vandy010

thanks guys. i never even thought to check AMS but have dealt with them before and found them pretty good. found a filter here locally in the meantime though, so just the cage. next week will see what can be done with the motor. looks like just a set of main bearings and seals will see it on it's way. thanks again folks.

Hey Don, i checked that rear sprocket but unfortunately it won't fit the std MX/SC 73/74 rear hub as they are different to the DT {cush drive} versions. and 44 teeth is just a no-go for my MX bike as i need around a 51~53. got the sprocket issue sorted now anyway. was able to put another sprocket from another bike in the lathe and machine the centre out to suit. main hurdle i need to jump now is an airfilter cage but if i'm unable to find one, it should be easy enough to make. that and time. anyone got any spare time?

sounds weird with the over-rev Kieth. part of me wants to suspect the motor is sucking in air somewhere. hopefully it's not from the main seal behind the flywheel {cuase they can be pretty hard to source}. it sounds like you're checking in the right direction with the carby/clean/file bizo. hows the cable? mines actually been converted over for vintage moto-x and runs a 34mm carby jetted to stock RT1MX specs with a new cable. so i'm a little unfamiliar with the plastic guide piece you speak of. as for CDI's, yeah, some people just want the earth for them and it's criminal. my local wreckers wants $80 a piece for a flywheel/stator/cdi box. just keep your eyes peeled and sooner or later one will turn up at the right price.

Hey Kieth, with all "flange" mount carbies, it's important not to overtighten the mounting bolts or you'll have throttle sticking problems. i usually work the throttle as i tighten these bolts till i find that happy medium. it may also be possible this is the same reason for your over-rev. as for the kick-back issue, read here... http://www.yamahaclub.com/forums/index.php?showtopic=14559 they are the kick-back king with the std points set-up. hope this helps.

mine came from the first monoshock DT400 but i think they are mostly the same. have a good look at yours first as thats the only real guide i had to go on as well. just found this one on ebay, http://cgi.ebay.com/ebaymotors/ws/eBayISAP...T&viewitem= it looks to be similar to what i have {it was a while back,memory check} but you'll still need to source a CDI box for it and if you have weak spark, possibly have the coil re-wound. sounds like a bit of a hassle but it'll be worth it for sure and transform your motor into something a lot easier to live with. can't be too sure which CDI you'll need for that particular set-up, but i have mixed 'n' matched a few early yammie CDI's from one bike to another just by following the same number/same colour of wires from the CDI to the stator and have had no trouble. i almost forgot to mention, you'll need the stator/flywheel and CDI. i don't recomend mixing the flywheels around with stators, keep them compatible to each other for sure.

this thread seams to have taken a bit of a turn over to the YZ side of things. i'm in Oz and am currently building an MX250 and have found the rear sprocket to be the hardest part so far to source. the crankshaft/rod kit was also looking a little dodgey but i've managed to find another motor with a good bottom end/crank so that solves that. piston sizes go up to 2mm o/s and can be easily found but i'm still on the lookout for an origional air-filter element and cage if anyone knows of a good source.

ditch the points set-up for sure! this is the main cause for that sonofabi@%h kickstart wreaking havoc on your leg. use a latter model DT 250/400 cdi set-up and you'll be pleasently surprised. my RT1 is fitted with a DT400 stator,flywheel & CDI. it all just bolts straight in with the only difference being the RT1 flywheel weighs 1650grams and the DT400 weighs in at 1800grams. a little more torque you'll recieve as a result but i threw mine in the lathe and trimmed it back to 1650grams. cool bikes the old RT's.