petrol in my oil

[philwright]

After refitting my carbs i turned the fuel switch on my 88J to Prime ,it started OK and i let it idle for a good five or ten minutes ....then like a twat i forgot to turn it back to 'ON' and left it overnight on Prime, after i realised what i had done i had a whiff of the oil filler cap and there was a definite smell of petrol,looks like it had fooded past the pistons etc. I drained the old oil and gave it a fresh lot....will i have done any damage?

[dupersunc]

It'll more than likely be fine. done similar a couple of times with I'll effects.

[wraith]

Put some new plugs in as well, turn it over with no plugs in then put the new plugs in and start it up let it run and threat as normal 

[kiwi]

If you look in the sight glass you'll know how much petrol by the level, but if its that much drain and refill with fresh oil and new filter, if it was running fine beforehand wouldn't worry about plugs as petrol all went into your sump, unless its due a seervice anyway.

[philwright]

10 minutes ago, kiwi said:

If you look in the sight glass you'll know how much petrol by the level, but if its that much drain and refill with fresh oil and new filter, if it was running fine beforehand wouldn't worry about plugs as petrol all went into your sump, unless its due a seervice anyway.

Changed the oil as soon as I realised...hopefully should be OK.

[jonny1bump]

Does not sound like you run it with fuel in oil so as long as you done oil and filter change it be fine.

 

[wsn03]

Needle floats aren't doing their job, they should have stopped this happening. I flood test all the carbs I build on a bench, they should never piss fuel no matter what is loaded on them. I'd be checking/ changing them if it were me just to keep things right

[Dezza]

As said above by wsn03 it would be useful to remove the carbs and check where the leak is coming from as this should not happen if all is well. In addition to worn needle valves/seats, such leaks can be down to perished O'rings where the needle valve seat goes into the carb body. Fuel then effectively bypasses the needle valve and flows directly into the float bowl.

[philwright]

7 hours ago, Dezza said:

As said above by wsn03 it would be useful to remove the carbs and check where the leak is coming from as this should not happen if all is well. In addition to worn needle valves/seats, such leaks can be down to perished O'rings where the needle valve seat goes into the carb body. Fuel then effectively bypasses the needle valve and flows directly into the float bowl.

I stripped the carbs down and had them ultrasonically cleaned then replaced all o rings and the needle jets just before i refitted them , shouldnt have leaked but i wont be leaving it on Prime again anytime soon.

[wsn03]

2 hours ago, philwright said:

I stripped the carbs down and had them ultrasonically cleaned then replaced all o rings and the needle jets just before i refitted them , shouldnt have leaked but i wont be leaving it on Prime again anytime soon.

If you replaced everything with non OEM you can expect them to leak (Ive had too many on my bench not to know this).

The fact is your carbs are failing. I dont know the fuel burn rate at tickover vs the fill rate on the tank but I suspect you might be inviting more problems than you realise.  Starting, ticking over...all opportunity for flooding - had this with a Bandit 1200...filled the engine with fuel without being on prime. 

You really need to bench tests those carbs! I'll test them for you if you like? Will cost you a jam donught and 3 cigarettes tho. I really think its worth sorting this.

Edited December 13, 2018 by wsn03

[Jaydee]

1 hour ago, philwright said:

I stripped the carbs down and had them ultrasonically cleaned then replaced all o rings and the needle jets just before i refitted them , shouldnt have leaked but i wont be leaving it on Prime again anytime soon.

I'd try to narrow it down to where the problem is. As in which carb and whats causing it.

Just because the carbs were ultrasonicly cleaned, doesn't mean that there's no debris trapped in one of the passages to a float needle. Only takes the tinest spec to hold a needle off its seat and empty a tank overnight. There's a chance that the float needle seat o-ring was pinched/sheared/tore on installation or it was defective and is leaking in to the bowl.

The little springy pin on the back of the float needle could be jammed in. Seen this before where needle not long enough to shut properly. 

Or the old classic, a slightly tight float stopping the needle engage fully.

I consider a good healthy set of float needles to be the last failsafe in keeping fuel in the tank, a must with down drafts.

I would remove and bench test to narrow down which carb leaks and investigate it further.

[philwright]

Thanks for the replies chaps, i got all the bits from wemoto...I'm led to believe they are closest quality to Mikuni. I Did actually bench test them and they didn't leak..I went through everything meticulously and everything was clinically spotless...or so I thought...looks like I'm gonna have to strip it all down yet again , a PIA cos it's running pretty well.

[wsn03]

6 hours ago, philwright said:

Thanks for the replies chaps, i got all the bits from wemoto...I'm led to believe they are closest quality to Mikuni. I Did actually bench test them and they didn't leak..I went through everything meticulously and everything was clinically spotless...or so I thought...looks like I'm gonna have to strip it all down yet again , a PIA cos it's running pretty well.

Could be the minutest spec of dirt like Jaydee says. I always fit an in-line filter, never had anything get past them ever. Its a no-brainer but most people don't fit them.

Please let us know what the problem was when you find it.

Good luck 

Edited December 14, 2018 by wsn03

[Macduff]

If you go to the trouble of fitting an inline filter make sure it can flow more fuel than the tanks petrol tap can. I fitted one and it caused fuel starvation where the engine drained the float bowls faster than the filter let fuel through. It was old unused filter  meant for a carbed 900 ducati but I suspect as that bike had a fuel pump they didn't care to much if the filter restricted the flow a touch . On my gravity fed slabby it was just too slow a  flow. 

[wsn03]

4 hours ago, Macduff said:

If you go to the trouble of fitting an inline filter make sure it can flow more fuel than the tanks petrol tap can. I fitted one and it caused fuel starvation where the engine drained the float bowls faster than the filter let fuel through. It was old unused filter  meant for a carbed 900 ducati but I suspect as that bike had a fuel pump they didn't care to much if the filter restricted the flow a touch . On my gravity fed slabby it was just too slow a  flow. 

Its a good point. I tend to use big filters so I've never experienced this

[jonny1bump]

Ive never found inline filter on bikes ive been happy with, car filter work really well but too big for bikes.

[wsn03]

I usually fit something like this...for the gsxr carefully rested on top of my carbs

[nlovien]

if i'm fitting inline filters - I use x 2  - ref: to reduce flow restriction

apart from oil contamination - important to prevent carb leakage because this can lead to a bent rod ( hydraulic lock when turning over ) - if I spot this - 1st turn the engine over slowly by hand - or take the plugs out 

[wsn03]

1 hour ago, nlovien said:

if i'm fitting inline filters - I use x 2  - ref: to reduce flow restriction

I didn't know that 2 would restrict flow restriction,. makes sense though. Ive enough issues getting 1 filter tucked away as it is.

I've not had any starvation issues using decent size filters on any of my bikes. I guess people fit those tiny filters and it all goes wrong from there 

 

I will put up a photo of my filter in situ

[jonny1bump]

Not convinced at all. I use two sintered filters in past ended up binning them and throughly washing tank instead. 

[Gixer1460]

1 hour ago, jonny1bump said:

Not convinced at all. I use two sintered filters in past ended up binning them and throughly washing tank instead. 

What ? Like one of these things? Prefer the second type - plenty of gravity flow to supply an S&S draw thro turbo install for me.

Just don't fancy that small area in the sintered type!

[jonny1bump]

It was billet screw together type. The filter in tank should get any proper Debri just does not stop sediment type muck.

 

[nlovien]

they are a pain to fit - can cause supply issues - look nasty and are not needed if the tank side is clean and you have reasonable in tank filter screens - hmm what does that sound like ? - an elastoplast fix 

going to wise up and take a better approach - forsure use them during initial build - sort out - its a right pain chasing a flooding carb - will circulate a good few tanks worth through em - then remove

[Buzuki]

In my 88-R750J  I use just one Bosch Diesel in line fuel filter but positioned under the carbs , Diesel fuel filter can not cause fuel starvation since is not paper based but is  plastic fine mesh type,  just one rubber pipe comes from fuel tank tap to under to filter , tap second output is closed with one short rubber pipe and one bolt , from filter output I use one plastic T piece to connect to carbs two fuel inputs ,  by positioning filter under the carbs he also colect water from fuel , water is heavier than gasoline and can not raise in the carbs float bowl chambers , 

btw ,I have also instaled four small neodimium magnets ( about 4mm dia and about 2mm thick taken from some old PC hard drives), one on each float bowl bottom to collect rusty dust which comes from fuel tank , those small magnets can not move and cause carbs mallfunction since they become magneticaly glued for drain metal bolts .

and yes , from my experience carbs fuel overflow is allways caused from bad O rings above needle valves , thats one very very critical point for carbs corect function.

[wsn03]

My filter in situ