Backfire through airbox?
#1
Backfire through airbox?
I run a stock '01 Hawk. I think it is low on power (it wont power wheelie, even in 1st). However, I live in Denver, at 6000' above sea level, so I know I wont be making the horses you lower elevation guys get.
Occasionally when I blip the throttle, the engine just stumbles, and it backfires through the airbox.
Could this be caused by running too rich, due to the thin air / incorrect jetting? What else could be causing it? Also, anyone else from high altitude have the low power I get, or might it just be my bike needs a trip to the Dr.?
ps.. New to this board.. I'm Justin.. this is my 6th bike, and the best so far. Glad to meet you guys.
Occasionally when I blip the throttle, the engine just stumbles, and it backfires through the airbox.
Could this be caused by running too rich, due to the thin air / incorrect jetting? What else could be causing it? Also, anyone else from high altitude have the low power I get, or might it just be my bike needs a trip to the Dr.?
ps.. New to this board.. I'm Justin.. this is my 6th bike, and the best so far. Glad to meet you guys.
Last edited by punkwood2k; 09-10-2009 at 12:09 PM.
#3
When cars had carburetors GM made high altitude models for the Denver/Rocky Mountain area. I don't think Honda did that with their motorcycles. Carbureted vehicles run richer at altitude, and the stock Superhawk runs lean. I know that my VTR which before shimming the needles would sometimes stall at almost every stop light and surge and pop at low speeds while near sea level, but would run GREAT above 2,000 and up to 6,000 feet in the mountains. Not a single burp.
So unless you are well versed in carb work, a trip to a good shop that knows carbs should solve your problems.
Also some members have had problems with TPS adjustment or failure. That could be the problem as well, and relatively easy to fix. You just need an ohmmeter. Do a search under "TPS adjustment".
So unless you are well versed in carb work, a trip to a good shop that knows carbs should solve your problems.
Also some members have had problems with TPS adjustment or failure. That could be the problem as well, and relatively easy to fix. You just need an ohmmeter. Do a search under "TPS adjustment".
#4
When I bought mine new the dealership jetted it for 6000ish feet (whatever their height was). The thing has run as good as I think it can, I really have to hold on in first gear to NOT get it to wheelie. I'm good keeping both wheels on the ground =)
Up around 13k it backfires like crazy if I downshift, but otherwise it runs great! I'm all stock except for 6x 1/4inch holes drilled in the back of each exhaust pipe (partial bafflectomy?)
Edit: Welcome to what I think is the most fun mountain twisty bike Justin!
Up around 13k it backfires like crazy if I downshift, but otherwise it runs great! I'm all stock except for 6x 1/4inch holes drilled in the back of each exhaust pipe (partial bafflectomy?)
Edit: Welcome to what I think is the most fun mountain twisty bike Justin!
#7
When I bought mine new the dealership jetted it for 6000ish feet (whatever their height was). The thing has run as good as I think it can, I really have to hold on in first gear to NOT get it to wheelie. I'm good keeping both wheels on the ground =)
Up around 13k it backfires like crazy if I downshift, but otherwise it runs great! I'm all stock except for 6x 1/4inch holes drilled in the back of each exhaust pipe (partial bafflectomy?)
Edit: Welcome to what I think is the most fun mountain twisty bike Justin!
Up around 13k it backfires like crazy if I downshift, but otherwise it runs great! I'm all stock except for 6x 1/4inch holes drilled in the back of each exhaust pipe (partial bafflectomy?)
Edit: Welcome to what I think is the most fun mountain twisty bike Justin!
Last edited by nath981; 09-11-2009 at 09:57 PM.
#8
13k FEET This may not be an inline 4, but it IS Colorado! And yeah, mine makes all KINDS of racket (exhaust) when engine braking coming down from about 9k RPM's. Backfired a couple times and the guy in front of me on his inline 4 was looking down at his bike! We had a good laugh later =)
#10
#11
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#12
13k FEET This may not be an inline 4, but it IS Colorado! And yeah, mine makes all KINDS of racket (exhaust) when engine braking coming down from about 9k RPM's. Backfired a couple times and the guy in front of me on his inline 4 was looking down at his bike! We had a good laugh later =)
#13
13k FEET This may not be an inline 4, but it IS Colorado! And yeah, mine makes all KINDS of racket (exhaust) when engine braking coming down from about 9k RPM's. Backfired a couple times and the guy in front of me on his inline 4 was looking down at his bike! We had a good laugh later =)
#14
my buddy can attest to the flame... he thought it was going to catch his bike aflame... I have had some strange "anticipation" backfires coming from the carbs on occasion. Just enough to startle you, rich right?
#15
You need to rejet for higher altitude. Start with adjusting the mixture screws in 1/4 turn. You may want to consider smaller main jets too. Above all, get the carbs syncronized. That may help the majority of your problem.
#16
My exhaust pops when I close the throttle too. I like it though.. Sounds like my old Two Brothers pipes.
#18
The PAIR system.. I've read the threads about removing it, a relic of CA emissions, right? Does removing it have any benefits besides a couple ounces of weight savings?
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