QT60

[cutie fifty]

it's getting close to winter here people!!!, time to put the peds away (if you live in a cold weather area).

anyway, i bought another qt50 last month, i've done a bunch of cool mods, and i'm looking forward to finishing it this winter. i have an older qt50 but it's pretty crappy and doesn't run, so i'm using a bunch of parts from it to make mods for the new one, that way if i ever want to sell the nice one, i can put it back to original condition and either keep the mods, or sell them with the bike for extra money.

first thing i did was take the oil pump out and made a plug to fit the hole using my older qt50 oil pump. i cut and ground on that thing forever, filled it with jb weld and started grinding and shaping some more. it's not done yet, but i got so excited i had to put it on and see what it looks like (pictures below).

then i converted the oil tank to a gas tank, this is a cool mod, the only downfall is that you have to fill both tanks, the gas doesn't level itself out like i thought it would. i'm still thinking of a better way to do this mod, so if you have a way that works better than just connecting the two hoses, feel free to let me know.

next up, qt60.

i'm definitely going to be upgrading to the qt60 package this winter and from what i've read, it sounds like keeping the stock gearing is better because it will give you more low end and take off power verses the yamaha zinger gears that make you go faster on the top end. i don't really need to go faster, i just would like it to be able to climb hills a little easier, not that it has a problem, but it can slow down to 22-25 uphill.

i also have two heads for it now, and my dad is a tool and die maker.. so i'm wondering what is a safe amount to mill off of the head? keep in mind i might be using the milled head on either a qt60 or a qt50, if that makes a difference in how much off i can take. will i need to make a gasket to put on the bottom of the jug to make up for the difference, what is the proper way to do it, do i just mill the head and bolt it back on?????? i'm new to this, but i can have the work done for free, so why not? (thanks for the help on this one!)

here's some pics of my plug and oil tank conversion..

note: these are not final, just seeing what can be done, and how it needs to be done.

[oilyhans]

use 2 base gaskets.... but only if you really need to
shaving the head is easy
just glue some emery paper on a flat surface i use a sheet of 1/4" glass
some guys don't use a headgasket just some permatex gasket sealer

one word here BEFORE you fire it up turn the motor over by hand to make sure the plug doesn't hit the piston if your useing a plug with a "P"
BP5XX that is a projected plug meaning that the end/electroid sticks
out farther from the bottom of the plug this is to help keep the plug from fouling..
use one that is a B5xx no "P" its a shorter plug that will help with the clearance needed

oilyhans

[cutie fifty]

cool, thanks for the tips!

i guess my main question is, how much can safely be taken off of the head?

[donp]

when shaving a head, never remove more than .015" at a time, and make numerous measurments.

[dustin]

who makes the 60cc kit, or is it a oem yamaha topend from a diffrent bike? also does anyone know if the 80cc topend from the pw80 will fit a yamahopper?

[tumbleweed]

use a stock qt=50 head on a yt 60 cylinder and it will be enough.you can shave the 50 head all the way down to the flats on the fins and it will run good,about 11-12 to 1,as near as i can tell a 50 head on a 60 cylinder is about 10-1 or so

[cutie fifty]

heh, i'd be curious to see if the 80cc head fit on a qt50 as well.

thanks for all the help people!!!!

[xrongor]

just for future reference, if you pull the stock oil pump and simply remove the plastic gear off the end (and its associated pin)you can just put the oil pump back in and its disabled as well as plugged. if you want to re-enable it just put the gear back on.

check that the venting on the oil cap is working by blowing through it. if you look at it theres a hard plastic inside and a rubber outside. if the outer part gets turned even a small amount it blocks that vent. poor design imho.

that said, i just pull both caps when filling and use a funnel to fill the 'oil' tank because it still doesnt level itself as fast as i'd like it to. if you're using it as a reserve as i do you dont have to fill it very often anyway. i open it about once a month and run it mostly dry just so the gas doesnt get too old in there.

other than that there's really not much you can do to make it level faster besides simply drilling holes in the wall between the two tanks. use a long drill bit and go through the gas fill hole. then clean it out real good. only downside is that its not a reserve tank any more.

its been pretty well documented that you can take at least .030 off a stock head without any clearance or other problems. do some searching on whats called squish clearance and how to measure it if you want to take it to the limit.

if you get the YT cylinder and just put a stock QT50 head on it that should be plenty of compression. im well into the 40's that way and ive hit 50. if you still want more power i would look into exhausts before id start boosting compression higher.

randy

[wuhuilin11]