1981 carb issues

[smokienutz]

i have a 1981 gs450L w/ roughly 19k+ miles that is having a few idleing issues. i was having an issue of the exhaust going out the top of crankcase. i think i have fixed that problem. but i haven't fixed the main problem, which is the idle raises from a good solid 1200 r so rpm to up past 4k rpm. i adjust the idle then after a short i come back and it does the same. today i took the hose from the crankcase valve (which is where the smoke originally was coming out) to the air box. i did it for a short run, but it runs smoother and my rpms drop faster and raise faster. i like it better w/out the hose, but should i leave it like that? maybe block off the airbox hole and put an air filter on crankcase valve? or is there a better solution?

[Steve]

The hose should be in place while the engine is running.

It would be far better to fix your carburetion problems so the bike runs better. It sounds like you have a leak in the intake tubes between the carbs and the engine. This is typically caused by bad o-rings between the intake tubes and the cylinder head. Those o-rings are easily available from cycleorings.com. You can also get stainless allen-head bolts to replace the Philips-head bolts that are there now, but will likely be destroyed when you try to remove them.

Oh, while you are at it, the carbs probably need some attention, too. While you are ordering your stuff at cycleorings, get an o-ring kit for the carbs, too. Then get a can of Berryman's Carb Cleaner Dip from Auto Zone and fully clean and refurbish your carbs.

May as well go whole hog while you are at it. Adjust your valves while you are waiting for the carbs in "the dip".

With clean carbs, adjusted valves and new intake o-rings, your bike will run better than you ever imagined.

.

[smokienutz]

The hose should be in place while the engine is running.

It would be far better to fix your carburetion problems so the bike runs better. It sounds like you have a leak in the intake tubes between the carbs and the engine. This is typically caused by bad o-rings between the intake tubes and the cylinder head. Those o-rings are easily available from cycleorings.com. You can also get stainless allen-head bolts to replace the Philips-head bolts that are there now, but will likely be destroyed when you try to remove them.

Oh, while you are at it, the carbs probably need some attention, too. While you are ordering your stuff at cycleorings, get an o-ring kit for the carbs, too. Then get a can of Berryman's Carb Cleaner Dip from Auto Zone and fully clean and refurbish your carbs.

May as well go whole hog while you are at it. Adjust your valves while you are waiting for the carbs in "the dip".

With clean carbs, adjusted valves and new intake o-rings, your bike will run better than you ever imagined.
.

this issue your telling me would one of the symptons be like one of the cylinders isn't running quite right? meaning, i can definitly feel a difference in the exhaust, between the right and left one. the left one puts out more pressure/power than the right one.

[Steve]

this issue your telling me would one of the symptons be like one of the cylinders isn't running quite right? meaning, i can definitly feel a difference in the exhaust, between the right and left one. the left one puts out more pressure/power than the right one.

Very definitely.

Your bike is supposed to be set up to provide a proper mixture of fuel and air to the cylinders. If you have a leak after the carbs (which control the mixture), you will have extra air, making it lean. Besides the erratic idling issues that you have already noted, you should know that a lean mixture burns hotter. If left in its present condition, it is possible to melt your engine due to the excessive heat. That lean mixture will be harder to light, meaning a reduction in power because that side is not firing. Because it's not firing, the exhaust flow will be less because firing expands the mixture.

If you care for your bike at all, please fix it before riding it again.

.

[pete]

Listen to Steve, he 100% knows what he's talking about

There's a carb cleaning guide on BassCliff's site done up by Flaming Chainsaws specifically for the 450's, and there are a few around the place that have recently done or about to (in my case anyway) do the full clean and rebuild on the 450 carbs.

There are also other carb tips on that site as well.

The cycleorings.com 450 kit has all you need including intake O rings, carb O rings, and new stainless allen bolts for the intake boots too so you can get rid of the dodgy philips head screws.

[smokienutz]

Listen to Steve, he 100% knows what he's talking about

There's a carb cleaning guide on BassCliff's site done up by Flaming Chainsaws specifically for the 450's, and there are a few around the place that have recently done or about to (in my case anyway) do the full clean and rebuild on the 450 carbs.

There are also other carb tips on that site as well.

The cycleorings.com 450 kit has all you need including intake O rings, carb O rings, and new stainless allen bolts for the intake boots too so you can get rid of the dodgy philips head screws.

srry if i sounded like i was makeing steve sound wrong. i wasn't, just trying to do more of a verification. so it looks like a carb rebould, and valve adjustements. this suck because i paid a mechanic already to fix this. o well guess u live a learn right.

[Dave8338]

Steve knows nothing!

[chef1366]

Steve knows nothing!

Steve who?

[BassCliff]

this suck because i paid a mechanic already to fix this. o well guess u live a learn right.

Hi,

You've paid someone to fix these issues already? And you still have the issues? This is another fine example of why the vast majority of us here do our own work. It is very rare to find a "professional" shop that really knows and appreciates these vintage machines. As has been mentioned, I have collected extensive information for most of the regular maintenance items on my little website, valve adjustment, carb cleaning, charging system, etc. Please feel free to take advantage of others' experience and ask questions when you need help. I'm sure you can get your bike running better than any "professional" mechanic in your area. Keep us informed.

Thank you for your indulgence,

BassCliff

[Steve]

Steve knows nothing!

Hey, I live in my own little world, but that's OK, they know me here.

Steve who?

Must be that other Steve.

Couldn't possibly be me.



.

[smokienutz]

well i have gotten down to more of the problem. i am thinking it isn't my carbs. and this is why. i just took of my exhaust to fix my rear brake. and has simple it may be, i actually fixed it lol. i am really proud of my self for addressing it and actually fixing it, with very little help. well anyway back to the main (wth?) issue. i went to put the exhaust back on and i noticed fresh oil in the pipe at the header. it was like i dumped it out of the jug and put it in there. it does have a fresh oil change. also i noticed the heat coming from the top of the crankcase is actually fuel. it's so much u can light it. are these sign of valves issues or something more in depth?
also i really appreciate everything y'all are doing do help in all my projects.

[pete]

Hmmm oil in the exhaust? I wonder if that means oil's getting past your rings?

That fuel on top is concerning too.

Have you checked your fuel tap (petcock)? Maybe it's leaking? Does your oil smell like fuel?

I may be way off track here but thought it worth a mention...

[smokienutz]

the petcock isn't in the best of shape, but the oil doesn't smell. but then again i don't have the best sniffer atm.

[chef1366]

Get a new petcock

[pete]

Get a new petcock

Took the words right out of my mouth... err... fingers... I am typing aren't I?