DR350 Fun Build

Discussion in 'Thumpers' started by Hscarborough, Aug 9, 2016.

  1. Hscarborough

    Hscarborough Long timer

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    Hello everyone,

    I've been a motorcycle rider and tinkerer for quite some time now and on my last full motorcycle build I realized the value of sharing progress and problems on a public forum like this. The last motorcycle I went through and repaired was a DR350 that I bought for a reasonable price, fixed and then sold for a profit. After selling I went "you know what, that was a good bike and I'd like to build another one". So this time I'm going at it a little different. This bike will be built for FUN. Not resale, not with return on investment in mind. Just fun. With $1700 in hand (from selling my first DR) I began my search and this is what I found.

    Here's the long and mechanically gory back story...

    The bike is a 1993 DR350 Dual Sport version with approximately 14k miles on the odometer. The original owner melted a big fat hole in the piston and swallowed up 2 valves. The owner was mixing up his own personal concoctions of gasoline at home with his roommates (he worked at a fuel laboratory and I guess they brought their work home?). See below.
    [​IMG] [​IMG]

    Regardless, he sold it with this blown engine and moved on. The next owner purchased a complete engine on eBay with only 4k miles but when it arrived and he went to install it, he realized the cam journals had seized up and the cam shaft snapped in two (seriously, the cam shaft sheared into two pieces).
    [​IMG]

    So... After going back and forth with the ebay seller, the owner had enough with it and sold the bike with lots of extra goodies (including the old blown engine) to me for $500. Here it is on the way home.

    [​IMG]

    So that's the story behind the bike. Now for where I'm going with it... Considering the purchase price of the motorcycle, I want to do all the things I'd dreamed of with my first DR but couldn't justify because of price and resale value. This time, I have a $500 bike with $1200 left to spend on it.

    I'm just beginning to catch up on this build so stay tuned!

    Also, feel free to comment with any ideas or tips for this build.
    #1
  2. Hscarborough

    Hscarborough Long timer

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    Alright back to type some more...

    Sit rep: I now have a 1993 DR350 with an engine that has 4k miles and a head with bad cam journals.

    After doing some kicking around on craigslist, I scored a motor from a 1997 DR350SE (electric start model) for $150 but it was next to a brush fire so it got covered in soot and a few of the plastic bits melted. Because of potential damage to seals, I decided not to directly swap it into the bike. What do you guys think? I know engines are designed to handle heat but enough heat to melt plastic and wires? Yikes! See the motor below.
    [​IMG]

    Nonetheless, the bike was a clean running 1997 with only 7k miles so in theory, the head is good and can be swapped onto the current motor in the DR. Also included was an extra set of forks and a front brake rotor and hub assembly which is a nice little goody to have.

    Until next time....
    #2
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  3. plugeye

    plugeye MC responder

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    this will be entertaining
    #3
  4. Hscarborough

    Hscarborough Long timer

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    Hello Plugeye! I hope it is. Stay tuned! I'm trying to take enough photos to make it a good read...

    For now though, I realized it would be helpful to give a quick inventory of parts so here you go:

    -1993 DR350 with engine installed (bad cam journals) $500
    -1993 kick start engine with hole in piston
    -1997 electric start engine from fire bike
    -spare forks
    -spare front wheel hub and rotor
    -spare front brake caliper

    Now for a list of wants...

    -New muffler: A FUN bike needs to sound fun! So i purchased a DG exhaust and it's ready to go on
    -Pumper carb: Do I go TM33 or TM36? Thoughts?
    -440 Big Bore: I figure I have 2 extra cylinders to play with, so why not make one of them a 440?
    -RMZ250 USD Forks: Anybody done this with factory tire setup? I've seen a supermoto setup but wondering about ride height with stock wheels (RMZ front of course)
    -New seat: bought a seat cover that should arrive soon and my wife is going to recover it. The old one is well... old.


    Anybody want to add to my list? I'm still relatively new to the DR350 so any experience would be great.
    #4
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  5. Alaska1WD

    Alaska1WD Long timer

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    Sounds like an interesting build!

    For the carb, I suggest a TM36 if you are going to big-bore it to a 441 kit. Porting the head and getting your camshaft upgraded would be a good idea if you want to get the most out of a TM36 too.

    If you make an electric start engine, you can add the kick start parts from the other motor(s) on. I did it, it's good to have a backup

    In that picture of your bike, it looks like the kickstand is wearing into the swingarm. You should do something about that before it gets worse. And buy a skid plate if you plan on doing any off-road, you don't want to snap an oil line off and they are protected by the skid plate. Super cheap on ebay FYI
    #5
  6. TwoTrackMind

    TwoTrackMind Long Way Round Here

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    I'll second the TM36 on a 440. Spend a little more over the TM33 and you'll be happy with the increased top end.
    #6
  7. brownvv

    brownvv Been here awhile

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    if your not making it an e start I would use an fcr37 carb. I have one on my 441 and its sweet. the fcr wont clear the e start I don't think
    #7
  8. buzzword

    buzzword Been here awhile

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    The USD forks have ~1.25" more travel (30mm) if I recall correctly. That can be corrected with different springs, or just moving the fork legs up in the triple if you've got the room under your bars.

    Carry on!
    #8
  9. Hscarborough

    Hscarborough Long timer

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    Alaska1WD, Thanks for the tips! Would the TM36 work with the stock boring if I were to put it together as is? Or would I need to run the stock CV until I get the 440 cylinder in? At the moment, I don't plan to do any porting but I know how much that can help. Is this something that is done by hand? Or is it a CNC operation? Do you have any ballpark guesses on price? Also, a more aggressive cam would be great but at this time, I'm trying to get a solid bike and begin the fine tuning after that.

    I may switch to the E start lower end at some point but for now, it's going to stay kick start. I have 2 kick start mechanisms though if somebody needs one!

    Also, good eye. You are correct about the kick stand rubbing on the swing arm. Do you know what commonly causes this? I looked it over and it's nothing obvious. Either a bent kickstand or a bent mount. I'll dig into it eventually and post what I find.
    #9
  10. Hscarborough

    Hscarborough Long timer

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    DeutschMark, thanks for heads up! I am looking online at powerbarn. Do you have any tips on where to buy the kit besides there? Looks like $500 for the TM36 and $420 for the TM33. Looks like a REALLY complete kit but I'm not sure if I need the manifold adapters.
    #10
  11. Hscarborough

    Hscarborough Long timer

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    BrownVV, I'll do some digging on the FCR carb. Some day when I'm getting tired of kicking it, a magic button might seem kinda nice though...
    #11
  12. Hscarborough

    Hscarborough Long timer

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    Buzzword, extra travel is always nice! I know they are both 21" front wheels but can't seem to find the total fork length. I'm worried the steering stem would be up too high and mess with the handling of the bike. Maybe I'm overthinking it.
    #12
  13. buzzword

    buzzword Been here awhile

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    I'll measure both suspensions tomorrow and post back. I have an 03 RM250 fork on my bike which I think is the same OAL and travel as the RMZ. The steering setup isn't too tall - it actually ended up slightly lower on mine because I have an Applied top triple clamp and Pro Taper risers.

    Still have my full '99 cartridge setup - no bites here, on eBay, or CL locally yet. Selling it for $275 with the complete front wheel, and it's all really clean and tight. Thought someone woulda swooped it by now for sure!

    Additionally, I'd love to take one of those kickstart mechanisms off your hands... Whatcha want for one?
    #13
  14. Alaska1WD

    Alaska1WD Long timer

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    I don't know much about a larger 36mm carb. A quick math check says it has 19% more volume, which doesn't sound like much to me so I think it should be ok.... Someone else here able to answer this?

    I also don't know much about porting either, but I think it should be ok to dremel it out a bit and at least grind all the rough cast surfaces a mm or two. Who here has ported theirs?

    I can answer the third Q. That's caused by kicking with the kickstand down and bending the tab. It warps the metal tab the kick stand bolts on to when too much force gets thrown onto it. It seems common tho. You can grind a bit off the inside of the kick stand foot if you want a short term fix or it barely touches, but the long term fix is to hammer the tab back into position or get some welding done.
    #14
  15. Alaska1WD

    Alaska1WD Long timer

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    I thought someone made an FCR carb fit by adding a spacer to the air intake manifold to move it back for more room. You are right tho, it is a really tight fit with the E-start there
    #15
  16. brownvv

    brownvv Been here awhile

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    I remember someone was going to try to get it to fit. I never saw if they finished it or who it was. I want to put one on my e start really badly.
    the tm33 wears out because the slide sticks to the body. I believe the tm36 is the same? not only that but the stiction on the slide makes letting off the throttle abruptly at high rpms rough and jerky. its not terrible, but its annoying.
    the fcr uses rollers so its buttery smooth and does not wear out. for around 150 bucks you can pic up a used fcr37 on ebay if you shop around. there is a gsxr intake boot that makes mounting it to the engine a bolt on procedure. might have to get an adapter for the rear though.
    another thing I have noticed since I am running a tm33 on one bike and an fcr37 on the other is ease of rejetting.
    I can loosen the clamps on the fcr, turn it sideways and rejet without removing the tank. I have to take the side covers, seat, and tank off to get the bowl off my tm33
    #16
  17. plugeye

    plugeye MC responder

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    one annoying feature of the flat CR carbs: slide rattle
    #17
  18. Hscarborough

    Hscarborough Long timer

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    Buzzword, please let me know what the suspension length is on your RM! That would be good info. Probably the best measurement would be to go from the top of the fork tubes and follow the line of the fork all the way to the ground. Your 99 cartridge setup sounds awesome! But I must admit, I have my heart set on the look of USD forks... I will keep that in mind though. Hopefully someone comes along here and picks them up from you!

    For the kick start mechanism, make me an offer! I don't see any available online to compare with but I trust you'll come up with a fair offer. I could take those parts off, throw them in a flat rate box and send it your way in just a few days if you wanted.
    #18
  19. Hscarborough

    Hscarborough Long timer

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    Brownvv, you have a TM33 and an FCR on Dr350's? Big bore on both? I can't seem to find a kit for the FCR carb. Do you know what throttle assembly and jetting it would take to run stock bore or the 440 bore? I am not afraid to put together my own kit I would just feel better knowing it's been done and I have a baseline jetting to go off of.
    #19
  20. TwoTrackMind

    TwoTrackMind Long Way Round Here

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    I bought the kit off of Ebay Germany. I used a 36mm manifold and the spacer that I got from Keintech. I bored out the spacer to match the manifold.
    #20