Hey everyone! Happy to see the forums are active on here, I'm currently working on rebuilding a CBR900RR for my first bike. This bike was dropped once in the past and put in a garage for 7 or so years before I purchased it, I've gotten it to start once since I've had it. I'm currently rebuilding the carbs (for the second time) because I believe there is a gas leak, when we drained the oil to replace the oil and filter there was a lot of gas in the oil. I'm waiting on replacement gaskets and jets for the carbs, the ones I ordered were too small so I'm getting them from an OEM part supplier this time. I originally just cleaned out the jets and got rid of that old gas grime. I also got a new petcock just in case that was the issue but this petcock didn't come with a gasket and is now leaking from the top of the nut. I just want to ask where is the best place to get a replacement petcock and if I'm going in the right direction for the issue I'm having, I've been browsing partzilla for OEM replacement parts but they don't sell fully assembled petcocks.

Any other advice you guys are willing to give on working on these bikes would be great as I am completely new to the world of motorcycles and working on them. I have a 96 CBR900RR as a parts bike and everything on it is good but the engine. It looks like something above the alternator blew clean out of the side right above the cover and they tried to JB weld it closed. I'm also in the market for fairing brackets and F/R turn signals due to the LH side being the side it got dropped on. I think I'm gonna steal the alternator cover off of the parts bike to replace the scraped one on the current bike. I'm tempted to leave the parts bike where it's at and look for a new engine to drop in it and just buy the parts I need for the other bike.

TL;DR: Gas in my oil, replacing carb gaskets and petcock. Should this fix the issue or is there something else to watch out for? Looking for recommendations for part suppliers and a replacement petcock fully assembled or a petcock gasket.

 

Hi @Goregrind and welcome to the forum. You can go to this link for OEM parts. They do sell the complete petcock for your model, but you better be sitting down when you look at the price for it. This place actually has the best pricing I've found for OEM. The O ring is available for only a few $ so, that might be an option for you.

#3 is fully assembled petcock
#7 is the O ring.

https://www.ronayers.com/oemparts/a/...2da6/fuel-tank

 

Thank you my friend! You'll see me here a lot as I'm getting close to completing the "rebuild." After this fuel leak issue is resolved I just have to slap the fairings on, get a new set of tires on her, and some new turn signals and I'm ready to ride. (Until I find something else wrong! lol)

 

Hi, gas in the oil is most likely a float or float valve issue, if the float valves aren’t seating correctly they allow the float bowls to fill up beyond the correct level, from there the fuel will go into the intakes and down into the bores and from there into the oil, it will most likely also come out of the overflow (black pipe at the right hand side of the carbs).
The bad news is that aftermarket float valves are a bit hit and miss, some work, some leak, original float valves are still available at a ridiculous £27 each!, so careful inspection of the float valves is required, if they are perfect including the viton tips having no wear and the spring nipples working well then clean the float valve seats and re-fit them, if not then bite the bullet and buy an original new set, also check that the float heights are correct, they are not adjustable so if you find an incorrect float height that float will need to be replaced with a new one, or a used one that is in good condition.
wherever possible use OE parts in your carbs, good luck.

 

Petrol in oil is 2-part problem. BOTH leaking float-valves AND petcock are leaking. Because if either were working, then no petrol in oil. So fix them both. I think petcock was also used on CBR600F2 and F3 models.

https://www.partsgiant.com/p388180-p...ly-rebuild-kit

 

He’s already fitted a new petcock, admittedly it leaks from the tank joint 🙂, but that’s a seperate issue.

 

Yep petcock will be resolved once I get the O-ring in, I will be checking on the floats too I appreciate all of the advice gentlemen! Floats are stained green from bad gas but seem to have good range of motion, I'm gonna look up a video for checking float quality and I'll chime back in if I have further issues. OEM jets and carb gaskets are on the way still as well, the jets I got from a cheap carb rebuild kit seem like they're made of copper so I'm going to OEM. I'll post pictures soon too, my parts bike is the classic red/white/black fairing and I believe they're OEM but my worked on bike has a painted black frame and I've got all black aftermarket fairings.