This one has me and my mechanic puzzled. I just installed the Hetrick pipe and clutch kit, Adjustible CDI and K/n on my sons Scrambler 90. It is tuned and runs absolutely great! Until we start up a hill, then it starts sputtering and has no power. It doesn't happen everytime either and sometimes does happen on flat ground. It seems to happen when running full throttle for a couple of minutes. I have changed fuel filters, completely removed the carb and cleaned it. Removed the float and the jets, couldn't be cleaner inside and out! Took the compressor and blew out the fuel lines. What am I missing??
Any help would be appreciated![img]i/expressions/face-icon-small-confused.gif[/img]

 

is the little fload stopper in place... i think there is a little rubber stopper that keeps the float from goin all the way closed when on an incline... just a thought

 

try adjusting the pilot screw on the carb. i cant remember where it is but it is there somewhere, i had the same problem on the 90 i sold and the pilot screw fixed it.

 

another thought,,, call me crazy,

but is it full of gas? if theres only a litle gas in it it could expose the gas line in the tank and then start sucking air.

i have done it before. but on a 90 but my 250.

just a thought,

X

 

I have changed fuel filters, blown out all the fuel lines, completely removed and cleaned the carb twice. Adjusted the float replaced the CDI. Plug looks good. Still stalling out, still runs put no power. Then turn it around downhill or shut it off and away she goes for a while then the same. I have tried everything me and my mechanic buddy can think of. I have tried what you have suggested so far. Still no luck. It is killing me and my sons xmas is ruined as we were going to go on a riding trip but can't until I fix this. Please help![img]i/expressions/face-icon-small-mad.gif[/img]

 

have you tried to just block it up in the garage at different angles and run it without a load to see if you get the same problem? If you did what angle did it start? to me to sounds like a wire is grounding out and killing the spark. I would start going over all the wires and see if any are loose.

 

Check the fuel tank vent for restriction/pinched hose, do you have good fuel flow from the tank to the carb?

Have you rejetted for the mods? With the pipe and K&N you'll need to increase the fuel flow in the carb to match the increase in air flow......

 

Rejetted from a 82.5 to 110 as per instructions from the mfg. It really rips when it is running. My mechanic has it dialed in real nice. I have checked the flow of fuel and it seems fine, if I open the float overflow it pours out. It is just intermittent and seems to happen on inclines. I will check the wiring and run it on different angles. Keep the ideas coming and I will post updates. Together we might pull this off. Thanx for your help!
Cam

 

This might be a little far fetched but is it possible that the engine is using more fuel than the system can supply? Try loosening the gas cap just to eliminate a vent problem, then you could try to take the carb drain hose and route it straight up beside the carb extending it up above the tank level (so it doesn't run out all over) open the drain screw and ride it monitoring the fuel level in the float bowl to see if the carb is actually running out of fuel. If by chance it is then you have to open up the fittings and use larger fuel line to increase the volume...... Be sure there's no water in the tank.

The ignition system may also be suspect, it may be failing under the heavy load of climbing a hill. A weak coil, bad coil wire or plug cap could act this way. Try closing up the spark plug gap some to see if it helps at all....

 

After all this it turns out that the jet that was sent with my Z shield and K/N intake was shorter that the stock jet. Once I put a longer jet in it is good. Thanx for all your help!