Retrohowla Posted August 29, 2011 Share Posted August 29, 2011 Ok so i finally pulled my old 1970 DT1 out of storage yesterday after 8 Years in the dark, i bought it blind back then, never started it just put it away for when i had the time and money to do it up, well i still have neither but its about time the old girl went back on the road so here goes! Firstly im not sure its all original, for a start it has reed valves and a dykes top piston ring, am i correct in thinking this could be post 73' top end? Also the air box has been scrapped making me think maybe post 73 carb too? The most pressing issues for me at the moment are, it needs a piston kit and con rod kit and i dont know what to buy and from where, if it is the later top end then piston kit is no issue but can anyone confirm this for me? Secondly, the crank cases say DT1-F so con rod i guess needs to be DT1? Any ideas where i can get one? Also crank seals etc? Link to comment Share on other sites More sharing options...
splittie65 Posted August 30, 2011 Share Posted August 30, 2011 I've been restoring a 1973 CT3 and have found its often cheaper to buy parts on the american ebay site, even with the occassional import duty. Parts are alot more common there too. Link to comment Share on other sites More sharing options...
chrisp Posted August 30, 2011 Share Posted August 30, 2011 My crankcases also say dt1-f, and its a 1973 DT250 DT3- do you have any pictures or bodywork? what colour is it? Almost nothing exsists in the UK for this bike, get everything from ebay U.S Link to comment Share on other sites More sharing options...
Tommy10bikes Posted August 30, 2011 Share Posted August 30, 2011 I have just had my DT1B crank rebuilt by Keith at Motolink http://yamahaspares.uk.com/ .From what i can remember most of the conrods and bearing are from the DT / YZ range so a fairly easy fix, he can also supply some seals and bearing buti think you will find they are also stock Yamaha sizes. As Spittle65 has said most of the other parts will have to come from the states but the exchange rate is very good at the moment, one site i did find usefull was http://vintageconnections.com/ who supplied all the silver sheathing and tape. It does sound that you have the later DT3 engine if its reed valve as all the early DT1 where piston ported, i finished my DT1E over xmas this year and i have semi started my DT1B but on hold until i finish my 1975 xt500c, i also have a CT3 but thats next years resto. TTB Link to comment Share on other sites More sharing options...
Retrohowla Posted August 30, 2011 Author Share Posted August 30, 2011 Thanks guys, i didn't expect anyone to reply if im honest! Thanks Tommy for the links that will prove very usefull. My bike looks almost identical to the red/brown/bronze one above, tank is the same, pipe is the same, fenders the same, etc etc, although its been resprayed dark blue at some point the original colour of the tank looks to be orange. As for bearings and seals i have sourced all of them from a local bearing supplier who was very helpful, every crank and gearbox bearing and seals all for £100, didn't think that was too bad. All i have left to find is the con rod, i have done alot of research and found that the 1977 yz250 should be the same and Yambits list a conrod kit for this model so its looking brighter already. All thats left to find is the piston kit but the one thats in there looks decidedly dt250mx to me so maybe someone has fitted this previously when they couldn't get the earlier one? I have been looking on the ebay usa site but would like to find things in the uk if poss due to my last 3 packages from the us all getting hit by import duties, maybe i was unlucky but it made it alot more costly as they added their handling fee as well Oh and can anyone date and model my engine from the cankcase number? Thanks again guys, its nice to know there are other people out there working on similar stuff. Link to comment Share on other sites More sharing options...
chrisp Posted August 30, 2011 Share Posted August 30, 2011 yes, if you can post the chassis number an accurate date date can be arrived at. Link to comment Share on other sites More sharing options...
Tommy10bikes Posted August 31, 2011 Share Posted August 31, 2011 I managed to get my piston from this seller on the bay, he has been very good and all that was ordered arrived well packaged. http://cgi.ebay.com/ebaymotors/Yamaha-DT1-Piston-Ring-SET-2nd-OS-OEM-NOS-NEW-/110664849193?pt=Motorcycles_Parts_Accessories&hash=item19c4239729#ht_572wt_1163 Im not sure what oversize you want but it looks as he has them all Hope it helps TTB Link to comment Share on other sites More sharing options...
Retrohowla Posted August 31, 2011 Author Share Posted August 31, 2011 I have had the chassis dated by yamaha and they came back with feb 1970?, its the engine i was after a date for, (dt1f 110030) it seems the crank cases have the same number as the chassis but the top end is not original due to having reed valves? Thanks Tommy for the link, i will email him Thanks again guys Look forward to hearing your views on the chassis/engine number Link to comment Share on other sites More sharing options...
Retrohowla Posted September 1, 2011 Author Share Posted September 1, 2011 Got in touch with Keith at Motolink today, he seems to think my engine is a very early dt1 due to the 24mm crank pin i have, had it been the later 25mm pin he could have supplied a con rod kit no problem but hes looking into it for me now. I also seem to have a DT250 twin shock piston fitted at present so replacing this will be no bother. I will try an upload some pics of the body work for you guys to see what you think in a bit. Hopefully you will be able to tell me what year its from. Link to comment Share on other sites More sharing options...
Retrohowla Posted September 1, 2011 Author Share Posted September 1, 2011 Here is my first shot at uploading pics, hope it works Link to comment Share on other sites More sharing options...
Retrohowla Posted September 1, 2011 Author Share Posted September 1, 2011 And some more Can anyone date these body panels and head/barrel? Link to comment Share on other sites More sharing options...
Retrohowla Posted September 1, 2011 Author Share Posted September 1, 2011 From what i can make out the tank looks 72/73 ish? Is that about right? Link to comment Share on other sites More sharing options...
chrisp Posted September 1, 2011 Share Posted September 1, 2011 Yep its either a '72 0r '73 DT2 or DT3. it's obviously been repainted at some point in the past, and the oil tank is missing the "tourque induction" emblem, but my money is on it being one or either of those. There's only minor mods between the Dt2 and 3 so the vast majority of parts are interchangeable. look on US ebay for parts books which will be a great help to you. Link to comment Share on other sites More sharing options...
Retrohowla Posted September 1, 2011 Author Share Posted September 1, 2011 Thanks Chrisp, yes the more i look around the more it looks like a DT2/3, strange that Yamaha has dated the frame number as 1970? Engine number matches the frame number also?? Well even though it seems to be a bitsa, its all there and pretty tidy so should be worth what im spending so far should i decide to move her on at a later date. Do you know roughly what these fetch in nice (not mint or 100% original) condition? Link to comment Share on other sites More sharing options...
chrisp Posted September 2, 2011 Share Posted September 2, 2011 I'm restoring a 1973 DT3, (see my pics in "new member" or other section here.) Very rare bike in this country, though andy at Yuniparts is bringing bikes in now. I think he's selling a DT3 for about £2000 ish. Mine was in such a state i've had to replace everything so it will be more of a recreation than a restoration. Let us know how yours is progressing! Link to comment Share on other sites More sharing options...
Retrohowla Posted September 2, 2011 Author Share Posted September 2, 2011 I knew it was rare when i bought it as i had never seen or heard of it before and i like my classic dirt bikes so kinda got me interested straight away, bought it blind nearly 8 years ago and never even rode it, fogged the engine and put a sheet over it in the back of the lock up. Turned its wheels for the first time sine then this week..............onto the flat bed and up home. The strip down has revealed a very good motor, nothing really needs replacing but i like to do things properly when it come to the motor so new con rod kit on the way, main bearings and seals, gearbox seals and bearings, new gasket set and a ist oversize rebore. New points and condensor and anything else i consider consumable. As for the rolling chassis, new steering races, fork seals, rear shocks and that's about all that needs. I'm not going for concourse as its going to get used and used well so i don't want to be afraid of scratching it but it will be loved non the less and constantly fettled to keep her prime. So that's where i'm at, stripped down, awaiting parts for full rebuild of the motor(be here monday), paint for the frame and swinger, polish for the rims etc and fit the bearings to the headstock. Hope for an Mot late next week Link to comment Share on other sites More sharing options...
Retrohowla Posted September 6, 2011 Author Share Posted September 6, 2011 Well i got my con-rod kit through today, bit of a disappointment as its not the same as what's in the bike. Basically its all OK apart from the conrod length, the one I've been sent has 130mm centres and the one fitted to my bike has 125mm centres? Can anyone shed any light on this as Keith at Motolink says the dt1 should have a 130mm centres con-rod? Anyway he's been very helpful and is sending the 125mm rod down but now I'm worried there may be port timing problems if my barrel does not match the stroke properly. So now I'm confused, Yamaha dated my frame as 1970, my engine number matches my frame number but i have 72/3 bodywork and it seems a 72/3 engine? I wonder what else i am going to struggle with when i get this back together? Also, I'm struggling to source a new set of rear shocks for it, has anyone found a supplier? Looks like it wont be on the road soon after all Link to comment Share on other sites More sharing options...
Tommy10bikes Posted September 6, 2011 Share Posted September 6, 2011 I have just measured the rod length that was built up for my DT1B and its 130mm centres, also i have just crossed referenced the rods for the DT1 and there all the same part number so DT1 DT1B DT1E DT2 DT3 MX250 as well all use the same rod. Obviously the top end isnt original for the bike and with it having only a one ring piston then, i would have thought that there may be 5 mm difference in the piston you have and an original piston, so by going with a standard rod and piston may give you the correct stroke. Just a thought. Regarding the shock i have used these on my DT1 and my DT360, i have also bought a set for the DT1B that i will do one day. http://www.ebay.co.uk/itm/NOS-Yamaha-DT1MX-Replacement-Shocks-RT1MX-DT2MX-RT2MX-/290606631638?pt=Motorcycles_Parts_Accessories&hash=item43a9814ad6#ht_500wt_1156 TTB Link to comment Share on other sites More sharing options...
Retrohowla Posted September 6, 2011 Author Share Posted September 6, 2011 Hi tommy, thanks for the info, i really don't know what i have engine wise, in the past i think someone has been playing and really messed it up. My engine has a 24mm crank pin, now i believe most DT1's have a 25mm pin? Also, i have a reed valve cylinder, telling me i have the later top end i guess if not a later bike all together. (Yamaha dated it as 1970 but everything else points to a later model) Also, i have a later piston kit fitted, the type with a dykes top ring Now i have just inspected the barrel to see if i can tell where the piston was topping out at, shame as i have already honed the bore and cant quite tell where it was falling at tdc. Should the DT1 stroke finish with the piston right at the top of the bore, or slightly lower? Im in a right mess here, the crank is at the machine shop so i cant put it back together and check the stroke, i don't know if the bike ran ok on this set up or not either as i have never ridden it, it seemed to have good compression as i recall but im trying to think back 8 years here. I think i need to go back to the drawing board, do a dry build on the motor and check the stroke etc. I t would be very helpful if i knew what on earth i have here, as at the moment i don't know what's what. Link to comment Share on other sites More sharing options...
Retrohowla Posted September 6, 2011 Author Share Posted September 6, 2011 Oh and thanks for the shock link, however i have just found a chap who can supply pattern shocks to match the originals over here. They look identical, have 325mm centres, eye eye fitting and trail type soft progressive springs for trail use. If they turn out to be the ticket i will post up a link Link to comment Share on other sites More sharing options...
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