Planet Minis

glamourshades · 03-10-2008, 12:06 PM

I want a GPX engine for my 71 CT70. Currently I have the stocker 3-speed. I am not looking to do 90 mph and don't have disc brakes, new forks or shocks. Maybe someday... I just want the think to start.

Which GPX engines fit without modification? 124cc? 150cc? 160cc? I read a post where the guy that put the 160cc in had to grind a bit on the motor.

What else do I need? Wiring harness, which exhaust? Where should I buy it?

Bren

fatcaaat · 03-10-2008, 12:10 PM

A GPX doesn't come with a lighting coil, so there is strike 1.

Most engine packages will come with everything you need. The Lifan 120 base is a good cheap start. They all have the same engine mounting so you shouldn't need to do any grinding whatsoever.

I would suggest the new Lifan 150 IMO with the daytona style clutch cover. Swing a deal with Pitster to get you all the needed accessories and you'll have something that will be perfect for street use.

You'll need the motor, the ignition, cdi, clutch cable and clutch lever, rectifier, wiring harness, keyswitch and of course an intake manifold and carb. Go for the VM26 for ease of jetting.

firepower354 · 03-10-2008, 12:31 PM

All the "modern" engines are 12v right? Are there aggressive enough regulators to tone it down to 6v and still hold up, or is a 12v conversion the way to go?

myown · 03-10-2008, 12:39 PM

Fatcatt, why do you think a lifant 150 is better for street use?
I hessitate between 150 lifan, 150 yx and 160 yx

Matified · 03-10-2008, 12:39 PM

You can get the GPX 150 that is in the Motard bikes with a lighting coil, and also get a complete wiring harness for that style of bike that is already 12v.

FastMC · 03-10-2008, 03:18 PM

I had a GPX 125 in my CT last season with a TB 146kit and BVH. Easily hit 70mph and will do more I'm sure...We've bought 3 of these now and all had lighting coils...Wired up no problem...You can get the motors for around $300. No fitment issues, but you will need a pipe that has a slip type silencer or make an extension bracket to mount the pipe which will be the same on all the import motors.

glamourshades · 03-10-2008, 03:53 PM

Quote:

Originally Posted by FastMC

I had a GPX 125 in my CT last season with a TB 146kit and BVH. Easily hit 70mph and will do more I'm sure...We've bought 3 of these now and all had lighting coils...Wired up no problem...You can get the motors for around $300. No fitment issues, but you will need a pipe that has a slip type silencer or make an extension bracket to mount the pipe which will be the same on all the import motors.

Real nice bike.

FastMC · 03-10-2008, 04:46 PM

Quote:

Originally Posted by glamourshades

Real nice bike.

Wait till you see it this year : ) . Thanks

fatcaaat · 03-10-2008, 04:48 PM

Quote:

Originally Posted by myown

Fatcatt, why do you think a lifant 150 is better for street use?
I hessitate between 150 lifan, 150 yx and 160 yx

I'm of the opinion that for street use, a longer stroke is preferred. The Lifan 150 has a 59mm stroke. The YX comes with a 53mm stroke.

I prefer a torquier ride on the street. Off road, I'd certainly pick the YX style.

myown · 03-11-2008, 04:09 AM

Thanks, but nowadays there is stroker yx, the 160 cc's, what about it?
It could be streetable too?

Dan_Lorenze · 03-11-2008, 02:47 PM

The GPX160 from Pitster does have a lighting coil, the lights on my CT70 work really well from it. I was the guy that had to grind away at the back motor mount, just a little bit to clear the swing arm. No big deal really... I could've modified the swinger to make it work too. I'm knee deep on another CT70 project, for that one I want to give the Lifan 150 a try. I put a lot of miles on my last Lifan and lasted pretty long. But to answer your question, the GPX/YX 150/160's work great with small modifications...

Dan_Lorenze · 03-11-2008, 02:50 PM

Quote:

Originally Posted by FastMC

Awesome bike!!!!!

03-10-2008, 12:06 PM	#1 (permalink)
glamourshades PM Newbie Join Date: Jun 2007 Posts: 20	GPX Engine for my CT70 I want a GPX engine for my 71 CT70. Currently I have the stocker 3-speed. I am not looking to do 90 mph and don't have disc brakes, new forks or shocks. Maybe someday... I just want the think to start. Which GPX engines fit without modification? 124cc? 150cc? 160cc? I read a post where the guy that put the 160cc in had to grind a bit on the motor. What else do I need? Wiring harness, which exhaust? Where should I buy it? Bren

03-10-2008, 12:10 PM	#2 (permalink)
fatcaaat 3rd Gear Member Join Date: Sep 2004 Location: Arlington, VA Posts: 3,778	Re: GPX Engine for my CT70 A GPX doesn't come with a lighting coil, so there is strike 1. Most engine packages will come with everything you need. The Lifan 120 base is a good cheap start. They all have the same engine mounting so you shouldn't need to do any grinding whatsoever. I would suggest the new Lifan 150 IMO with the daytona style clutch cover. Swing a deal with Pitster to get you all the needed accessories and you'll have something that will be perfect for street use. You'll need the motor, the ignition, cdi, clutch cable and clutch lever, rectifier, wiring harness, keyswitch and of course an intake manifold and carb. Go for the VM26 for ease of jetting.

03-10-2008, 12:31 PM	#3 (permalink)
firepower354 Advertiser Join Date: Oct 2006 Location: Flint MI Posts: 10,993 My Mood:	Re: GPX Engine for my CT70 All the "modern" engines are 12v right? Are there aggressive enough regulators to tone it down to 6v and still hold up, or is a 12v conversion the way to go? __________________ If it has my name on it I did it;) FirepowerMinis.com Custom FPM parts and engines. Parts and service for all makes. Honda Trail Bikes parts and accessories. Pitster/Piranha/Thumpstar bikes, parts, engines and accessories.

03-10-2008, 12:39 PM	#4 (permalink)
myown PM Newbie Join Date: Dec 2006 Posts: 10	Re: GPX Engine for my CT70 Fatcatt, why do you think a lifant 150 is better for street use? I hessitate between 150 lifan, 150 yx and 160 yx

03-10-2008, 12:39 PM	#5 (permalink)
Matified Pitster Employee Join Date: Feb 2008 Location: USA Posts: 1,887	Re: GPX Engine for my CT70 You can get the GPX 150 that is in the Motard bikes with a lighting coil, and also get a complete wiring harness for that style of bike that is already 12v.

03-10-2008, 03:18 PM	#6 (permalink)
FastMC Sporting the Merkin Join Date: Mar 2004 Location: boston area Posts: 5,072 My Mood:	Re: GPX Engine for my CT70 I had a GPX 125 in my CT last season with a TB 146kit and BVH. Easily hit 70mph and will do more I'm sure...We've bought 3 of these now and all had lighting coils...Wired up no problem...You can get the motors for around $300. No fitment issues, but you will need a pipe that has a slip type silencer or make an extension bracket to mount the pipe which will be the same on all the import motors.

03-11-2008, 04:09 AM	#10 (permalink)
myown PM Newbie Join Date: Dec 2006 Posts: 10	Re: GPX Engine for my CT70 Thanks, but nowadays there is stroker yx, the 160 cc's, what about it? It could be streetable too?

03-11-2008, 02:47 PM	#11 (permalink)
Dan_Lorenze 2nd Gear Member Join Date: Mar 2006 Location: Moorpark CA Posts: 451	Re: GPX Engine for my CT70 The GPX160 from Pitster does have a lighting coil, the lights on my CT70 work really well from it. I was the guy that had to grind away at the back motor mount, just a little bit to clear the swing arm. No big deal really... I could've modified the swinger to make it work too. I'm knee deep on another CT70 project, for that one I want to give the Lifan 150 a try. I put a lot of miles on my last Lifan and lasted pretty long. But to answer your question, the GPX/YX 150/160's work great with small modifications... Last edited by Dan_Lorenze; 03-11-2008 at 02:52 PM.

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