DR350 Thread

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

  1. xKLR_John

    xKLR_John Been here awhile

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    I understand but...

    No danger of damaging my gear or case at the moment because you can spin the engine with your hand using the kickstart lever w/o touching the decomp lever. If the decomp lever is clicking like it should when you rotate the engine to the starting position is that a sign it's adjusted ok?

    Edited to add... Thanks for the advice.... I'll take off the exhaust valve cover and check out how the decomp works. (or doesn't)

  2. yondering

    yondering Long timer

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    That's pretty much it, although it will still click when adjusted wrong. To check the adjustment, look at the outer end of the shaft, where the cable attaches. With the decompression lever released, the shaft arm should be ~1mm away from the stop on the valve cover, and it should be putting some tension on the cable.

    Here's how it works: When actuated, the shaft pushes down on the exhaust rocker arm, but only opens the valves partway. This is enough to let you kick it over. When the cam comes around and opens the exhaust valves further, on the exhaust stroke, it releases tension on the decompression shaft, and allows it (and the lever) to snap back to the rest position. This leaves the engine stopped on the exhaust stroke, so your next kick will push through an intake stroke and a compression stroke to fire it off.

    Lack of compression could be from the decompression lever, but unless you've adjusted the cable too tight, it's not likely. The cam chain is not a likely suspect either, unless it broke, which yours didn't because the decomp lever snaps back indicating cam movement. More likely, you've got internal top end damage: broken or bent valve(s), bad/broken piston rings, or a holed or cracked piston. Time for a big bore kit and pumper carb!
  3. xKLR_John

    xKLR_John Been here awhile

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    Thanks for the details. I already have the pumper carb. I'll post a pic when I discover the root cause. A big bore kit would be cool, time will tell.

  4. BikePilot

    BikePilot Long timer

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    John, it should only take an hour or two to pull the head off and have a look.

    Sounds like yondering has you squared away on the decomp mechanism - I've only worked on the automatic versions anyway. With either if its holding the valve open when it shouldn't it should be pretty obvious from a visual inspection though the valve clearance check plates on the valve cover - you'd have no valve clearance at all on the exhaust side.




    I've no idea how to decode pt#s into carb models. Have you actually measured the ID of the 250's carb? It'd have a different partnumber regardless as the jetting and probably other specs are different (slide cut etc). I know the dirt model has the 31mm carb, but I was always under the impression the street model was 33mm (probably from reading it in the manual years ago). If I'd known the street model had the small carb I'd have swapped my old BST33 onto it, but I didn't hang onto the old carb. Oh well.

    Bummer it didn't work out. I still think its gotta be possible to make it work well, but it may not be worth the trouble. Oddly the 350 runs just fine with a 37mm carb or so I'm told.

    Good luck with whatever bike you are onto next! (I bet a 346cc kit would make the 250 plenty snappy off the bottom with the 33mm carb :evil ).
  5. Bob Onit

    Bob Onit Rocket Surgeon

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    Of course I did ... it measures 31.70mm
    My Tm33 measures 33.40mm

    I've spent far too many hours of my time and I've taken up far to much time of others with a lot of tuning knowledge and busy lives on this project so it's time to put it back to stock and sell both the bike and the carb setup since the TM31 is scarce and more than I'm willing to spend on a DR250.

    And seeing that I already own five bikes as it is, the least useful one goes first. :beer
  6. SprintSix

    SprintSix Been here awhile

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    From a factory service manual 90-95. For the 250.

    It lists the BST33ss for all S and SE models. However, the 90-92 models have different internals.
    90-92 Had four types, E-03/15D1, E-33/15D3, E-24/15D2, E-21/15D5.
    93 E-03/15E6, E-33/15E7.
    94 only shows the E#, E-03and E-33.
    95 also only E#, E-03, E-33, E-24.
    The 93-95 internals are the same. The 95 E-24 is different than the 90-92 E-24. The E-33 is the california model, but is the same inside as its same year counterpart the E-03. The 90-92 E-21 is the same inside as the 90-92 E-24.

    90-91 TM31ss, 15D0.
    92 15D0.
    93 15E8.
    All 3 have different jets.

    The 90-92 models have different ignition timing and exhaust valve clearences than the 93-95 models.

    I would like to see the 350's info if anyone is willing to post it.
  7. Bronco638

    Bronco638 Nobody Home

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    No, I know you didn't. :D But, I kind of got that impression from SprintSix (see below). But, in retrospect, I think I misunderstood the intent of that post. I thought that the TM31SS might be used as a "third choice" for the 350 and that probably isn't the best choice for that engine.
  8. jrknecht

    jrknecht '14 hondaGROM

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    Okay looking for a little insight before I dig into my DR. the other day I was out riding the DR around town and it was dying at every intersection and sputtering at low RPMs (acting like it was running rich). So I took it home cleaned out the carb and then moved to the air-box and fount that the intake hole had been clogged by a piece of cloth. Once the air-box was unclogged it ran great I road it around the rest of the day and parked it.
    The next day I went out and started the bike up to head out and it was sputtering and backfiring horribly. I let it run for a little bit and when it didn't improve I put it away and drove the truck (as I was late). I just figured I had fouled the plug running it too rich the other day.
    The next day I went and got a new plug from the local shop and took it home and installed it and started turning it over, it didn't want to start before the battery died so I bump started it. I tried bump starting it in 2nd as I usually do and it wouldn't turn over so I shifted to 3rd and tried again, it started up and sounded like it was fine except that it was pouring white smoke and I mean POURING. I let it run for several minutes and when it didn't stop I shut it off and parked it. I pulled the plug again and found that it was covered in oil.
    I dont know what happened that it would be running fine one day and on starting the next be taking on oil. I am planning on tearing into the engine tonight and checking the rings and valves but I thought I would see if anyone had any idea as to the problem so I could be more focused on my search?
    Thanks all,
    Jack.
  9. Wylie

    Wylie Back in the saddle again

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    Valve guide seals?
  10. Konk

    Konk n00b

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    Does anyone out there know if rims and hubs off of any of the RM bikes will swap onto a DR350? I'm looking for an extra set to mount DOT tires on, and seems that the RM wheels are easier to find than the DR ones. Thanks
  11. slartidbartfast

    slartidbartfast Love those blue pipes Supporter

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    If you bother to look back a few pages or (heavens!) do a search, you will find lots of information on that very subject. I think the answer is No!
  12. FlyingWman

    FlyingWman Been here awhile

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    has anyone heard of dairyland cycle insurance? i got a damn good quote, just wonderin if its legit, thanks
  13. yondering

    yondering Long timer

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    Question for those of you with pumper carbs on your DR350: Have you noticed your pumper carb seeming excessively sensitive to altitude changes? Mine is very sensitive, but my engine mods may be contributing as well.

    I'm running a #40 pilot and #140 main jet, at or close to sea level. Idle and mid throttle is great, but at 5-6K rpms uphill at WOT, it pings; obviously a little lean. This setup runs great at ~ 3000 ft elevation.
    If I change to a 142.5 main jet, it runs great at sea level, but at 3-5000 feet elevation and 3/4-WOT position, it stumbles and loads up badly, obviously too rich. Anybody else run into this?

    Like I said, the engine mods confuse things a little. It has: airbox mod, head porting, torque grind cam from Web Cams, 376cc Wiseco piston (10.5:1 compression), and large header with FMF Q muffler. Huge power increase from stock, but the altitude issue is a pain; there's a lot of mountains here.
  14. slartidbartfast

    slartidbartfast Love those blue pipes Supporter

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    Yes, heard of them. Had quotes myself but have not used them. They've been around a while but I have not heard anything much from other riders - which could be a good thing I suppose.
  15. BikePilot

    BikePilot Long timer

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    Yondering, I haven't had my 350 anywhere with significant altitude changes yet so not sure. I do know that other than idle mixture its been reasonably consistent from about 40 deg F to about 80 deg F - not a huge spread, but that's about all I've had chance to sample with it so far.

    I think if it were me I'd put the jetting to your good at 3k' setting and then run higher octane fuel or just a touch of octane booster if you are already using the best they've got at the pump in your area. Also, make sure your plug, cap, wire and coil are in good shape - a weak spark can make jetting much more sensitive I've found, especially on the loading up issue. I've also read that some folks have found an improvement after replacing the resistor in the plug cap (take the cap off the plug then use a small flat bladed screwdriver to unscrew the brass bit you'll see when you look up where the plug goes, under that brass bit there's a funny little resistor) with a bit of wire. I just did my 250 and didn't notice a difference, but its worth a shot, you can always put the resistor back in if you want. I'd probably slide an iridium plug in there for good measure too as if you end up way rich the seem to tolerate it better than most - it'll be the same pt# you usually use but with an "EIX" after the heat range number IIRC.

    I'm at 40 and 140 and don't get any pinging at sea level, but mine has the stock cam, stock header and stock bore. Otherwise I'm setup the same - FMF Q, 10.5:1 wiseco, airbox opened up etc.

    Thanks, now I know :thumb Sorry for all your troubles. I'm pretty happy with my 250SE and its stock CV carb, but its just used for puttering around town. My 350 is my main ride for dual sport/off road stuff and my CR is for pure off road.

    If you did wanna keep fiddling with the 250, the honda CRF150R comes with, I think, a 31mm FCR which would be super sweet on the DR250.
  16. shearboy2004

    shearboy2004 KIWIINUSA Supporter

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    My DR is bored out to 450cc with Jesse Header and IDS2 Super Trap and pumper carb.

    In order to reduce popping on decel i went to 45 pilot , worked wonders .

    The main i have in now after many different changes is a 130 it runs great at anywhere from 5000ft to 12,000ft . I know that is way small but it is what works best here for me.
  17. RandyM

    RandyM Less talk, More ride

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    A 1990 RMX250 front wheel is exactly the same as the 1999 DR350SE and bolts right up. It even works with the odometer. It should work on the 1998 street model and 1997-1999 dirt models also.

    The 1990-97 street models and 1990-96 dirt models use a 15mm front axle so the front RMX250 wheel will not work.

    For rear wheel, most of the early DR350 and DR250 models used cush drive rear wheels. They will bolt onto the later models without cush drive if you use the spacers from the cush drive wheel. The rear wheels of the RMX250 have different part numbers than the DR350SE so they probably are not a strait replacement.

    To some degree you can use a site like bike bandit or ron ayers to match up part numbers to see what is compatible.
  18. cookiebox

    cookiebox Adventurer

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    we've used dairyland for the last 30 years, one good payoff on excrusion diversion was the only claim we have had, recently had a drastic drop in rates. we insure 5 bikes. they have always been easy to work with.:clap
  19. Country Doc

    Country Doc Wanderer

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    I currently have the Jesse header, modded stock pipe, and Tm33 pumper carb on my 94. How would you compare the performance of your big bore bike with the aftermarket pipe?

    Thinking about doing the same thing (440 kit, big valves, maybe cams, and a new pipe).

    dc
  20. deserteagle56

    deserteagle56 deserteagle56

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    My bikes have been insured with Dairyland for as long as I can remember. Haven't been able to find anyone cheaper. But then, I've never had a claim.