1980 Liquifire won't idle down at times.

[Blown 331]

I know a vacuum leak is the number one cause of a high idle. I've experience that many times on other machines so I know what that is like, this is different. Plus I could not find anything with carb cleaner and everything is tight.
I might be a little off on my RPM's here but just use them as some idea. I would say the high idle occurs 90% of the time.
When I first start the engine it will idle around 1200 rpm but if I rev it to say 4000rpm then it will only idle back down to around 3000 and will not go lower. Its like this when riding too, when I left off the gas and stop it will idle around 3000. But heres the weird part. If I hit the kill switch and wait for the tach to get down to 1000rpm then turn it back on while the engine is still moving it will fire back up and idle around 1200. This trick with the kill swich works 100% of the time to get the idle back down. So every time I stop and let the engine idle I have to idle at 3000rpm or hit the kill switch for a few seconds then turn it back on to get a normal idle. Any ideas?

[Danzig]

start it up with the air box off, watch it run and look to see if you have a slide sticking in a carb......also check for a bind on the throttle cable under the dash.....flip the dash panel up with it running and test do the same with it down also...

[Blown 331]

start it up with the air box off, watch it run and look to see if you have a slide sticking in a carb......also check for a bind on the throttle cable under the dash.....flip the dash panel up with it running and test do the same with it down also...

So you think it would likely be a mechanical prob rather than a carburetion prob? I will check these things out. And that got me thinking. When I bought this thing it had a broken throttle cable so I bought and installed a new one. I will have to check the adjustment. I didn't give much thought to a mechanical problem since turning the kill switch off for a bit to get the idle back down has nothing to do with the throttle cable but stranger things have happened. I'll check it all out and report back.

[Matt]

start it up with the air box off, watch it run and look to see if you have a slide sticking in a carb......also check for a bind on the throttle cable under the dash.....flip the dash panel up with it running and test do the same with it down also...

Hey Paul, where ya been?

[jdsledhead]

I know a vacuum leak is the number one cause of a high idle. I've experience that many times on other machines so I know what that is like, this is different. Plus I could not find anything with carb cleaner and everything is tight.
I might be a little off on my RPM's here but just use them as some idea. I would say the high idle occurs 90% of the time.
When I first start the engine it will idle around 1200 rpm but if I rev it to say 4000rpm then it will only idle back down to around 3000 and will not go lower. Its like this when riding too, when I left off the gas and stop it will idle around 3000. But heres the weird part. If I hit the kill switch and wait for the tach to get down to 1000rpm then turn it back on while the engine is still moving it will fire back up and idle around 1200. This trick with the kill swich works 100% of the time to get the idle back down. So every time I stop and let the engine idle I have to idle at 3000rpm or hit the kill switch for a few seconds then turn it back on to get a normal idle. Any ideas?

I believe the issue has to do with the timing curve set in the CDI box. These machines are real finicky to tune for idle. Some guys will say to set the idle up at 2,500 - 3,000 and forget about it/live with it. I'm sure someone will chime in on the topic and bring some clarity.

[Blown 331]

Well thats real interesting. Makes since with hitting the kill switch for awhile correcting the issue as well.

[Danzig]

The timing curve is also an issue, I set the idle on mine at 3200 rpm's to assist in correcting this. However...do not over rule mechanical problems with the throttle cable.

[Blown 331]

I'm off work tomorrow so I'll check the throttle cable then. Seems like a possible cause since I just changed it. But back to the timing issue. I guess theres really nothing that can be done and I should just accept a 3000rpm idle? Its really not a problem I guess but it doesn't look that great amungst the newer sleds. Everyone is like WTF is wrong with your sled! lol.

[harleysportster]

I don't know why JD had to be different but Kawasaki has the idle set at 3,000 rpm on the Invader.

[harleysportster]

I found this on Vintagesleds...
http://vintagesleds.com/bs/index.php/topic,62104.0.html

[Mr. Deere]

Wow theres a name i havent seen in a while! 2 actually.

[rnp]

Every Liquifier I've ever owned has been like this

[sledder670]

set it so it idles around 1800 rpms, check your air screws and make sure the carbs are synced at idle. High perfromance engineering sells a carb vacuum thing you put over each carb with the air box off and measure the air it draws in. If one is just a slight bit higher it will hang around 3 and not come down. most of the time the pto side is higher since it is easier for everyone to adjust and the idle gets set off of one carb. Also a good breathing engine does like to idle higher.

[AirborneX4Special]

Is your speed limiter operating?

[sledder670]

1980 models arent equiped with the rev limiter.