I bought a really nice 1985 fl 350 from a guy 80 miles from my home. I took the guy for his word and I still believe him, that he said it runs really well and didn't ride it. After I got it home, it wouldn't go faster then 10mph. I have changed the jets and it doesn't make a difference. He lived at about 2000 feet and I live at 800 feet. When I get on it, it just won't open up. I even checked the compression and it is right on. The motor (( Internal Combustion Engine ? )) has been rebuilt too. I checked the spark plug and it was fouled. I'm thinking it's a carb issue but I'm not really good at this and could use some help, thanks.

I had a similar situation when I bought mine. Ran great till I punched the throttle. I noticed a bunch of oil coming out of the silencer connection. I pulled the silencer off to look at it and found the spark arrestor was plugged solid with oil/carbon. I pulled it out took it for a rip now no bog and ran pretty damn good. No more oil leak either!

I have noticed a little bit of oil, come out of mine. How did you take yours off?

Mine was aftermarket pipe had a spring connection, popped it apart, pulled endcap bolts to expose spark arrestor. Cleaned it up put back together.

Does it act like a rev limiter? The neutral safety switch could be bad

Remove the air box lid, if it has one and see if that doesnt help

Thank You for all of the input, I will be checking into these in the next couple of days. I will be letting you know what the results are.

What is the main jet now

The main jet is 148

Remove the airbox then go for a ride and see if it gets better! When I changed to my 36 carb it had a much bigger jet than I needed, therefore it would only go 10mph also and the plug was fouled also. Jets are kinda easy to change... Are there any modifications done to the machine? Aftermarket exhaust? Dual intake etc?

It has the DG exhaust and it doesn't have a box it has a UNI Filter that is open.

After you check you spark arrestor for clogging and neutral safety switch and since you don't know how long its been since its been run, my suggestion would be start with the fuel system. Make sure pump is working and that the pulse line has good connection just behind the clutch, you can check filter for gunk and drain gas tank and look for rust or anything that could clog the filter. Then go to carb and make sure its not varnished, pull off and clean if necessary, probably don't need a kit or anything just a good cleaning. Install a new spark plug, whatever the manual states for your climate. Next go to jetting, based on your pipe,air filter setup and altitude, let the FL350 guys tell you what Main jet to start with and where to put clip on needle. Use fresh no ethanol gas with a good quality 2 stroke oil. Take it for a spin, you should be rich on your "dial in" of jetting to start with. You can do a search her for jetting tips. If you feel you have it jetted close and still cant get above 10mph I would look to make sure your clutches are "clutching". Lots of good info here in clutches,also make sure you have a belt that is within spec or close. Also might be a good idea to do a leakdown test before you strart riding dirty!!

Thank you for the help. I have the next two days off, I will be looking into these.

I just took my stock spark arrestor off and did the old carbon burn off with the rose bud oxy acetlyne torch. Heard you can also throw it on the barbeque cooker hot coals and that will do it too, sure would give a steak a whole new flavor, heard a camp fire would work too. I used the rose bud on my pipe also, seemed to burn the carbon off.

There is a plate on the bottom of the spark arrestor it is on the bottom side near the end of the can with two bolts in it
I believe it is 10 mm I started trying to figure this out on mine because it was clogged also. mine really didnt want to run out
either when I first fired it up I had some guys push me to get me going , lol little pieces of debris kept hitting my arm it was
the old belt so check that also. To get the drive and driven clutches lubed up you can use comet clutch spray lube. Alot of good reading on those as well . Good luck with it .

A while back, my brother had an issue where the rev limiter was kicking in and wouldn't go over that speed.

We swapped everything from mine to his in order to isolate the problem and nothing worked.

He ended up just using it as it was and after a couple of runs the problem rectified itself. Still to this day we have no idea what the problem was and he's now got an 1100acre farm near my dad and runs his machine often without any issues.

If you can't fix it, then maybe the same issue could be plaguing yours??

Hope you get it sorted soon.

I took the spark arrestor off and it ran how it should. The spark arrestor was clogged. I put it back on and it runs great now. Thanks for the help everyone.

GOOD STUFF!!

glad to hear that you got it going. Thanks Billy

Sure it was not your clutches not shifting out and you were then hitting the rev limit?