View unanswered posts | View active topics It is currently Thu Sep 19, 2019 4:41 pm



Reply to topic  [ 9 posts ] 
 Zuma 2T 70cc BBK 
Author Message
Newb
Newb

Joined: Tue May 07, 2019 7:30 pm
Posts: 6
Post Zuma 2T 70cc BBK
Hey guys. I've tried to experiment and tried to search.

After assembling the 70cc bbk and carb - before doing anything with the gears I wanted to fire it up and check the temps of the motor. It's running hot, high rev to the point where the wheel turns. Within a few minutes the temps will gear near 300 degrees. So I figured at first maybe the idle screw was too tight. So loosened that all the way- same issue. Killed the gas, took the carb apart to see the jet sizing that came stock. The jet I do have is a Polini CP 21, bought as a kit from Scooterswapshop. However its memorial weekend and they cannot help me as they're closed at the moment. The stock jet sizing on this thing is : main jet 100 and slow jet of 40. The scooterswapshop got me : main jets of - 100-118 and slow jet of 32-40. I've tried switching the main jet to a 102 and still got high rev, hot temps. Tried going to a 106 and now it wont start. Am I missing something?
My friend mentioned something about air leaks - but would this be from the top end ? Motor ran perfectly fine before doing this swap.

_________________
2004 Zuma 2T 50CC
Mods : 70cc Airsal, Polini CP 21 : 100MJ 40SJ, Polini Intake, Stage 6 Replica Exhaust, NYC Compression Spring (15), NYC Clutch Springs, Naraku Rollers, Polini Gear 13-44


Sat May 25, 2019 2:54 pm
Profile
Silver Member
Silver Member

Joined: Fri Aug 31, 2018 5:18 pm
Posts: 624
Location: Fox Valley Wisconsin
scooters and mods: 2 2004 Vinos 2004 Zuma
Post Re: Zuma 2T 70cc BBK
300 is not too high 350 getting there 400 cooked .
Mine runs around 300 all the time .
Did you plug chop the 102 ?
Is the 106 fouled ?
When you blip the throttle does the temp drop ?
It should I do this when I come off going wide open i blip it a few times to get some cold fuel mixture .
What kit and what plug are you running ?
Stock likes a 7 Cast iron likes a 8 and aluminum likes a 9 .
Post a sig line so others can chime in .

_________________
2004 Vinos Derestricted exhaust and variator stock carb with mikuni 70 main jet needle down 1 clip 40 mph
Athena Sport BBK waiting to go on

2004 Vino Malossi sport 70cc Malossi Wild Lion pipe malossi multivar 6.5 sliders green polini clutch springs stock carb 75 mikuni main one clip rich 47.5 mph Michelin S1 90/90/10 rear tire Michelin S1 3" x 10 up front

2004 Zuma Malossi sport 70 cc Technigas next r 2008 zuma torque driver polini high speed variator 5.5 grams sliders malossi delta clutch yellow contra yellow clutch springs Stock Carb 84 main jet 46 pilot jet needle 1 clip rich stock athena 14/42 gears 11 to 1 final ratio 56 mph

2005 Eton Beamer (Taiwan Zuma Clone) Airsal sport 70cc 9200 peak rpm top speed 42 77.5 mikuni jet needle 1 clip rich (sold)


Sat May 25, 2019 4:54 pm
Profile
Silver Member
Silver Member

Joined: Fri Aug 31, 2018 5:18 pm
Posts: 624
Location: Fox Valley Wisconsin
scooters and mods: 2 2004 Vinos 2004 Zuma
Post Re: Zuma 2T 70cc BBK
Check to make sure exhaust is buttoned up tight by taking a gloved hand and rag and plug the exhaust pipe with it running.
If it kills you are in great shape
If it doesnt you need to find the leak it is either at the cylinder exhaust port or at the silencer if you have one.

To check for air leaks you would need a leakdown tester you can make one for under 30 bucks .
Check you tube I bought some pieces from harbor freight and lowes to make mine.
You plug the exhaust port pressurize to about 6 psi and dont over pressurize or you will blow your seals and see if you hold that pressure for 10 minutes if you dont you check carb cylinderd seals in behind variator and behind flywheel.
Use soapy water and look for bubbles the same way you check a tire .

_________________
2004 Vinos Derestricted exhaust and variator stock carb with mikuni 70 main jet needle down 1 clip 40 mph
Athena Sport BBK waiting to go on

2004 Vino Malossi sport 70cc Malossi Wild Lion pipe malossi multivar 6.5 sliders green polini clutch springs stock carb 75 mikuni main one clip rich 47.5 mph Michelin S1 90/90/10 rear tire Michelin S1 3" x 10 up front

2004 Zuma Malossi sport 70 cc Technigas next r 2008 zuma torque driver polini high speed variator 5.5 grams sliders malossi delta clutch yellow contra yellow clutch springs Stock Carb 84 main jet 46 pilot jet needle 1 clip rich stock athena 14/42 gears 11 to 1 final ratio 56 mph

2005 Eton Beamer (Taiwan Zuma Clone) Airsal sport 70cc 9200 peak rpm top speed 42 77.5 mikuni jet needle 1 clip rich (sold)


Sat May 25, 2019 9:14 pm
Profile
Newb
Newb

Joined: Tue May 07, 2019 7:30 pm
Posts: 6
Post Re: Zuma 2T 70cc BBK
So high idle & temp part solved, I think? I took everything apart put the 100mj in, 40sj in (this is what came stock in my Polini CP). I finally got it to idle where I'd like it. However now it's smoking while idle (light) and under throttle it smokes a lot and does sound kind of boggish. However this is not real street testing as the scooter is still apart. So as far as any air leaks , so far I think the motor is sealed well. I was a dummy and since I couldnt figure out how to set up my choke pull thing I left that thing opened. So that was my air leak. Dumb newbie mistake I know...

Seriously - thank you for your help :) So now got to figure out why it's running a lot of smoke.

_________________
2004 Zuma 2T 50CC
Mods : 70cc Airsal, Polini CP 21 : 100MJ 40SJ, Polini Intake, Stage 6 Replica Exhaust, NYC Compression Spring (15), NYC Clutch Springs, Naraku Rollers, Polini Gear 13-44


Sun May 26, 2019 8:13 am
Profile
Silver Member
Silver Member

Joined: Fri Aug 31, 2018 5:18 pm
Posts: 624
Location: Fox Valley Wisconsin
scooters and mods: 2 2004 Vinos 2004 Zuma
Post Re: Zuma 2T 70cc BBK
mybone headed move of the day is i pulled the starter off with the variator a 20 minute roller change became a 6 hour starter rebuild because of rounded screws

All my 2 strokes smoke at idle
I run yamalube switching to Lucass 2t because I can get that more places .

Get that thing on the road and run a tank of gas through it you might be burning through your assembly lube .
And dial in the main jet with som plug chops that might bring down your smoke screen .

_________________
2004 Vinos Derestricted exhaust and variator stock carb with mikuni 70 main jet needle down 1 clip 40 mph
Athena Sport BBK waiting to go on

2004 Vino Malossi sport 70cc Malossi Wild Lion pipe malossi multivar 6.5 sliders green polini clutch springs stock carb 75 mikuni main one clip rich 47.5 mph Michelin S1 90/90/10 rear tire Michelin S1 3" x 10 up front

2004 Zuma Malossi sport 70 cc Technigas next r 2008 zuma torque driver polini high speed variator 5.5 grams sliders malossi delta clutch yellow contra yellow clutch springs Stock Carb 84 main jet 46 pilot jet needle 1 clip rich stock athena 14/42 gears 11 to 1 final ratio 56 mph

2005 Eton Beamer (Taiwan Zuma Clone) Airsal sport 70cc 9200 peak rpm top speed 42 77.5 mikuni jet needle 1 clip rich (sold)


Sun May 26, 2019 6:41 pm
Profile
Newb
Newb

Joined: Tue May 07, 2019 7:30 pm
Posts: 6
Post Re: Zuma 2T 70cc BBK
Oh wow , that's a bummer!!

So after todays adventure playing on my own since none of my friends that are into scooters have a 2T and can chime in other than simple sayings. So this is where I'm left at at the end of the day.

I went ahead and finished my gearing (other than changing out my top end gear). Checked out my spark plug and it was certainly running rich - gas/oil was all over the plug. So I down jetted my slow jet from a 40 to a 36. Since I don't have a spare plug atm I cleaned that one off the best I can and going to try to run it tomorrow. Maybe the excess smoke is possibly from assembly and the "flooded" engine from running too rich. When I throttle the motor sounds muffled not tingy like most videos I see.

_________________
2004 Zuma 2T 50CC
Mods : 70cc Airsal, Polini CP 21 : 100MJ 40SJ, Polini Intake, Stage 6 Replica Exhaust, NYC Compression Spring (15), NYC Clutch Springs, Naraku Rollers, Polini Gear 13-44


Sun May 26, 2019 7:21 pm
Profile
Newb
Newb

Joined: Tue May 07, 2019 7:30 pm
Posts: 6
Post Re: Zuma 2T 70cc BBK
End of the day update after quitting for the day :

Came to the conclusion that the main jet that came on the carb is possibly still too rich. Again, the MJ is a 100. I did down jet the SJ from 40 to 36. This morning I let it idle and noticed a oil leak from the paper gasket between the top end and crank case - so I took it apart and made a new paper gasket by hand and got that thing all nice and sealed. Also put copper paste on the spark plug cover metal gasket AND the exhaust gasket as well. NO MORE LEAKS.

So after running it again for a while even though I know its running rich - I noticed oil collecting by the ignition fan dealio. Thought OH BOY here we go ANOTHER LEAK by the crank case behind the dang ignition fan (DAMNIT). But after looking around I've found that there's a leak going on by the oil sensor! So now I need to figure this out. Maybe I can find threads or videos on correcting this problem.

_________________
2004 Zuma 2T 50CC
Mods : 70cc Airsal, Polini CP 21 : 100MJ 40SJ, Polini Intake, Stage 6 Replica Exhaust, NYC Compression Spring (15), NYC Clutch Springs, Naraku Rollers, Polini Gear 13-44


Mon May 27, 2019 5:44 pm
Profile
Scooterologist

Joined: Tue Apr 16, 2019 5:55 pm
Posts: 45
Post Re: Zuma 2T 70cc BBK
The oil sensor on the top of that oil tank is known to leak. Its an easy fix. I took the oil tank out, pulled the sensor (you cannot miss it), then bought some thin shrink wrap. I put the shrink wrap on the plug (oil sending unit) and put some rtv sealant around the top and put it back together. No more leak. There are videos on youtube. Good luck.

_________________
2008 zuma. Throttle mod, 6.5g rollers, stock exhaust, 80 main jet in carb. Top speed 37mph.


Tue May 28, 2019 7:53 am
Profile
Newb
Newb

Joined: Tue May 07, 2019 7:30 pm
Posts: 6
Post Re: Zuma 2T 70cc BBK
Jason3814 wrote:
The oil sensor on the top of that oil tank is known to leak. Its an easy fix. I took the oil tank out, pulled the sensor (you cannot miss it), then bought some thin shrink wrap. I put the shrink wrap on the plug (oil sending unit) and put some rtv sealant around the top and put it back together. No more leak. There are videos on youtube. Good luck.



Thanks! Going to play with that after I get my jetting done properly.

_________________
2004 Zuma 2T 50CC
Mods : 70cc Airsal, Polini CP 21 : 100MJ 40SJ, Polini Intake, Stage 6 Replica Exhaust, NYC Compression Spring (15), NYC Clutch Springs, Naraku Rollers, Polini Gear 13-44


Tue May 28, 2019 1:01 pm
Profile
Display posts from previous:  Sort by  
Reply to topic   [ 9 posts ] 

Who is online

Users browsing this forum: Gregorypneup, VincentWen and 4 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group.
Designed by STSoftware for PTF.