LOW mpg, overheats and smokes, weird suction sound from gas cap

[Carterc]

so like the title says, when I ride my bike for longer than 15 minutes it overheats really badly and starts to smoke from the engine and so i'll turn it off and i can hear that suction sound coming from the gas cap, no idea if thats bad or not. I'm not scared to buy anything from RPM so please let me know if he has something worth looking in to. I know the carbs need work but i don't know what else that could be affecting. I believe they are out of sync because i have a slow/lagging throttle on the way down to 900 rpm's. I put on a two brothers racing exhaust and had a guy back home re-jet the carbs and try to tune them but it messed it up. there is oil on the left side of my engine where oil has previously leaked from somewhere, it looks like its coming from near the spark plug but i dont know. any suggestions?

1986 Fj1200
40,000 miles
last oil change: unsure, need to change it but dont know how to (im not a smart man)

[Pat Conlon]

Chris, we have not heard from you for a couple of years.
So...you've had your bike for what...2 and a half years now? (March 2011 was your first post)
Don't you think it is time you learned some basics? Have you bought a Haynes or Clymer manual yet?

Based on past history, I would recommend that you take it to a shop.

[Carterc]

Pat, yes i've had the bike awhile but i moved overseas shortly after and JUST got it back, my clymers manual is nowhere to be found.

[Carterc]

but you're right, i'll just take it to a shop. thanks

[novaraptor]

Yup, if you don't have the interest or the necessary skills to do your own maintenance, then the shop is best for you. If you do decide to look into it, it may be that it isn't overheating, it's just getting hot enough to smoke leaked oil off the engine. Pull the tank and side panels and see if you've been dumping oil.. Best luck to you.

Novaraptor

[red]

so like the title says, when I ride my bike for longer than 15 minutes it overheats really badly and starts to smoke from the engine and so i'll turn it off and i can hear that suction sound coming from the gas cap, no idea if thats bad or not. I'm not scared to buy anything from RPM so please let me know if he has something worth looking in to. I know the carbs need work but i don't know what else that could be affecting. I believe they are out of sync because i have a slow/lagging throttle on the way down to 900 rpm's. I put on a two brothers racing exhaust and had a guy back home re-jet the carbs and try to tune them but it messed it up. there is oil on the left side of my engine where oil has previously leaked from somewhere, it looks like its coming from near the spark plug but i dont know. any suggestions?
1986 Fj1200 - 40,000 miles - last oil change: unsure, need to change it but dont know how to (im not a smart man)

Carterc,

Sounds like the gas cap should have a vent hole, and that vent hole is plugged.  Do this test with less than half a tank of gas, so no gas can spill from the tank. Open the gas cap, then close it, but do not seal the cap completely shut.   Run the bike long enough that the bike would overheat.  If this test ends the overheating problem, then fix or replace the gas cap.

Sure, just change the oil, out of hand.  Change the oil filter, also.  Be sure about the oil change/ oil filter mileage, from here on.  This project will not fix anything, but it may prevent catastrophic damage, later.  An experienced rider can show you how, or just pay a shop to do it.  Bite the bullet on the carb set-up, and get a qualified mechanic (or shop) to get the carbs set up correctly, and balanced.

The motorcycle shop can sell you an engine cleaner (Gunk is one brand) that will clean up your oil leak.  Read the directions, because some cleaners can attack some surfaces, such as plastic or paint.  Use an old paintbrush to scrub the engine fins, as needed.  Then, keep checking for more oil to appear in a while, so you will know what part needs fixing.

Get written estimates from several shops for any repair work, before you hand over the bike.  Do not tell one shop what another shop charges, for the same work.  If all estimates are reasonable, then pick the best shop, by reputation among bikers.  Personal note: Never put yourself down.  The world has volunteers, on staff, who will do this for you at no charge.      Ignore the flak.  Have fun.

[Carterc]

Novaraptor, I checked the other day and found some oil and wiped it clean and I havent seen smoke or dripping oil since then...yay!

and Red, thanks for the advice, ill check that out asap!