DisTech's DR350 rebuild

Discussion in 'Thumpers' started by DisTech, Nov 27, 2009.

  1. DisTech

    DisTech Been here awhile

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    616
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    Last winters project was my DR650 and I had a blast with it this summer on some of the local trails. Winter is almost here again and I want a new project. mx_rob and ProCycle had me psyched about putting a big bore kit, high compression piston and web cam on the DR650, but then I started thinking what if I wanted to take some epic journey into a land of low octane? Also on tight trails the DR650 girth is limiting/exhausting. Better to leave the DR650 as my reliable long haul adventure bike.

    Still liking the idea of a big bore project, wanting a less limiting bike for single track and being a sucker for brand loyalty I selected the DR350 as my next subject. I want it to be at least 75lbs lighter than my DR650 and with the right components I should be able to approach the stock DR650 HP and torque.

    Here's what I have so far.

    [​IMG]
    1994 DR350 (no plastics, no tank, no seat) $250

    [​IMG] [​IMG]
    1993 DR350S (broken cylinder, damaged head, no wheels, completely disassembled in boxes, premium paid for WA street title) $450

    The PO said the rod broke and it ate the piston, cylinder and chewed on the head some. He was going to rebuild it but lost interest.

    [​IMG]
    The cylinder will be re-sleeved for a big bore kit. So is this usable?

    [​IMG] [​IMG]
    That left valve seat is out of round and has some gouges. Is this head repairable? Top of the head looks good, no scoring.

    The 94 motor is complete. So if the 93 top end is shot it's not the end of the world.

    [​IMG]
    2007 200xc forks, wheel and I have the brakes as well. Let's just say these cost more than both DR350's.

    To do:
    • Sand blast & powder coat the frame
    • New bearings everywhere
    • 441/450/480 big bore
    • MegaCycle cam & springs
    • Performance exhaust
    • Excel rim, black for rear
    • Rebuild/jet TM33
    • Rebuild dirt shock
    • 4860 WP forks
    • LED dual sport light kit
    • HID headlight?
    • Trailtech Vapor
    • Renazco seat
    • Acerbis tank
    • Maier rear fender
    #1
  2. BikePilot

    BikePilot Long timer

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    Looks like a great project:clap You'll probably want Ti valve spring retainers to go with that cam as well. I know kibblewhite does them, not sure if megacycle does or not.

    If you are sure you are going big bore you might try for a 37mm FCR rather than the TM33.

    you might also add an aluminum airbox to your list - they are supposed to offer a moderate boost in performance as well. I have one, but haven't fitted it yet.

    I'd also box in the rear swingarm if you plan on pushing it hard off road, especially with the extra power you'll be making. An alternative might be to fit a different swinger. The Scotts swinger is ideal, but was $$ and now hard to find. You'd need a stiff swingarm that's solid accross the front and would more or less fit. From memor an XR650L/XR600R swinger might work (don't know if the dimensions are right, but its at least solid accross the front).
    #2
  3. SloSolo2

    SloSolo2 Been here awhile

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    I've got the same ugly purple handlebars on my 98.:lol3
    Jamie
    #3
  4. jeep8

    jeep8 Been here awhile

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    looking forward to reading about and watching this, takes plenty of pictures.
    good luck
    #4
  5. Phreaky Phil

    Phreaky Phil Long timer

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    I am looking forward to this one myself. I got a 99 kickstart street model here in NZ a couple of months ago and am slowly working on along similar lines. I picked up some YZF250 forks and clamps and just picked up another barrel so I can do a big bore, although I was talking to a local suzuki dealer and he said they've had several kitted ones through the shop. He said head gaskets seemed to be a problem. Would be interested to hear of other peoples experiences
    #5
  6. brucifer

    brucifer Long timer

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    Sweet! Another DisTech build! :thumb :lurk
    #6
  7. procycle

    procycle Long timer

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    Since you're going big-bore the cylinder will be fine.
    The head could be repaired but it might be less expensive to buy an undamaged used head.
    #7
  8. Olas

    Olas the darkness

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    [​IMG]

    I'd use the good parts from this motor, that head might be salvageable but it might cost more to do that than what it's worth. Seems like you've got a lot of parts already...what are you waiting for? :lurk
    #8
  9. Fubars

    Fubars What would Scoobydo?

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  10. LukasM

    LukasM Long timer

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    So you are at it once again Distech, nice!! :clap


    I wanted an enduro bike as well but chose the easy way out this time - KTM 525 EXC. Nice bike but of course it won't be half as special as a custom rebuild.

    Let's go! :lurk
    #10
  11. DisTech

    DisTech Been here awhile

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    Thanks, I've read a lot of your posts on ADV, TT & maximum-suzuki. I appreciate your input.

    Megacycle sells their cams along with a R/D valve spring kit with titanium tops. I'm not committed to one brand over another yet, so the more input the better. I picked megacyle over a web cam because their mild cam is a little more aggressive. Probably talk to Jesse or ProCycle for more advice.

    Point taken. I listed the TM33 because I have it already. Did some searching over at maximum-suzuki and saw lots of discussion about the FCR 37, but didn't see a good manifold solution. Any ideas?

    Is this the Vortex Aluminum Airbox? Is that the same one that Jesse sells or used to sell (I can't find any current links to it)?

    I saw a Scott's swingarm on ebay before I was interested in this project and haven't seen one since! There are some old references to thumper-racing boxing the swingarm, have to check if they still do.
    #11
  12. DisTech

    DisTech Been here awhile

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    HA! Depurpleization was one of the first steps of my 96 DR650 project. Though it should be much easier on this one.

    Thanks, will do!

    I don't know yet what I have to do to the triples to get them to work. I'll post whatever I do and I hope you do as well. Head gaskets, hmmm...

    Brucifer! Welcome aboard!
    #12
  13. BikePilot

    BikePilot Long timer

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    Yep re the airbox, there were a few other places selling them too I think (cyclegear for one). As far as I know they are no longer available. I got mine used on e-bay. Its missing the side cover, but otherwise intact and the cover is just a flat bit that should be easy to fab up.

    I don't know a lot about the FCR - I didn't think about you already having the TM33SS - might as well use that for now. I know a few folks have FCR's fitted and working. Sudco sells manifolds in various sizes. It would probably be a hassle to get it all fitted up, but once done would flow better and provide a bit more percise tuning options. Only really worth doing after you've got the cam and big bore and even then you'll need to do some pretty serious head porting to match up with the larger carb bore. I think G-man on maximum-suzuki has posted up some specifics on this. I can't run the FCR as my DR's are e-start and there's physically not enough space so I haven't looked into it too closely.

    I didn't realize the megacycle cam came with the Ti retainers - I imagine they work just fine. I'm still on a stock cam, though I am running the kibblewhite springs and ti retainers just to make sure there's no way I can float the valves should I get a bit frisky with a downshift at high rpms.

    I don't think thumper racing still boxes the swingarms, but I haven't checked to verify. They used to sell plates that fit inside the rear C-section of the swingarm which were then TIG welded in. It wouldn't be hard to cut out such plates if you happend to gain access to a mill ( could also be done with less sophisitcated means, but a mill would make it easy).

    Oh, you might as well be on the lookout for stiffer springs for the KTM forks - the Dr is quite a bit heavier than the KTM and will have even more weight on the front wheel once you put in 4+ gal of gas (that's about 26lbs I belive). Guessing about .46kg should be rougly correct. It will certainly be rideable (and probably still a lot better than stock) with the stock KTM forks so no rush there.

    have fun:clap
    #13
  14. DisTech

    DisTech Been here awhile

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    Thanks, Jeff. That's good news about the cylinder. BSR-1 said the same thing about the head. Since we are talking about big bore options, is there any 480 news?
    #14
  15. DisTech

    DisTech Been here awhile

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    Was hoping to have two complete motors, oh well. Let's get this party started!

    I've been following that thread and some of those guys are talking way over my head. I like the idea, but if it broke I'd be screwed.

    OK! Away we go! Good to have you along Lukas.
    #15
  16. BSR-1

    BSR-1 Adventurer

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    sounds like you've got many fun filled nights in the garage ahead!
    #16
  17. Phreaky Phil

    Phreaky Phil Long timer

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    I hope to make mine look something like this one, but with a bigger tank.
    [​IMG]
    #17
  18. DisTech

    DisTech Been here awhile

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    I'll see if Jesse still sells the airbox. TM33?! Now you've gone and got me looking at the FCR37!! I did see the manifold chart at Sudco. The FCR37's aren't that expensive and there are quite a few on ebay. I'm still searching for swingarm stiffening. I had to respring my DR650 so I was expecting that on the DR350 as well (I should add that to the todo list). Thanks.
    #18
  19. DisTech

    DisTech Been here awhile

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    Odometer: 1? I swear I've seen you on ADV before. Thanks for joining.
    #19
  20. DisTech

    DisTech Been here awhile

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    Oh man that is fine! And damn it's got WP forks too. Here is my inspiration.

    [​IMG]
    It's Boomhauer's over at maximum-suzuki.
    #20