Rebuilding The Rotax 399cc

[KartFab]

rushking, i saw that video on instabam nice!

 

[rushking19]

rushking, i saw that video on instabam nice!

thats great thanks for watching

 

[rushking19]

Hey your lucky i found sand in my engine and had to go through all three cylinders to clean them out .I got lucky the sand was really fine dust like what you would find in a house . when i opened the head antifreeze flooded the 3 cylinders .I also had to clean that out and after cleaning all the mud dust in the engine i poured more antifreeze in it and carb cleaner in the intakes and vroom vroom sounds like 2 250 two stroke dirt bikes smokes bad though could just be the old crud burning off .Cylinders where still smooth like a babies butt lol no scratch marks i got lucky all of it built up on the top of the head.
https://www.youtube.com/watch?v=oHDx-Fj56eo

Awesome Video And The Engine Sounds Amazing, BTW What Do You Plan On Putting It On

 

[BirdFanatic]

Awesome Video And The Engine Sounds Amazing, BTW What Do You Plan On Putting It On

the engine has about 100 HP i cant put it on a yard kart in less i want to throw nice chunks of metal all over the place lol . So here in california we have sand rails so i thought hmm this would be a cheaper more powerful toy for someone then a Volkswagen a Volkswagen 1600cc has about 32 hp granted its 4 stroke and lasts longer but if your going to be climbing dunes you need power not reliability so i thought of selling it to someone who wants a much cheaper form of power .If i ever cant sell it maybe i will find a sand rail body find some tires put the engine in it and go .
https://www.youtube.com/watch?v=TRhAMdgHNsk
https://www.youtube.com/watch?v=d6rmdM6dixc
On another note i found thoughs K and N air filters from the kt-100s i have had they fit great maybe make a little more power.

 

[rushking19]

the engine has about 100 HP i cant put it on a yard kart in less i want to throw nice chunks of metal all over the place lol . So here in california we have sand rails so i thought hmm this would be a cheaper more powerful toy for someone then a Volkswagen a Volkswagen 1600cc has about 32 hp granted its 4 stroke and lasts longer but if your going to be climbing dunes you need power not reliability so i thought of selling it to someone who wants a much cheaper form of power .If i ever cant sell it maybe i will find a sand rail body find some tires put the engine in it and go .
https://www.youtube.com/watch?v=TRhAMdgHNsk
https://www.youtube.com/watch?v=d6rmdM6dixc
On another note i found thoughs K and N air filters from the kt-100s i have had they fit great maybe make a little more power.

True Well That's Nice Someone Put One Of Those On A Mini Bike
https://m.youtube.com/watch?v=DAUUEEFo5Tw
And On A Go Kart
https://m.youtube.com/watch?v=ZKLaBisv6YE

 

[BirdFanatic]

True Well That's Nice Someone Put One Of Those On A Mini Bike
https://m.youtube.com/watch?v=DAUUEEFo5Tw
And On A Go Kart
https://m.youtube.com/watch?v=ZKLaBisv6YE

wow what moronic ideas these people come up with all they can think about is going fast not about hurting yourself and possibly others . the formula kart looks to be well built but a mini ike thats like strapping a yamaha r1 to a tag kart and saying ok lets go what ignorance .I know this forum is about DIY but its also about keeping safety in mind .

 

[rushking19]

wow what moronic ideas these people come up with all they can think about is going fast not about hurting yourself and possibly others . the formula kart looks to be well built but a mini ike thats like strapping a yamaha r1 to a tag kart and saying ok lets go what ignorance .I know this forum is about DIY but its also about keeping safety in mind .

Exactly I would not dear to ride the mini bike it's like strapping a leaf to a 120 or more HP engine, and like you said I would definitely ride the go kart it looks well built and strong and has some weight to it so it will stick to the ground and had amazing disk brakes for great stopping

 

[BirdFanatic]

Exactly I would not dear to ride the mini bike it's like strapping a leaf to a 120 or more HP engine, and like you said I would definitely ride the go kart it looks well built and strong and has some weight to it so it will stick to the ground and had amazing disk brakes for great stopping

Lol i found out that what i found to be a brownish mud looking liquid on the top of the head and inside the engine cylinder was actually very old oil that was in the exhaust and got into the engine again and then built up on the top of the head.Because some idiot put the exhaust manifold on upside down making it look like a u instead of like a n because the down slope of the manifold keeps crap from getting back in well if its upside down all the stuff just flows back into the engine after the piston goes down .Pressure check all my cylinders there at 120 Psi all three

 

[rushking19]

Lol i found out that what i found to be a brownish mud looking liquid on the top of the head and inside the engine cylinder was actually very old oil that was in the exhaust and got into the engine again and then built up on the top of the head.Because some idiot put the exhaust manifold on upside down making it look like a u instead of like a n because the down slope of the manifold keeps crap from getting back in well if its upside down all the stuff just flows back into the engine after the piston goes down .Pressure check all my cylinders there at 120 Psi all three

That's great that you found the problem

 

[rushking19]

Got The New Piston And Cylinder In The Mail Today Just A Few More Parts To Get It Running And That's Going To Be Soon ,

 

[rushking19]

My Question Is Do I Have To Replace These Piston Rings On This Slightly Used Piston And Cylinder, And The Cylinder Kinda Looks Like It Was Honed Already Because It Still Has The Cross Hatch Pattern

 

[firemanjim]

I would replace it since you're already there..... You could end up with 120psi in one hole and 95psi in the other....... Best to do both....Imo....

 

[rushking19]

I would replace it since you're already there..... You could end up with 120psi in one hole and 95psi in the other....... Best to do both....Imo....

True and it's just 24 dollars for 2

 

[rushking19]

Soon as rebuild the motor I'm going to start another thread called Project Rocket Kart #2