OzVMX Forum
Marque Remarks => Yamaha => Topic started by: Iain Cameron on July 23, 2010, 11:41:27 pm
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Hi gents are the rt motors like the dt1 motors with different length cons from non reed to reed thanks iain
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i'm not totally sure of what your asking there Ian but the RT/DT1,2,3 should all run the 214 Rod.
if you've got a motor with something else then it's probably been doctered.
(http://i1035.photobucket.com/albums/a438/vandy010/ozvmx%20stuff/rodspistons.jpg?t=1279895006)
we discussed this some time back and i stitched together some posts & pics from that conversation.
this pic is all about that.
hope this helps.
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(Right click - save) ;).
Thanks 8).
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Hi vandy thanks for the info . what I want to do is put a nonreed cylinder on a rt2 bottom end . Iain
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Hi vandy thanks for the info . what I want to do is put a nonreed cylinder on a rt2 bottom end . Iain
it'll bolt straight on Ian as thats how most of these pre~70 RT/DT's start out {by converting the 2,3 back to 1 spec} and is exactly what i've done with mine.
i used a pro-x rod kit from a later model YZ250 {same as a 214 rod}. my Yamaha dealer here in Brisbane sorted it out for me.
went straight in, no hassles.
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Thanks vandy the reason I asked was that I know the dt1 & dt2 have different lengths and was not shaw about the rts .I have a five part artical in dirt bike (us) from 73 on a dt250 project which gives how to set up for the suzuki piston using a spacer. iain
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Just been through this myself, building both a pre 70 PPort with a Dt1 and a RT1.
What seems to have happened is the 311 and 428 rods seemed to turn up when some people at some time put a new rod in there Dt1/rt1 bikes and put them onto Reed top ends. The non reed piston with the short rod crashes into the crank webs, but going the other way ( which they were doing) was fine you can run any rod and it seem to work just dandy, maybe even runs cooler as it now has less compression.
Any how going back the other way ( to PPort) you must go back to the correct 214 rod as the lower skirt on the piston port motor locks onto the crank web regardless if its the DT1 or RT1 bottom end.
You didnt say which bike you were doing but you CANT use the prox YZ250 kit with the Dt1 as it uses the 24mm crank pin, but can do on the RT1 as they both use 25mm pins.
YOU can do some other tickery by mixing and matching a mid 80's 250 rod (24mm big pin), but you then have to run the larger small end bearing cage ( ie YZ465, 250 ) from that era, as they are like 22mm OD not the normal OD bearing in the small end. I have just messed around for the last 2 months mixing this around to get it to all fit on the cheap and now have a list of the bits that fit and dont fit. So next time i can just keep an eye out and stockpile the bits, then rebuilt them when i have all the bits, not like this time where i went from one miss match to another. ( im putting the DT1 on alchy so im ready for rebuilds)
*** IN short it can be real easy and will all bolt straight back up if your using the 214 Rod, but saying that you CAN use other option but you need to be sure you have the other alternate bits you need for it to bolt back up.
IF you get stuck tell me what bike your going to do and what bits you currently have and i can tell you what your missing or what will pulg straight in.
Can you also scan me a copy of the 5 page article as im curious as to what they are doin gand why ( maybe the 214 rods where in short supply back then too) but running a 6 mm higher piston would close up the squish and push the Comp up to about 10:1, from what i can see with the cc ing i have done on the heads i have and the amount ive taken off from the barrel and head.
cheers Freaky
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will do over w/end Freaky , I have about 10 boxes of old dirt bike/trail&track/mx action/aus dirt bike so it might take some time to find Iain
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Foot note : i just fitted a 214 rod in a DT1 bottom end, up to a normal Dt2 reed barrelr and put in a wiseco 234 piston, guess what , the piston sits out of the barrel by 5 mm, so im guessing here that the YZ250A barells must be 5mm higher thus, the pistons are from the gudgeons as well. Note to self to check later.
Actually should have checked before i got the barrell honed out to suit that piston, doh got boxes of stock ones wonder why i used that one...................
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Freaky can't you cut a spacer out of alloy plate for the bottom of the barrel say 3mm with a gasket either side to bring it up to the 5mm you need.jimson
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yep going to have to, not sure what going on ther, checkede 4 red valve barrelss and they are the same height, yet its too high ? but isnt with the smaller rod.
Turned out the wiseco is the same as the normal reed piston , so again its that bloody mis match thing.
the reed wont work with a 214 rod, that 5mm comes back to haunt you.