82 SECA 400 - fuel in oil

[Fart_in_the_dark]

Last time I checked, this was a 4stroke bike.. so this is an issue that I need to address.

New to me 82 SECA 400, carbs disassembled and cleaned, crankcase drained of oil and fuel from p/o and refilled and drained several times now.

The issue is that fuel keeps ending up in the crankcase.
I installed a fuel shutoff after stock petcock to see if the fuel was pushing past the float valves, I haven't checked to see if the fuel is back in the oil yet.

Is this a common issue? Any first hand experience? Can I blame crappy E10 fuel?

Any help or advice is greatly appreciated.

 

[HoughMade]

If you are sure the fuel is being shut off when the bike is parked and you still get fuel in the oil, then it sounds to me like the float needles are leaking. However, if fuel were pushing through when the bike is running, I would expect it to run poorly. I had a float level issue that caused fuel flooding. In addition to the float level issue, it could be wear to the needle or debris on the seat.

Blame E10 if you want to (who knows) but even if you could change fuel, you now need a repair. A properly functioning float needle should block the fuel from pushing through even if the petcock is left on. The petcock should be a safety mechanism and not strictly necessary for function...though I always use mine.

 

[Fart_in_the_dark]

Thanks for your quick reply.

Bike runs well all through the rpm range, I have even left it idle for a bit to see if it would load up with fuel, but you jump on it and it just goes.. no black smoke.

I've had the petcock apart, no holes or tares in the diaphragm as far as I can see nor is there any corrosion. The o-ring was still pliable. I'll track down a rebuild kit for he petcock.

I've bought misc rebuild kits from keyster before, some of their parts are trash at best.. are their 400 kits okay? same with the float jet kits?

Thanks again

 

[eric123]

I don't like anything Keyster...Too many problems...

I like your username BTW

 

[Fart_in_the_dark]

it is a pretty epic username

where is a good resource for parts for this bike?
local cycle center isn't interested in helping me unless i am wearing a had made out of $50's

I'll be needing clutch plates/steels soon, revs out of grip in high gears along with a jet kit most likely.

these are Mikuni CV carbs, correct?

 

[eric123]

Yeppers they are Mikuni's. I get alot of my parts from Mike's and the local Yamaha dealership in the next town over. I will buy stuff like float bowl gaskets online though, as they are usually much cheaper. Ironically enough, my local cycle salvage place has a good selection of carbs parts.

 

[Fart_in_the_dark]

good stuff. i'll keep my eyes out, I find some great prices and then the shipping is almost half of what my parts cost. DOH.

by the way, to revisit the initial issue I had, the petcock AND the float valves are leaking. best to replace at the same time anyway I imagine

 

[OnePhate]

it is a pretty epic username

where is a good resource for parts for this bike?
local cycle center isn't interested in helping me unless i am wearing a had made out of $50's

I can sympathize on that one! No shop even wants to take a look at my '82 SECA unless I smash their windows with solid gold bricks, throw a garbage bag of 1's in the air, and donate my heart, lungs and kidneys to their cousin.