Won't start after sitting a long time

[Retcol]

I'm sure this has been asked before, but I could not find this thru searching. I bought a very nice 1980 900C that was running before the PO parked it with gas in the tank and let it sit for about 6 months. Now it won't start of course. I'm sure the carbs, fuel line, etc are gummed up and need cleaning. However, before I go to the trouble of pulling the carbs, is there a first try this solution of some type of de-gumming solution I could pour into the gas or squirt into the carbs to try to clean them without removal? I heard about Seafoam, but can this be put into the carbs while mounted? Is there any disadvabntage or risk to trying a de-gumming solution first. Any help would be appreciated.

[Re-run]

There isnt really a way to de-gum something. Drain your tank and put in some fresh gas and seafoam. From there, try to drain the float bowls. If they drain, great, fill them back up with fresh gas and see if you can start. If the gumming was not too bad, the gas and seafoam will clean things out. If nothing drains at all, then you will need to clean things up. If it starts but runs really hard, then the jets need a cleaning.

[Retcol]

Thats kinda what I thought I would try, thank you for your help. What mixture of gas to Seafoam works the best?

[Piute]

 My 77 set for 6yrs with gas ,I thought it best not to even try,I turn the engine over with kick by hand and bought it(250.00$).Guy said it did run .He bought at ox-tion with 3 others,they were newer,
  I Took home dumped out gas took off bowls sprayed everything with carb cleaner (was nasty),put back together ,mixed sea foam and gas 1 gal,NEW NGK Iridium plugs. FIRED RIGHT up ,shut it down and took carbs completely apart and cleaned and back together better then it was,Only had to buy accelerator pump kit ,was not squirting right,Fired right up again but keep it running trying to set A few thing (Fuel).
  Found a few probs but thats how I 1st started mine,still not perfect
                                           Getting there

[Retcol]

Thanks Puite, I'm feeling a little better now. When you took off the bowls and sprayed carb cleaner, I assume you left the carbs on the bike and just sprayed up into them? How did you wash them out after spraying them?

[TOOLS1]

You do not need to wash out the spray carb cleaner. It evaporates.
TOOLS

[Piute]

 I took off all 4 cleaned and put back on ,The dang guy put the floats on up-side down (but still burped N farted),why he had probs after re-doing carbs from when he got it,(he put less then 200 miles on it)Carb cleaner will evaporate fast WEAR SAFETY glasses ,get passed reg. glasses ,like mine.I NO.
  Ya see the 1st time I just wonted to hear it Fire / burp and fart,(gas N fire) It will start ?
   Then I took linkage and carbs completely off and apart cleaned every Lil thing there ,throttle Didn't respond right ,Didn't need to run to check that. I left off return cable (bought new didn't matter)new choke too,used A small Allen wrench to set sliders (sprayed Lil silicon on them before putting back in).Fired and ran till got hot was sucking air near heads on manifold boots.
   Then check wiring had coil wires switched yellow and blue no prob didn't hurt bike but never ran with a load then,gave all the wires a quicky,
  Now 6months later starting from the front taking every nut and bolt and wire soldering or using loc-tight nothing coming loose,I will know this bike at least were the bolts and wires are and are better then just o.k.
   I am not a mehcanic , I am learning these 750s ,I can take apart / back together most H.D.s with-out worry,(book in hand).
  But with the help of these guys (book in hand)and good use of search and other forums.don't rush make sure it's safe to go any were's.

   

[shinyribs]

Six months shouldnt have hurt it too much.Mine sat for almost 8 years and after doing an oil change it started and ran without ever pulling the carbs.Not very well of course,but it was enough for me to gauge if the engine was usable or not without going in to a lot of extra work.I'd just try draining it and adding fresh gas.Not that i thought you would refill with the old gas,of course

[Retcol]

Thanks for the great info and advice. My impatience gets in the way some times, but I'll go slow.

[sgtslag]

You can run the engine on pure SeaFoam, but I would not recommend it.  There is a stronger varnish solvent for gas tanks, than SeaFoam, available at auto shops, if you feel the need (essentially, an industrial strength gas tank solvent).


Add the specified amount of SeaFoam to the gas tank, run it for five minutes, to fully circulate the mix through the fuel system, let it sit for a couple of hours, or overnight, run it down the highway, for an hour straight, then ride it as often as possible, to drain the tank; repeat with another tankful of SeaFoam'ed gas, riding normally.  Cost:  around $9, and five minutes of your time in prep'ing (riding time doesn't count...  )  Time will tell you if more work needs to be done.

[LukeM]

+1 for SeaFoam. I've used it several times, both as an initial clean-out service, and as ongoing maintenance. It doesn't hurt to run it all the time.  One weird thing I ran into: after using a heavy concentration of it, it DID turn the insulator of my bike's spark plugs a soft orange color, almost like an octane booster would.

Works in the gas, the oil system too.

Check this link for SeaFoam uses.

Luke M