OzVMX Forum
Marque Remarks => Yamaha => Topic started by: kenny on December 04, 2017, 12:47:52 am
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hi
i had a question about the dt1 250 from 71
i bought an dt1 from the usa but the headlight is a sealed beam one and it is broken i know back in the day you just throw it away and got youself a new one , does anyone have an idea what kind off headlight i can use to replace mine
also i bought a dt1 barrel with on the side YC 246 cc i ve been told its a barrel of a dt1mx from 71 or 72 does annyone know if this is correct ?
thanks
kenny
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The original headlight wasn't a sealed beam, they had a removable bulb. The light was the same pretty much on all the DT/RT series. They used a 6 volt 35 watt dual filament bulb.
If the barrel is an MX it will be chrome plated inside. I have had a look at one I have here and it only has the 246 marking on it with nothing else.
Of course it has to be piston port to be a DT1. The first of the DT2's came out in 71 with the reed intake but all the engine numbers started with DT1 up until the 74 DT250.
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DT1MX had a boreable cast liner cylinder [i have one] but DT1GYT kit cylinder was chrome [i recently sold one]. Assembled them new where i worked plus fixed them when they broke which was often lol. The DT1MX cylinders wore out pretty bad but the Chrome GYT Kit cylinder lasted well. I did end up with someones stuffed chrome bore that had an LA Sleeve fitted that was made out of real good stuff & lasted for ever & only recently sold that on a motor. I'll fight my way the crap & have a look at what's stamped on the side of the cylinder [DT1MX cylinder]. I'll find a pic so you can have a laugh at what it's on & not been run for years but does go & actualy fair goes like hell/ Just remembered i have a 360 crank in that one so 70x70mm whatever that works out too.
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DT1MX had a boreable cast liner cylinder [i have one] but DT1GYT kit cylinder was chrome [i recently sold one]. Assembled them new where i worked plus fixed them when they broke which was often lol. The DT1MX cylinders wore out pretty bad but the Chrome GYT Kit cylinder lasted well. I did end up with someones stuffed chrome bore that had an LA Sleeve fitted that was made out of real good stuff & lasted for ever & only recently sold that on a motor. I'll fight my way the crap & have a look at what's stamped on the side of the cylinder [DT1MX cylinder]. I'll find a pic so you can have a laugh at what it's on & not been run for years but does go & actualy fair goes like hell/ Just remembered i have a 360 crank in that one so 70x70mm whatever that works out too.
All the ones I've seen must be the GYT kit. All the one's I've seen in the last 20 years has had the chrome bore and all are stuffed. I thought the DT1MX's were just a Dt1 with a factory fitted GYT kit but obviously not.
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DT1MX had a boreable cast liner cylinder [i have one] but DT1GYT kit cylinder was chrome [i recently sold one]. Assembled them new where i worked plus fixed them when they broke which was often lol. The DT1MX cylinders wore out pretty bad but the Chrome GYT Kit cylinder lasted well. I did end up with someones stuffed chrome bore that had an LA Sleeve fitted that was made out of real good stuff & lasted for ever & only recently sold that on a motor. I'll fight my way the crap & have a look at what's stamped on the side of the cylinder [DT1MX cylinder]. I'll find a pic so you can have a laugh at what it's on & not been run for years but does go & actualy fair goes like hell/ Just remembered i have a 360 crank in that one so 70x70mm whatever that works out too.
All the ones I've seen must be the GYT kit. All the one's I've seen in the last 20 years has had the chrome bore and all are stuffed. I thought the DT1MX's were just a Dt1 with a factory fitted GYT kit but obviously not.
Yep still plenty of oversize single ring DT1MX kits on ebay. Be lucky to find a genuine kit for a chrome bore as had a ring with parallel faces as opposed to keystone tapper top face that i 'think' the DT1MX had but might be wrong on that, different thickness anyway. Chrome cylinder ring was of a different material & F$%n Dopey Me finished off a pretty worn but usable cylinder that i had for 30/40 years & thought--give it another run & had a genuine piston but no ring, so shuffled through a box of old rings & thought 'that one' do as fitted ring groove & the bore. Took about 1 minute to absolutely bugger it beyond use & pissed myself RIGHT OFF. Mate did that in the mid "60's on a square barrel villiers starmaker motor, think he got a special cylinder for it & did the same thing without realising. I thought--i'll never make that mistake lol. DT1 GYT Kit we got in late "68 for the new square S/arm DT1. Complete top end plus carb & chamber plus a "21 front wheel. DT1MX by memory would've arrived in 1970 with the round tube S/arm & ready to race out of the box--well till the gearbox gave up the next week!!. Boss got an RT1MX--same bike bigger motor. I pinched that motor for my "68 DT1 for a meeting while he was off overseas. Was a bit of fun for sure. Anyway--forgotten the question.
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DT1MX had a boreable cast liner cylinder [i have one] but DT1GYT kit cylinder was chrome [i recently sold one]. Assembled them new where i worked plus fixed them when they broke which was often lol. The DT1MX cylinders wore out pretty bad but the Chrome GYT Kit cylinder lasted well. I did end up with someones stuffed chrome bore that had an LA Sleeve fitted that was made out of real good stuff & lasted for ever & only recently sold that on a motor. I'll fight my way the crap & have a look at what's stamped on the side of the cylinder [DT1MX cylinder]. I'll find a pic so you can have a laugh at what it's on & not been run for years but does go & actualy fair goes like hell/ Just remembered i have a 360 crank in that one so 70x70mm whatever that works out too.
All the ones I've seen must be the GYT kit. All the one's I've seen in the last 20 years has had the chrome bore and all are stuffed. I thought the DT1MX's were just a Dt1 with a factory fitted GYT kit but obviously not.
Yep still plenty of oversize single ring DT1MX kits on ebay. Be lucky to find a genuine kit for a chrome bore as had a ring with parallel faces as opposed to keystone tapper top face that i 'think' the DT1MX had but might be wrong on that, different thickness anyway. Chrome cylinder ring was of a different material & F$%n Dopey Me finished off a pretty worn but usable cylinder that i had for 30/40 years & thought--give it another run & had a genuine piston but no ring, so shuffled through a box of old rings & thought 'that one' do as fitted ring groove & the bore. Took about 1 minute to absolutely bugger it beyond use & pissed myself RIGHT OFF. Mate did that in the mid "60's on a square barrel villiers starmaker motor, think he got a special cylinder for it & did the same thing without realising. I thought--i'll never make that mistake lol. DT1 GYT Kit we got in late "68 for the new square S/arm DT1. Complete top end plus carb & chamber plus a "21 front wheel. DT1MX by memory would've arrived in 1970 with the round tube S/arm & ready to race out of the box--well till the gearbox gave up the next week!!. Boss got an RT1MX--same bike bigger motor. I pinched that motor for my "68 DT1 for a meeting while he was off overseas. Was a bit of fun for sure. Anyway--forgotten the question.
DT1 talk certainly brings back memories for me having bought a round swingarm one S/H when I was 14. It came from a guy that worked at a Yamaha shop. Had all the lights on it but they soon came off and it also came with a GYT kit which went on. Certainly went better with the kit fitted but noisy as hell with that open chamber. My plan was to start racing it with a lowered frame after reading a magazine article on converting it into a MXer. I was talked out of it by my local MX expert and shop owner and bought a 73 TM125 instead. I kept the GYT stuff and sold the bike on but after looking at the barrel some 15 years ago found the chrome coming off with corrosion under it. Have made a sleeved and fitted it and just recently sold it for use on a VMX bike.
Not much to do with his original question but you get that.
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thanks for the information guys
the cylinder i have is boreable with reed intake
on internet i cant find anything of a cylinder that starts with YC
cheers
kenny
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thanks for the information guys
the cylinder i have is boreable with reed intake
on internet i cant find anything of a cylinder that starts with YC
cheers
kenny
Reed intake will make it a DT2/3 or possibly a DT2MX, I had a look on a DT2 barrel and can't see YC anywhere only 246cc. Can you post a picture or a link to a picture?
A lot of people have been conned into buying bikes that are listed as DT1's only to find they are DT2/3's as they all start with DT1 engine and frame number. What type of cylinder is on the bike reed or piston port?
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Found this on Ebay.
https://www.ebay.com.au/itm/New-Yamaha-Headlight-Bulb-CT1-CT2-CT3-DT1-DT2-DT3-RT1-RT2-RT3-175-250-360-400-DT-/281985258943
It is a sealed beam probably like the one you have but there is a list of other Yamaha's that share the same size light.
I may even order one for my RT3 and keep it as a spare.
Thought I'd put up a photo of the RT3. It's had a front wheel rebuild with a new trials tyre and a new repo seat cover since the photo.
(http://i1078.photobucket.com/albums/w490/Georgem15/DSC_0090.jpg) (http://s1078.photobucket.com/user/Georgem15/media/DSC_0090.jpg.html)
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Oh hell that's suddenly opened a different can of worms. reed i "72 on so you've either bought a DT2 or DT3 cylinder if it looks the same in the way it fits on, base gasket, head gasket etc. Or it's a DT2MX cylinder which looks a bit squarer in the fining, head fins are taller too if you have the matching head. Need pics please if pos. Only problem will be--if you 'do' have a "71 piston port DT1 7 go to fit a reed cylinder then there's a conrod length difference of about 5 or 6mm. Same problem doesn't happen with a 360 going from piston port to reed. Confusing myself now so i'll leave it at that.
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Oh hell that's suddenly opened a different can of worms. reed i "72 on so you've either bought a DT2 or DT3 cylinder if it looks the same in the way it fits on, base gasket, head gasket etc. Or it's a DT2MX cylinder which looks a bit squarer in the fining, head fins are taller too if you have the matching head. Need pics please if pos. Only problem will be--if you 'do' have a "71 piston port DT1 7 go to fit a reed cylinder then there's a conrod length difference of about 5 or 6mm. Same problem doesn't happen with a 360 going from piston port to reed. Confusing myself now so i'll leave it at that.
5mm longer conrod for the DT1 with a 5mm lower piston from the pin which puts the top in the same place.
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Found this on Ebay.
https://www.ebay.com.au/itm/New-Yamaha-Headlight-Bulb-CT1-CT2-CT3-DT1-DT2-DT3-RT1-RT2-RT3-175-250-360-400-DT-/281985258943
It is a sealed beam probably like the one you have but there is a list of other Yamaha's that share the same size light.
I may even order one for my RT3 and keep it as a spare.
......
I'd guess its wrong pattern for legal use in aus.
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Found this on Ebay.
https://www.ebay.com.au/itm/New-Yamaha-Headlight-Bulb-CT1-CT2-CT3-DT1-DT2-DT3-RT1-RT2-RT3-175-250-360-400-DT-/281985258943
It is a sealed beam probably like the one you have but there is a list of other Yamaha's that share the same size light.
I may even order one for my RT3 and keep it as a spare.
......
I'd guess its wrong pattern for legal use in aus.
That could be a problem but the Ebay site gave a long list other Yamaha's that share the same lens which could help in finding something.
One would have to be pretty brave to ride at night with those 6 volt light these days.
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thanks for the link off the head light
the cylinder that is now on my dt1 is one without a reed , i bought the other cylinder as a spare
here are some pic s off the cylinder and the dt1
(https://s33.postimg.org/q8s8smxcb/SAM_2282.jpg) (https://postimg.org/image/q8s8smxcb/)
(https://s33.postimg.org/ogz9xqlp7/SAM_2285.jpg) (https://postimg.org/image/ogz9xqlp7/)
(https://s33.postimg.org/8vhydshgr/SAM_2286.jpg) (https://postimg.org/image/8vhydshgr/)
(https://s33.postimg.org/5d5yh467f/SAM_2100.jpg) (https://postimg.org/image/5d5yh467f/)
(https://s33.postimg.org/d5wm93jwb/SAM_2101.jpg) (https://postimg.org/image/d5wm93jwb/)
cheers
kenny
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My guess would be DT2MX as there are no fins cut away for the side pipe.
Looks like a lot of work on the bike to bring it back to original.
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Hi Kenny. You should stick with the stock DT1 barrel. The Reed cylinder has a different rod length and head?? so stick with what you have.
The tank and front wheel are classic DT1 stuff and the pipe heat shield seals it for me. It is a either a 70 or 71 model. (1968/69 had a square section swing arm)
I have attached a link for a photo. (not sure if it will work as I haven't posted anything with photos for a while. ( Thanks to Vandy for the original photo)
https://imgur.com/2iAzhzS (https://imgur.com/2iAzhzS)
A good seat base is the hardest thing to find and the early ones are smaller than the DT2/3 I think. If yours is in OK nick then live with it. Clean it up, fix the rust and strengthen on the foam side.
Hot up tips and there are quite a few, RT1 carby, small porting clean up, complete ignition off a DT250/400 from 1977on (Stator, fly wheel and cdi needed). YZ and IT also fit but good luck finding one and no suitable lighting coil! All bolt straight in and give you almost total reliability. (The charging circuit from the lighting coil goes straight into old harness).
Put the engine and frame numbers up. That will clear any questions.
I'm in the middle of a DT3 rebuild for vintage plate rego so happy to share information.
Good luck with it.
Peter B
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my guess is just an ordinary DT2 cylinder as 'i think' only the head on the 250 is recessed for the pipe. Dt2MX has equal fins all around plus the pipe is sunk into the fins at the port. Found a pic on the net below if it works. I've been wrong before--just can't remember when lol. Always wife chimes in!!. ps forgot how to load pics now fotobuckets fkd. Found a link that works, man they're a nice looking bike & had one out of the crate new.
https://motocrossactionmag.com/classic-motocross-iron-1972-yamaha-dt2mx-250/
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my guess is just an ordinary DT2 cylinder as 'i think' only the head on the 250 is recessed for the pipe. Dt2MX has equal fins all around plus the pipe is sunk into the fins at the port. Found a pic on the net below if it works. I've been wrong before--just can't remember when lol. Always wife chimes in!!. ps forgot how to load pics now fotobuckets fkd. Found a link that works, man they're a nice looking bike & had one out of the crate new.
https://motocrossactionmag.com/classic-motocross-iron-1972-yamaha-dt2mx-250/
You could be correct the barrel with the fins cut off are the DT1 GYT that is sitting here. Still something doesn't look quite right with it for a stock DT2/3 barrel and the YC isn't on my DT2 barrel.
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i'd missed the pic with yc cast in somehow, i went above and below it--yeah that's interesting & wonder if it stands for 'Yamaha Competition. That's just a wild guess. Maybe it's a go fast DT2 cylinder but wasn't aware kit bits were available as the DT2MX full blown racer was just around the corner. The plot thickens. Getting confused what forum i'm on lol, i'll run it by the vintage yam one i get lost on at times.
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thanks for information guys
the vin number off the bike is dt1f 30*** its from 71 if im not mistaking
im not gonna make it original , i dont have a title on it , im gonna use it for occasionally riding on the track
i have another dt1 250 from 71 that is original for riding on the street
im gonna use the original cylinder the other im gonna keep as a spare
the seat pan is ok , but i was thinking off putting another seat on the bike maybe one off a mx 250 from 73 im not quiet sure about that yet
i already found another fuel tank for the bike , i bought a aftermarket exhaust ( not gyt really like one off those ) parts off these bikes are hard to find in my country i got lucky when i found these bikes in germany
for now im gonna use the original ignition , maybe in the future ill change it , from it s i have a few spare complete ignitions for back up for my it s
here are some pics off my other dt1 it original comes from wisconsin
(https://s33.postimg.org/9xjv7r40b/101_2152.jpg) (https://postimg.org/image/9xjv7r40b/)
(https://s33.postimg.org/hqaizqx4r/101_2155.jpg) (https://postimg.org/image/hqaizqx4r/)
(https://s33.postimg.org/8iiaj1xsb/101_2156.jpg) (https://postimg.org/image/8iiaj1xsb/)
(https://s33.postimg.org/dtx73r4ff/101_2157.jpg) (https://postimg.org/image/dtx73r4ff/)
(https://s33.postimg.org/3wm6apjyz/101_2161.jpg) (https://postimg.org/image/3wm6apjyz/)
(https://s33.postimg.org/ejfzg3x97/101_2162.jpg) (https://postimg.org/image/ejfzg3x97/)
cheers
kenny
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Kenny there is a page on Face book that is devoted to the DT1 , lots of parts . With the ignition any of the DT400 CDI systems will bolt straight in no problems . The GYT pipes are around but the price shows how rare they are . With the GYT pipes you also need to change the jets in the carbie , lower the compression or use a GYT head , the ignition needs to be reset to these changes as well . Iain
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Love your Wisconsin 250, Kenny. Gorgeous!!
Man ... they were such trick designs.
Imagine parking it outside a cafe !!!!!
(PS: Click on Kenny's icons to expand into full pages)
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thanks im glad i found the bike
ill check the facebook group out
the gyt heads they are not easy too find aswell i assume ?
cheers
kenny
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The GYT heads pop up on US evilbay quite often , But any high comp head will do . Webco , ACE , and GEM made heads for the DT1 . even a DT2MX head will bolt up .
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Or use a 74/75 YZ head.They would just have extra holes as would the DT2MX.
Bill Davis Texas Vintage Racing Club.
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Long time no hear Bill .
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Still around Mates.Hoping to come over again next year with my wife.She's never been.Any Racing over there in January or February ???
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Its the hot months here in Jan and Feb I don't think we have any down in my state but up on the mainland there might be some . Send me a PM when your close to coming over as I will be on the mainland in Queensland in early Jan . Iain
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Since we are talking about DT Yamaha's thought I should put a couple of photos of the DT/RT clutch worms as I still have a few from the last batch I made. Cost $50 plus post. Simple to fit and gets the clutch actuator back to good health. Made from bronze and with a bit of grease every now and then will last well and give a more positive clutch action than the original.
(http://i1078.photobucket.com/albums/w490/Georgem15/DT%20Yam%20clutch%20worm%20001.jpg) (http://s1078.photobucket.com/user/Georgem15/media/DT%20Yam%20clutch%20worm%20001.jpg.html)
(http://i1078.photobucket.com/albums/w490/Georgem15/DT%20Yam%20clutch%20worm%20004.jpg) (http://s1078.photobucket.com/user/Georgem15/media/DT%20Yam%20clutch%20worm%20004.jpg.html)
PM me if anyone wants one.
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hi
i had a question about the dt1 250 from 71
i bought an dt1 from the usa but the headlight is a sealed beam one and it is broken i know back in the day you just throw it away and got youself a new one , does anyone have an idea what kind off headlight i can use to replace mine
also i bought a dt1 barrel with on the side YC 246 cc i ve been told its a barrel of a dt1mx from 71 or 72 does annyone know if this is correct ?
thanks
kenny
just saying I have a CT1 reed valve jug with yc on it
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Does anyone know how to join the Facebook DT1 site, please? I've tried sending request, and also messaged two members - all to know avail over this past two weeks.
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I just joined and had no problems at all
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Ive tried your real name to no avail.
Have you got a facebook friend on the DT-1 Yamaha group.That would work.
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The Facebook group I found is called 'DT-1 Yamaha' and is listed as a closed group.
The header picture are two yams - red on left, gold on right.
I clicked the "+ JOIN GROUP" request to join, but I'm stuck on 'pending'
(I've canceled it a couple of times, and re-applied past week or so.)
Maybe they've heard about me!
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Maybe they've heard about me!
Would you really want to belong to a club that would have the likes of you as a member?
;D
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Looked up admin and sadly it was Robin Hannah Vmxr from USA,organiser of CZ World Championship event.
Whom passed away just recently.
Ill send a message and see how we go from there RH.
Regards A
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I'm regularly on https://yamaha-enduros.com/index.php/forums/recent-2 great site for DT1's & everything related to all those yamaha models around those years. I go by RT325 due to using a 250 crank in a 360--long story & 'why would ya bother'--coz i'm experimenting lol. Anyway, check out the site & join up then you can post pics straight from your computer onto the site.
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Would you really want to belong to a club that would have the likes of you as a member?
;D
Bahahahaha