BGF engine trouble?

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bluenosegoat

New Member
Dec 29, 2009
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arizona
I have purchased many engine kits from BGF in the past few years but the last two are giving me serious engine troubles. Wondering if any of you out there have had the same issues? Z280 and a Z80.
1. The set screw for the flower nut on the clutch ground into the clutch cover at start up! Terrible noise to say the least. Ended up the clutch gear was not tightened up properly and I needed to add another gasket- not to major.
2. Once the engines are warmed up the piston sounds like it hits the cylinder head at near full rpm. These two engines have a different head on them. This is the first time I've seen them. Very shallow combustion chamber and the spark plug is way up inside. On the first engine I just swaped heads to a pk80 style and problem gone. On the engine I'm working with now the engine is making a clicking sound? I've changed the heads back and forth, tried thicker base gaskets, swaped intakes and carbs to see if it was a vacuum leak but with all the messing around it still clicks and just flat out refuses to idle. Just touching the idle adjustment screw sends the idle rpm high then it dies. I was sure it was a vacuum leak but I've changed everything and the problem is still there.
I have sent BGF a message via ebay but I'm just stumped as to what the problem is? Just a bummer because I really need to get this bike running right for a customer. Any sugestions or similar experience with these kits would be much appreciated. I believe these kits are the Z80 what ever that is supposed to mean and the one I just swapped the head on to remedy the problem was a Z280.
 

bluenosegoat

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Dec 29, 2009
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I thought that might be it also. I've tried different gaps-different plugs and wires but still nothing.
After taking the engine apart again I noticed a small scratch just above the exhaust port on the cylinder wall. The rings seem unaffected though. I removed the piston so I could turn the engine over with a drill so the noise is definately in the top end. I was able to smooth out the scratch a bit and the clicking seems less but the bike still will not idle decently. The engine runs really well when riding (minus the slight clicking) so I am just stumped as to what the idle situation is. Hopefully BGF will kick me a cylinder, or a good deal on a replacement engine.
Here is a pic of the little scratch and the clutch cover. I know these engines are just slaped together but they used to be test run at the factory. The last 6 or 7 engines I've purchased were never ran at all at the factory (even 3 seconds will leave a trace) so I'm getting pretty disapointed in the recent China girls. I love the challenge but I've spent 3-4 days messing with this engine and got virtually no where.:-||
 

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bluenosegoat

New Member
Dec 29, 2009
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So the first of the "z" motors has come back to me from a customer. The engine was running perfectly for her on a very nice old school chromoly shcwinn mt bike until it just locked up. After a complete tear down I found the crank bearing on the mag side destroyed and it took the seal with it. Now I have x80 engines with thousands of miles on them and no problems. I'm a bit upset with Rick Shi's lack of response. 5 emails in 5 weeks and still no reply. These new super cheap "Z" motors aren't worth the box they come in imo. The mag side bearing is garbage and the clutch side (left) feels a little gritty. I saved my first 49cc engine for parts-I knew it would come in handy some day! Just a bit frustrated with these "Z" engines- never again.
 

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biknut

Well-Known Member
Sep 28, 2010
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Dallas
I'm kind of a fan of these motors, but I've learned the hard way you need to disassemble the whole motor, and carefully assemble it.

I had a X80A from LEB that failed at 500 miles. After that I bought a T80, and a Z80 from BGF. I took both motors apart, and found several problems needing attention. After careful assembly with some higher quality bearings the T80 is the quietest running motor I've had so far.
 

bluenosegoat

New Member
Dec 29, 2009
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I'm kind of a fan of these motors, but I've learned the hard way you need to disassemble the whole motor, and carefully assemble it.

I had a X80A from LEB that failed at 500 miles. After that I bought a T80, and a Z80 from BGF. I took both motors apart, and found several problems needing attention. After careful assembly with some higher quality bearings the T80 is the quietest running motor I've had so far.
Good to know, I've been curious about the T engines. I guess I've gotten so used to the x80's I've bought in the past- just mount em up and go. I've built over 20 bikes with the x80 and not one has failed in the past 3 years. Maybe that was just luck. My "luck" with these Z motors is 3 outa 3 suck! It wouldnt be that bad if I was building for myself but when time is money the z motors take any profit I might make and a failure like this bearing puts my customer out of a ride. I found on the forum a good source for bearings so I guess I should just stock up on some bearings and make engine tear down part of the build. I hate having a bike come back to me. Other than the lack of communication concerning my issues BGF is still my favorite vendor- fastest shipping and the price is right.
 

biknut

Well-Known Member
Sep 28, 2010
6,631
409
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Dallas
Good to know, I've been curious about the T engines. I guess I've gotten so used to the x80's I've bought in the past- just mount em up and go. I've built over 20 bikes with the x80 and not one has failed in the past 3 years. Maybe that was just luck. My "luck" with these Z motors is 3 outa 3 suck! It wouldnt be that bad if I was building for myself but when time is money the z motors take any profit I might make and a failure like this bearing puts my customer out of a ride. I found on the forum a good source for bearings so I guess I should just stock up on some bearings and make engine tear down part of the build. I hate having a bike come back to me. Other than the lack of communication concerning my issues BGF is still my favorite vendor- fastest shipping and the price is right.
My Z motor had poor quality bearing too. i removed them, never used, and they felt notchy like they had square rollers of something.

There's only minor differences between the T, X, and Z motors. All the internal parts are the same, but the Z motor seemed to have different brand bearings from the X, and T. I noticed the T, and Z motors have the same crappy head, with poorly shaped combustion chamber. The one on the X looked a little better. The T, and X both have bigger block front motor mounts. The Z has the smaller size front motor mount. Those are the only differences I saw, except the X80A was painted silver.

All three motors have the same crankshaft assembly with 2 piece flywheels.
 

moonerdizzle

New Member
Jun 28, 2009
874
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Cheese head capitol
So the first of the "z" motors has come back to me from a customer. The engine was running perfectly for her on a very nice old school chromoly shcwinn mt bike until it just locked up. After a complete tear down I found the crank bearing on the mag side destroyed and it took the seal with it. Now I have x80 engines with thousands of miles on them and no problems. I'm a bit upset with Rick Shi's lack of response. 5 emails in 5 weeks and still no reply. These new super cheap "Z" motors aren't worth the box they come in imo. The mag side bearing is garbage and the clutch side (left) feels a little gritty. I saved my first 49cc engine for parts-I knew it would come in handy some day! Just a bit frustrated with these "Z" engines- never again.

My mag side bearing grenaded with only 25 miles on the motor. It was a rico group motor from BGF
 

Al.Fisherman

New Member
Sep 9, 2009
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Calera, Alabama
My mag side bearing grenaded with only 25 miles on the motor. It was a rico group motor from BGF
It's not the brand of kit you buy, it is the LACK of quality control in ALL kits and the junk parts that the Chinese make. I find that the better bearings made in the U.S., or Japan made bearings are so much superior. Keep in mind that a bearing "Made in the U.S." doesn't necessary mean that the components are also all made in the U.S. Many manufactures buy components from overseas and build the bearing in the U.S.
 
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moonerdizzle

New Member
Jun 28, 2009
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Cheese head capitol
Thats what my guess was Al. I ran into the same problems with china bearings on my gocart wheels. kept popping on me so I sprung the extra bucks for some jap bearings. Them are still running strong after 2 years
 

bluenosegoat

New Member
Dec 29, 2009
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arizona
I could not get any of the heads off the z motors to work. I ended up swapping for the heads that come with the x motors. This is the link I found in Norms section here on the forum for bearings. Hydraulic Cylinder Components, Products Seems like a good place to get the 6202 for cheap compared to the companies that advertise on this forum. While I was in this z engine I found all the 6202 bearings (clutch and crank) were notchy. Replaced with bearings from an old engine and it runs like a champ again. To me the extra cost of a x motor far out weighs the troubles with the z motors from BGF. The X engine on my daily rider now has over 3000 miles and I have not had one single issue.