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Posted

My 84 STILL has a bit of a gas stink issue when parked after a ride. Not immediatly after but within 30 minutes it begins.

 

I changed all the fuel lines & filters, nothing is leaking, carbs have been extensively run with Seafoam. The diaphrams were replaced by the P.O. & Muffinman did the carb sync for the P.O. She runs great & gets excellent MPG but she stinks after a ride. It usually stops after a few hours. I'm sure the problem will turn out to be a 20 cent o ring somewhere

 

The next morning if I take here out, the fuel pump clicks like crazy. IDK

 

ANYWAY, I have a 1984 parts bike as well & I was thinking that I could rebuild that carb bank & then over next winter slap the rebuilt bank on mine, but I am clueless on where to start. I don't even know what screws adjust what!

 

So has anyone done a good writeup?

Posted

Consider this. The carbs sit on top of the hot engine. Heat rises. The carbs soak up the rising engine heat, and the fuel in the carbs begins to get hot and evaporate, and this produces the aroma. When tuning both my bikes with the air box off, I've seen the carbs begin weeping fuel upwards out of the carbs after the warm/hot engine was turned off. I thought something was wrong, but the bikes start easy, run good, and get better than expected fuel economy, and there are no leaks.

-Pete, in Tacoma WA USA

'83,88

Posted

Pete

That's exactly the boat I'm in. My problem is my 1st Gen is a garage queen & with the garage door closed she's a stinker!

This is my 1st Yam, I was ALWAYS a Honda CB guy (I also own a CB750 DOHC). When Hondas stink, it's because they are leaking!!

 

My Gen one only has 15K mile but she did sit for years when the original owner died. I'm thinking something has rotted. I can't believe these bikes were like this new.

Posted
Pete

That's exactly the boat I'm in. My problem is my 1st Gen is a garage queen & with the garage door closed she's a stinker!

This is my 1st Yam, I was ALWAYS a Honda CB guy (I also own a CB750 DOHC). When Hondas stink, it's because they are leaking!!

 

My Gen one only has 15K mile but she did sit for years when the original owner died. I'm thinking something has rotted. I can't believe these bikes were like this new.

 

I let her cool off outside then put it in the garage. Never any gas stink. When I put it away hot is when I get a gas stink

Posted (edited)

Try some Sea-Foam, or techraline first. Maby the float valves are simply Sticking.

Give it a week or so, to soak with a heavy dose in the fuel.

Drain the carbs several times during the week, Might fix the problem. Worth a try.

 

Good idea, to completly drain the tank also, Start with all new fuel .

 

Did you check the hose from petcock to the fuel filter??

 

Any leaks around the fuel filter??

 

Several rubber hoses, on top of the carb bank, possibly a leak there ?? ( pull air filter box for access )

Edited by GeorgeS
Posted
Try some Sea-Foam, or techraline first. Maby the float valves are simply Sticking.

Give it a week or so, to soak with a heavy dose in the fuel.

Drain the carbs several times during the week, Might fix the problem. Worth a try.

 

Good idea, to completly drain the tank also, Start with all new fuel .

 

Did you check the hose from petcock to the fuel filter??

 

Any leaks around the fuel filter??

 

Several rubber hoses, on top of the carb bank, possibly a leak there ?? ( pull air filter box for access )

 

I thought along the same lines, I replaced EVERY rubber hose, all the gas lines from petcock to carb. Did the filter & replaced all clamps. Not only did I run seafoam for 5 tanks, I initially pumped ONLY Seafoam STRAIGHT into the carbs & let it sit for 24 hours with it in. It was a bear to restart

Posted

Andy,

 

Perhaps your float needles aren't seating properly and it's dripping a bit past into the over flow tubes. If you have a set of carbs, and you rebuild them entirely, be prepared for some sticker shock. I have about $400 into the set on my '86 and about $250 to $300 on my '83, neither were absolute complete rebuilds.

 

When I started doing carbs, I had zero clue on what I was doing. I just took pics of the disassembly and tried to lay out things in the order that they came apart. It takes a long time to do carbs, so dont get in a rush. There is a guy I use (Dingy turned me on to him) on ebay named georgefix and thats who I purchased Vmax rebuild kits from, they work on the Ventures as well.

 

I have some limited knowledge on redoing the carbs. Dingy, is an encyclopedia on them. Dive into the spare set you have and we'll be able to help walk you through it. I wish you were closer, I'd come over and help you with them.

  • 3 months later...
Posted (edited)

I have scoured the forums and there is still a gap in my understanding. I hope someone can clarify it for me. The symptom is the fuel dripping out of the overflow. I measured the fuel levels and found the offending carb had a fuel level that was at about 30 mm above datum. Sure enough, that was also the carb that was overflowing.

 

So I removed the carbs, opened the float chamber, bent the tab a hair or two, reassembled, started her up and viola! Absolutely no difference. So I have the carbs off again and this time a cleaned out the valve. I hope that it was just dirt in there, but i will never know since I blasted it with an air can.

 

My question: Is there a way to measure the correct float position with the carb open and dry? I cannot believe that it is a matter of trial and error with a full reassembly in between each trial. I searched the forums and my manual but I cannot find specifics on this step, if it exists. Help! I have attached an image of the open float chamber and the float tab resting on the valve by gravity.

 

One more simple question. My spark plugs are always black and oily instead of dry and that light tan colour. To me this is the mixture adjustment but a cannot locate a spring-loaded mixture screw that is attached to the carb body. Can someone please point it out.

 

Thanks for your help.

Edited by Peaceful Warrior
spelling
Posted

The pic you have there is way wrong, that float is not even close to being correctly set. The 1st gens are a tough set of carbs to do as you have to atleast split them in half to get at the floats.

 

I have found that a measurement of 1" with a set of calipers is VERY close to being on the money. Here are a couple of pics of where I measured and the actual float level when measured on the side of the carb.

Posted

I went out yesterday and tightened the upper and lower clamps on the carbs and aligned the gasket under the air cleaner. The bike runs much better. I was surprised how much I could turn the clamp screws to tighten them. I'm hoping that that is the reason for my lower mileage and not so smooth running. Seems to run smoother. :happy65::cool10:

Posted

Try spraying some starter aerosol or use an unlit propane torch around your boots. if the idle changes at all you still have a leak.

Posted

Check that you are using the right specs for your model though. Different markets had different jets and different float heights specified for those settings. It's hard to believe it really made that much difference, but I guess those with bigger jets may have had lower float heights and vise-versa, so getting it wrong could make the mix overly weak or rich and if too rich, then it might smell a bit too. It's probably not the issue here, but I thought I'd mention it.

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