70cc Upgrade

BlackCat · Post by **BlackCat** » Mon Nov 30, 2009 2:16 am

Hi All,

I have a 50cc BlackCat. Looking to perform the 70cc cylinder upgrade myself. I have searched several threads here on MB....Anyone know of a detailed thread or video online showing the steps?

Thanks in advance and hope everyone's Turkey Day was good.

BlackCat · Post by **BlackCat** » Sun Dec 13, 2009 3:27 am

Just bought the 70 cc Malossi upgrade kit with a new variator, spring, and weights. I will have it installed by my local scooter shop this coming week and post my experiences.

weezool · Post by **weezool** » Mon Dec 14, 2009 5:21 pm

i have a rat 50cc and put a 70cc nyc kit new pipe ,rollers ,now i am trying to get my jetting just right.make sure you remove the de-strictor ring in the vairator,it will cause it to run hot and size

BlackCat · Post by **BlackCat** » Wed Dec 23, 2009 8:23 pm

Update:

Molassi 70cc cylinder
Molassi variator, 7 gram weights
Molassi 19mm Carb
new belt
102 jet

So far, so good. I have put about 75 miles on the new kit. Quick off the line and I actually haven't been WOT yet. I have a couple hundred more miles of break-in. I am really happy with the upgrades. However, it seems harder to start (kick start, battery dead) and I have a strange "whining" noise when I let off the throttle and the engine slows down. The noise sounds like it comes from the front panel area. Not a huge deal just a bit anoying.

I will keep everyone updated on the comple break-in and beyond.

nissanman · Post by **nissanman** » Thu Dec 24, 2009 3:36 am

The noise is the scooter complaining about going so slow

It wants to go FAST now.

weezool · Post by **weezool** » Mon Dec 28, 2009 5:46 pm

hay guys what is the stock carb on my rat 50? I have a NCY 70 cc kit ,pipe ,I am jetted at a 95 now ,with 6 grms weights, it seams to run smooth now ,I think my jetting is in the ball park now, but this summer when it gets hot should i jet it at a 100 ? any thoughts ? Also are you guys who are upgrading your garbs going to a larger manifold ,If so what are you useing.I have no shop around here in sc.,so i do all my mods my self .The shop were i got my rat sells choppers,and could give a shit about scooters

bigbropgo · Post by **bigbropgo** » Mon Dec 28, 2009 8:01 pm

i have not heard of anyone sourcing a aftermarket manifold. someone on genuinerattler.com had a stainless one made. jets are tough. usually most will buy the size they think is right and then 2-3 sizes above and below. summer to winter will run different and a jet could help or just the oil/air mix screw. not sure about the carb size on a 50cc. the stock on the 110 is a 19mm. hope that helps, glad the mods are workin out so far.

weezool · Post by **weezool** » Mon Dec 28, 2009 9:12 pm

thanks ! that helps some ,the oil / air jet, helps me to fine tune the 95 jet, but still sputters a little just on the rip,the mid range and top end are great i also removed the foam on my air box so it breaths better .i live in the south /below sea leavel ,so its humid

jmkjr72 · Post by **jmkjr72** » Wed Dec 30, 2009 12:17 am

weezool wrote:hay guys what is the stock carb on my rat 50? I have a NCY 70 cc kit ,pipe ,I am jetted at a 95 now ,with 6 grms weights, it seams to run smooth now ,I think my jetting is in the ball park now, but this summer when it gets hot should i jet it at a 100 ? any thoughts ? Also are you guys who are upgrading your garbs going to a larger manifold ,If so what are you useing.I have no shop around here in sc.,so i do all my mods my self .The shop were i got my rat sells choppers,and could give a shit about scooters

when it gets warmer you will actualy be richer the cold leans a 2 stroke out that is why snowmobiles run like shit if you run them in the summer
with the zumas most people are staying with stock carbs and stock manifolds you can actualy run most of the sport bbks with a stock manifold it isnt untill you get to the kits that need the larger carbs that you will gain much of anything from the manifold

scootertuner1000 · Post by **scootertuner1000** » Wed Dec 30, 2009 4:03 pm

nissanman wrote:The noise is the scooter complaining about going so slow It wants to go FAST now.

Your weights are too heavy. You should go with 3.9 grams

weezool · Post by **weezool** » Sun Jan 03, 2010 3:05 am

well back to the f@*k*ng drawing board it sized today ,it was about 40 outside ,so cold .It sucks pushing my rat !!!need a new kit ,think i got to jet it at 100 or 105 any commints

BlackCat · Post by **BlackCat** » Sun Jan 03, 2010 3:27 am

Scootertuner - You scoot with 3.9 gram weights? Seems really light to me.

Weezool - sorry for the seize. I run a 102 jet inside of my 19mm carb. However, I have not done a pull yet on my plug to see the mixture.

weezool · Post by **weezool** » Sun Jan 03, 2010 4:36 am

no i run 6 gr rollers ,i think a 105 will work ,i am below sea level ,this is a pain in my ass ,so tomorrow ill strip her down for the 400th time ,man you gotta love scooten to be were i am at! this is going on two years.oh well getta get a new head on monday....ps can anybody help me with posting photos on this thing ,maybe i am dumb ,sorry if i am !!!

Lostmycage · Post by **Lostmycage** » Sun Jan 03, 2010 6:59 am

weezool wrote:no i run 6 gr rollers ,i think a 105 will work ,i am below sea level ,this is a pain in my ass ,so tomorrow ill strip her down for the 400th time ,man you gotta love scooten to be were i am at! this is going on two years.oh well getta get a new head on monday....ps can anybody help me with posting photos on this thing ,maybe i am dumb ,sorry if i am !!!

Sorry for the run of bad luck!

To post pictures:
Try setting up an account on Photobucket or Flicker (there's other sites, of course. Those two are free).

Then just <a href="viewtopic.php?p=137466#137470">follow the directions in the FAQ</a>

weezool · Post by **weezool** » Sun Jan 03, 2010 7:14 am

THANKS FOR THE HELP ,,I AM FROM R.VA GROW UP IN THE FAN..SHE IS SICK ILL START WORKING TOMORROW AND POST PHOTOS

Lostmycage · Post by **Lostmycage** » Sun Jan 03, 2010 7:22 am

Sweet-lookin Rat! I love the hand guards. Is that a custom windscreen?

Hehe.... the fan. So many memories.

bigbropgo · Post by **bigbropgo** » Sun Jan 03, 2010 8:02 am

Where have I seen this scooter before?

BlackCat · Post by **BlackCat** » Sun Jan 17, 2010 2:52 am

Black Cat DOWN!

Hey all,

My scoot is in the shop. After 200 miles on the new kit and carb, the scooter was, what I believe to be, being flooded with too much fuel.
Does a #102 main jet seem quite high for a 70cc, 19mm, UNI filter scooter?
At first, I didn't think so because the scooter performed very well, for the first 100 miles. But, after pulling the plug several times after stalling the scooter in traffic (fun times) it was very BLACK.

In addition, my mechanic suggested putting the stock air filter back on.
I brought it to him and he will re-install the stock filter in addition to re-jetting the carb lower. Anyone have any operating issues with opening up their air filter or installing a UNI?

Thanks all.

jmkjr72 · Post by **jmkjr72** » Tue Jan 19, 2010 12:30 pm

for some reason the h/m engines are very finley when you add an open element filter most dont like to run them unless you have a full race or a mid race kit on

BlackCat · Post by **BlackCat** » Fri Jan 22, 2010 12:03 am

UPDATE:

Got the scoot back today. Stock air box is back on and jetted to 88.
Started right up and rode well. I actually like the not so obnoxious sound coming with the stock air box going back on.

Maybe a bit less power and loss of top end? But, that was just from the ride home and still breaking in the new pistion and rings. More to come...

Modern Buddy

70cc Upgrade

70cc Upgrade

70cc Upgrade

Re: 70cc Upgrade