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Post by bluesi808 on Jan 16, 2012 15:59:11 GMT -5
So today I went for a max speed run, I had my china speedo up to 55mph and my gps up to 52mph, then I heard a loud pop similar to a soft fire cracker, then I quickly let off the throttle, hen it started making softer popping sounds about 5 of them in quick succession, I'm wondering what it was. Anyone ever experience that before? I rode it pretty aggressively after that for about a mile and here was no power loss. Could it be backfire?
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vvtr
Scoot Enthusiast
Posts: 243
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Post by vvtr on Jan 16, 2012 16:17:43 GMT -5
yeh i think you should check the plug.. maybe a bit of carbon and theres a lot of unburnt fuel in the exhaust.... or could be the exhaust is not scavenging fuel back into the cylinder.... like this:  notice how the (green) fresh charge is blown out then pushed back in by the expanding hot exhaust gas in the expansion chamber??? that's what the expansion chamber is for, otherwise you'd just have a pipe like 4t. could be nothing at all, but if its backfiring at peak rpm & power, there are gains to be had by stopping it happening!!! you could be throwing fuel (and power) away!!! ask someone to ride behind you and see if they can smell unburnt fuel... if this is the case and everything else is ok, then maybe you could increase the exhaust duration a bit by raising the port a little to allow it to scavenge better at high rpm..... and also may be worth looking at the design & shape of your exhaust by comparing it against the ideal shape from that expansion chamber design software... dont be fooled into just buying an expensive exhaust though... some are rubbish! |
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Post by bluesi808 on Jan 16, 2012 16:48:14 GMT -5
Ah, that makes sense my rx7 used to do the same thing but it actually shot 3-4 ft of flames, cause it was too rich, the shop did readjust my jets on sat, and so far in the last couple of days I noticed my mpg a lot lower. I thought it was do to the acceleration, even though im not on wot as much now. I'm relieved
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Post by bluesi808 on Jan 16, 2012 16:52:44 GMT -5
Do u think adding a outer/inner ignition system might also fix the issue. I have a zxr leo Vince and it's practically new so i don't really want to but a new exhaust just yet, I may ask the shop to derestrict my pipe.
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vvtr
Scoot Enthusiast
Posts: 243
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Post by vvtr on Jan 16, 2012 16:56:37 GMT -5
have a look for the obvious first.... is the plug black / wet... do you still have the oem ignition coil? (theyre crap lol!) i honestly wouldnt know if changing the ignition woud help m8.... im sure the guy in the shop will tell you it will, and it will get you laid, and rich.... :s *did it do the poppng when you knocked the throttle off?  if so it could be drawing air into the exhaust somewhere... possibly from re-using an old exhaust manifold gasket? |
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Post by bluesi808 on Jan 16, 2012 18:18:19 GMT -5
I was on full throttle and it made a loud pop, then i quickly pulled my hand off the throttle and it popped about 5 times but it was a little softer sounding, do u have to remove the pipe to get to any transmission parts or to tune the carb? Cause I bought everything new, with all new gaskets. But if they did have to remove the pipe to get to the carb or any trans part then they may have reused some gaskets. I have a stock airbox with 17.5dellorto.
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vvtr
Scoot Enthusiast
Posts: 243
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Post by vvtr on Jan 16, 2012 18:29:35 GMT -5
er i would guess the cvt cover is on the left and the exhaust on the right, as per normal....
if someone else has done the job, you can't be 100% certain it has been done properly.
as you can guess i am a major advocate for DIY!
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Post by bluesi808 on Jan 16, 2012 19:48:23 GMT -5
That true it's just I have no where to work n my scooter, I live in a condo so they are pretty strict. They did retune the carb and I have no idea where it is or how to get to so I'm not sure if they had to remove the pipe
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Post by jmkjr72 on Jan 18, 2012 15:34:49 GMT -5
if you have a leo pipe ment for the us market there isnt a resricter on it
sure you can pull the baffel outof the pipe but when you crunch the numbers you need to adjust the head pipe to get anything out of it
like was said try replacing the coil and the plug if it still happens then move onto replacing the reeds
and if you have oem stamped steel reeds i would do that first they make a mess of things when they fail
get some good carbon fiber ones
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Post by bluesi808 on Jan 18, 2012 17:17:43 GMT -5
What's a coil? I'm taking my scooter in this weekend to install the stage 6 quick throttle, so I'll have them change the spark plug again. I already have an iridium ngk I put in 400 miles ago. I'm waiting on the stage6 reed cage with cf reeds cause they don't have it in stock right now
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Post by bluesi808 on Jan 19, 2012 3:23:36 GMT -5
Ok so i did some research and schooled myself on what a coil is. So what brand of spark plug wire are you guys using? I was thinking of the ncy high performance wire.
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Post by 90GTVert on Jan 19, 2012 8:17:51 GMT -5
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Post by jmkjr72 on Jan 19, 2012 19:01:04 GMT -5
i do not care for the nology hot wire and doubt the claims that they make about increase in power
plus you cant run a resistor plug with a hot wire
i was doing a tune up for a guy who put one on put it away for the winter and spring it wouldnt run right well he thought a dirty carb and paid me for a carb clean and tune up
i clean the carb and put a fresh bpr7hs in as it was a stock scoot and it still wouldnt run right
till i realized it had a hot wire and tracked down a bp7hs and away she went good as new
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Post by scootpootjim on Jan 28, 2012 19:11:33 GMT -5
My scoot has done that twice. It made a very loud pop and then shut off. It cranked back up and ran like normal. I would say that I was running a little rich on fuel and not enough on oil. I adjusted my oil pump setting to a more suitable ratio.
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