Dumping gas between carbs?

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brentamental
Posts: 6
Joined: Thu May 09, 2019 10:08 am

Dumping gas between carbs?

Postby brentamental » Mon May 27, 2019 1:12 pm

I am totally new to motorcycles, so forgive me if I am not asking this quite correctly. I recently bought a 82 CB650 (posted a pic yesterday) that starts well and seems to run pretty solid. The guy I bought it from said he had just rebuilt the carbs. It has a drip from the second carb from the right (carb 2? Please correct if mistaken) after being ridden a bit. I was gonna try the screwdriver handle thing today, but when I started it up, gas started running out between what I guess to be 3 and 4. It doesn't appear to be coming from any of the fuel lines. This wasn't happening before today and the only thing I've noticed that was different is that a small black line just behind, but not connected to the petcock had come off the nipple. I put it back and temporarily secured it with a zip tie, but the leak is still happening. Any help is appreciated. Image

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GeorgeSweety
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Location: UK.

Re: Dumping gas between carbs?

Postby GeorgeSweety » Tue May 28, 2019 2:23 pm

Hi and welcome, we were all new to bikes at one point so don't let that worry you :wink: The carbs are numbered left to right as you are sat on the bike, the far left carb is number one, the far right carb is number 4, this goes for cylinders as well. The pipe that I think you are referring to is your vent pipe and shouldn't have fuel coming out, there should be one vent pipe between carbs 1+2 and another between carbs 3+4. I think that you are going to have to remove the carbs to get to the bottom of your problem. Carb 2 has an accelerator pump which has a small rubber O ring between the pump casting and the float bowl (bottom carb cover held on by four screws), this may be leaking or have even been left out by the PO (previous owner). Can you confirm which carb is dripping fuel now that you know how to number them sat on the bike? ps. where are you located?

brentamental
Posts: 6
Joined: Thu May 09, 2019 10:08 am

Re: Dumping gas between carbs?

Postby brentamental » Tue May 28, 2019 10:40 pm

Thanks George! Given that info, it's definitely between 1 and 2. I will have to give it another proper look when I have a chance (stupid day job). I'm getting the feeling that the PO didn't do such a hot job with the rebuild, but I'm excited to get in there and sort it out. I ordered the Clymer manual already, but if you or someone you love could point me toward a solid rebuild kit, I would be grateful.

I'm in Culpeper county, VA. Know someone local?

Thanks again!

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GeorgeSweety
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Location: UK.

Re: Dumping gas between carbs?

Postby GeorgeSweety » Wed May 29, 2019 2:02 am

Hi Brent, when I rebuilt my carbs I had no choice but to buy carb repair kits from Taiwan, they were pretty useless TBH, I just used the float bowl gaskets. I ended up buying selections of nitrile O rings from ebay as none of the kit O rings fit and I was dubious about using the brass parts. Now David Silver has the gasket sets in stock, https://www.davidsilverspares.com/CB650 ... rt_308241/
you may find them cheaper if you search but I would remove the carbs first to check the condition of the gaskets "fitted" by the PO. The sets at DSS are for an 82 Nighthawk but they have the same carbs as your bike.

brentamental
Posts: 6
Joined: Thu May 09, 2019 10:08 am

Re: Dumping gas between carbs?

Postby brentamental » Wed May 29, 2019 5:20 am

Excellent, thank you! One thing I have noticed already is that it looks like the PO used permatex or something similar around the float bowls. Maybe that's common...I don't know.

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GeorgeSweety
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Re: Dumping gas between carbs?

Postby GeorgeSweety » Wed May 29, 2019 4:29 pm

If Permatex is gasket goo then I'd be willing to bet that the PO didn't use any new gaskets, you shouldn't need any type of goo with new gaskets other than to tack the gaskets in place to aid assembly.

brentamental
Posts: 6
Joined: Thu May 09, 2019 10:08 am

Re: Dumping gas between carbs?

Postby brentamental » Wed May 29, 2019 6:30 pm

Yeah...that's kinda what I was thinking. I probably won't be able to dig in until next weekend, unfortunately. I'm sure I will have more questions, so thank you again and in advance

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