'82 GS 450T - Mikuni 34mm CV help

[thevillaindylan]

I have a '82 GS 450T, the carbs are Minkuni 34mm. I have jetted the carbs, installed k&n pod filters and a Mac performance 2into1 exhaust. I used a 125 for the main jet. The bike will idle but, for only a short time. If I turn the choke on all the way, when the bike starts it revs high, around 4K+. The only way I can get it to idle for any period of time is to run the choke around halfway but, it won't idle for very long. If I twist the thrttle it will die. I've ordered a new fuel cock to eliminate any problems there. I've played with the idle mixture screws but, if it won't idle I can't adjust them properly. I've also noticed that if it sits for a little while it will fire back up. Any suggestions?

 

[BassCliff]

Greetings and Salutations!!

Greetings and Salutations!!

Hi Mr. thevillaindylan,

Without knowing the full history of your bike all I can do is encourage you to go through the usual maintenance checklist in order to get your bike running right; properly cleaned carbs, new intake boots and O-rings, well-adjusted valves, charging system checked, etc. Did you enlarge any of the other jets? Have you checked the float height? It still sounds lean to me, but I'm not a carb expert. For CV Carb jetting, see the very informative article at Factory Pro. Also see the carb jetting tips at Motorcyclecarbs.com, Inc. There's much more information in your "mega-welcome".....

If there's anything you'd like to know about the Suzuki GS model bikes, and most others actually, you've come to the right place. There's a lot of knowledge and experience here in the community. Come on in and let me say "HOoooowwwDY!"....

Here is your very own magical, mystical, mythical, mind-expanding "mega-welcome". Please take notice of the "Top 10 Common Issues", the Carb Rebuild Series, and the Stator Papers. Now let me roll out the welcome mat for you...

Please click here for your mega-welcome, chock full of tips, suggestions, links to vendors, and other information. Then feel free to visit my little BikeCliff website where I've been collecting the wisdom of this generous community. Don't forget, we like pictures! Not you, your bike!

Thanks for joining us. Keep us informed.

Thank you for your indulgence,

BassCliff

 

[thevillaindylan]

Thanks BassCliff, the bike was completly stock with 6K on it when I purchased it last fall. I rode the bike for a month or so until I parked it because or fuel problems. I could ride the bike for several miles then it would die. When I would park the bike gas would run out of the overflows. The bike had a new float installed by a dealer before I bought it, so I would think the float height would be correct.

Question - I understand that you should measure from where the float bowl gasket would be. Where on the float do you measure to. I have digital calipers that allow me to get an accurate distance.

 

[BassCliff]

Question - I understand that you should measure from where the float bowl gasket would be. Where on the float do you measure to. I have digital calipers that allow me to get an accurate distance.

Hi,

There are lots of pictures on my site that show you where to measure.

Is your petcock working properly? Are you using an inline fuel filter?


Thank you for your indulgence,

BassCliff

 

[thevillaindylan]

BassCliff, I have ordered a new petcock, should have it in a day or two. Yes, I am using a inline fuel filter.

 

[Steve]

If I turn the choke on all the way, when the bike starts it revs high, around 4K+. The only way I can get it to idle for any period of time is to run the choke around halfway but, it won't idle for very long. If I twist the thrttle it will die.

So far, it all sounds normal. The "choke" on these bikes is not like a car's choke, it relies on the high vacuum of a CLOSED throttle to pull gas through a different set of passages that are opened up when you activate your "choke" lever. This an "enrichment system", which is why I always put "choke" in quote marks when I talk about it. If it dies when you go to half "choke", try 5/8, or whatever it takes to keep it running until you can turn it off.

I've played with the idle mixture screws but, if it won't idle I can't adjust them properly.

True enough, but you should be able to set them to a point where it will work. Won't be perfect, but it will start and run. Turn the screws all the way in until they seat lightly, then turn them back out three full turns.

If this does not work, then you will have to bite the bullet, take the carbs off and do a full clean and rebuild of them. Not as bad as it sounds. You can get a set of o-rings from GSR member Robert Barr at cycleorings.com. He sells 4-cylinder kits, so you will have parts left over, but that's OK. A can of carb dip is about $20 at Auto Zone. Follow the rebuild guide found in the garage section of the forum or follow the links in BassCliff's site.

The bike had a new float installed by a dealer before I bought it, so I would think the float height would be correct.

Please don't kid yourself. Too many times, even a dealer won't know how to work on these old bikes. Measure it yourself to be sure.

Question - I understand that you should measure from where the float bowl gasket would be. Where on the float do you measure to. I have digital calipers that allow me to get an accurate distance.

BassCliff has pictures (thanks to me for some of them ) on how and where to measure the floats.

Yes, I am using a inline fuel filter.

Your filter could also be part of your problem. Most filters that you get at an auto parts store are designed for pressurized fuel systems. In our gravity-fed systems, there is very little pressure, and the filter will actually block fuel flow. You already have a filter in the tank, on the inlet of the petcock and another filter at the top of the inlet for each carb, so you really shouldn't need one inline, too. If you really insist on having one, get one that is designed for a lawn mower, as they have gravity-fed systems, too.

.

 

[thevillaindylan]

Steve, I should get the new fuel cock today and I am going to remove the inline filter, I didn't even think about the pressurized fuel filter. As for cleaning the carbs that was already done when I installed the 125 main jet and raised the needle. I have already installed a new o-ring kit from Robert Barr. This included a new set of intake boot rings. The intake boots look good but, if I get the new fuel cock on and it still acts funny I'll replace them. Those will be about the only thing I haven't replaced.

 

[thevillaindylan]

Installed new fuel cock today. Removed inline filter, bike idled fine and could rev the engine. Got to ride up and down the road a few times, about a mile. It died as I turned back into my drive way. I'm following the Factory Pro Tune Like a Star. I could not get the bike to stay above 7k. Does that mean i'm not getting enough gas, too much air? I'm running a 125 main jet, I also raised the needle one step.

Also, if I turn the choke on full the engine revs really high? Is that normal?