the big cylinder gulps will pull more fuel. Pablo kept going DOWN in jet size to find the right one. Might want to give that thread a read. He did use a TM33 pumper so not entirely the same beast as you are dealing with.

    I have a cheap/generic BST33 rebuild kit that I use for some of the NON fuel metering bits. But always use Mikuni jets.
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  17. Woodland_Johnny

    Woodland_Johnny Adventurer

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    Awesome dudes! Good stuff....

    I think you're right about the detonation. At the time I was having a real strange issue where the bike seemed to run rich at low rpm (very sooty exhaust and remnants on tail), but at high rpm's it seemed to be starved, would stutter and once in awhile would totally die... only to start again a few minutes later. Almost like there was too much air in the system and the fuel had to catch up? No idea...

    Anyway, after the big bore it didn't do that as bad but still felt starved on the high end. It definitely *feels* better to my untrained senses after I put the 145 in (mikuni # not dyna). I never thought about the fact that the jet is the ratio and the bigger jug is just sucking in more air anyway... but like I said the airbox is wide open and a cobra exhaust ... I don't know, but it feels better now than it did with the 137.5 which is what I hear it should be after the airbox and exhaust mods.

    Thanks for the link, ordered the O-rings. Maybe I have to adjust where the clip is on the needle or should it not flood no matter what?

    And I imagine running high octane gas would prevent detonation as well? I have been running the cheap stuff in it.... I wonder if this could explain my terrible mpg....

    Thanks again
  18. motolab

    motolab Long timer

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  19. Woodland_Johnny

    Woodland_Johnny Adventurer

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    Thank you! So what would you look for as a cause to detonation problems in a stock DR350? Things to think about so I can rule them out and prevent this from happening again.

    Cheers
  20. MrPulldown

    MrPulldown Long timer

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    Sounds like you had a problem before the BBK and you are still dealing with it.
    The stock DR350 has a very low compression ratio (9.5 to 1?). You can run horse piss in it and it will still purrr. Aren't most 440 BBK 12 to 1. That would need the high test stuff.
    Have you always been running that Acerbis tank? How is it vented? Those short cap breather and the little dohiky on top can plug causing the tank to vacuum lock and not deliver enough fuel at higher demands.
    You should never flood if the float valve is in good shape. Though I typically do not mess the float height, it could be way off and need to be adjusted.
    Read up on carb tuning. Each bit of throttle opening (not RPM) is tuned by a different part of the carb system. Low is pilot jet and idle fuel screw. Never seen the need for anything more than the stock jet size with a BBK. But you might need to give the screw a 1/4 to 1/2 turn out.
    Hugh B likes this.