I was considering a new project. I was thinking about looking for a GASGAS rolling chassis. Would a CR500 engine or KX500 engine fit in a 2010/2011 GasGas B Frame? I know the motor mounts would have to be moved, down tube may have to be cut, head on the 500 would have to be turned around for the head mount to clear the fuel tank. Has this ever been done?
Will a 500cc Two Stroke Engine fit in an 2011 GasGas Frame
- Thread starter Moto7man
- Start date
nambo-trev
New member
I can see it now... "Why would anyone want to do this???" "What a useless bike that would be!!!" Whatever to that bro I'm with ya I love projects like this that involve some real fabrication challenges. I haven't seen anything like that so I hope you give it a go!
Jakobi
Super Moderator
I'm on the lets make this happen train!
First thing would be getting some measurements and specs for both and then deciding if its feasable and how much work would be involved. I'm guessing you don't want to modify the chasis too much as you'll be looking at retaining the gasser feel just with more grunt!
First thing would be getting some measurements and specs for both and then deciding if its feasable and how much work would be involved. I'm guessing you don't want to modify the chasis too much as you'll be looking at retaining the gasser feel just with more grunt!
GasGas
New member
The GasGas motor was stolen from a late 80's Honda motor. Could go either way. If you want a cheap gasgas rolling chassis, look for a 450 with a lunched motor. That chassis would have more room for the 500 mill. Find a nice one with low hours, U-rims, and the zinc plated frame.
bowhunter007
New member
I'm waaaay on board. What about using the KX500 mainframe & attaching the rear half of a Gasser to it. Shave the mounts for the KX shrouds off the frame, drop in the GG fuel cell...blah, blah, blah
djroggen
New member
Frame is the same on 450 and 2 stroke frames, just the mounts are different. So any bike is the same frame size anyway.
This is where I got the idea. I've been a member for a couple of years.
http://www.kxriders.com/forums/
This would be an additional bike. I want to keep the bike as close to original GasGas as possible. I am considering the KX and CR engines but I think the CR engine is shorter and more compact. I'm going to try to put some numbers together to see if it is feasible. Any input is welcome!
Hell yea! Sounds like a great idea and who cares how well "it works"? Here is my old bike "Trouble". 1040cc, welded lightened crank, 28mm carbs (as she sits here) ran 11:40's with street tires, mufflers and 26 mm carbs. She was fast and I weighed 125 pounds. Drove her 2 years out here on the dirt roads, she was legal, tag under tail fin. Never dropped her in over 30 years. She was built from a bare frame and cases and new pieces for me in 1980. !977 frame. Notice the disc brakes front and rear 
You can never go wrong with more power and craziness!
Ed
You can never go wrong with more power and craziness! Ed
Attachments
+Hell yea! Sounds like a great idea and who cares how well "it works"? Here is my old bike "Trouble". 1040cc, welded lightened crank, 28mm carbs (as she sits here) ran 11:40's with street tires, mufflers and 26 mm carbs. She was fast and I weighed 125 pounds. Drove her 2 years out here on the dirt roads, she was legal, tag under tail fin. Never dropped her in over 30 years. She was built from a bare frame and cases and new pieces for me in 1980. !977 frame. Notice the disc brakes front and rear
Ed
I like it.
i did one a few years ago with a 2004 crf 250 frame , was a good project , but just way too much grunt for me, if its just for fun go for it
Thats a nice bike,,,,yea they have a lot of grunt.....
djroggen
New member
Hell yea! Sounds like a great idea and who cares how well "it works"? Here is my old bike "Trouble". 1040cc, welded lightened crank, 28mm carbs (as she sits here) ran 11:40's with street tires, mufflers and 26 mm carbs. She was fast and I weighed 125 pounds. Drove her 2 years out here on the dirt roads, she was legal, tag under tail fin. Never dropped her in over 30 years. She was built from a bare frame and cases and new pieces for me in 1980. !977 frame. Notice the disc brakes front and rear
Ed
That is an awesome bike!
JP4
New member
Can't wait to see this happen!
A CR500 motor stuffed into any chassis is cool, using a GG is waaaay cool. Who cares if it is at all practical ... just find a wide open space, and grab a handful! Who doesn't love a big-bore 2t?
Damn the AMA/FIM etc. rules, I wish some company would build a 350-400cc 2t MX bike to compete with the 450's.
A CR500 motor stuffed into any chassis is cool, using a GG is waaaay cool. Who cares if it is at all practical ... just find a wide open space, and grab a handful! Who doesn't love a big-bore 2t?
Damn the AMA/FIM etc. rules, I wish some company would build a 350-400cc 2t MX bike to compete with the 450's.
That is a good idea, I know that the 2011 frame is a little smaller.
CACTUSREID
New member
i've done 2 franken-bikes over the last few years.
1st was a 03 kx 250 2t stuffed into a 03 kx125 frame. that one was easy,we just cut and lenghtened out the engine cradle hoop by an inch or so, and fabbed up some new motor mounts.
last winter i did one for my wife. i put her honda crf230 air cooled 4t engine into a crf250r aluminum chassis.we lowered the suspension internally and with a kouba link,and revalved it for trail riding.so she now has the bike that honda should be building for a trailbike
34.5" seat height
good suspension on both ends with adjustability
good disc brakes on both ends
air cooled reliability
weight is 30-40 lbs lighter than the crf230f
oh yah- it's got e-start and a kickstand!
the one tip/trick i learned is to get the countershaft sprocket as close to the same place on the build bike, as it was on the donor bike. but also equally important is the lenght,placement of the shifter on the build bike in relation to the footpegs. you want the shifter to be as close as possible in length as the original build engine was , so it shifts well without being short and notchy/hard to shift, or to long and to long a throw to get from gear to gear.
but go for it, these builds are really cool!
1st was a 03 kx 250 2t stuffed into a 03 kx125 frame. that one was easy,we just cut and lenghtened out the engine cradle hoop by an inch or so, and fabbed up some new motor mounts.
last winter i did one for my wife. i put her honda crf230 air cooled 4t engine into a crf250r aluminum chassis.we lowered the suspension internally and with a kouba link,and revalved it for trail riding.so she now has the bike that honda should be building for a trailbike
34.5" seat height
good suspension on both ends with adjustability
good disc brakes on both ends
air cooled reliability
weight is 30-40 lbs lighter than the crf230f
oh yah- it's got e-start and a kickstand!
the one tip/trick i learned is to get the countershaft sprocket as close to the same place on the build bike, as it was on the donor bike. but also equally important is the lenght,placement of the shifter on the build bike in relation to the footpegs. you want the shifter to be as close as possible in length as the original build engine was , so it shifts well without being short and notchy/hard to shift, or to long and to long a throw to get from gear to gear.
but go for it, these builds are really cool!
