Peter Day

Yamaha FZR750R OW01  & YZF750 specialist


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Forum Home > General OW-01 Discussion > YZF750R General Dump Carb Question

Bobby B.
Posts: 5

HI All,

Over the past few weeks, I've been working on getting my '96 YZF750R running again. Long story short, I let the bike sit for too long and when I went to start it, it wouldn't fire. Lesson learned... No fuel stabilzer and time equals carb rebuild.

I've been using an ultrasonic cleaner and dish soap to clean most of the parts. But for the main jet needles, I wanted to soak them in Gumout. So I removed the circlip and plastic doughnut stopper and dropped the needles in to soak. That's where I'm at now and that leads me to my dumb carb question... Before I took the needles apart, I noticed that the circlip prevents the needle from moving towards the main jet. But there doesn't appear to be anything that prevents the needle from moving in the other direction. Why is that?

December 11, 2017 at 4:45 PM Flag Quote & Reply

Posts: 64

The CV diaphragm spring (the tension) and plastic grommet hold them in place.

Be careful with alkaline dish soap, as it will blacken the aluminum. Use a ph neutral, product such as truck wash (safe for use on alloy parts wheels, bull bars, etc). After cleaning rinse thoroughly and dry with compressed air, and warmth.

December 14, 2017 at 8:44 PM Flag Quote & Reply

Posts: 1

The 750 carbs require maintenance even without letting them sit with old gas, the pilot jets will be plugged , the needle and seats need pulled out and float level is crucial, and replace all the orings for the main jets, the block that the jets screw into and the plastic housing that the slides sit in, there are so many places in these carbs that fuel can leak through when the orings go bad, hope that helps, let me know if you have any more questions.

December 22, 2017 at 7:24 PM Flag Quote & Reply

Bobby B.
Posts: 5

Thanks for the replies Ralph and YZFTX,

The project is coming along. I've been methodically disassembling the carbs and have them all cleaned. One or two of the pilot jets were a little difficult to get out and ended up buggering up the head, so new ones are going in all around. I have all the new seals and o-rings. The diaphragms look surprisingly good and still pliable. But I had to order new choke valve kits because the seals ended up getting torn on removal. And I'm going to order a DynoJet stage three kit so I can use them as replacements for the main jets.

Here's where I'm at now with it all...

I do have another question... What is the purpose of the vent tubes in the link below? The reason I ask is that I was thinking about ordering some new rubber hose for them because the ones that came off the bike seem a little dried out. I found an outfit that sells rubber hose in short lengths that have a 45 degree bend already formed into them. So I thought they would make a perfect replacement, but they're made out of silicone and shouldn't be exposed to fuel. I'm just wondering if these are just breathing tubes or if it's possible for fuel to find its way into them.

January 13, 2018 at 4:22 PM Flag Quote & Reply

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