X-80 z-80 engine

SlowBalt

SlowBalt

Member
Just wanted to let everyone know I will only buy these kits in the future.
Both these engines have an improved high compression head with a proper squish band. And also come with an improved aluminum intake that solves the erratic idle that most kits have. both engine kits are identical except for the sprockets. The z comes with a 41 and the x comes with a 44. these kit also has the heavy duty 415 chain.
I've also switched the head and intake from my dead z kit that I roasted over reving it to 55 mph with a 30tooth to an older tired feeling engine and it ran like a beast.

(looking over boy go fasts auctions todat, it apears he's selling a diffrent engine now and still calling it a z-80. Leb still has the good x-80) when looking to buy, look for aluminum cast intake and muffler with a heat shield. I beleave Pirate cycles picked up a container of them.
http://www.piratecycles1.com/66bienkit.html
 
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I just bought a Z80S from bgf is this the same as what your talking about? How long is to long of a run time for these engines? Sellers says 30 min...
 
I'm not shure but I think it's the same just with the small front mount. When you get it take the head off and take a pic of the inside of the head and the intake, and i'll let you know. Also It's always a good idea to pull the head and look for debris befor the first run. With crapy china packing i found a nut in the cilinder one time from all the packing roling around in shiping.
 
SlowBalt said:
Just wanted to let everyone know I will only buy these kits in the future.
Both these engines have an improved high compression head with a proper squish band. And also come with an improved aluminum intake that solves the erratic idle that most kits have. both engine kits are identical except for the sprockets. The z comes with a 41 and the x comes with a 44. these kit also has the heavy duty 415 chain.
I've also switched the head and intake from my dead z kit that I roasted over reving it to 55 mph with a 30tooth to an older tired feeling engine and it ran like a beast.
Click to expand...

Have you actually taken both of your motors apart? The reason I ask is because I bought both a X80 and Z80 motor kit, and I found several distinct differences.

A major difference was the engine blocks. The X80 had a wide 50mm front mount. The Z80 was regular size 40mm. The heads on mine are different.

The crank assemblies were identical, and were the bolt on flyweight type. The cylinders, and pistons were identical.

In this pic the X80 head in on the right, Z80 left. As you can see there's quite a bit of difference.

The sprockets in my kits were the same as you mentioned, and the X80 kit came with the bigger size gas tank.

picture.php


I should also add that the crankshaft in my X80 motor was a lemon that was so out of true, and out of balance, that to motor went south in 500 miles.

The crank in the Z was better true, but still had way bad balance.

The question is, are these findings any different from any other China girl kits? IMO no.
 
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The head on the right is the head that came on both my z and x 80kits. I actualy had the older manic head witch actualy lost compreshion and power compared to the head on the right. I also have the head on the left witch came off one of my older kits i bought off BGF. I think he shiped you one of his older kits by acident. He's ben known to do that from time to time.
 
SlowBalt said:
The head on the right is the head that came on both my z and x 80kits. I actualy had the older manic head witch actualy lost compreshion and power compared to the head on the right. I also have the head on the left witch came off one of my older kits i bought off BGF. I think he shiped you one of his older kits by acident. He's ben known to do that from time to time.
Click to expand...

That wouldn't suprise me at all.

I put 500 miles on my X80 motor before it blew. Performance wise I had no complaints. It ran 37 mph with a 36T and even did 39.8 once.

the motor itself was very noisey right out of the box, and vibrated badly starting about 25 mph. Above 25 the motor started making an imbarrisingly loud squaking noise, that only reduced slightly at even higher speeds.

Even though my crank was lousy, I think everything else was pretty good quality by China Girl standards.
 
SlowBalt said:
The head on the right is the head that came on both my z and x 80kits. I actualy had the older manic head witch actualy lost compreshion and power compared to the head on the right. I also have the head on the left witch came off one of my older kits i bought off BGF. I think he shiped you one of his older kits by acident. He's ben known to do that from time to time.
Click to expand...

What size were your front motor mounts?
 
That's not a z or x engine . The way to spot them is slotted bolts . They don't have Philips heads, also head bolts are 13mm socket on the x-z older are 14mm.
Both mine are large front mount.
 
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Wow these are some fine running engines! 8500 rpm is great out of a basically stock HT. Been considering trying another one. My first experience wasnt great, but figure might be fun to try to build one for longevity. This looks like a great place to start.
 
SlowBalt said:
Just wanted to let everyone know I will only buy these kits in the future.
Both these engines have an improved high compression head with a proper squish band. And also come with an improved aluminum intake that solves the erratic idle that most kits have. both engine kits are identical except for the sprockets. The z comes with a 41 and the x comes with a 44. these kit also has the heavy duty 415 chain.
I've also switched the head and intake from my dead z kit that I roasted over reving it to 55 mph with a 30tooth to an older tired feeling engine and it ran like a beast.
Click to expand...


Do you have a link to these?
 
Like most say its still luck of the draw with these engines. I'm glad to hear that some of you are having good luck with the Z engines. The last 3 I've purchased had major problems- from crank bearings to scored cylinders and the piston slapping the head! I have all 3 z heads sitting in the junk box because they just didnt work. Now on the other hand I've purchased 5 x80bk in the past couple months with great success. My first x80bk I got over 3 years ago and its still running strong with well over 3,000 miles. The old x80's had the longer bent clutch arm and 3 outa 5 I've got recently had the same. You never really know what your gonna get is what I'm trying to say.

Also the last batch of x engines came with a flat sprocket, not the normal chrome dished sprocket. I've had to bevel the teeth on these flat sprockets for proper chain fit- no big deal but now that I know that, its much easier at the bench grinder before installing on the bike.

I never did hear back from Rick Shi at bgf on my z engine problems- 3 emails no response. Kind of strange as he used to be pretty good about that?
 
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