New project - 1980 Yamaha Champ

[typeone]

The Champ came out of hibernation, been rippin' the hood with my shock troubles last season, wrong length, out of stock, etc. i got to thinking ... she may need to get the drop instead

should be pretty straight-forward with cut springs, just need to check for motor tilt + peg clearance. center stand could go bye-bye, which is fine because it rubs the fat tire now anyway.

hmmmmmm.. .

[typeone]

finally found the correct length shock, rides mint

[csmutty]

finally found the correct length shock, rides mint

That sticker...

Looks awesome dude!

[typeone]

That sticker...

Looks awesome dude!

right?! ... thanks, man

[Shwar]

Hi Typone,
I just picked one of these up in the UK.
Looking to do something similar with mine, I'm just curious if you swapped out the carb or are you still on the original?
Also, when you deleted the oil injection, did you make any modifications to the tank to incorporate the oil tank into the normal fuel tank? Would be nice to have the extra capacity.
Cheers!
Josh

[typeone]

Hi Typone,
I just picked one of these up in the UK.
Looking to do something similar with mine, I'm just curious if you swapped out the carb or are you still on the original?
Also, when you deleted the oil injection, did you make any modifications to the tank to incorporate the oil tank into the normal fuel tank? Would be nice to have the extra capacity.
Cheers!
Josh

hey, Josh ... i'm still running the original carb with a cheap plastic petcock but i would like to upgrade at some point. it's constantly gummed up come spring even though i treat the fuel for storage. eventually i'll get rid of all the auto-choke stuff, carb, and a better throttle cable + controls. figured i'd do all of this when we go to a Malossi 70 kit + high comp head.

on the oil tank, i have not used it for fuel but all i would need is to T the lines together. we just ride it around the neighborhood still so the reg tank is fine for now. reminds me i need a new cork gasket for the fuel cap though.

good luck with your project! would love to see some pics

[typeone]

The Stray is finally getting some motor love, big bore kit (only 10cc bump to 60cc) and a proper carb from a PW50. the bike has been running really poorly, i think due to the bi-valve (auto-choke, essentially) in the head prob not functioning anymore. it's always super, super rich, bogs and stalls after some ride time.

everything is coming apart smooth and in relatively good condition despite being built in 1979!

[xrocket21]

Big Bore!!!!!!!!!!!!

[typeone]

Big Bore!!!!!!!!!!!!

yeah, if this kit works out, i would like to move to the Malossi 70cc + high comp head at some point but this was much cheaper to freshen things up for now. fingers x'd she runs smooth because it's a really fun hoodRide when she's running.

EDIT:

btw, like zero wear so far, no play in crank, etc. amazing. lots of carbon + spooge from running way too rich but no scoring, etc. love it.

[Carbonzx10]

Nice, I put the polini 70cc kit and a high comp head on my chappy and it really woke it up.

[typeone]

Nice, I put the polini 70cc kit and a high comp head on my chappy and it really woke it up.

awesome, thanks for the feedback! looks like i'll be going that direction sooner than i thought

-----

been out of town all week but had some time yesterday to wrap up the top end and carb additions ... had to make a custom cable from Champ throttle > PW carb, was super frustrating to get the multiple lengths right, still needed to use the cable splitter that's used for throttle + oil pump (i converted to pre-mix a while back) but it's all functioning until i can make new cables with the length and routings i want. the choke on the PW carb is cable operated, which is annoying. i'll prob make a shorty cable and mount to plastics but i'd hate to cut those.

bike fired right up, sounded great, felt great. rode it around, did two heat cycles then took off for a hood rip ... seized in about 5min as soon as i hit a small hill apparently i need to tweak jetting, blah. i knew i'd need some tuning but not immediate seizure, hahaa. ah, well, i guess it's Malossi 70cc + head time.

[xrocket21]

But I bet she was screamin before she seized!!!!!

[typeone]

pissed i just ran it but yeah, felt so good to have her back then... skkiiiiddddddd. hahaa. prob tear the top end off tonight. i was able to free it up right away so it kicks over but no fire, didn't check comp.

[typeone]

i wrote to the company i bought the top end kit from, they said a rejet isn't normally needed and are sending out a replacement asap. sweet! i'm still going to rejet but awesome they are standing behind the 90 day warranty. dig it.

[xrocket21]

I didn't see that coming!

[typeone]

me either, already have priority tracking info

[typeone]

i'll take some pics later, or maybe tomorrow when all the parts are in hand, but i tore down the top end to inspect. plug a little light, cylinder looks totally fine, piston a bit of burn on the exhaust port side but overall doesn't look bad at all. piston moves freely so i bet a set of rings would get it running but i'll have to feel for scoring.

i read a handful of reports from QT50 owners (same bike for the most part but moped style) 'soft seizing' the top end when juicing up an incline after a 60cc kit install. the head builds up too much heat if not tuned. makes total sense.

a stock PW50 uses a 70 main jet, bumping to a ~90 seems to be the standard after 60cc kit + pipe + open filter. bought a range of jets from 90-97.5 to test out.

[FriskyDingo]

Can't believe it's been so long since this project started, and it still holds your interest

Imagine how difficult this type of project would be in 2001 without all the internet forum information.

[Carbonzx10]

I think I went from 65 main to an 85 with the big bore, head and pipe on my LB50

[typeone]

Can't believe it's been so long since this project started, and it still holds your interest

Imagine how difficult this type of project would be in 2001 without all the internet forum information.

i know, right?! i looked back at the first page the other night and was like, shit, amazing ... the good thing is a lot of parts swap over from a whole mess of bikes but hear you, the internet has killed the good 'ol fashion DIG.

EDIT: and on the interest, with 6 bikes in the garage and 5 of them minis, there is plenty of fiddling to do

I think I went from 65 main to an 85 with the big bore, head and pipe on my LB50

thanks, i thought to grab an 85 as well but with the open UNI, 90 might be the place to start.

[Point37]

EDIT: and on the interest, with 6 bikes in the garage and 5 of them minis, there is plenty of fiddling to do

photos required

[typeone]

photos required

i have a pretty ridiculous bike-spread shot i'll have to dig up ... some have left, some have joined since then. my wife hates me

[Point37]

i have a pretty ridiculous bike-spread shot i'll have to dig up ... some have left, some have joined since then. my wife hates me

yes please!

[typeone]

new top end on and phatter jetting in, fired up easy, everything running smooth, did one heat cycle and some basic runs. will have to take her for a rip tomorrow in the light.

interesting finding, the markings on the seized piston were completely opposite of the replacement kit, wonder if this played into the problem (?) the way the plug sits in the head it’s offset a bit, not directly in the middle of the dome. this new kit seemed better aligned to that. huh. the hot spot was actually worse on the intake side. pics tomorrow.. .

[typeone]

another heat cycle this morning and a little air screw tuning, running well. took a bunch of pics to show damage, which is actually pretty light but the rings did melt in. you can also see the 180 degree difference in the 60cc piston when comparing to the OEM 50cc piston.

intake ports



exhaust port



OEM 50cc left, 60cc right, intake side



50 left, 60 right



notice the shaping of the piston skirt and placement of the wrist pin hole, the 60cc kit piston is opposite of what it should be



exhuast side



intake side



buttoned



stupid long choke cable, i have a lever type coming that i'll shorten and find somewhere more convenient for it



frankenstein throttle cable using the PW splitter



i have a short run vid as well but need to figure out how to upload, not sure a linked file will just play but will test.