Dax gp50 9hp wow !!

GoldenMotor.com

2door

Moderator
Staff member
Sep 15, 2008
16,302
175
63
Littleton, Colorado
Duane,
I think you need some comprehensive field testing on that engine. In fact, my new Captain America chopper would be a perfect candidate. Just drop one by the house and I'll get it mounted up and start testing. :) You have my phone number.
Tom
 

Nashville Kat

Well-Known Member
Apr 20, 2009
1,501
55
48
Jacksonville, Florida
Do you have a width on this engine?- DAX doesn't have it and I don't want to call.

Mostly, does this require the use of a wider crank?

i'd rather do without the kick start than have to go wide on the cranks.
 

thatsdax

Member
Feb 22, 2008
868
4
16
www.thatsdax.com
Width is only 8in including the kick starter. See pic. Height is only 9in. Weight is only 17lbs. This Engine is Engineered in Austria and Germany currently made in China. Engineering and build quality appears to be first rate. The factory that manufactures this engine has been doing so for many years and has a excellent reliability record as the Germans are the main buyers and they use them for mini MX racing and training for younger riders. I have known that this factory has been selling to Germany for many years and I have been waiting to see. My take is that if the Germans are buying them and using them for years now, they must be good. But.. I will still need to know personally so I will be installing mine into my own personal ride. The others that I have are sold. I will be getting feed back from other owners as well as my personal usage. I hope to get started today on this install. I am excited to be sure. My first task will be to find an Air Filter and Exhaust pipe. For Exhaust, I want it to be quiet, even if it takes a little of my HP it is ok as I feel this engine will have power in excess and toning it down may be a good idea. I will let you all know. I will make videos and post them of the progress. I am considering my Firm strong bike as I did install a 4hp Case Reed motor on that bike since it has a weldable steel frame. I will yank the case reed motor and replace it with this GP50 which has more than 2 times the power on paper anyway.. It may be more.. It seems as though the 415 chain fits the engine sprocket nicely and I will be using that to a rag joint sprocket on the rear. I wish to see how well this setup can take the power.. It will be fun, and exciting. Pray for me.. Sincerely.. Duane..
 

Attachments

Last edited:

bandito

New Member
May 22, 2009
783
0
0
colorado
Duane I know you know your stuff but won't a 9hp motor tear up the spokes using a rag joint? Sure seems like it would.
 

thatsdax

Member
Feb 22, 2008
868
4
16
www.thatsdax.com
Probably would if you dump the clutch.. Since it is an auto clutch that will not fully engage until 4000rpm, it should be ok.. We will see.. But your thoughts were also my thoughts.. Still are.. Anyone else have some input here on rear sprocket attachments? I will start out slow for sure.. And then gradually power up. If I attach my sprocket the way I want, I will have pinch against the hub, as well as all the spokes on one side. Should be a strong or as strong as can be for the wheel. It may be that the wheel can not take it no matter how you do it. It may be that the bike and frame can not handle it. This is my main concern. I just returned from shopping and found some pipe to adapt and make an exhaust. So. It will not be long now until she is done !
 

thatsdax

Member
Feb 22, 2008
868
4
16
www.thatsdax.com
I am sure my Frame can handle the power, my main concern is the rear wheel and mainly the spokes. I found a rear wheel that uses 12ga spokes and 2.125 wide steel rim and hub is free wheel type. I must admit, I do like the rag joint mounting type if you can get a hub that is tight against the sprocket hole so it pinches it and centers it. This shares in the friction along with the spokes when power is applied. I have done over 300 installs using this method and I like it a lot for bicycles. Now that I am going from 3hp to 9hp or there about, I really think that the 12 ga spoke rear wheel is looking good. Keep in mind this 9hp GP50 is a 2 stroke and the 9hp is the rate and not the torque. I will keep my rear sprocket smallish to keep torque down as to not tear up my wheel as I am sure this 9hp has some torque to it. The 4 stroke Titans have good torque and never had any problems using quality wheels with 14ga spokes at speeds up to 48mph or more. But with the hp this GP50 has and running a smaller sprocket, I am sure the torque will be good and the speed number will be off the chart for a bicycle. I am guessing 50-60 mph. I have found that once you get above 40-45 mph, wheel balance plays a big factor in rider safety. I will order this 12ga 26 inch super duty wheel . Until it arrives, I will work on mounting the motor to the frame. I have enough tools and welders to make it happen. The Build will begin in earnest tomorrow. Enjoy the ride..
 

thatsdax

Member
Feb 22, 2008
868
4
16
www.thatsdax.com
I am thinking 41T. I am not sure of the reduction built into the motor. But the motor cycles used for this motor has a 12in rim with a large knobby tire and they use a 42T. They will top out at around 50mph or so.. I will get back to work here at the office and finish up so I can start this build !! Enjoy the ride..
 
Last edited:

bandito

New Member
May 22, 2009
783
0
0
colorado
This bike is going to be a 50cc motorcycle. Cops will be scratching their heads when they stop you for going 60mph on a 50cc motorized bicycle.
 

thatsdax

Member
Feb 22, 2008
868
4
16
www.thatsdax.com
I am concerned with excessive torque if I use a 56T. I do have them. They are the size of dinner plates. I would prefer a smaller sprocket with less torque and more speed. HP and speed is easy to control with the throttle. All you need is self control. After 5 hours or so of break in and some run ups, I will take her on to Deer Creek canyon and open her up and see what she will do !!! I have not been able to do anything on this build as duty called. My stuff takes a back seat to everyone else .. I will attempt to get started after dinner tonight. Should not be too hard. I will get some strap steel, drill, cut and weld.. Motor should be mounted soon.. Enjoy the ride...
 

thatsdax

Member
Feb 22, 2008
868
4
16
www.thatsdax.com
Here is a pic of the bike I have chosen. Currently has a DAX Case Reed 5hp motor on it that I was testing to see how 5hp would do on a bike. I will finish stripping it down and then place this new GP50 9 hp motor in the frame. There is a 36T rear sprocket installed already. I am going to use it since it is there already.. It should be good for 65-75 mph. I do not think the engine at 9hp will allow it to go that fast. But 50-60 should be real.. I will get to work striping her down. Enjoy the ride.
 

Attachments