Garage smells like gas...

[doggscube]

And I noticed gas on the clamp for the K&N pod on the left-hand carb. No pool of gas or anything like that just apparently a slow leak.

Bike runs fairly well, though it doesn't like to idle at a regular speed with the headlight on (new development after I installed the JC Whitney 7" H4 conversion).

I've had the bike for a month (it's my first), so I know nothing about the condition/setup of the carbs. Petcock is set to "on", there is no off or prime. '81 GS450S.

Jeff

[Billy Ricks]

You've likely got two problems, a malfunctioning petcock if it is the vacuum type and maybe bad o-rings on the float seats. Check your oil for the smell of gas.

[doggscube]

I did check the oil for a gas smell, but I can't tell if I'm just smelling the gas in the air around it. Would it be really strong, like if I smelled the opening to the gas tank? The oil level has not increased.

The float is in the bowl, right? The drop of gas was definitely on the clamp attaching the pod to the carb, not the bowl.

Jeff

[Billy Ricks]

If the oil level hasn't risen and you don't get a good whiff of gas that's probably fine. Check around the fuel line connections and if there is a T shaped fuel rail between the carbs see if it might be coming from there. You may be able to see a dirty spot on the carbs where the fuel is leaking from. You're most likely due for new o-rings. robertbarr sells o-ring kits cheap and he is a member here. You can adapt the Carb Cleanup info from the homepage to fit your application.

[doggscube]

Here's my petcock: http://alpha-sports.com/spst/1981%20GS450S/28.gif

Is that a vacuum type? Should I even rebuild it? I saw in another thread that a single hose means the problem is definitely in the carb.

I'll be looking at the Clymer manual tonight, and will look around here some more today. I've never taken apart a carb except when I disassembled a B&S lawnmower engine to see if I could fix it. I'm not one to shy away from something significant like a carb rebuild, but the bike runs well otherwise.

Jeff

[Billy Ricks]

Here's my petcock: http://alpha-sports.com/spst/1981%20GS450S/28.gif

Is that a vacuum type? Should I even rebuild it? I saw in another thread that a single hose means the problem is definitely in the carb.

I'll be looking at the Clymer manual tonight, and will look around here some more today. I've never taken apart a carb except when I disassembled a B&S lawnmower engine to see if I could fix it. I'm not one to shy away from something significant like a carb rebuild, but the bike runs well otherwise.

Jeff

It looks like it has the vacuum chamber on it. If it has a small hose running to the backside of it from the front of the left carb it is. Check the little things like clamps and stuff, maybe you'll get lucky.

If it has a vacuum line pull it of and check it for fuel. Pull if off at the carb. If there's no fuel in it try sucking on it to see if it holds vacuum. If it won't hold vacuum the diaphram in it is leaking. If it holds vacuum then things are fine with the petcock.

[doggscube]

I'll be ordering an o-ring kit, intake o-rings/SS screws, and a petcock rebuild kit. There's evidence my bike is running lean (popping on deceleration), so I probably should do much of this stuff to get it right before I damage the engine. I haven't looked at the plugs. I hate to park the bike so soon after I got it.

Jeff

[Billy Ricks]

I'll be ordering an o-ring kit, intake o-rings/SS screws, and a petcock rebuild kit. There's evidence my bike is running lean (popping on deceleration), so I probably should do much of this stuff to get it right before I damage the engine. I haven't looked at the plugs. I hate to park the bike so soon after I got it.

Jeff

Just a minor setback. Nothing you can't handle and you'll have things right.

[doggscube]

I'm no stranger to wrenches or dirty fingernails. I most recently replaced half of the brake lines (not hoses) on my car myself. I actually enjoy working on vehicles, with the qualification that it goes right. :-D

Now to print the carb rebuild pages...

Jeff

[doggscube]

Would it be OK to ride the bike before this work is done? How serious is the popping on deceleration? The bike doesn't knock (pre-ignition), I definitely know what that sounds like.

Jeff

[Billy Ricks]

As long as you don't have fuel puddling on the engine or anywhere you can probably ride it okay. Replace the o-rings on the rubber manifolds too. The popping may be coming from small leaks there. Check the condition of the mainfolds as well.

[doggscube]

By manifold o-rings, do you mean these? http://www.cycleorings.com/intakeb.jpg

If so, that's what I mean by intake o-rings.

The gas isn't puddling anywhere, and I'll watch the oil level and smell for gas (when it's outside, it'll be easier to check that).

BTW- the only instance where I've seen this level of helpfulness is at an R/C airplane field. When there are problems there, guys will stop flying to help out their club member. Broken part? Guys start looking in their boxes for it (even servos, etc.) I had one guy tell me I hadn't sufficiently broken-in my engine, and spent an hour doing it for me. Seems like this would be the same for this board if the gathering place were physical.

Jeff

[Billy Ricks]

That would be them. Most people here would do the same for others as you've found on the other board. I've offered many times to have people send their carbs if they aren't sure they can handle the job. I've given small away parts I don't need. Nothing special.

[rustybronco]

I most recently replaced half of the brake lines (not hoses) on my car myself. Jeff

I replaced ALL the brake lines, hoses, wheel cylinders, springs, one rotor, master cylinder and booster because the return spring in it rusted so much that it would not return the pedal...
OH and it was on a 1982 "very rusty" bronco that was given to me.

There is not a thing you can't do, once you have a mind for it.

[doggscube]

I realized this morning I left out a possibly important detail. Two or three days before I noticed the problem, I added 2 oz. of B-12 Chemtool fuel additive to the tank, and I didn't run it for that period of time. Could the additive have compromised the petcock or carb o-rings?

Interestingly enough, the garage didn't smell like gas this morning, so perhaps running the bike for a day may have helped free up something sticking open. I didn't ride to work this morning so it'll probably sit for 24-36 hours before I run it again, we'll see if it's still holding. I'm going to change the oil just in case there is fuel in it. I still need to replace the intake o-rings as the bike doesn't like to idle when cold and then idles too high when it's hot.

Jeff