Is a mild gx390 faster than a wild 197cc clone

C

Catmac 83

New Member
#1
#1
Well I got a fairly well built clone on my mini. The motor will turn about 8000rpms and has 8.3 gearing. It will walk away from 125 2 stroke dirt bikes off the line. But the motor is always having issues and im always having to work on the thing to keep it running well. I have a gx390 siting on the self, and im ready to take this bike to the next level. I would like to run with 250 2 strokers and have something more reliable and dependable.
Does anyone know if this gx390 in a mild form can run with a 250 2 stroker or am i just dreaming?
 
tundrabeagle3

tundrabeagle3

Member
#2
#2
I think your dreaming no offense I dont think you could keep up with a newer 125 2 stoke even with a gx390. Mine has at least 37 hp revs up to around 13000 rpms and has six gears.It will wheelie through 3rd gear and tops out at least 85mph. 250 strokes have at least 43 hp with a ton more torque. These industrial engines are no comparison to Japanese motocross bike engines.
 
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texasfabguy

texasfabguy

New Member
#3
#3
tundrabeagle3 said:
I think your dreaming no offense I dont think you could keep up with a newer 125 2 stoke even with a gx390. Mine has at least 37 hp revs up to around 13000 rpms and has six gears.It will wheelie through 3rd gear and tops out at least 85mph. 250 strokes have at least 43 hp with a ton more torque. These industrial engines are no comparison to Japanese motocross bike engines.
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Well your in for a big surprise then! :thumbsup:
 
tundrabeagle3

tundrabeagle3

Member
#4
#4
250 two stokes have more than twice the hp power of a modded gx390 , 5 speeds , 13000 rpms bigger wheels and tires, awesome suspension and a crazy powerband.
 
texasfabguy

texasfabguy

New Member
#5
#5
I'm sorry but to many videos to that not true,you can get 50+ HP out of a 390 more out of a stroker big bore and the bike only weights 120#.cr250 weights more. I have been racing sport bikes on mine so I know what can be done...surprised me too.




I'm not against your dirt bike,I owned many including a tricked cr500. But a 4 stroke makes tons of torque.
 
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tundrabeagle3

tundrabeagle3

Member
#6
#6
I have never seen a gx 390 push out 50 hp. It sounds kinda scary on an industrial engine not made for that type of power and would not be cheap. a 450 four stoke pushes out at least 50 hp and could be had for about 2 grand , has a much more balanced frame and plush suspension. I think a mini bike with a big block would be cool for the street but a 450 would be awesome on dirt.
 
texasfabguy

texasfabguy

New Member
#7
#7
tundrabeagle3 said:
I have never seen a gx 390 push out 50 hp. It sounds kinda scary on an industrial engine not made for that type of power and would not be cheap. a 450 four stoke pushes out at least 50 hp and could be had for about 2 grand , has a much more balanced frame and plush suspension. I think a mini bike with a big block would be cool for the street but a 450 would be awesome on dirt.
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Are you comparing apples to walnuts? A trophy truck has a better suspension than any dirt bike and makes 750 HP. But since we are on a mini bike forum lets strict to that.
 
tundrabeagle3

tundrabeagle3

Member
#8
#8
Since hes trying to keep up with motocross bikes I am just letting him know that it will never happen on a mini bike on dirt and probably not on street either. 250 2 strokes are in the 450f class for a reason.
 
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J

jkay

New Member
#13
#13
race

Catmac 83 said:
Well I got a fairly well built clone on my mini. The motor will turn about 8000rpms and has 8.3 gearing. It will walk away from 125 2 stroke dirt bikes off the line. But the motor is always having issues and im always having to work on the thing to keep it running well. I have a gx390 siting on the self, and im ready to take this bike to the next level. I would like to run with 250 2 strokers and have something more reliable and dependable.
Does anyone know if this gx390 in a mild form can run with a 250 2 stroker or am i just dreaming?
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why don't you come out when we get together and run yours against one of my small blocks or mark's(txfabguy) mild bigblock.then you can see where you stand.my small block runs about the same as his mild bigblock pound for pound.my smallblock has more done to it though.how much is done to your smallblock?
 
texasfabguy

texasfabguy

New Member
#15
#15
My boy went down on one tonight racing 1/8th mile big end,he got some really bad case of road rash all over.
Mom says he's done racing:( Bike needs work now too,got some good road rash but have not looked it over yet. Spent 4 hours in the ER last night. Moms pissed at me right now for putting him on mine....:doah:
 
graygoose420

graygoose420

New Member
#16
#16
texasfabguy said:
My boy went down on one tonight racing 1/8th mile big end,he got some really bad case of road rash all over.
Mom says he's done racing:( Bike needs work now too,got some good road rash but have not looked it over yet. Spent 4 hours in the ER last night. Moms pissed at me right now for putting him on mine....:doah:
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Damn! Sorry to hear that . Hope he gets well fast.
 
graygoose420

graygoose420

New Member
#17
#17
tundrabeagle3 said:
I think your dreaming no offense I dont think you could keep up with a newer 125 2 stoke even with a gx390. Mine has at least 37 hp revs up to around 13000 rpms and has six gears.It will wheelie through 3rd gear and tops out at least 85mph. 250 strokes have at least 43 hp with a ton more torque. These industrial engines are no comparison to Japanese motocross bike engines.
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Sorry dude don't underestimate the gx390 or the gx 200 .
Here's a 390 whoopin on 1000cc street bike. Maybe this will prove it.
jds 390 w/home alone beats a 1000 in the 8th!!! - YouTube
 
J

jkay

New Member
#18
#18
texasfabguy said:
My boy went down on one tonight racing 1/8th mile big end,he got some really bad case of road rash all over.
Mom says he's done racing:( Bike needs work now too,got some good road rash but have not looked it over yet. Spent 4 hours in the ER last night. Moms pissed at me right now for putting him on mine....:doah:
Click to expand...
glad he's ok.was he on your purple bigblock bike?gonna have to get him some leathers.
 
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