75-76 Yamaha DT400 Build(s??)

Discussion in 'Old's Cool' started by TravisK, Nov 30, 2016.

  1. TravisK

    TravisK Adventurer

    Joined:
    Nov 10, 2015
    Oddometer:
    79
    Location:
    Toronto
    Hey everyone, first time posting here at ADVrider. Love the site, been lurking forever. I figured I may get some interest in my projects here. I hope its posted in the right place.

    On the street I ride a 2008 Suzuki GS500. A couple of years ago my uncle gave me a 1969 Honda CT90, which I am currently finishing up a restomod with. I love working on bikes, and have a lot to learn.

    My Yamaha DT story starts with this bugger. I picked it up for $300 Canadian, drove 2 hours through a blizzard and fit it in the back of my Jetta. I knew less than nothing about these bikes, or 2 strokes in general. I was told it was a 1976 DT250, but I later found out it came with a '75 DT400 engine
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    I brought it home and started stripping it down. My plan at the time was to do a full on nut and bolt restomod, hopefully doing some adv riding with it.
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    It was my first time working on a 2 stroke engine, with only 1 other engine build under my belt (my CT90). Splitting the cases was nerve wracking.
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    All the engine internals in clean, vaguely labelled bags. I like to keep myself guessing :lurk
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    Here I am checking to make sure the engine mounts are all good. I suspected they were bent but the engine fits just fine.
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    This is where the story takes a turn, and I imagine most people in the Old's School forum will sympathize. I saw an ad for a 1975 DT400 for $400 in the same town as the last one I bought. A weird coincidence. Must be fate. So I take the Jetta out, and pick it up. I take the engine out and front end off in a parking lot, and cram it into the car. All the while, I'm saying "This is the last time, this is the last time..."

    I don't have any pics of that one unfortunately. I bought that one without ownership, so I had to go through the process of getting it transferred in my name. It wasn't difficult, I did it in an afternoon (I'm in Ontario, Canada, I can offer help if you need a walk through of the process).

    I stripped the second one down, and noticed the frame was bent. I was lucky that Denis from CMR Racing agreed to take a look over BOTH frames, and fix a few things here and there. He will also be making and fixing a kickstand bracket to the first frame, which was missing.

    The frames are still there, so while they are out of my hands, I got back to work on what I could.
    The joys of cleaning out old fork tubes! Most of the fork oil looked like chocolate milk.
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    Painting a lower triple (no before pic, but I promise it was bad)
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    Painting fork ears (first time painting anything)
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    But you are saying to yourself "There are 6 fork ears there, that must mean 3 bikes!" Nope, 4. I saw an ad for 2 1976 DT250 rolling chassis for $300. So I took the Jetta out there and crammed BOTH in the car. Those two were living life outside for a while, so I was killing spiders in my car for a week afterward.

    So this is where you find me at today. Four titled frames in my name, all pretty much identical. I have enough parts to make 2 complete DT400s, and I have enough to make a DT250 rolling chassis. I am missing a seat and an engine for that one (I have the carb already).

    Needless to say my "part's department" has grown. Those totes are all full of (new and old) bike parts, mostly DT but some of it CT90 related.
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    So I'm planning on building the 2 complete DT400s up by (hopefully) the summer. Both frames are still at CMR Racing. I have the 4 fork tubes all tidied up. I have new Renthal bars for both bikes. I've ordered a nickle-plated custom exhaust from Circle F for one of the bikes, and if it fits and works well I'll maybe get one for the other. I have all new parts ready to go on.. brake shoes, sprockets, chains, bearings, you name it. Both engines are gonna get full nut-and-bolt rebuilds. I have two PowerDynamo 12v alternators for both bikes, which gives me good reliable ignition and 12 volt electrics.

    But while I'm killing time waiting for the frames (and stuck right now with the CT90 as well), I figured I'd get some practice painting. I am still new to this, so I'd like to experiment and learn and gain some confidence with a spray can. I don't have a compressor, so all my work is spray can for now.

    A good candidate, one of the extra '76 frames I have in my garage. Both frames have old wasps nests in the down tubes.
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    Spent some time with a wire wheel to strip off loose paint and rust, then a good wash with Simple Green and a rinse
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    Primed with a few coats of Krylon Rust Protector primer
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    Finished with the same type of Krylon, but enamel top coat
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    It's not flawless, the enamel ran more than I expected. But it looks good to me right now. I'll have a more in-depth opinion once it dries and I can see how it stands up.

    So, I'll keep you all updated on the progress over the winter (not in January, thats vacation time :drink)

    Cheers,
    Travis
    #1
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  2. Solo Moto

    Solo Moto Hands are bruised from breakin’ rocks all day

    Joined:
    Apr 13, 2014
    Oddometer:
    323
    Location:
    Northern Idaho
    Ahh yes, my very first bike back in high school was a 1975 Yamaha DT400B. Paid $995.00 cash brand new. Sweet Mammories and wheelies all day!
    #2
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  3. RonKZ650

    RonKZ650 Been here awhile

    Joined:
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    Oddometer:
    867
    Location:
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    I bought the 75 DT400 new for $900 as well. It was a close out in late 1976. I think they had the DT250 for $800 the same time. They were a great bike. I rode mine 14,000 miles in the 16 months I had it and had zero problems. Good luck on the DT.
    #3
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  4. TravisK

    TravisK Adventurer

    Joined:
    Nov 10, 2015
    Oddometer:
    79
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    Cheers you two. I'm excited to get my first taste of 2 stroke.

    Glad to hear you didn't have issues. Ultimate goal for one of the bikes would be to do the Trans Canada Adventure Trail coast to coast, which is something around 15,000 km or 9400 miles.
    #4
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  5. TravisK

    TravisK Adventurer

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    Denis contacted me today, they are working on the first two frames at CMR Racing. As we suspected, one of the shock mounts from the 2nd frame is off. They'll try to get it back into good form, and do a few odd jobs to bring both frames back to stock spec.

    From Denis,
    You can see both frames in the second picture. The one in the jig really needs some new paint!

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    #5
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  6. TravisK

    TravisK Adventurer

    Joined:
    Nov 10, 2015
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    Still working my way through, cleaning and painting spare parts.

    Today I finished a pair of fork tubes which came with one of the rolling chassis. I'll use them with the frame I painted in a previous post. I also painted three triples, upper and lower. All fork ears are painted. So, I have 3 front ends ready to go.

    The fork tubes I did today were awful, I'd be willing to bet the last person to go in there was at the Yamaha factory. These ones smelled like wet cat food inside and had an inch of sludge at the bottom. The tubes were both rusted.

    I stripped both tubes down, cleaned everything and reassembled with new fork seals. I cleaned the rust with blue Scotchbrite and Simple Green. It worked out pretty well.

    They both looked like the one on the right. This is after I finished the left one.
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    The right tube from the previous picture, all cleaned up.
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    What was sitting in the bottom of the fork tube... it was the same for both tubes.
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    That's better.
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    I started work on the rear shocks, but hit a number of walls. All I managed to accomplish was removing one spring and cleaning it. I think it is cleaning up fairly nice, compared to what it was. This was, again, scotchbrite and Simple Green.
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    You can see the left shock is broken, down at the bottom of the spring. This is a set back. I'm not sure what I'm gonna do about it yet.
    #6
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  7. Todd157k

    Todd157k Long timer Supporter

    Joined:
    Aug 14, 2012
    Oddometer:
    2,541
    Location:
    Ventura, CA
    and there lies the biggest problem with restorations. From the looks of your work above, you'll think of something.. or make something.
    It's looking GREAT. Looking forward to watching this build.
    #7
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  8. TravisK

    TravisK Adventurer

    Joined:
    Nov 10, 2015
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    Toronto
    Thanks for the kind words! This was my first stab at working on these Yamaha thermal flow shocks. I have two other pairs, in better condition than these, that I'd also like to freshen up with a rebuild.

    Ultimately I'd like shiny new high-tech rear shocks, but I'd have to rob a bank to buy them. A pair of Progressive 12 series would run me 500$ CAD and that's middle of the range stuff!

    The benefit of the thermal flows is I can rebuild them if need be, and with a minor modification they can be made to accept a standard oil seal size, instead of the hard-to-find Yamaha OEM seals.
    #8
  9. Powderfinger

    Powderfinger Been here awhile

    Joined:
    Mar 3, 2013
    Oddometer:
    117
    Location:
    SW PA
    Your projects are looking good. You should consider getting a vibratory tumbler, it would clean so many of your parts while you are doing something else and they get stuff incredibly clean inside and out.
    #9
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  10. rufus

    rufus We're burning daylight...

    Joined:
    Sep 26, 2004
    Oddometer:
    5,351
    Location:
    Coweta Oklahoma
    Vinnie The Snake--( ADV name)---has 2 DT 400s that he built completely from NOS parts. If you can contact him he may be able to give some advice on where to get parts. He works out of town a lot and may be hard/slow to contact.
    #10
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  11. TravisK

    TravisK Adventurer

    Joined:
    Nov 10, 2015
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    Toronto
    That's a great idea. I actually have some sort of tumbler in the basement, I totally forgot I had it :rofl

    Cheers, that may come in handy!

    On to today's work...

    The paint on the frame and a triple are dry, so lets start putting one of these things together. This bike, right now, is meant to become a rolling chassis. I'm using all extra, or bottom shelf parts for it, and keeping the good stuff for the other two. I need to source a 250 engine for this one. But there is a chance I will become impatient and use one of my 400s, and source a 250 engine for one of the other frames later. I frequently change my mind throughout builds it seems :(

    Patient is ready
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    Everyone's favourite activity, steering bearings
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    Front end is on. I'm not crazy about the gators, but I've cleaned too many dank fork tubes lately to go without. I do like the black and grey color scheme though. Let's see where that takes us
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    After I got that together, I refocused my attention on the rear shock from yesterday. I managed to get it all disassembled.
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    Now, I need to machine out where the oil seal goes. From http://www.yamahaenduro.com/showpost.php?p=64451&postcount=4

    As for the broken piece on the other shock, I ordered a set of thermal flows off of ebay for 25$ USD so I'll salvage them for parts and we should be good!

    Lastly, I tried to find a set of handlebars to go on this thing. I have 3 sets of original handlebars. The first (and only) one I looked at today were bent like crazy. Probably off by a solid inch. I'm sure one of the other two sets will be more agreeable. I have 2 sets of Renthal High bars (613) for the other two bikes.

    Motorcycle restoration is not for the arachnophobe...
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    #11
  12. TravisK

    TravisK Adventurer

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    I just found oil seals that are 12mm ID, 23mm OD, and 7 and 8mm thick. So one of each of those should fit in the shock without machining. I'll give that a go first. The seals are from avxseals.com, I have no idea who they are but for 1.50$ a pop I'll take a risk.
    #12
  13. TravisK

    TravisK Adventurer

    Joined:
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    Oddometer:
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    I found front reflector mounts, so my front end is now pretty well close to stock I think. My top triple is about 1/8" too high though, the fork ears still have some up-down play...

    What I'm liking about this build is I'm learning what to expect for the next two bikes, so they should go smoother.

    Now if I could only find the reflectors! The brown on the metal isn't rust, it's grease. I'm not sure how long this bike will sit so I'm not taking chances with rust.
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    I found a set of decent handlebars for this bike. They aren't really bent out of shape, but they aren't exactly showroom fresh either.
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    Rear fender. This is one of four I have, each frame came with one.
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    Front fender. I have 3 of these. I don't have a good history painting plastic so this one worries me. I think a brand new one is like 25$ so if I botch this, I might go that route.
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    A headlight bucket. 1 of 3 or 4 I have. Not pretty, inside or out.
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    Painting the handlebars, 2 handlebar clamps, rear fender and headlight bucket today. Hopefully they come out decent. I am still rather inexperienced with painting, and I'm the king of over spray. I need to keep telling myself to get the can farther from the part.
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    The list of stuff to get this to a proper rolling chassis is still long, off the top of my head (and for my own record),

    Big stuff:
    - Clean and respray airbox, under seat tool tray, swing arm, brake torsion arm, front fender and lower rear fender (both plastic)
    - Finish rebuilding/painting rear shocks
    - Remove old tires, clean rims as best I can, replace wheel bearings, mount new tires (Kenda K270 3.00-21 and 4.00-18 ), new brake shoes, new rear sprocket
    - Where does the battery go??? I may need to find, clean and repaint some sort of battery tray?
    - Rebuild 250 carb if I'm going that route

    Smaller stuff:
    - Handlebar controls, clean, rewire and mount
    - Lights and indicators, clean rewire and mount
    - Should I use my only engine bash plate on this build? For some reason, out of all 4 bikes I have, only one came with a bash plate.
    - Fuel tank? Maybe clean and repaint one of my extra tanks, or get a Clarke tank

    Need to source:
    - Engine
    - Seat
    - Maybe new exhaust, the one I have slated for this build is probably gone beyond repair
    #13
  14. baloneyskin daddy

    baloneyskin daddy bikaholic

    Joined:
    Oct 21, 2009
    Oddometer:
    3,516
    Location:
    southcentral PA.
    I thought that the headlight ears had little flat rubber O-rings that fit above and below the ears on the fork tubes and would probably take up that little bit of space you're seeing.
    #14
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  15. Old Mule

    Old Mule Long timer

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    Location:
    Overland Missouri, home of 1950s sidecar tech.
    Keep us updated, please
    #15
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  16. spokester

    spokester Long timer

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    If you're really feeling sicko, paint the inside of the headlight shell white to make it easier to see the wires, ha ha ha!!! DSCN0715.JPG
    #16
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  17. TravisK

    TravisK Adventurer

    Joined:
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    Oddometer:
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    You could be right. If that's the case, this bike didn't come with those o-rings unfortunately. Right now I have Lower triple -> rubber ring -> reflector mount -> fork ear -> metal spacer -> upper triple. I'll figure something out to fill that gap. I don't like the idea of the fork ears rubbing against the chrome fork tube. Right now it's greased up well under there to help avoid any damage.

    Will do! :beer

    Agghhhhh that's sweet!!!! Love it! I don't have any white spray paint on hand right now but that may now change...

    Now, today started with removing old tires. I have 3 sets of rims, so the worst set are designated for this rolling chassis build. This 'using the worst' has really taught me that even some terrible looking stuff can turn out great with some care.

    My plan is to remove the old rubber, clean the rims as best I can, hopefully getting them to shine. Then I'll spray the outside of the rim (under the rubber) with Tremclad to stop the rust from advancing. New rim tape, and new tires and tubes then. Hopefully then I have shiny rims that aren't rotting away on me.

    The candidate rear tire. Time for that old rubber to go. The rim isn't too bad, but the spokes are pretty well rusted.
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    This was my first time doing any tire work. Breaking the bead was a little tough on this one, I think due to the rotted rubber and rusty grime that was caked on in there.
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    I've seen better, but we should be able to get them to an acceptable level (I hope)
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    Now the front tire. Much of the same, though cleaner under the tire
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    That's it for tires today, they are too grimy so I'd like to power wash first to make my life easier.

    Here's the headlight bucket from the previous post, all dry (and unfortunately all black inside, spokester :nah). It looks infinitely better, and this paint, semi-gloss Tremclad (I know, not high-end stuff here) has a nice satin finish.
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    Here's the rear fender, and the handlebars
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    Now this can start looking more like a motorcycle
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    And lastly for today, the lower rear fender. This is a plastic part, and this particular one seems to have had a hole burned in it at some point. I'm not sure how or why. But, staying true to form, this is the worst one I have so on the bike it goes. I'm not sure how I'll feel about this part being so damaged, it may get replaced later on depending on how much it bothers me.
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    And now, mounted on the frame.
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    I just sprayed the front fender with Krylon Fusion black. We'll see how that goes, but like I said previously, I'm not holding my breath. The last time I painted plastic, it was a tragic tale. The Krylon Fusion also takes 7 days to fully dry, so it won't be on the bike until next week likely.
    #17
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  18. spokester

    spokester Long timer

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    Good job with the rattle cans, bro! I love to spray paint stuff, not that I'm any good at it :)
    #18
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  19. TravisK

    TravisK Adventurer

    Joined:
    Nov 10, 2015
    Oddometer:
    79
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    Toronto
    Cheers! I'm new to this spray painting game, so I'm still learning as I go. I think I've been more lucky than anything. Let's see if it lasts!

    As for today, I needed space in my "spray booth" (liberal use of quotations). The front fender was dry to the touch, so I gingerly put it on the bike to let it fully cure there.
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    The fender is not flawless, you can see imperfections in it (including the lip there to the left of the tubes). But, its good enough for me right now. A plastic painting success story, who would have thought...
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    Next up is painting components more critical to getting this thing rolling.

    Kickstand, and brake torsion arm. The opposite (far) end of the torsion arm I suspect has been botched together at some point. It's not beautiful, but the welds look strong and hopefully the dimensions are correct. I'll know for sure when I mount the rear tire.
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    The swing arm. Not beautiful, but my other ones (being reworked by Denis) were worse. I cleaned up the passenger peg bosses with a dremel and a grinding disk.
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    Painting all three (plus an extra fork ear I screwed up) black. I decided to do the swing arm black, in order to keep this whole two-tone thing going. We'll see how it turns out.
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    Tomorrow I head out to Belleville to pick up my two frames from Denis at CMR Racing. I'm not sure I'll be doing anything with them until February. I want to have this one rolling before I leave for vacation near the end of December.
    #19
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  20. EricV

    EricV Long timer

    Joined:
    Apr 16, 2008
    Oddometer:
    1,297
    Wow man- you're making good/fast progress. Thanks for posting all of these pics. Great memories as my Dad (way back then, in the seventies) rode a DT and I had my little GT80. Good times....
    #20
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