my new/used Yamaha PW50 thread

[my67xr]

the seat height on the PW50 is 435mm, PW80 has a seat height of 635mm ( i could have lowered it if needed)
my DS80's seat height was 620mm, but is now 720mm with the lift kit
the DS also has a clutch (heavy springs too) with 5 speed trans, where as the PW80 is a 3 speed semi auto




i have decided to keep the PW50 for a bit longer now.
i can always upgrade it as needed, lift kit, 44mm big bore 60cc kit, higher bars, foot brake conversion etc etc

 

[my67xr]

well, good news for Cj,
we have just booked him in to go on the South Coast MX Club Ride Day on the 23rd of February
it is a limited number, free open day for all non licenced MA riders, aged between 4 and 16, with under 100cc bikes.
the club membership forms are on their way to us too.

here's a couple of picture's from their Facebook site

we will try and get some videos of him riding, and we'll be sure to spread the word about Miniriders too !

Motorman, i had better order some stickers too!!


cheers, craig

 

[my67xr]

so the day at SouthCoast MX Club went well for all that went,
Cj didn't get to go on the track due to bike problems, but he still had a lot of fun riding around with the others.
i really had to persaude him to come home at 3pm.

i pulled the carby off today and checked it all out.


with the carby pulled right down,
i noticed the Needle Jet Tube had a little damage where the Needle Jet sat
it had an almost oval shape instead of being round.
after a bit of playing around with it, i managed to massage it back into shape
i gave it all a good blow out to, nothing noticable came out
the brass Choke tube that sits into the bowl was slightly bent too, i straightened that as well.

i reckon the Needle Jet Tube could have been causing havoc with the atomised fuel being drawn out of it.

i ended up swapping the Pilot jet for a leaner one, probably due to the new expansion chamber i made for it.
and i swapped the Main jet for a richer one too
it sounds a lot better when accelerating now, but i still need him to try it out.

 

[my67xr]

a couple of pics from the ride day

 

[my67xr]

 

[timeeh]

so the day at SouthCoast MX Club went well for all that went,
Cj didn't get to go on the track due to bike problems, but he still had a lot of fun riding around with the others.
i really had to persaude him to come home at 3pm.

i pulled the carby off today and checked it all out.


with the carby pulled right down,
i noticed the Needle Jet Tube had a little damage where the Needle Jet sat
it had an almost oval shape instead of being round.
after a bit of playing around with it, i managed to massage it back into shape
i gave it all a good blow out to, nothing noticable came out
the brass Choke tube that sits into the bowl was slightly bent too, i straightened that as well.

i reckon the Needle Jet Tube could have been causing havoc with the atomised fuel being drawn out of it.

i ended up swapping the Pilot jet for a leaner one, probably due to the new expansion chamber i made for it.
and i swapped the Main jet for a richer one too
it sounds a lot better when accelerating now, but i still need him to try it out.

Far out man, you certainly are the spanner spinner. When my carby comes off, i see if the jets are blocked and that the slide moves, what you just described, i would have no idea what all tht stuff is supposd to look like let alone if it were damaged.. Reps to you Craig Top work yet again :clap:

 

[my67xr]

thanks Timeeh,

you can see the top of the brass Needle Jet when you lift the slide, it sits in the bottom of the carby bore, and it's what the Needle lowers into
and you can also see the other end of it when you take the main Jet out from the underside of the carby.
on some carby's, the Main Jet will screw into the bottom of the Needle Jet,
and on other's, the Main Jet holds the Needle Jet in.

i had another go tuning it today, but is still a touch too rich.
i noticed the Main Jet i fitted yesterday wasn't bigger it is smaller. the 62.5 Jet looked like a 67.5.
so i went to Show and Go today and ordered another couple of jets, they should be here next week hopefully


so with the new exhaust now flowing more, it is pulling more fuel through the carby, that's why it's needed smaller/leaner jetting.
can be a bit confusing sometimes...

this is what the PW50 Needle Jet looks like (pic off the net)
those holes through the sides can block up (just like in the Pilot Jets) and not let much air into the fuel mix
so the fuel is hardly atomised when it goes into the engine, making it harder to burn
the thinner end to the left of this jet is the end that had been ovalled out

 

[my67xr]

i'm thinking about partly pulling the bottom end down, just to check a few things out in the gearbox.
with this bike being built in 1981, i think some components may need replacing?

there is a little clunk when you accelerate, possibly the primary reduction gear rubbers are shot ?
and i reckon the clutch springs could be worn/stretched too, due to age, and also an adult having a ride every now and then

the clutch rubbers are easy enough to source, genuine for $8 US the pair plus post.
and i've found some heavy duty aftermarket clutch springs from Pax Racing in the US
i have just emailed them with a few questions on the springs, will hopefully get a reply soon
then i can order them.

i have also just ordered a new set of Carbon Fibre Reed Valves for it too, $27 delivered
i think the ones in there now could be a bit off form too

 

[my67xr]

i have found a good used PW50 clutch, the seller had some other engine bits too.
i ended up getting an almost complete, fire damaged, bottom end from Victoria for $65 delivered, good price i reckon.
and the Carbon Fibre reeds are in transit too.

i also found someone that sells pistons to suit the PW50, he has 44mm (59cc) and 47.5mm (69cc) in stock

 

[my67xr]

just saw that my PW parts engine has been marked as posted, yey!

 

[my67xr]

the PW50 bottom end arrived today, i have pulled it apart and am a bit dissapointed.
the 2 major components i needed are no good, the Clutch is close on shot, and the Primary Driven Gear has a cracked inner and a stuffed rubber.
it must have had a really hard time, at least i got my moneys' worth with the rest of the parts, and some spares.

now i need to get plan 2 into action....

 

[Blender]

thats a shame you cant use the parts you needed, but atleast now you have those other parts. so whats this plan 2 ?

 

[my67xr]

another engine.....




i have found one a couple of hours from here, and the best thing is it has a good PW50 upgrade part on it too (Secret!)
and its only $10 more than what i paid for this fire damaged engine.
i would have bought it instead if it was advertised before i saw the other, oh well.

and ricky_191,
if you are wanting a good Stator, Source Coil, or Flywheel for yours, i will have one i could sell you.



this is the clutch, see the red friction material, it has a lot less than i'd hoped for. (3mm less on each shoe)




the Primary Drive gear, the longer rubber is supposed to be 15mm longer but has worn/collapsed




good genuine Kickstart Lever, i can use this instead of my customised china kickstart lever.




good Kickstart Shaft/Gear




spare Reed Cage, with worn out Reeds




good spare Clutch Cover




good Engine Cases, with a very good Crankshaft/Bearings, and Conrod
the Stator Wiring was melted, so i can just replace the wires that join to the copper windings on the Coils

 

[GooseMan]

hmm, I am guessing either a 60cc bore kit or a QT gear kit?

 

[my67xr]

damn, the other engine fell through, someone beat me to it.

i picked up another PW50 clutch today off Vlasta, it looks pretty good.
and found a Mikuni off a Suzuki FR70 in his boxes of carbys,
he want's $50 for it, but i need to measure up the one on the PW to see if the Suzy carb is any bigger than the PW VM12.

 

[GooseMan]

thats a shame, what was this secret upgrade part?

 

[my67xr]

it was a basically complete bike, a QT50 for $75,
so i would have swapped over the diff gears into the PW housing
and i would have opened up the bore from 40mm to 47.5mm

 

[my67xr]

oh yeah, i forgot to mention i called past Show and Go today to see if the Jets had arrived.
they had, but they sent the wrong ones, :mmph:
the #35 Pilot Jet i ordered, they sent a #30, and the #60 Main, they sent a #30
got another week to wait now.

 

[GooseMan]

Aw man that's sucks, things just aren't going your way lately are they. Sorry to hear man.

 

[my67xr]

i have the new jets now, correct sizes and all.