1973 RD250 Becomes a New Commuter...

Discussion in '2 smokers' started by Kiba, Feb 19, 2014.

  1. Kiba

    Kiba Dances With Huskies

    Joined:
    Nov 8, 2013
    Oddometer:
    2,664
    Location:
    Houston, Motorcycle Purgatory
    [Note: I've crossposted this over at 2strokeworld as well]

    I have harbored a secret love for two-strokes for a long time and yesterday I finally gave in.

    [​IMG]

    [​IMG]

    [​IMG]

    A new (to me, that is) 1973 RD250! :clap

    Not a project either, rolling, running, and registered, albeit it with cosmetic issues and a few missing bits.

    I'll be cleaning her up and restoring her a bit, all factory, no mods for style or speed, just reliability. At most, I will put on clubmans for a track day if I get her running right, than swap back to stock on the way home.

    I've always liked RDs and I'm thrilled to be able to get one. She is staying stock both because I believe this and its big brother are one of the best-looking Japanese standards ever made, and because it will be a commuter to sit beside my other bike. It has to be predictable/reliable, no seizing at traffic lights or fiddling with pod filters, etc.

    I'm car free, and while the XT600 has been stone dead reliable I still want a backup bike just in case. That's what I tell myself, anyway...

    So, anyway, she's being shipped down from michigan in a couple of days - can't wait. More pics, and a slow saga of restoration, to follow.

    Any advice for a new RD250 owner? Quirks, maintenance shenanigans, tasteful and period-correct reversible mods for reliability? :lol3
    #1
  2. Rango

    Rango Phaneropter

    Joined:
    Oct 30, 2012
    Oddometer:
    1,203
    Location:
    Kingdom of Belgium
    Congrats, looking good.
    Do you need to mount indicators at the front?
    #2
  3. Kiba

    Kiba Dances With Huskies

    Joined:
    Nov 8, 2013
    Oddometer:
    2,664
    Location:
    Houston, Motorcycle Purgatory
    Not in Texas, but I will anyway. They'll be coming in from ebay in a few days. Probably before the bike, actually.
    #3
  4. Kiba

    Kiba Dances With Huskies

    Joined:
    Nov 8, 2013
    Oddometer:
    2,664
    Location:
    Houston, Motorcycle Purgatory
    *Crossposted at 2strokeworld*

    Bike came in last night. If was raining and cold (of course) by the time it got here, so no pics of first arrival.

    But fresh off the truck on a chilly morning, here she is:

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]

    And she runs, too! I can't really tell if the motor's running well or not but it sounds alright to me. I've only run it for a minute or two to make sure everything works. Choke on for about 15 seconds in 46 degree weather, then choke off and she idles fine.

    Needs a good clean of course and that'll be part of my duties for the day today. But so far, a cursory inspection shows:

    -No airfilter.
    -Has baffle in right exhaust, appears to be no baffle on left.
    -No right sidecover or front blinkers, as expected.
    -Sticky, uneven clutch feel
    -Little bit of play in the shifter
    -Both brake light switches (f/r) in "always on" position
    -Needs tires, might as well do it right before inspection
    -Missing a bunch of little fittings, non-oem mirror, little annoyances here and there.

    Already ordered the airfilter last night. I do want to ask, looking at the Haynes service manual, the crank seals can only be replaced by splitting cases? Or can you carefully wedge them on like people on here have done with the R5/DS7?

    If I do need to split the cases I can, just makes me nervous. If indeed I do, I might as well do things correctly and replace anything that needs replacing. If I split the cases I don't want a do-over for a while. What tools do I need to check parts and replace them in the bottom end? Should I do the big end bearings, etc or if they check out should I leave them alone? Remember, I've only done top end work on vehicles, so forgive a stupid question if I ask one.

    On the plus side the carbs were rebuilt, battery is new, lights are bright, horn is loud, and the gauges and fender chrome are really nice looking.
    #4
  5. ken_the_carp

    ken_the_carp Adventurer

    Joined:
    Jan 27, 2006
    Oddometer:
    96
    Location:
    Montreal Quebec
    Looks good!
    Question where's the oil tank? Is that not the RH cover.
    Girlfriend owned a gold and black DS7 the 72 model, I drove it everywhere our only transportation at the time.
    Almost identical to the 350, very reliable.
    I'd not worry about crank seals doesn't look like it sat outside for the last 40years.
    I guess they still had points then, timing is important.
    Enjoy Ken
    #5
  6. anotherguy

    anotherguy Long timer

    Joined:
    Jun 18, 2009
    Oddometer:
    15,491
    Location:
    the hills
    Yeah the right side cover is the oil tank and it's on intergalactic backorder.

    Why are you worried about crank seals? Any symptoms of bad seals? The reason I ask is because if it were mine splitting just to do seals on an unknown engine is a waste IMO. Rebuild if you split the cases. The trans will be in good shape more than likely so the crank is all you've got to worry about. How many miles?
    #6
  7. Kiba

    Kiba Dances With Huskies

    Joined:
    Nov 8, 2013
    Oddometer:
    2,664
    Location:
    Houston, Motorcycle Purgatory
    Hey, actually it isn't, tank is on the left on this one. Got the sidecover in the mail today though so it looks right again :D.

    I wish you were right on the crank seals, but everyone on the 2-stroke forum seems adamant about doing a rebuild.
    #7
  8. anotherguy

    anotherguy Long timer

    Joined:
    Jun 18, 2009
    Oddometer:
    15,491
    Location:
    the hills
    Why are they saying it needs a rebuild? Is it displaying any symptoms?
    #8
  9. LasseNC

    LasseNC XSessive!

    Joined:
    Jan 27, 2008
    Oddometer:
    1,100
    Location:
    Denmark, Danimarka, Danmark, Dänemark
    Seals dry out, can leave the bike running lean. Everything explodes. Assess what you have, then rebuild, best way.
    #9
  10. sprouty115

    sprouty115 Long timer Supporter

    Joined:
    May 29, 2012
    Oddometer:
    8,105
    Location:
    Providence, RI
    I'm assuming you've never refurbed a 40yo 2T? The OP should do a leak-down test (not to be confused with a compression test) and then he will see that he needs to replace the seals. It's a simple fact of the age of the bike and how the engine operates that make it necessary. Fortunately the entire process can be done in a basement with simple hand tools. The first time will take you the better part of the weekend, do it enough and it can be done in about 4 hours.

    BTW, the fact that the bike is running means nothing. I bought a '75 RD 250 that started on the second kick and seemed like it ran fine, it ended up having a loose stator, bent crank, low compression, and lots of leaking seals.

    All you need to know can be found here: http://www.aircooledrdclub.com/smf/index.php?topic=25398.0
    And here:http://www.2strokeworld.com/forum/index.php?topic=1570.0
    #10
  11. Kiba

    Kiba Dances With Huskies

    Joined:
    Nov 8, 2013
    Oddometer:
    2,664
    Location:
    Houston, Motorcycle Purgatory
    Thanks. That's about what I've been finding out.

    One problem has been finding a definitive list of necessary replacements- single use wear items like gaskets, piston rings and clips, seals, plugs, etc- I will be doing this over a weekend, and its kind of pointless to have all the gaskets and seals except one and leave the thing waiting for a work week in the garage. I understand if I have bad luck and find a serious issue in the bottom end (bearings or something) and can't build it up, but otherwise I don't want to leave the thing in bits for any longer than I have to.

    If I get lucky and have a good crank and good bearings and good bore/pistons (compression test was good, and I already tested clutch and tranny, neutral switch and tacho work), am I correct in assuming that I need only

    A- full engine gasket set
    A2- Yamabond or equivalent
    B- full engine seal set
    C- Piston rings
    D- Piston pin clips
    E- Clutch plates (they're worn)
    F- Two carb rebuild kits
    G- Air filter
    H- Clutch puller tool (already have)
    I- Flywheel puller tool
    J- Box o'plugs (already have)
    K- Caps/wires (already have)
    L- Points/condenser kit


    This thing also needs f/r brake switches, gas cap seal, fork seals and oil change, tires/tubes, one exhaust baffle, and possibly brake shoes.

    But, all light bulbs work fine. Cables are fine. Battery is new and chain/sprockets are good. Wheels are true. Gauges work nicely. Horn is loud. Freed up the mirror and the controls are nice.

    Probably ditching the signals for now since it's a PITA to find OEM ones. I've labeled the wires and saved the rear lamps for future use, but for now its one less thing to worry about.
    #11
  12. papawhellie

    papawhellie Been here awhile

    Joined:
    Jul 27, 2012
    Oddometer:
    129
    Leak down test is surefire but spraying a little brake or carb cleaner with covers ajar and around the jugs can reveal a leak. I would put crank seals as a matter of course. Lots of 2 stroke experts on yamahaenduro.com. Also parts interchange knowledge. Nice bike. May I ask what you paid? Ebay Cl or hoew did you aquire it? Need plug reading experience. A lean condition can hole a piston quick. Ask me how I know???
    #12
  13. sprouty115

    sprouty115 Long timer Supporter

    Joined:
    May 29, 2012
    Oddometer:
    8,105
    Location:
    Providence, RI
    The list is pretty complete. Though for some reason I'm at a loss as to how the clutch was pulled. I'd would also add the following:

    Bolt Kit - Allen Engine Bolt Kit Economy Cycle $17.99
    Oil pump re-buil kit Economy Cycle $29.95
    Clutch tool Economy Cycle $15.00(?)


    And finally one quick note: the stator is NOT removed with a puller, it is popped off by threading one of the rear motor mount bolts into the center hole of the stator and then bolt is lightly struck with a hammer (see link below).

    Some links if you're so inclined:

    Forums
    http://www.2strokeworld.com/forum/index.php?board=27.0
    http://www.aircooledrdclub.com/smf/
    http://www.rzrd500.com/phpBB3/?sid=59df27e672234421f91bcce03e4b52b7

    Manuals
    http://www.scribd.com/doc/10925658/yamaha-rd250400-19651978-repair-manual Clymer manual
    http://www.2strokeworld.com/manuals/vmmanual.pdf Mikuni VM manual

    Pictures
    http://www.flickr.com/photos/37135917@N00/sets/72157632416182221/

    Parts (decals, bolts, gaskets, etc.)
    http://www.hvccycle.com/ Parts - OEM, good selection
    http://www.economycycle.com/servlet/StoreFront Parts - OEM, good selection
    http://www.diablocycle.com/-Yamaha-Twins-RD-and-RZ/ Parts - generic, decals
    http://www.reproductiondecals.com/default_frameset.html?content.html~main Decals
    http://www.bikebandit.com/houseofmotorcycles/1975-yamaha-rd250b/o/m7509#sch216869 Parts - OEM, good selection
    http://www.partsnmore.com/parts/yamaha/rd350a/?filters[fitting]=custom Parts, small selection, cheap prices
    http://www.boats.net/parts/detail/yamaha/Y-93315-23612-00.html Parts - OEM, OK selection
    http://www.fastener-express.com/metric-screws-nuts-washers.aspx Screws

    Autolube
    http://www.2strokeworld.com/forum/index.php?topic=13142.msg99858#msg99858 Excellent exploded views and setup info

    Stator removal
    http://www.2strokeworld.com/forum/index.php?topic=15034.msg114924;topicseen#msg114924
    http://www.2strokeworld.com/forum/index.php?topic=16923.0

    RD Rebuild with pics
    http://www.aircooledrdclub.com/smf/index.php?topic=25398.0 Page 11 for engine reassembly
    http://www.fjrowners.com/forums/8-fjr-central/13362-latest-ride.html Oil pump rebuild starts with reply #36
    http://www.fjrowners.com/forums/8-fjr-central/13362-latest-ride-13.html Clutch rebuild starts with replay #121
    http://www.2strokeworld.com/forum/index.php?topic=6840.msg50340#msg50340 Testing the stator
    http://www.scribd.com/doc/10925658/yamaha-rd250400-19651978-repair-manual Clymer Manual

    Cylinder reboring
    http://bore-tech.com/thankyou.php

    Crank rebuilding - Lyn Garland (no web site)
    Vintage specialties
    c/o Lyn Garland
    274 Oak Rd
    Jenkinsburg, GA 30234-2136
    770 775-3249[​IMG][​IMG]
    VINTSPCLTY@aol.com

    Tips
    http://www.tholt.com/rdtip.html A page with a couple of RD-specific tips
    http://home.comcast.net/~todwatts/motorcycle_7_mods.htm#electronic_ignition An older page with some useful info
    #13
  14. LasseNC

    LasseNC XSessive!

    Joined:
    Jan 27, 2008
    Oddometer:
    1,100
    Location:
    Denmark, Danimarka, Danmark, Dänemark
    Expecting to rebuild an engine over the course of a weekend is a very bad idea honestly.

    Split the cases, measure and check the parts.

    Order what you need.

    Assemble.

    That way is the simplest and will give you the least amount of headaches.

    Expect to have the crank rebuild.
    #14
  15. sprouty115

    sprouty115 Long timer Supporter

    Joined:
    May 29, 2012
    Oddometer:
    8,105
    Location:
    Providence, RI
    Actually I would agree with that. I was merely trying to convey the time it takes to disassemble and reassemble the entire engine. It's quite simple in terms of turning wrenches.
    #15
  16. 309

    309 Special Purpose

    Joined:
    Jul 25, 2004
    Oddometer:
    6,120
    Location:
    Boulder, CO
    I'm about to embark on an RD350 motor rebuild myself. Doing the same compiling of pats and knowledge you are.

    One thing that was pointed out to me:

    http://www.vitosperformance.com/atv_parts/product.php?productid=11577&cat=474&page=1

    NEW crank for less than most charge for a rebuild. I'll split the cases and assess before ordering anything, but my inclination is to go ahead and throw in a new crank and pistons while I've got it on the bench.
    #16
  17. sprouty115

    sprouty115 Long timer Supporter

    Joined:
    May 29, 2012
    Oddometer:
    8,105
    Location:
    Providence, RI
    Looks like a pretty good deal.
    #17
  18. Bud Tugly

    Bud Tugly Gnarly old curmudgeon

    Joined:
    Feb 14, 2007
    Oddometer:
    307
    Location:
    Formerly Ishpeming, MI now Eugene, OR
    I had the 1972 version and it appeared to be identical except for the paint scheme. It was a lot of fun on curvy back roads and will make a nice commuter. Looks like you've got great advice here and a firm grip on what needs doing to get it up and running reliably. I'll be following your progress!
    #18
  19. Kiba

    Kiba Dances With Huskies

    Joined:
    Nov 8, 2013
    Oddometer:
    2,664
    Location:
    Houston, Motorcycle Purgatory
    Just a quick bump to show the bike is still here.

    Progress has been slow. Nonexistent, actually- mostly due to funds. Unfortunately the vintage project has to take a backseat to my more practical bikes.

    However, I did something today! :D

    Cleaned the entire garage and tools, got out the service book and took the engine out. Right now it's a roller.

    Good news: All the lights and switches work! Hi/low, tail/brake, gauge lights, idiot lights, switchgear and switches, etc. I can't test the TS since I don't have any at the moment.

    I've got to say these things are cake to work on. Easiest to understand bike I've ever had.

    Has anyone here used the Michellin Gazelle tires on these bikes? Mine is currently 2.75/18 front and 3.00/18 rear, and the gazelles are 3.00/18 front or rear. They are damn cheap too, about $30 on bikebandit. I won't be pushing this bike too much when it's built but I don't want a crap tire either.
    #19