General Topics/Tech TipsDiscussion on break in periods, rider comfort, seats and pad suggestions. Tech tips as they become available will be posted here.
Hi, all. I have a 2003 Sporter 883 hugger.
The bike starts fine and idles fine, but when I give it some gas, it bogs down and stalls out.
I have to let it idle until it gets warm, like 15 minutes or so, and then it starts idling fast, so I have to adjust the idle screw.
When I'm on it in first gear, it bogs down and stutters and sometimes the carb pops, until it catches up and finally go smooth into second. After first gear it starts running more smooth.
I can't ride it like it is. I've rebuilt the carb completely, I used ethanol free gas, new spark plugs, wires, good air filter. The spark plugs themselves aren't sooted and gapped to 40.
Please help! I'm at my wits end. Yes, it's a Sportser.
#1 From your picture you have a different exhaust and air filter from stock; if you have not re-jetted the carb it may be running lean, you may want to have someone who knows how to tune carbs look at it.
#2 Even though you say you rebuilt the carb, you could still have crap in it. I had an issue with my petcock filter screen being crapped up. I drained and cleaned my tank and replaced the petcock filter screen and cleaned out all orifices in the carb and it fixed my problems. Sounds like your choke (enrichner circuit) may not be working the best.
#1 From your picture you have a different exhaust and air filter from stock; if you have not re-jetted the carb it may be running lean, you may want to have someone who knows how to tune carbs look at it.
#2 Even though you say you rebuilt the carb, you could still have crap in it. I had an issue with my petcock filter screen being crapped up. I drained and cleaned my tank and replaced the petcock filter screen and cleaned out all orifices in the carb and it fixed my problems. Sounds like your choke (enrichner circuit) may not be working the best.
It's been running fine for years with that air filter and exhaust. Until recently. I also recently took off the tank and sealed it and changed the petcock. However, I should mention that it leaks gas out of the overflow.
It's been running fine for years with that air filter and exhaust. Until recently. I also recently took off the tank and sealed it and changed the petcock. However, I should mention that it leaks gas out of the overflow.
Probably have a float issue and need to go back in and adjust or check the float & float valve. Additionally, check for air leaks around the manafold and check that the Slide Diaphragm is not torn or has a hole in it.
As you recently sealed it and changed the petcock, I would also look at the vacuum line going to the petcock and look to see if any sealant got loose and is causing issue with the petcock filter screen.
Probably have a float issue and need to go back in and adjust or check the float & float valve. Additionally, check for air leaks around the manafold and check that the Slide Diaphragm is not torn or has a hole in it.
As you recently sealed it and changed the petcock, I would also look at the vacuum line going to the petcock and look to see if any sealant got loose and is causing issue with the petcock filter screen.
I will check all those things and report back. I replaced the petcock with a vacuum-free one, and blocked the vacuum line going to the original. Could this be an issue?
I will check all those things and report back. I replaced the petcock with a vacuum-free one, and blocked the vacuum line going to the original. Could this be an issue?
Shouldn't be. Not sure why you did that but now you really always need to shut off fuel at petcock. For most, that's hard to do. And people always say they do and then forget. Especially if in a group and someone distracts you.
As is, it's can fill open cylinder with as or have a pool of gas surrounding bike for a real disaster if you forget and the needle and seat get trash under it. And most old carbs may leak and you not know it because the idle can use it.
nothing wrong with manual pet ****.
you are perhaps inducing your problems. the enrichen circuit is a stand alone circuit and if you have base idle correctly set with a engine at normal operating temp then you do not need to chase with the idle screw, this will upset the system especially so with the next cold start.
it is normal for a cold engine to be picky and play nice when temps rise. a cold intake requires more fuel than a warm one. this is the reason the idle increases. the enrichen circuit has its own extra fuel and air inlets that assist the normal circuits and if you have issues, start there. if the slide/needle/chamber is not right, issues will arise and it will effect both low and high end of the engine operating ranges even at normal engine temps. these cables have been an issue as i too have replaced mine.
if you have issues with acceleration, the accel pump and circuit could be the cause and could be linked to timing/diaphragm/check/nozzle.
99% of the time a carburated bike, lawn mower, any thing falls on it’s face on accell means the low speed jet in the carb is restricted, or the passage way the jet screws into is restricted.
99% of the time a carburated bike, lawn mower, any thing falls on it’s face on accell means the low speed jet in the carb is restricted, or the passage way the jet screws into is restricted.
Thank you..you're probably right. I broke down and took it to a shop. They changed the carb out with another one and it runs like a dream now. The shop owner was scratching his head for a few days about it because he changed a few things in the carb already and it didn't fix it. So he changed it all, it worked great, and he wasn't sure what exactly was wrong. I even put a new china carb on and it still acted weird, so I'm stumped, too. Originally, the shop owner thought it to be a leaking intake gasket, which makes sense to me. But I appreciate all the feed back I got on here and yours as well! Makes sense to me. It works great now and I guess we'll never know why.
11-01-2021, 08:23 AM
Bike bogs down when throttling until warm
