Morning start issues.

Hey all. Color tuned and synced again last night and the bike was running fantastic. Started first thing this morning with half choke. Started to drive and she started to bog down. Let it idle for a bit, and it seems like the warmer the engine gets, the better it runs. Why would it do this?

 

A carburated engine has to warm up to run well.
Keep the choke (enricher) on until the engine RPM starts to climb to about 2,000 RPM, then slowly back it off to drop the idle a bit.
At that point you can ride, and then turn the choke off after a few minutes.

 

Here's another interesting thing. Went for a good ride. Idles at about 1200. After 20 minutes or so, idle goes up to 2000. I'm hoping new shaft seals will solve that issue.

 

That's normal. As the engine gets hotter the idle will rise because the fuel is being buned more efficiently.
When setting your idle speed you'll want to find a good balance between reliable cold starts, and RPM being around 1500 - 2000 RPM when stopping after a hard ride. Your 2000 RPM idle is not an indicator of a vacuum leak at the throttle shaft seals, or anywhere else.

 

That's good to know. I just don't remember what it did 27 years ago, so it seems kind of odd to me, but that's just me.

 

I use my choke as K-Moe says and after warm up my engine idle is about 1100 rpm as spec I believe.

 

My bike is the same. The fuel condenses on cold cylinders I understand so a richer mixture in needed to get it started.

 

adjust your idle after 10 or 15 minutes of riding

 

My 82 xj650 maxim is the same as well. Needs choke to start, but after a few seconds it can go down to half choke.
A minute or two of riding, I can close the choke. When it's fully warmed up, the idle is rock solid at 1100 rpm.
3rd gear + 7k rpm =
Bob

 

I've been doing as K Moe suggested, but it seems like it's getting too much fuel because it sputters and farts and boggs down. Then after it warms up, everything is good. She starts great. Gets to 2000. Let her sit for a bit and slowly reduce the choke.

 

Bikes are for riding, not sitting there whilst warming up. Start it, make sure all is well, ride it, reducing the enrichment as you go. The age old advice to "warm the machine up on the stand before moving off" was nonsense.
Just be gentle and kind until the oil is warm.
Set the idle mixture and speed when properly hot.

 

If she's bogging then just reduce enrichment a tad.

 

I tried that today. If I reduce it too much, it has a hard time keeping idle unless I keep reving the engine. Then when I take off it sputters and farts. I drive like that for a bit and kill the choke and it takes a good hit on the throttle to clear the sputtering and then all good.

 

It’ll take a bit for you to get the feel of it. Keep in mind that ambient air temperature plays a big role in how much fuel is needed during warmup. It may be easier to let it warm on the stand for a minute or two, but it shouldn’t need much time doing that in the Summer.
Typically I’ll start mine and by the time I have my helmet and gloves on it’s warm enough to start riding, unless it’s very cold out.

 

Thanks k-moe

 

On a summer morning, mine requires choke to start. Then by the time I get down the driveway, and the rpms are up on the street, I turn off the choke. Runs great after that.

If it hasn't been run a few weeks, I might have to turn petcock to "prime" for a couple minutes to refile carbs (evaporation?), then turn it back to run.

 

Started up fine this morning. Ran with the choke on for a bit and slowly cut it back. Bike almost stalled. Opened the choke back up and then it stalled. Couldn't get it started after that, so I pushed it back home, only a few blocks away. Put the battery on the charger because it didn't seem like it had much power when turning the bike over. See what it does after work.

 

Bike started up right away after work. Battery was fully charged and is at 13.31. 14.7 at 2500 and same at 3500. When I first took it off the charger and tested the battery, it was dropping very slowly without the bike running.

 

after charging battery will settle to12.8 volts. measure voltage in morning before starting and test voltage drop when turning over.

 

Well I think you need to get to know your bike a bit better - sometimes a throttle blip every now an again helps clear the throats. Give it enrichner, only as much as it needs, slowly reducing until you can move off, the odd blip here and there, and off you go. Maybe your synch and/or mixtures aren't quite right?

 

Honestly, I think that we've all been spoiled by too many years of fuel injected engines in our cars and trucks.

 

They were, but I'm going to check again tomorrow

 

Just checked the oil level because of all the troubles I was having with flooding, and I know I left a little space in the window, but it's gone. Gas in the oil again. Taking the carbs off again tomorrow.

 

This exactly - modern efi has the injectors right by the valves, and only one throttle. A mile apart from our bikes, not to mention a computer controlled idle air valve.
In the meantime you need to rebuild your petcock ( unless you're leaving it on prime?), and check which carb is dribbling at the float valve - why not do this before removing them? A simple level check, repeated once or twice would no doubt tell you a lot.

 

And you can extract codes on efi engines which help in identifying which part of the system is faulty. I am no expert but it is interesting how it works.

 

I did rebuild the petcock, and fixed the problem I had before where the thing with the holes in it had moved. I'll check that again as well. No it's not on prime unless someone was playing with it while I was at work.

 

if carbs are overflowing when running it will cause the issues. after you do what is needed to caebs, start and run some before putting on the airbox boots that way you will see if they leak

 

Just drained the oil and checked the petcock. Oil had some gas in it. Petcock was fine.
Could it have gone that badly out of sync? Everything was fine before.

 

the petcock stops the fuel when the bike is off, read that again.
when the petcock stops the fuel, there isn't enough fuel left in the line to see any change in the oil window, even if the floats let it all drain out.
whatever fuel went into the crankcase had to go past the petcock.
ride it and pull the fuel line and route it to a can overnight

 

I'll give it a try.

 

I have the tank off right now, and not a drop comes out. I didn't take it for a ride yet though.

 

i would think if you were to put two drops of gas in a new bottle of oil and shake it, it would smell like gas

don't know about that one

sync has nothing to do with it

 

i have a theory, you do the test.
next time you park it, open the gas cap

 

What will that show me?

 

maybe your vacuum line is sucking fuel,

 

Can I do that with the tank off the bike?

 

well after a ride and you park it the gas and gas vapor is right over the hot engine.
if the vent in the gas cap isn't working right maybe the gas expands and forces it's way through the petcock.
it's only a theory but it's the only one i got

 

Well, I started it up, no problem. Raced to 3000 and turned back the idle screw to 2000. Let it go for a bit and slowly eased off the choke. Had it at half choke for a bit and it slowly died. Waiting for a bit to try again.

 

Slaps forehead with palm. I hardly had any gas in the tank. I'm an idiot. LOL Going for a ride and then test the gas cap.

 

Petcock was rebuilt with parts from Len

 

So will I see an immediate change in the oil level?