Complete 70cc Racing Cylinder Big Bore Kit with 10mm Piston Pin for Yamaha JOG Zuma 2 Stroke 50cc Scooter Minarelli 1E40QMB Engine

It's a decent kit if one takes care on assembly. I installed this kit on a very tired 2004 Yamaha Zuma. The power increase was very noticeable. The speed and all around performance are much improved. Not bad for a cheap iron kit. Now to get reliability out of it the cylinder ports must be chamfered or the piston rings WILL snag on the port and ruin the kit. Also no cylinder head is supplied. The stock head can be used but base gaskets might have to be added to get compression lowered. And the carb likely will need a up jet.On my Zuma I had a 70cc head available to use so I didn't have to stack base gaskets. But I had to up jet to a size 80 jet. The stock jet was a size 72. With light variator and clutch mods. And a little better exhaust my scooter runs much faster and better. Top speed around 45mph.i am happy with this kit.

Unless you really, I mean really, know what you are doing with port work, I would leave them be. Not quite Pollini, but for the money, great little cast job. Probably true the exhaust port, and leave the others alone. If you have a 47.6 piston, it won't fit.

Got what I paid for.. The cast still had sand in the ports had to remove and deburr ports... Would have failed if I didn't.. Otherwise a great deal for the price.. Jog 50 runs great... As long as I get through the break in.... I do recommend for the price if you know what to look out for

This product is JUNK. Seriously do not buy this, I put it on my scooter and drove less than 10 miles and it broke. Along with the part breaking it blew pieces all over my crankcase and a big piece wedged in my crankshaft. DO NOT BUY this, it is not a good quality product and it will cost you more money to fix the damage that it cost to repair your scooter than it would to buy a quality product off the bat. Now I have to spend a couple hundred to fix my scooter since I tried to go cheap on this part. REALLY DO NOT BUY, quality parts are going to cost money. Chinese scooter parts are JUNK.

Like other reviewers have said, you really take a risk. I saw someone else say their piston blew apart while running and I believe it. Only after I got the rings on and inserted it into the head did I notice the one piston arm is really pitted. Much deeper than the pictures even show. Thankfully caught it in time.

My scooters fast af now lol thank youu

Good package , cylinder provides decent power , lower revving good torque . Definitely a good upgrade for the money can do 55mph maybe even 60mph with good tuning and a few mods

The cylinder came in good shape but oddly it didn't come with a matching head for the cylinder so now I don't know how I can use it without a head that will work for this unnamed generic cylinder.