I recently bought a 95 Fantic Section on Ebay for $760 with aspirations to get back into trials after a 10 year hiatus. I picked it up in Alabama and it was neglected but seemed to be in decent shape. I changed the fluids, cleaned the carb, put in a new air filter, fixed a few stripped bolts, started it up and took it for a test ride. It runs, but not very well.

The seller was a street bike dealer who had no prior knowledge of the bike and for some reason the previous owner took out the thermostat located behind the spark plug, plugged the hole and connected an on/off switch. So my only option with the fan is on or off. Is there a reason for this? Could this be why it doesn't run well? I used to own a 89 Fantic 305 know how well the engine should run but I've never had a watercooled bike.
On my first test ride the engine wouldn't idle and had trouble at low rpms and slow manuevers. However at high rpms it ran well and I could go up some ledges in third gear the way I used to with my old Fantic.
I cleaned the carb again and modified the airbox. The original filter was a box shaped bowl that fell apart when I took it out so I replaced it with a flat foam sheet. There were two oval ducts that partially obstructed the air flow so I took those out. The bike now idled well and ran good at low rpms but at higher rpms it was boggy with no power. I don't know if this was because of the 2nd cleaning or the airbox mod. I tried all the needle clip settings and the bottom setting was too rich and the top one the idle was too high. The middle two still had the same boggy problem. Adjusting the idle and air screws didn't help. The spark plug, a Bosch Platinum WR7DP, was black and oily.
Could these problems stem from the lack of a thermostat? If so, how do I replace it?
I plan to clean out the whole exhaust system and judging from the way the muffler looks, I'm sure it needs it. I've heard about a power valve that operates from the throttle cable to the exhaust but it looks to be disconnected.
I hoping to get this bike running good so I can compete in the upcoming Newnan Trial. Any advice is appreciated.
Thanks,
David

David, I live near Charlotte, NC in a little town called Unionville. I have a 97 Fantic Section that runs flawlessly.
Prior to the Section, I had a 1991 Fantic 309, it too ran flawlessly.
My first guess would have been to clean the carb really well, but you said that's been done. I still suspect the carb!
As for the power valve, mine is operational, BUT many people wired them open. Either way, not a huge difference. The power valve should not be the problem!
I'd clean the exhaust really well, and again, I'd clean the carb. Go to a local parts house like, Advance Auto, Auto Zone, etc. They sell a one gallon bucket of carb cleaner that you can use to soak the carb in. Be sure to remove all rubber parts and the bowl gasket first!
Then, using an air hose, or a compressed air can, blow out all passage ways. Pay attention to the idle circuit!
I'm assuming that your carb float is OK, and your needle & seat are good.
You DO need a thermostat in the bike.
You can also post your querstions at Trials Central, that have "bike specific" forums, and a pretty active Fantic Forum too!

http://www.trialscentral.com/forums/index.php

You can Call Mike for parts, at the Tryals Shoppe, (315) 497-3268
I wish you were close enough to help physically!

Tony Powers
704-493-4528 cell

Thanks Tony for the advice. I did the carb soak and that cleaned it a lot better than the spray stuff. When putting it back together I saw a small jet under the idle jet that I didn't see before. I needed a real small screwdriver to get it out. It has tiny holes that were probably clogged before. It still didn't run right after putting the carb back on. I lowered the needle, which didn't help before, but this time it made it run correctly.