Idles GREAT. Accelerates GREAT. But when I let go of the throttle after accelerating (right before shifting) it backfires. Not like those LOUD gunfire types of BF but more like some sputtering. Any ideas?
(Simulation):
1st - wwwwaaaaaaAAAAAA..... ... .... ..... .
2nd - wwwwaaaaaaAAAAAAAA.... ...... ..... ..
3rd - wwwwwwaaaaaaaAAAAAAA... .... .... ....
The gaps in the periods are the sputters.
2007-06-27 14:40:31 · 9 answers · asked by Jason V 3 in Cars & Transportation ➔ Motorcycles
1990 Vulcan 750
2007-06-27 15:24:56 · update #1
A little rich in the jetting ? If so it's OK but you can go faster if you're spot on. Don't go lean BC you'll overheat.
2007-06-27 17:52:36 · answer #1 · answered by Jimbob 4 · 0⤊ 0⤋
I'm not sure what the simulations all about. Makes it sound like the bike is loosing power toward the top of the power band. Like it's running out of fuel.
If the problem is just a little popping when you back off the throttle my suggestions would be to check your intake and exhaust. The intake can be checked by spraying some WD 40 at the back of the carb. where it meets the intake manifold and then where the intake meets the head. With the bike running at an idle if you're sucking air at these spots you should hear the idle pick up a little when you spray the WD 40.
For the exhaust you just need to listen and feel around the exhaust collar at the head where your pipes bolt up.
If I'm right about the simulation you might start with a new air filter. Other than that you could be looking at anything from carburetor problem to a flat cam. You don't state what the bike is or how old. If it's old enough might be points or something else electrical.
2007-06-27 23:46:29 · answer #2 · answered by puttndutchman 3 · 0⤊ 2⤋
When you fitted non standard exhaust to make it louder, did you change the jetting?
Thought not.
Don't believe the hype that you don't need to change anything but the pipe. These sales guys work on commission from sales, not commission from workshop. They are also afraid you wont buy stuff if the fitting costs are too high.
You need to check for air leaks and possible spring about $180 for a Dynojet jet kit
2007-06-28 12:27:44 · answer #3 · answered by 1crazypj 5 · 1⤊ 1⤋
Usually a lean condition causes the following noises:
1st-wwwwuuuhhhAAAHHHooooOOOOAAaawwEEEhhoo
2nd-bbbbblllAAAGGHHHeeeYYiiiippppeeeddddddddddooo
3rd-FFFLLLUUggghhhpppssssBBBRRRRMMM
4th-hhmmmm....... ....... ****** """""" gggaaaahhhhh
the asterixes indicate a hollow rattle that may be caused by a loose bracket contacting the cam cover. The quotation marks are more of a high pitched sound, a cross between a buzz and a "ting."
2007-06-28 03:12:48 · answer #4 · answered by Deckard2020 5 · 1⤊ 0⤋
Always give year, make, engine size and model # when asking questions. We need all of that info to give an informed answer.
A lean mixture will cause a backfire on deceleration.
Check for an air leak between the carb and engine.
Contact me for a carb troubleshooting guide.
It will help to decipher the problem.
2007-06-27 21:46:20 · answer #5 · answered by guardrailjim 7 · 1⤊ 2⤋
Lol, sounds like an exaust leak, check your gaskets, bolts, and muffler.
2007-06-27 21:43:59 · answer #6 · answered by arcangel2271 3 · 3⤊ 1⤋
Running a little lean
2007-06-27 23:11:52 · answer #7 · answered by Charles s 4 · 0⤊ 3⤋
Sounds like carbs to me.....
2007-06-28 07:26:17 · answer #8 · answered by uniquelyhd 1 · 0⤊ 0⤋
check your plugs and wires thats my only suggestion. that 's what caused my car to do that
2007-06-27 21:46:16 · answer #9 · answered by hpyfthr 1 · 0⤊ 3⤋