OzVMX Forum
Marque Remarks => Yamaha => Topic started by: Dono113 on January 21, 2013, 02:39:53 pm
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Feeling the waters for a piston port barrel for a RT1 360
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just put my pp RT1 cylinder back on after running an RT2 top end for a while,[just an old 'rat' play bike, had for decades] damn thing doesn't go as good as i thought it used to. Might find the porting specs for the RT1mx cylinder & have a play--could be dangerous.
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Dono they are about but expect to pay top dollar for one . http://www.ebay.com/itm/68-71-YAMAHA-DT1-DT1F-RT1-CYLINDER-BARREL-JUG-PISTON-/150290395615?hash=item22fe0171df&item=150290395615&pt=Motorcycles_Parts_Accessories&vxp=mtr
Iain
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I wish I could help you Dono but they're getting pretty scarce. They only made them for two years which doesn't leave all that many survivors when compared to the reed model. I was given a NOS RT1 GYT cylinder back in 1992 and I've never seen another one for sale since. Keep an eye on US eBay, that's your best bet.
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Sorry about the evil bay link found it in a search on RT1 's and didn't read any further . Like Firko said they are hard to get Ive only got 2 and one of them is on its last rebore 2mm over the other is std and it took me about 4 years to find .
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Here are a few:
http://www.ebay.com/itm/71-YAMAHA-RT1-360-ENDURO-CYLINDER-/360499782711?hash=item53ef762437&item=360499782711&pt=Motorcycles_Parts_Accessories&vxp=mtr
http://www.ebay.com/itm/Yamaha-RT1-360-2120-Cylinder-Piston-Barrel-Jug-/360434675059?hash=item53eb94ad73&item=360434675059&pt=Motorcycles_Parts_Accessories&vxp=mtr
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Yeah seen those yesterday, was thinking about buying Kipo's 360 Mark for pre 70 dirt track, Nifty tells me that they are a carry over and I would just need to change the top end
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As i'm sure you can see by the pics 99% of RT1 cylinders on ebay are RT2/3 with reed, sorry didn't really need to tell you that. Obviously the old RT1 engine number prefix tricks them. bit of a shame as get's me going then--bugger. What do you recon is going on with the [supposed] DT1 cylinder through the link given?, with cut outs in the piston [if piston belongs to it] do ya think it had an aftermarket reed assembly bolted on to original flange as we see it. seen it up there for a long time. Did plan to try [silly idea] blocking off the boost port in an RT2 cylinder with some metal set stuff & see how she'd go using an RT1 piston, mmmm ok, think ill try it. Changing story back to RT1, i see the piston at tdc is way above the top of the inlet port. to increase inlet duration is it always best to lower the inlet or can i follow the piston up a bit?. tis a std porting RT1 cylinder & an unmodified piston so must be how they are. Thanks.
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Mean't to say run it minus the reed set up with boot port blocked off
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must be loosing it [lost it] as i said further up in the posts, my RT1 top end used to go real good [i thought i remembered] but not since re-fitting last week [flat as]. Dummy me--thought to check the point gap [ie ign advance] & barely opening. Gave em a nipping 15 thou & doubled the horsepower. Trouble is--the clutch now slips & in the process i found the left main is [up n down], more likely been spinning on the shaft & grooved it. Mag is a rare one [might be RT1MX] with the advance mechanism. thought i'd be smart & swap flywheels for the normal one but points are mounted slightly further out so i seems. Cam measure about 37mm std was around 31mm so put original back on. Always something new to learn even when you think you "Know It All", can hear "Mr Know It All" sayin--you really should have known!! Another rebuild gonna have to happen sometime. Now i'm thinking 'if only' i'd checked the points when i had the RT3 top end on but in saying that--i think the piston port is a nicer old motor, albeit with a lot more inlet noise. Keep chopping & changing the bike every year or so but has an AT1 tank, PE type forks n yokes, [forks came around & hit the std tank but just miss the smaller one] RM swinging arm & shortened subframe with shocks made of Short Gas Girling [all i had]Medium Damped Shocks arc welded [stand back she could blow!!] into PE bodies to get the overall length & PE spring location. Mums teapot for a K&N filter box & [on & on it goes] Rides nice for a dungga--pro circuit old rm250 pipe that's right. Had longer forks & shocks on [still short heavy damped girlings inside] but was way too tall plus i think it's an XT250 seat which is quite thick & not ideal [all i had]. Sorry about the long story. Cheers.
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how does one go about loading photos. Can they go on any page i'm writing a story on or is there a special page. looks like i have to join up separate from the 'forum' as such & have activated that part so will see what comes back via email [maybe a code to get in or something] No biggy. [you'll only laugh at my bikes]. Cheers.
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Morley.....Join up here, the rest will come easily............http://s1112.beta.photobucket.com/ (http://s1112.beta.photobucket.com/)
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thanks firko, will do.
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http://s1276.beta.photobucket.com/user/gasgirlings/library/
Kids are going to have me put down haha [& i'm not laughing], recon i'm bloody useless but 'yay' i've loaded some [talking points] Rat Bikes onto photobucket, just didn't know how to copy & past the [url think he said] thought that was a Russian bike--well close to it ural?.
too much to write but probably been said in my other posts but ask [laugh] or whatever. looks like we'll be away for most of the week but anyway. Hope the link works [thanks to 'firko']. One obviously [motor] is an RT1 piston port & other is an experimental RT2/3 with a 250 crank [80x64] or 80.75 by memory. RT1 is a long [sometimes sad] story. When i got this frame about 30+ years ago it had-had a 3TA or tiger90 motor in, never saw it as such but must've fitted snug as front down tubes were bent forward a little to accomodate, only needed a pat with a big wooden mallet. That was years ago of course & i altered the subframe over the years, even sold it once with an RT2MX top end & real good homemade pipe then was given the bare frame back years later & found enough bits to start again. Had it longer legged forks & shocks till recently but better as it is reduced a bit. Not a serious bike but was once & realy enjoyed annoying the hell out of the young guys on their YZF250 type things [when i was a bit younger haha]. This S/arm arrived in a MudBug farm bike heading to the dump, wrecker didn't want it so glad he stopped here--think these forks were on it too by memory. Till Later, Cheers.--hope link works or we'll try again later.
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mean't to say, [as you can see in a couple of pics] the top yoke is a couple of mm or more too big but found a couple of top fork bush out of something that fitted perfect. Might've been bottom bushes, Teflon coated looking i think--anyway. front wheels kdx200.
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Morley...You're almost there. Once you open your Photobucket album, DOUBLE CLICK ON THE PHOTO you wish to post. Then single left click on the IMG CODE window and it should turn yellow and 'copied' appear. Then left click again on the post where you want the photo to appear and..voila! the URL for the photo will appear. Click on PREVIEW to check if its all correct and if it is...click on 'POST'.
(http://i1276.photobucket.com/albums/y476/gasgirlings/PIC_0781_zpsce980866.jpg)
nice 'Mexican blanket' upholstery.
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ok, i'll give it a shot with one pic then worry about it later in week. Did sort of think the idea to leave on photobucket only via a link was to avoid filling up thee ozvmx site with pics [of old crap like mine haha]. Firko, the good wifey just bought home the latest vmx with your RT1mx story--good one. I remember riding Tim [Gibbes] one down home here after assembling it & was impressed with the power [after my 1969 DT1-GYT kitted] but preferred mine to ride [what ya get used to i suppose] so put his 360 into the DT1 for one meeting & didn't want to give it back did i.
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(http://i1276.photobucket.com/albums/y476/gasgirlings/PIC_0763_zpsdb2a2373.jpg)
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Hey Morley, they look neat in their own way, even if a bit rough (as you say).
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What's the alloy swing arm off Morley, looks like a 79 rm?
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Hi, to the replies above, using up motel internet but will post my [call them 'ratbike'] pics at end of week if i can. Son showed me how in the end in a practice shot then said 'you do it', took a bit more tuition but got one up there, Yay.
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yes i think the s/arm is RM125, possibly '79. Had a shorter arm in [thinking back], well this one seems a bit too long. The old use what ya have trick. KDX front wheel & a Chinese scooter cable altered for front brake & throttle. I got a 'free' bundle of assorted cables [scooter type] & a good starting point for making one. Have an old fashioned cable oiler you seal the cable into, fill with oil & pressurise it, works great & the chinese cables are made 'dry' but made well i recon. Gota go.