TaoTao ATM 50 100cc

[caliboy2010]

So I've been having extreme problems with my tao tao, i put a 50mm bbk on it, replaced the crankshaft with a naruka HD crank, put in the a9 performance camshaft, put in a carb that is tuneable, a new air filter on it, etc.  but I'm having the biggest trouble with tuning  the carb. I have tried every combination between 85-105 jets and for each i've tried all heights for the needle and each time i tune the air fuel mixture screw too. No luck. It runs fine at the current level up until what i believe is when it overheats. It will start to backfire and bog down heavily. I have no idea what the issue could be, if needed i will gladly take video's/pictures, i just need HELP. Are there any kits to liquid cool or increase cooling power to the engine? Do i need a bigger size carb? The spark plug turned black on the once white part due to the constant tuning. I'm lost. and this week we are supposed to have great weather so i'm free to work on it all week

[90GTVert]

To be clear, it will run like nothing is wrong up to a certain speed or a certain RPM or certain throttle position or what exactly?

[caliboy2010]

It will run like nothing is wrong up until i've gone about 2 blocks then it just dies and doesn't want to start again. idles perfectly fine at 1550-1700 and tops out at 8100 rpm, no bogging initially, just decides to die at some point and not start again till it cools

[90GTVert]

Are you using the stock head or a big bore/big valve head? The combustion chamber of the stock head is probably too small for a 50mm kit and the high compression could cause heat issues. I had a local scooter shop that did tons of 50mm kits tell me they quit installing 50mm bores with stock heads because too many came back with overheating issues. That sounds really severe though to die out in 2 blocks.

Might wanna make sure the fuel system is working. See how it flows. Make sure the fuel filter isn't dirty. Check the float height. Try leaving the gas cap loose or off (don't lose it and it's best with a low fuel level so it won't splash on a quick trip if you're careful).

[caliboy2010]

I'm using a big bored head that came with the kit i got. So the top of the engine is not stock except for the cap that covers the very top. It's getting fuel, and fuel filter is clean.

[caliboy2010]

Also, I'm like 90% sure it's the carb. I just went and tried to start it after giving it 45 minutes to cool down. It would start, but just barely and as soon as it started, it would die. Could i need a new carb or even replace the rubber pipe between the carb and the engine?

[90GTVert]

Before spending the money and the wait time I'd pull the carb off and check the float height, clean it with compressed air and carb cleaner, and check the intake for cracks. Check the vacuum connections and hoses as well. You haven't capped of the PCV or anything else with the BBK have you?

[caliboy2010]

Float height's fine, cleaned it again, intake has no cracks, vacuum connections and hoses are good. PCV is blocked off with the kit. the head that came with the bbk came pre-capped for the pcv so i took all that vacuum lines off and everything

[caliboy2010]

I did have one incident where i was driving and it was bogging severely and backfiring like crazy and when i got home i noticed a lot of oil everywhere...

[caliboy2010]

That was the last occurance where i was able to drive more than 2 blocks without it dying. At the moment it will not turn over. But after that occurance, i took the engine entirely out, apart, cleaned it all, changed all the gaskets, replaced the crankshaft, put it all back together, new oil, new spark plug. It started just fine. But now it won't even turn over.

[Upgrayedd]

Apr 12, 2014 16:21:57 GMT -5 caliboy2010 said:

Float height's fine, cleaned it again, intake has no cracks, vacuum connections and hoses are good. PCV is blocked off with the kit. the head that came with the bbk came pre-capped for the pcv so i took all that vacuum lines off and everything

your crankcase needs a way to breathe you can route it into a small breather filter of its own if you have an open air filter on your intake.

[caliboy2010]

I just have the blowoff valve at the top of the engine flowing out into the air since i changed the stock airbox that it was flowing into. I now have a chrome metal air filter on the carb

[caliboy2010]

When i took the engine apart, the piston head was very black same with the head and spark plug... what do i do about that? or is that normal?

[Upgrayedd]

Apr 12, 2014 17:33:10 GMT -5 caliboy2010 said:

I just have the blowoff valve at the top of the engine flowing out into the air since i changed the stock airbox that it was flowing into. I now have a chrome metal air filter on the carb

ah.  im not familiar with those type setups. i opted to keep my airbox, and left mine breathing into it past my filter.

[Upgrayedd]

Apr 12, 2014 17:35:18 GMT -5 caliboy2010 said:

When i took the engine apart, the piston head was very black same with the head and spark plug... what do i do about that? or is that normal?

this may or may not help you www.4secondsflat.com/plug_chart.html

i only have experience with this one small scooter engine im running, there are others here who could likely offer far more opinion on that. i like to run a little rich especially on an air cooled engine. . and some black is normal in that case but too much can cause plug fouling and too much buildup on a piston can even cause detonation/pinging if your compression is up enough.

perhaps you are running too rich, and fouling your plug after a couple few minutes of riding and that's whats causing your issue.

*edit* my 2 cents: on that plug chart, i would not go past plug picture #16 in one of these little engines, my plug looks most like #11 or #14, but thats my opinion and liking - others may run leaner than that. i prefer not to. leaner = hotter... too rich though and you'll foul plugs and have carbon everywhere / aka a 'coked up' head with black soot caked up.