lost power

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wan37

Member
May 29, 2011
354
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Illinois
I have a 48cc sky hawk it's been running good until I noticed a leak at the exhaust gasket.I put a new gasket and a new stock muffler on and now it lost power from 1/4 throttle to wot it just kind a bogs.So I thought since it had a exhaust leak it would run leaner, so I raised the needle up one notch after I fixed the exhaust leak and it starts better cold but it has no power Thur mid range.I tried to drop it back down and still no power.My question is what should I try to do ? I Need some Idea's.
 
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maniac57

maniac57

Old, Fat, and still faster than you
Oct 8, 2011
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When's the last time you checked the air filter? Due to the reversion of the piston port style engine, the filters seem to get real filthy real fast.
I've seen them come in so dirty the engine would not start.
 
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wan37

Member
May 29, 2011
354
4
18
Illinois
Thank maniac will check the filter but it look really good it's a performance one from sbp. I will pull it off and look inside, and clean it any way.
 
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wan37

Member
May 29, 2011
354
4
18
Illinois
I did to many changes at once. I changed the spark plug gap because the engine was making a clicking at low idle and it helped. Then found the exhaust was leaking so I had another new muffler. I stuck it on then. I started it up and let it warm up but did not ride it.So the next day I rode it and it was the day I posted this thread lost power. I was trying to find what was the problem,which still don't know.I did change the plug gap back but didn't fix it. Maybe I need to adjust the carb because the leaking exhaust now not leaking. I also cleaned air filter.So some idea's would help.
 
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Desert Rat

Desert Rat

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Jul 30, 2012
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Apache Junctoin Az
wan37 said:
I did to many changes at once. I changed the spark plug gap because the engine was making a clicking at low idle and it helped. Then found the exhaust was leaking so I had another new muffler. I stuck it on then. I started it up and let it warm up but did not ride it.So the next day I rode it and it was the day I posted this thread lost power. I was trying to find what was the problem,which still don't know.I did change the plug gap back but didn't fix it. Maybe I need to adjust the carb because the leaking exhaust now not leaking. I also cleaned air filter.So some idea's would help.
Click to expand...
Been there done that! lol what type of carb? maybe it's time to rejet
 
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wan37

Member
May 29, 2011
354
4
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Illinois
nt with a sbp performance air filter.Since I first posted this thread I moved the needle up from the third notch to the second from top but it ran worse so I went back down.It's very strange because plug chop shows that it's running rich at mid range and did one at wot throttle rich too.So lost what to do?
 
Desert Rat

Desert Rat

New Member
Jul 30, 2012
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Apache Junctoin Az
wan37 said:
nt with a sbp performance air filter.Since I first posted this thread I moved the needle up from the third notch to the second from top but it ran worse so I went back down.It's very strange because plug chop shows that it's running rich at mid range and did one at wot throttle rich too.So lost what to do?
Click to expand...

First
if you have the original air filter I would say put it back on and see how it
runs then, get it stable first make changes 1 at a time
and a few pics would help
Second
Since your running a performance air filter it's messing with carb,
I would bring c clip up to notch 1 and see what happens on a short ride,
also how is your throttle cable doing there is some adjustment there
and if you have a sharp corner in it it might be hanging up.
 
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wan37

Member
May 29, 2011
354
4
18
Illinois
I was running the air filter on this engine for a year now and it was running pretty darn good, until I change the exhaust and the spark plug gap. I found the exhaust leak at the top of the exhaust were it is welded to the mounting part. I don't know how to weld or I would just fix that spot. So I order a new one for it just like the older one. It really made it a lot quieter. Now it runs good at idle and really revs good, but as soon as you ride it there's no power and it just bogs when you give it any throttle,it climbs in speed but it takes a long time to get there. Any Idea's would help.
 
Desert Rat

Desert Rat

New Member
Jul 30, 2012
565
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Apache Junctoin Az
wan37 said:
I was running the air filter on this engine for a year now and it was running pretty darn good, until I change the exhaust and the spark plug gap. I found the exhaust leak at the top of the exhaust were it is welded to the mounting part. I don't know how to weld or I would just fix that spot. So I order a new one for it just like the older one. It really made it a lot quieter. Now it runs good at idle and really revs good, but as soon as you ride it there's no power and it just bogs when you give it any throttle,it climbs in speed but it takes a long time to get there. Any Idea's would help.
Click to expand...
sounds like it's still running to rich? and yes you can make one small change
or fix one small problem and then have to start from scratch again tuning it.

I just changed out my exhaust, getting old but no leaks, and just that little alteration and now I'm having to play with the jets and clip to get it back
to running right, what a juggling act it can be sometimes.

Remember I'm pulling for you
we're all in this together LOL :)
 
crassius

crassius

Well-Known Member
Sep 30, 2012
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wan37 said:
I order a new one for it just like the older one. It really made it a lot quieter
Click to expand...
I suspect that it is not 'just like the older one' if it makes it quieter. Try fixing the old one with a bit of JBWeld and see if that helps.
 
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Amarion1

Member
Sep 15, 2012
99
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37
Bellingham WA
I lost all power just like your saying. I went through everything and found nothing wrong. Then I took my muffler apart and tried breathing through the little tube and decided it was choking out my engine. I cut the tube just after the bend and it ran 120% better than before. Then I modified it better later on to give more power and quiet it down :)
 
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wan37

Member
May 29, 2011
354
4
18
Illinois
update I put the old one back on had it at a muffler shop I new a worker there he fix the leak and it's been good now...Wow that little changes makes so much different. Thanks guys..
 
maniac57

maniac57

Old, Fat, and still faster than you
Oct 8, 2011
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memphis Tn
Even if two pipes look the same, if one is quieter, it has more restriction. The insides of these things are likely to very different depending which factory built it and how the guy felt that day when he assembled it.
I've seen some seriously stupid mistakes made by the factory with these engines.
Remember: Chinese quality control is spotty at best with these engine kits. There is no telling what you might find.
 
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wakhoma

New Member
Mar 13, 2013
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hcm
if everything you check ok, maybe your engine' crankshaft oil seals leak (rubber seal at left and right crankshaft cover outside crankshaft bearings), and that worker fixed them for u.
 
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