Lack of power and speed can anyone help?

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KoolBreeze420

Member
Jan 2, 2014
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What was the old plug?
What is the new plug?
Is it a slant head or a straight head?
The spark plugs are the same, I have the GRUBEE SkyHawk GT5A 66cc Angle Fire Slant Head Bike Motor Kit.
The markings on the plug are LD Z4JC it's a 3 prong.
 
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KoolBreeze420

Member
Jan 2, 2014
66
0
6
Midland
Update: New muffler installed and all issues have been corrected the bike is running great both at low and high speeds no hesitation nothing, I still don't think she goes as fast as others report but she got to 50 kmh on a straight run. It also still needs to be broke in so I only did a quick speed test. They didn't have the black muffler with the heat shield so he sent me what they call a Short Potato Exhaust. I love the looks of this muffler and it looks like you could take this one apart and clean it if it were to get plugged.
I am still very interested into what happened and what caused the plug to pop.
 
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KoolBreeze420

Member
Jan 2, 2014
66
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Midland
Have you tried to clear the blockage in that muffler? Just curious as to what is/was causing it to be blocked. The only other thing that came to mind for me would be if the top of the piston connected with the bottom of the plug and "kicked" it out, but you'd see signs of it (impact damage on the piston) when you pulled the head off.
I have Googled and have not found any instructions on how to clear a plugged exhaust except for a torch and air which I have no access to. I would love to know why it is plugged so badly that not even water can penetrate through it especially on just a few rides.
I would like to unplug it having a spare exhaust could be helpful in the future any suggestions?
 

KCvale

Well-Known Member
Feb 28, 2010
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Phoenix,AZ
The spark plugs are the same, I have the GRUBEE SkyHawk GT5A 66cc Angle Fire Slant Head Bike Motor Kit.
The markings on the plug are LD Z4JC it's a 3 prong.
I've built at least MB's with the GT5, the only thing that makes any sense is the plug worked it's way loose and it just popped that last thread or two.

It is no doubt a slant head and it's not like it's hard to tell, either the spark plug sticks straight up from the head or it slants.
Not you can reverse a slat head so the plug slants forward, I do this on all mine as I like the CDI above the exhaust on the front downbar.

If you want a touch more power this is the best $6.50 you'll ever spend.
An Iridium spark plug, beats the pants off those tri-fire things.

http://www.sickbikeparts.com/catalog/product_info.php?products_id=111

Glad to hear your running.
 

CTripps

Active Member
Aug 22, 2011
1,310
1
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Vancouver, B.C.
I have Googled and have not found any instructions on how to clear a plugged exhaust except for a torch and air which I have no access to. I would love to know why it is plugged so badly that not even water can penetrate through it especially on just a few rides.
I would like to unplug it having a spare exhaust could be helpful in the future any suggestions?
If it's a gunk-based blockage, brake cleaner is good stuff. I rinse pipes out with it whenever they're off the bikes, and use it as a parts rinse/cleaner other times. Is it one of the pipes with a nut on the end, so you can pull it apart? I've had a few different pipes apart. They vary a little in assembly, but are pretty similar things. The 'catalytic converter' segment inside that many have is pretty easy to clog. Basically, it's a strip of corrugated metal that is then rolled up and then the exhaust has to pass through the (top to bottom) gaps in the roll. Most of those gaps are pretty tight, I imagine gunk deposits or maybe corrosion have closed those spaces. Could even be due to poor assembly, Quality Control isn't a big buzzword where these come from. Many mufflers also have poorly drilled holes in the internal pipe just past the CC, full of metal waste and debris, which can lead to faster clogging.
 

KoolBreeze420

Member
Jan 2, 2014
66
0
6
Midland
If it's a gunk-based blockage, brake cleaner is good stuff. I rinse pipes out with it whenever they're off the bikes, and use it as a parts rinse/cleaner other times. Is it one of the pipes with a nut on the end, so you can pull it apart? I've had a few different pipes apart. They vary a little in assembly, but are pretty similar things. The 'catalytic converter' segment inside that many have is pretty easy to clog. Basically, it's a strip of corrugated metal that is then rolled up and then the exhaust has to pass through the (top to bottom) gaps in the roll. Most of those gaps are pretty tight, I imagine gunk deposits or maybe corrosion have closed those spaces. Could even be due to poor assembly, Quality Control isn't a big buzzword where these come from. Many mufflers also have poorly drilled holes in the internal pipe just past the CC, full of metal waste and debris, which can lead to faster clogging.
Yes it has a nut on the end I took it off then further up is a disk with holes in it then you can see the rolled up metal, I am unable to move that disk. I am positive the muffler came to me defective it is brand new and only has a few short rides on it. If it has an actual physical plug then no solvent will work, and I bet it is physical since it basically came that way and riding probably just wedged it tighter, I honestly don't know but if I could remove that disk and get the metal out then maybe I could get it working again.

The new muffler is working amazingly and this one has a nut on either side of the caps. I haven't taken the caps off, but I removed the nuts to add loctight but I am sure that this one can be maintained and unclogged somehow maybe even repacked or something. I am going to have to pull the caps off to find out more but I won't do that until I run into an issue.
 

KoolBreeze420

Member
Jan 2, 2014
66
0
6
Midland
I've built at least MB's with the GT5, the only thing that makes any sense is the plug worked it's way loose and it just popped that last thread or two.

It is no doubt a slant head and it's not like it's hard to tell, either the spark plug sticks straight up from the head or it slants.
Not you can reverse a slat head so the plug slants forward, I do this on all mine as I like the CDI above the exhaust on the front downbar.

If you want a touch more power this is the best $6.50 you'll ever spend.
An Iridium spark plug, beats the pants off those tri-fire things.

http://www.sickbikeparts.com/catalog/product_info.php?products_id=111

Glad to hear your running.
I would like more hill climbing power more then speed, I live in area surrounded by mega hills. I will have to try and find that plug elsewhere I won't buy from there, becasue shipping is to expensive example that plug is $9.00 shipping, It doesn't even weight that much, heavier parts would cost me a fortune. I think I found the same plug on ebay I would have to buy 4 but it's free shipping making each plug about $5.50. I need to translate it but I believe the description gives the part number and the X4 is for 4 of them I will email them to be sure but if these are the same this is likely the way I would go about it.
it reads NGK Kupferkern Zündkerze BPR8ES (3923) X4
http://www.ebay.ca/itm/NGK-Kupferke...402865244?pt=DE_Autoteile&hash=item4ad51a865c
 
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KoolBreeze420

Member
Jan 2, 2014
66
0
6
Midland
I have a question about my new short muffler if anyone can advise great



I was wondering if it would be ok to open the slits on the top and bottom of the inside cage thing a little more, The picture is showing what is inside it's kind weird but it's all metal and has these slits that could easily be opened or closed, as you can see in the picture they are running vertically up towards the bolt, so I was wondering if I opened them if it would increase power at all or do they need to be left in the nearly closed position any opinions??
 

CTripps

Active Member
Aug 22, 2011
1,310
1
38
Vancouver, B.C.
I'd go over all the openings in it with a set of files or a rotary tool and make sure they're all nice and neat, with no left over burrs or crap around the holes first. Make sure you do a good clean-out afterwards so there's no flecks of debris for the engine to pull back into itself.