Bore question*updated 7/13 finally works*

[torinrage]

***UPDATE******


Ok installed new hoca piston and ring installed...pick up another 50mm jug around the the area the guy had gotten from scrappy dog.

Also fixed both the connectors in the coil was haven a spark isssues.

scooter now finally goes past 25mph which i rocked the gps on.... new i can hit around 33-34 mph... now will see what it does after i start fine tuning and breaks in.

************************

Hey guys new to the bored and new to scootering but i have a question.

I have a peace sports 50cc and i am a big guy 250lbs so with me was slow but still fun as hell so i modded it up.

I installed a big bore kit the cheap one off ebay everybody gets from robo.

I had the problem of the piston kissing the head fixed that and installed a bigger jet mine stock jet was a #78 in the scooter and i installed a 88 still ran lean so now i have a 105 in it.

THe scooter runs at idle perfect. It has GREAT get up and go even with 8g rollers in it and my ass on it. has stupid stump pulling turque will do a burn out.

so here is my problem With all that...25 mph is my max and with my friend on it he maxes out at 30...but it goes like a bat outa hell then falls on its face at 25 and with him barely gets 30.

We used the stock head instead the head that came with it since it seemed to have way to much slop in the valve lash.

Mods as of now

50mm big bore
stock cdi didnt like the after market one
8g rollers
bondo belt
scrappy dog exhaust
new plug wire
#105 main jet stock carb
stock air box

when my friend get back form work her is bringing his compression tester.

and as of now it blows zero smoke

[skuttadawg]

Lighter rollers I ran 5 gram on my 82cc 4T . Extra base gasket or a shim(s) will give more clearance and lessn compression since its so high with a BBK it can damage the engine .

Do you have a 50mm head or the stock 49cc head ?

[torinrage]

Running stock head. I had 5g sliders in there hated them, so put the 8g i have in it.
I do have the bbk head that came with it and am putting that on later after compresion test.
Didnt double gasket it or shim it.

I just know there is something i am missing to give it to run at 100% and not just have a 82cc scooter that runs like a stock 49cc

[peteyparado]

105main jet is way to big..try 92-98

[torinrage]

my plug doesn't show running rich at all nor am i getting any black smoke from the exhaust.

[torinrage]

compression test reads 190

[ososlow]

ok, do you have a 1p39qmb or 139qmb? if it is a P motor the problem with the valve lash is with the rocker arm asymbly. most kits come with a non P head. not a big deal you just have to get a non P rocker asy.

[torinrage]

it is the 1p39qmb.

my question is with the stock head will my top speed be 25mph and that it ad the head is what makes the big big difference.

I am just trying to figure out why installing a 50mm bbk would make my scooter run like a stock one minus no loosing speed going up hills.

[katastroff]

You got any restrictions on your CVT?

[torinrage]

no its a peace sport didnt come with one...

I did hear that the cvt restriction was actually built into the variator is that true...if so then i should buy a new variator?

[katastroff]

You could look here for a little bit of inspiration:

49ccscoot.proboards.com/index.cgi?action=gotopost&board=transtech&thread=409&post=4541

[torinrage]

What is the stock size of a peace sport variator. i saw a ncie hoca for 50$ that is 97mm.

if that doesn't fix i am stumped as all hell

[90GTVert]

105 sounds really big to me on the main. I'm essentially at sea level (40ft) and with a 150 carb and ported intake, UNI filter, big valve head, NCY cam, 50mm bore I was using 100-105 main. You sure the plug isn't being washed clean so it doesn't look dark? I think I'd clean the carb and at least try a 100 or 95 on a quick test ride to see if it acted any different.

If it went faster before and you've got the same CVT parts, I wouldn't be looking there just yet as long as you're able to keep the RPM where it needs to be for power.

If the scooter has never been faster than this, it could be in the CVT or elsewhere. I built one a while back and I hated that thing. 70cc, 80cc, didn't matter. Had no real power or speed. Eventually I put a degree wheel on it and realized that my flywheel was machined wrong. When the flywheel was at top dead center, my piston was 31 degrees from actual TDC. Replaced the flywheel and it was like a new scooter. I'm not saying it's that and I'd never buy a flywheel just to try because I hope that's not a common problem. Just an idea in case, something to look into if you can't get anywhere. But yeah, if it's never been faster then start looking at what's always been on the scooter. If it was faster than now, keep looking at the BBK's possible issues and tuning.

[torinrage]

I changed the main down to a 85. 30 is about what it always could hit runs like a stock scooter minus now it doesnt loose power going up incline or hill.

We tried increasing the timing ruff guess would be 8 degrees didn't help much made it worse actually.

it has bottom end all day accelerates like a champ does a burn out. But one it hits 25 mph it just falls on its face hard.. holds 25 mph all day up hills and what not but thats it. other than that my friend on it gets to 30 thats about it cause he is a little guy.

So now after rejetting the hell out the carb many times messing with fuel, timing, and what not. I think it is the cvt so today i am going to find out its rpms and measure the cvt and go from there unless i find some new ideas.

[katastroff]

Use a marker on both pulley in your CVT to see if your belt goes all the way up in the front and all the way down in the back.

If your motor is well tuned, it could be your contra spring simply being too stiff or the torque driver gone bad.