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Petrol in my oil after o ring replaced


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Hi all, I think it may be easier if I explain the full story on this one..

 

I bought an 05 DRZ SM from a dealer, for 2 months it had no problem however there was a whirring noise from the engine

2 months in, my big end seized which got replaced under warranty (thank god.) The shop replaced every gasket and seal in the bottom end along with a new big end an cam chain, the bike was in the garage for roughly 4 weeks

 

I got the bike back and it ran better than ever but then my carb had started to leak petrol from the overflow - I made do by closing off the manual petcock and ignoring the underlying issue.

I then eventually decided to research the issue which seemed to be a worn O ring on the float needle. I bought a new O ring and spent a few hours rebuilding it with a friend who has more knowledge than me on the matter (holy crap is the DRZ carb a pain to remove)

 

we replaced the o ring and hooked it up to the petrol tank while the float bowl wasn't attached and held the float shut manually - no petrol seemed to be leaking at all

we put the bike all back together, did an oil change with a new filter and then went for a 40 mile ride without any problems

 

I then decided to test if the issue was truly resolved by (stupidly) leaving the petrol tap open over night and now when ive come to use it today my shed stinks of petrol but I cant see any signs on it leaking anywhere, ive felt the bottom of the overflow pipe to see if it was still wet and it shows no signs of leaking/having leaked at all but checking my oil that was. ive checked my oil again and its already slightly cloudy and smells very faintly of petrol

 

completely stock SM apart from an aftermarket muffler

standard Mikuni BSR 36mm carb

 

also might be worth noting the float needle itself looked to be perfectly fine and like I said it didn't leak when we tested without the float bowl

 

am I just being paranoid or are there other problems than can lead to petrol somehow getting into the oil?

any help is appreciated 🙂

 

 

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I've gone through this twice now on a 2001 DRZ. It drove me nuts for about 18 months as I putzed

around with one thing and another.

 - My original Petcock leaked, so I replaced it. The new PC lasted about 3 months

- I rebuild the carb and replaced the float o-ring; not sure if this was the problem but the engine had 9,000 miles on it

- Replaced the PC again - leaked again after several months (could this be ethanol causing this?)

 

Eventually replaced the PC with a manual one (and blocked the vacuum tube) - bike has been 100% perfect since

BUT you do have to remember to turn the PC off after each ride. Just talked to a MC mechanic today - he just did

a PC replaced last week and is doing another one this week; Looks like they are troublesome items and he recommended

a manual PC and not depend on the float O ring to keep fuel out of the engine

Gerry 

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im not sure what suggestions i was expecting to get but I was hoping I wouldn't need to take the carb out again :banghead: although loosening up the subframe sure makes it a lot easier!

ill check the float height and maybe even replace the whole needle

 

if that doesn't fix it I guess ill just flush the oil again and live with having to turn the petcock off manually.. a little disappointing that the carb has these issues in the first place though

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Stokes, I've found it's easier to re and re the carb if you also get aggressive about moving the large rubber boot out of the way. And use a little heat to soften the rubber if you're dealing with cold rubber.

As for the remainder, I assume you are referring to the o-ring that is under the float valve seat? Mine has gotten hard and fractured, likely due to ethanol. As for rubber seats, you cannot be too clean or careful with them.....the smallest nano particle in the wrong place will cause an uncontrolled float level.

 

Carbs are funny, it seems I usually have to fiddle with it more than once....no matter how careful I think I've been. But then....I'm often good for at least 2-3 years

Edited by shuswap1
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You don't have to remove the carb to set the float height.

You can remove the float bowl with the carb in place (you have to rotate the carb to get 

at all 4 screws). Once you have the float bowl removed, rotate the carb back in it's

normal position and set the float height.

 

You can also set the float height by attaching a clear tubing to the float drain 

and measuring the fuel in the tubing - it should be X mm below the float bowl

gasket. Not sure what X is, it's either 3mm or 5mm - check the specs

 

Gerry

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In my other posts, I went through the same. Installed 2 vacuum petcocks, rebuilt the carb etc etc

It seems that the ethanol is working its "magic" on the rubber parts. The only real solution I

have come up with (along with others) is the use of a manual petcock - this will guarantee

that fuel will not get into the engine via the float valve.

 

BUT you do have to remember to switch it off............. put a red sticker on the key.....

Gerry

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Why does anybody bother leaving the vacuum petcock on the bike? Of the vac hose doesn't leak, the diaphram gets perforated and doesn't work. The needle and seat cant stop everything. Manual is better if you can remember to turn it.

Needle and seat NEED to stop the flow or the fuelling will be incorrect. I have a manual petcock and have had a leaking float valve set o-ring, so I've been there, done that. 

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I'd like to see what a FCR would do for me.....it's just that my BSR has been working so nicely....and if it's 600 for you it would be over 700 up here in the great wet north.

Check out the tt store, maybe call and get more info on shipping or import fees where you live. I got some accessories with mine to help boost the cost

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Thanks for the feedback guys, i never got around to taking the carb to bits again as its 50 quid for an oem float needle assembly kit.. ill just wait until i find a decent offer for an fcr as my bike is an ongoing project anyway.. its an 05 SM and had the manual petcock when i bought it.. and given that my big end went just 2 months after i bought it i get the impression the petrols been leaking into the oil for a long time!

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Maybe for vacuum PC's, like mine, it might be good to put another  small in-line valve in the fuel line between PC and carb. Currently, I have an inline fuel filter there, and there's not room for both.  I do like the vacuum pc concept (always off if bikes not running), but if your diaphram goes bad at the same time as your float needle/seat you  will get gas in your oil. I know this first hand.  But with standard pc, if you forget to turn it off, and have the same failure in your float valve you have the same problem. Some sort of "string tied to your finger" on/around the Key like gerryb noted is good advice! 

 

I just rebuilt my stock vac. PC....but with all of these "lasted 3 month" postings, and this stupid ethanol (even al gore admitted that's a bad idea and does nothing for "climate change"),  it's got me re-thinking my plan going forward for fuel valve solutions. 

Edited by DougBurgoyne
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It was mentioned to OP, that it may be a float height setting. The manual is somewhat vague on this procedure. You are supposed to make sure the metal center part of float is "just touching" the top of the valve assembly...and then make sure the "tallest point" of float itself is about 13 mm from the edge of the bowl mating surface (+/- a mm). However, I've found it's very hard, if not impossible to see in that little area to see when exactly the two meeting points are "barely" touching. So I'm never really sure if I got a good adjustment. Is there a better way?  One guy here noted you can actually do this with carb in the bike...apparently with carb in normal position and float hanging way down away from the needle valve. How is this possible exactly? Is there another measurement to use for this "free hanging" method? Please elaborate if so, interested in this way of doing it (any time you can avoid removing the DRZ carb,  it's a good thing!)

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