barn fresh yz360a

[holeshot buddy]

its the wrong motor its an rt :'(
eng no rt1-148257
need original or a 1971 rt2mx360 engine would do
if all else fails i will have to soup up this one

[Freakshow]

he he i was about to say that motor in the picture looks wrong.   I must have missed the bit in your post where you said it didnt have the original motor.

IF it was me id forget using a 360 in it if you dont have the original YZ motor for it.  Get a DT1 or build up a YZ inside DT cases.  the 250 can be ridden in infinately more rides per day than the 360 which is limited to only open class events.   That bikes going to be more fun , more compeditive and cheaper to race if you slot a 250 in it, reallity is without its yz360 motor you have absolutley nothing to loose and everything to gain if your going to be racing it.

PLus the double bonus is Parts will be cheap as shit, and you can make a dt1 engine honk , and i mean honk along.  This project looks better every time i hear more.

[vandy010]

i'd kind of agree with Freaky about the 250 being a good option. i'm sure the RT motor would still do up well but it ain't gonna pull like a YZ. the Rt's reed block is way smaller for starters.
whack either an MX or YZ gearbox in it for sure. if you want to run the 360 donk, use a flywheel of around 1450grams for mx. a good balance between power and torque. the rest is obvious, pipe carb ports etc
and if your not going to use the RT donk, mate, can i have it?

[Freakshow]

reason i say the 250 is the best option vandy is down here on club days its an up to 250 class pre 75 and then usually later in the program a pre 75 all powers, so the guys ride there 250cc in both events

Using the 250 give s you twice as many rides in the day.  Not sure if that applies up there with you guys ? 

[holeshot buddy]

i actually want her for an open class bike
i can fit 6 petal reeds from later yz
circle f or pro form pipe
port her up 38mm mikuni
dont worry i will get her to go
maybe even a lighter ignition etc
to get it to spin up faster
will keep everyone posted the more i think about it even if i had original donk i would
probably do up a race motor to thrash anyway

[Freakshow]

Exactly, your onto it now holeshot !

As they say you can ride it like its stolen, You dont have to worry so much when you can trash covers and port barrels knowing your good bits are safe sitting on a shelf inside the house all warm and toasty 

[firko]

At the moment I'm building my second RT1 engine for the Cheney and when it's finished it'll be a bit different to the other one. The first engine uses a DT2MX gearbox, YZ250A clutch, DT400 external flywheel CDI, NOS GYT barrel, Torque Industries DT2MX pipe, rare ARP head, AND "no name" DT2MX outer cases. That engine will hopefully be a good honest pre '70 class engine. The other engine has the YZ250A gearbox from my DT1, MX250 clutch, and PVL small rotor ignition.
I don't know whether to build a reed valve top end as I have three or to build another piston port pre '70 engine. I haven't got another piston port 360 barrel so if somebody has one they'd like to swap or sell, I'm more than interested.

If I decide to go with the reed engine I've got a few questions: Is there a later style reed conversion that replaces the inadequate appeaing steel originals? What carburetor would be reccomended for the reed engine. I'm possibly using a 36mm Bing on the piston port engine purely because I like them and have the jetting fairly worked out for a 350 sized engine. Because I haven't used a reed 360 before, I'm a bit short on knowledge on the right setup. Does anybody have any porting tips for both reed and piston port barrels? I was tempted to use similar specs to the Gary Treadwell ports on my DT1 but I'm hesitant to put a porting tool my a new, unused and irreplacable GYT piston port barrel. I'm interested to know which ignition you use with the 1450 g flywheel Vandy? Ports aside, the onlymajor difference between my two engines will be the ignitions. I've use DT400 ignitions on all of my 250 Yamaha engines and it works a treat but I'm short on knowledge on which will work best on a 360. I haven't weighed the flywheel but it's pretty close to the original points version.

In a way it's a good thing that your YZ doesn't have the original engine Holeshot as you can modify to your hearts content without the worries of destroying a rare restoration candidate. I reckon you've got the makings of a great open class pre 75 bike.

Freaky, a bloke named Gary Jansen had a YZ360A in Adelaide back in the mid 90s and I believe the Fast Freddie Richards, also from Adelaide, also had one. Any idea on the wherabouts of those bikes these days?

[vandy010]

in reguards to flywheel wieghts,
i'm still not sure why, but i've been wieghing all my flywheels and documenting them.
it may help down the line,
STD RT1     =1650 grams
DT400D       =1800 grams
and when i build my MX360a i'll be using a YZ490 set up thats 1450grams.
internal flywheel YZ250a =650 grams.{big difference hey}
when i put the DT400 set up into my RT1, it had heaps of usable torque but i wanted just a touch more rev, so threw the flywheel in the lathe and trimmed it back to the 1650 grams and for that motor in that bike, i'm happy. nice for pre~70.
but for a pre~75 donk with reeds i'd be wanting just a touch more, so i'll be opting for the 1450 gram.
i've not ridden an internal flywheel set up on these engines but a few blokes i've spoke to prefer the external flywheel for MX. flat track would be different for sure.
yes, the YZ490 stator plate and flywheel will need to be modded a little to fit in but they're here and in good nick, so i'll head down that path.
the reed block size on the RT2/3 is the same reed block as the YZ125c/d etc so if you can get a set of fibre jobbies for them, no probs but i too would be interested to know what 6 petal reeds may fit. c'mon HB, spill...
well thats my 2 bobs worth but am curious if anyone else has a few ideas.

[holeshot buddy]

made up my mind will repair frame back to original properly
run all the yz gear thats on it
swingarm hubs forks triples brakes tank seat etc
paint it up the same as a yz360a
but i will bomb an rt engine
make my own airbox alloy
decent shocks etc and make a fast race bike
and you never know one day i might find the original motor or another
the original was taken out to do enduros the 360 was too peaky for bush :'(
and they wanted lighting coil so there is hopefully a
motor sitting in some shed corner somewhere :'( :'( :'( :'(
just sold one of my bikes so i might start pouring $$$$
into it soon keep you posted. oh the reed block is a %#*&@
sorry something wrong with computer
have to tell you later

[Freakshow]

Arent the Cr 125 76+ boyesn reeds the hot ticket on the yams 250 ? ?

[TonyB]

What would the 360 go like with methanol? 

[Freakshow]

Quick...........

[shortshifter]

Hey Russ,what about a short track special?Just been on the Vintage Track page and into the museum thread.There are some tasty comp bikes in there.

[caps 999]

i recon go with what ya got make a mean rt cross yz hybrid motorcrosser 

[holeshot buddy]

just pulled motor out and stripped bike
piston seized big time
gunna take some work to get her out :'( :'(