Proformance Loss Question 1985 NQ50 Spree

[Kevindolin2]

Out of no where i have had a very sudden loss of almost all power in my 1985 NQ50 Spree. It has very little take off and its top end is only about 15 Mph. Before this happened i had it taking off nice and had a top end around 30-35 Mph. So far i have:
1. Cleaned the carb
2. New Spark Plug
3. Adjusted all carb settings based on what the book said

I still have to clean out the exhaust but other than all of that can anyone help me think of other things i could do to fix this problem i am having?

Also do you recommend me getting the Big Bore Kit? Is it work it?

Thanks, Kevin

[Wheelman-111]

Greetings:

Sudden loss isn't consistent with a gradual-onset issue like muffler carbon. Just because it's cheap and easy (somewhat like myself... ), I'd do a compression test before anything else.

http://www.harborfreight.com/cpi/ctaf/D ... mber=92697

Remove spark plug. Screw in tool. Open throttle all the way. Crank until the needle doesn't rise any more. Read.

<80: Hole in piston, broken rings.
80-100: See above, possible reedvalve failure.

Add 5cc GN-2 oil to cylinder via the plug hole & re-test.

Improves > 20PSI = rings
Doesn't change = reeds.