I've run it with the filters on and off but it doesn't seem to like either more or less than the other. I was at first concerned with a loss of air velocity negatively affecting the veturi, but it didn't seem to make a difference.
The exhaust could definiately be a problem area, but my excuse to myself for why it ran so well (at first) was that there's a lot of restriction in the pipes. Is it normal for a bike running 2 inch or so OD pipes to have a ID of around 3/4. Is that all carbon build up or are they inulated? It might run a lot better if I get the mufflers sealed on... but I hesitate to think it will solve my problem since it seems to run really well when it does, just not very long or consistently.
I settled on a air leak as my probable tick because it would make sense that as rubber parts heated up/softened holes could open up in them.
I'll try fitting the mufflers back to it tonight, I don't have anything to seal it with though so it wont really be a very good test.
tuning carbs
its probally running well with clean plugs. it could be carb problems but with out those other things in order you will be just guessing.
most likely its not rich. from to much fuel but from and incomplete mix of the fuel and air. causing pockets of unburn fuel to turn to soot and foul the plugs.
you may have a weak ignition or worn float valve's.
you can get by without mufflers if you can stand the noise. but you will no doubt lose some low/midrange power. but dont go with out and air filter as you will destroy your cylinder walls due to dirt.
you can always check for intake leaks with some carb cleaner,etc sprayed on the suspect area while the engine is running.
the pipes may be normal due to it being a 360 and they are trying to boost the exhaust scavaging at lower rpm's.
with no air filter no bike will handle a snap from idle. you can always close of some of the carb opening with duct tape to test. but still dont expect things to be perfect. your just sniffing out the problem at that point.
most likely its not rich. from to much fuel but from and incomplete mix of the fuel and air. causing pockets of unburn fuel to turn to soot and foul the plugs.
you may have a weak ignition or worn float valve's.
you can get by without mufflers if you can stand the noise. but you will no doubt lose some low/midrange power. but dont go with out and air filter as you will destroy your cylinder walls due to dirt.
you can always check for intake leaks with some carb cleaner,etc sprayed on the suspect area while the engine is running.
the pipes may be normal due to it being a 360 and they are trying to boost the exhaust scavaging at lower rpm's.
with no air filter no bike will handle a snap from idle. you can always close of some of the carb opening with duct tape to test. but still dont expect things to be perfect. your just sniffing out the problem at that point.
say what
that's what it means. just the correct term for it. the piston pushs out the exhaust but the vacum helps pull out even more. thus scavenging more. most sport bikes today come with a exhaust valve in the mid-pipe to boost low and mid- range power. it restricts the exhaust at lower rpm's then opens up under full load.mysta2 wrote:scavenging: I always thought that was using the pulse from one cylinder to help pull air from another at a junction. Can you define scavanging for me?
your bike needs to run at a wide rpm band. and a 360 does not push the volume of air through the exhaust as bigger engines do. so though your pipe diameter seems tiny it is just part of the tuned exhaust system. (if not plugged)
say what
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mysta2
- Legendary 300
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- Joined: Wed Mar 02, 2005 4:23 pm
- Sex: Male
- Location: Little Elm, TX.
the pipes on my bike actually never intersect.
I put the mufflers back on it last night and wrapped them pretty good with duct tape, and the bike ran pretty good (as good as before) for a few laps around the block (couldn't get much more riding though, for fear the mufflers would fall off, and the muffler was blowing the tape off)
is there any way for me to reproduce the same effect of the mufflers with shorter smaller pipe... soemthing like building mini glasspacks? the stock parts aren't relly appropriate for the bike anymore, and it sounds lousy.
I put the mufflers back on it last night and wrapped them pretty good with duct tape, and the bike ran pretty good (as good as before) for a few laps around the block (couldn't get much more riding though, for fear the mufflers would fall off, and the muffler was blowing the tape off)
is there any way for me to reproduce the same effect of the mufflers with shorter smaller pipe... soemthing like building mini glasspacks? the stock parts aren't relly appropriate for the bike anymore, and it sounds lousy.
you could make something work. but i would try to find a good stock system from a salvage yard first.mysta2 wrote:the pipes on my bike actually never intersect.
I put the mufflers back on it last night and wrapped them pretty good with duct tape, and the bike ran pretty good (as good as before) for a few laps around the block (couldn't get much more riding though, for fear the mufflers would fall off, and the muffler was blowing the tape off)
is there any way for me to reproduce the same effect of the mufflers with shorter smaller pipe... soemthing like building mini glasspacks? the stock parts aren't relly appropriate for the bike anymore, and it sounds lousy.
say what
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mysta2
- Legendary 300
- Posts: 361
- Joined: Wed Mar 02, 2005 4:23 pm
- Sex: Male
- Location: Little Elm, TX.
I'm trying to track down a new top muffler (the bottom one's pretty good), but I don't think that's going to solve my problem, let me describe it.
After sitting for a day or two, I can start the bike up like it was brand new (starts at three kicks at the most, at will restart after shut down in one or less than a full kick) it will sit and idle wonderfully or I can ride it up the block fine. After 15-20 min the rpm will start to drop off and it might start backfiring slightly. If I give it throttle it will come back up unevenly and not die. I can hold it alive for a bit by goosing it (and maybe make it home if I was bold/stupid enough to go up the block) By this time I've probably re started it a few times and now the idle is really uneven (pulses up and down) and it's definiately starting to backfire now if it wasn't before. Also it will "cough", like the sound of a muffled backfire, but coming from the block/head,airbox instead of the airbox (backfire on the intake side?!). After these symptoms get worse and worse, I reach a point where I can't start it at all, sometimes it will start at WOT, choked, but once I unchoke it and let the throttle out it dies.
None of this changes with the mufflers/air box on or off.
things I've checked:
compression is at 175-177 each, condensor and points are new, according to the marks on the stator the timing is right (haven't checked timing with it running) battery is new and good, I've sprayed carb cleaner anywhere I suspected an air leak without any change in idle. I just rebuilt the carbs. Fuel is new (it's premium though)
I bought this bike with a dead battery at the end of a 6 month park.
Any "right on the nose" answers, vauge theories or anything in between would be greatly appreciated.
thanks, for everyones help so far.
Kit
Oh, and something I keep meaning to bring up. When did the switch to unleadded fuel happen and could that be a possibility?
After sitting for a day or two, I can start the bike up like it was brand new (starts at three kicks at the most, at will restart after shut down in one or less than a full kick) it will sit and idle wonderfully or I can ride it up the block fine. After 15-20 min the rpm will start to drop off and it might start backfiring slightly. If I give it throttle it will come back up unevenly and not die. I can hold it alive for a bit by goosing it (and maybe make it home if I was bold/stupid enough to go up the block) By this time I've probably re started it a few times and now the idle is really uneven (pulses up and down) and it's definiately starting to backfire now if it wasn't before. Also it will "cough", like the sound of a muffled backfire, but coming from the block/head,airbox instead of the airbox (backfire on the intake side?!). After these symptoms get worse and worse, I reach a point where I can't start it at all, sometimes it will start at WOT, choked, but once I unchoke it and let the throttle out it dies.
None of this changes with the mufflers/air box on or off.
things I've checked:
compression is at 175-177 each, condensor and points are new, according to the marks on the stator the timing is right (haven't checked timing with it running) battery is new and good, I've sprayed carb cleaner anywhere I suspected an air leak without any change in idle. I just rebuilt the carbs. Fuel is new (it's premium though)
I bought this bike with a dead battery at the end of a 6 month park.
Any "right on the nose" answers, vauge theories or anything in between would be greatly appreciated.
thanks, for everyones help so far.
Kit
Oh, and something I keep meaning to bring up. When did the switch to unleadded fuel happen and could that be a possibility?
hehe backfire in its true form is out of the intake. afterfire is out of the exhaust.
i doubt its a valve problem since your compression #"S or good. did you check warm and cold numbers with the throttle open?
how long have you had this bike? you said it was fine till now and you havent changed a thing. when it starts to run bad does it seem like its straving for fuel or not getting enough.
so it runs good when cold but once warm it runs bad? did you look inside your carbs? clogged worn parts like needle jet's,float valves,emulsion tubes,etc??
you may also want to check the strength of the spark. a 10$ tester is a good thing to have. its like a spark plug but has an ajustable gap up to 10mm. it should be able to jump 6mm with no problems. just using a plug is not good enough. because its much harder to fire a plug under compression then out in the open air.
how many carbs that that thing have? they could be out of sync.
like i said all these things( even though some may seem minor) need to be in order for a good running bike. and its damn near impossible for me to diagnose it from a keyboard. if i was there i could probally sniff it out in minutes. unless you want to send me the bike
i doubt its a valve problem since your compression #"S or good. did you check warm and cold numbers with the throttle open?
how long have you had this bike? you said it was fine till now and you havent changed a thing. when it starts to run bad does it seem like its straving for fuel or not getting enough.
so it runs good when cold but once warm it runs bad? did you look inside your carbs? clogged worn parts like needle jet's,float valves,emulsion tubes,etc??
you may also want to check the strength of the spark. a 10$ tester is a good thing to have. its like a spark plug but has an ajustable gap up to 10mm. it should be able to jump 6mm with no problems. just using a plug is not good enough. because its much harder to fire a plug under compression then out in the open air.
how many carbs that that thing have? they could be out of sync.
like i said all these things( even though some may seem minor) need to be in order for a good running bike. and its damn near impossible for me to diagnose it from a keyboard. if i was there i could probally sniff it out in minutes. unless you want to send me the bike
say what