atc 70 project help...motor swap?

[parker88]

I might be getting an atc 70 with no motor for cheap. Ive never done a motor swap on anything or had any motor completely out of a bike before so Im gonna need some help from you guys.

Im wondering if this is a motor that will work for me and also is this everything Ill need? What can I use for some better brakes?
http://cgi.ebay.com/ebaymotors/LIFAN-125CC-ENGINE-MOTOR-HONDA-CRF-XR50-CRF50-Combo-Kit-/110593725985?pt=Motorcycles_Parts_Accessories&hash=item19bfe65621

thanx

[parker88]

anybody???

[86trizinger]

Your gonna need a kill switch and some sort of throttle. I am not sure if you have the stock 70 parts or if you could even wire then to work.
Also remember this is a kick start engine and the rear fenders will get in the way unless you do the pull start conversion on it.

[parker88]

Ok...Isnt there a site that sells the 70 parts and the whole motor swap kits?

[Rjfabwerx]

Wish you lived closer, I would GIVE you a 90 engine that runs great and is in my way all the time...

[rbake]

dratv.com sells everything you need, plus has the wiring diagrams. You will want to add the pull starter off of your honda engine because you can't kick start it with stock fenders.

[Mosh]

I just put a Pirhana 125 4 speed manual clutch in my 70..
I am no expert, but I will try to give you some good reading here for some good tips..

1st of all..Do you want it to be auto clutch or full manual?
If you want the auto clutch, then a Lifan 125 would be best, but I have heard that the trannies dont hold up well in a auto clutch engine above 110cc.
I used the 125 Pirhana engine with a clutch, specifically becuase I wanted something that had balls and clutch action, since I have a stock 70 to putt on.
So you need to make your decision. I would advise nothing bigger than a 125 either way..140 and 160 engines in a 70 chassis will wear you out in minutes. Unless you are a big boy..

2nd.. Only go with Pirhana, Pitster Pro or Lifan..They seem to have the best durabilty.

Now as long as you stay with the 125 engine or smaller, they almost bolt right in. You may have to grind about 1/8 inch off your frame at the rear upper motormount for the case to clear the frame..No biggie..Hell a file will work.
Get the complete set-up with the carb, and electrical..They hook up easy and are tuned right outta the box for the most part. You can even wire your stock thumb throttle killswitch to ground the coil and kill the motor.
You can use the stock cable, but it has to be modified for the bigger carb..A pain in the butt, for what a proper cable will cost, and be simple I would suggest the proper cable.
You will have to get a pipe. Either a 70 bigbore pipe from Sterdy, or you can use a cheap pitbike pipe and silencer and tweak the rear tube to clear your fenders. But it has to be done right or you will melt your fenders.

The 2 biggest problems are these.
1)The bigger carb will not clear the gas tank..There are many ways around this.
Some guys notch the intake bolt holes at the head, and rotate the carb to the inner frame rail, then dent the back side of the gas tank so the carb clears.
Others buy a shorter intake, that allows the carb to clear the tank, and others will cut the intake and reweld it so the carb clears the tank.
Some guys just adapt a different tank..
2)The starting..
You can either push start it...PITA
Or you can shave your fenders, and widen your axle and use the kickstarter like me...
Or you can buy a pullstart conversion kit...

Now here is some links for you...

This is a large thread of highly modded 70's, that has some great tips on how to make these engines fit..But you have to read the whole thread..They answer alot of questions..
http://www.3wheelerworld.com/showthread.php?98378-Mad-70s-In-action!!


Here is a link to my build, which is still currently under construction, but it is rideable now..
http://www.3wheelerworld.com/showthread.php?118372-Project-quot-SUSPECT-70-quot-With-125-engine.-Update.-9-23-10

Now I bought my engine from these guys..But they only deal Piranha engines..But they had it all in stock, great prices and 30 minutes from my house.
http://stores.wholesale-cycle.com/StoreFront.bok

Sterdy has a crap ton of parts for the 70 mods, and they are the ones that have the throttle cables you will need..
http://www.sterdyproducts.com/

And these guys have some things too. Dr ATV..They have the pullstart kits..
http://www.dratv.com/newreen.html

As far as the rear brakes, you either have to figure something custom out and adapt newer stuff, or add some front brakes..
Someone else can chime in on that.

It isnt that hard to do this conversion..And it is cheap..
Sorry for the long post, but it should give you some good ideas and a start point.

[parker88]

Wow Mosh, thanx for all the info. Im hopefully going to get the 70 in the moring. The guy who has it owns a boat repair shop and he put it up on the roof to attract customers but I just cant keep driving by it everyday knowing its just getting rustier(sp?) everyday...lol

[parker88]

Well guys I picked up the 70 today. Its a 82 model and its in pretty good shape. No motor but I was planning a motor swap anyway. I think Im gonna get the pirahna 125 motor. Thoughts on it? What kind of handle bar setups are you guys running on your modded 70s? Will I need a different top clamp? Also my 70 dosent have foot pegs. Can I just buy stock ones and mount them on the pirahna motor or do they mount to the frame?

thanx

[Race Demon]

Pro Taper crf50 bars or the cheap copies, you can find them on ebay,they fit the stock triple clamps, the stock pegs will work if you put a spacer between the pegs and motor, I use alot of the Pirahna motors and like them.:p

[parker88]

Thanx Race Demon...Will the new pirahna motor come with the bolts I need to mount the motor, cause I dont have them?

[parker88]

Heres the pics guys...

http://i519.photobucket.com/albums/u351/parker88-photo/atc70frontrightview.jpg
http://i519.photobucket.com/albums/u351/parker88-photo/atc70backleftview.jpg
http://i519.photobucket.com/albums/u351/parker88-photo/atc70seat.jpg
http://i519.photobucket.com/albums/u351/parker88-photo/atc70tank.jpg

These last two pics just show the main things its missing and the busted up sprocket cover...

http://i519.photobucket.com/albums/u351/parker88-photo/atc70frontwheel.jpg
http://i519.photobucket.com/albums/u351/parker88-photo/atc70chainguard.jpg

[thestud25]

Can't beat free!!! The 125cc will be a great Mod for that. The Lifan will bolt right in with no problems. Check out Mosh's threads above. Great info there.

[Race Demon]

Thanx Race Demon...Will the new pirahna motor come with the bolts I need to mount the motor, cause I dont have them? no you will have to buy some motor mount bolts, you will also need a clutch cable and clutch lever and perch, you will have some other mods to do once you get that far

[parker88]

what kind of chain and sprocket setup are you guys running with the 125 motors?
I dont have any of the stock wires or anything from the 70 motor. My 70 is just a roller. Is there anything from the pitbike motors that is supposed to hook up to any of the old wiring or anything?

[parker88]

bump...I need answers lol

[atc350xer]

what kind of chain and sprocket setup are you guys running with the 125 motors?
I dont have any of the stock wires or anything from the 70 motor. My 70 is just a roller. Is there anything from the pitbike motors that is supposed to hook up to any of the old wiring or anything?

http://www.3wheelerworld.com/showthread.php?118372-Project-quot-SUSPECT-70-quot-With-125-engine.-Update.-9-23-10&highlight=suspect+70

[Race Demon]

The Piranha motor comes with all the wiring you need, the only stock thing you use is the on off switch, you will also need an air cleaner, the stock sprockets from a 70 will fit that motor, since you don't have a front sprocket I would start with a 14 tooth on the front and run the stock back one with 420 chain for stock tires, the gearing is a bit high for stock tires but you will have plenty of motor to start with, as you get adjusted to the motor you may want to change the gearing to suit your riding

[86trizinger]

I run a 16 tooth on my 140 Piranha engine.

[parker88]

The Piranha motor comes with all the wiring you need, the only stock thing you use is the on off switch, you will also need an air cleaner, the stock sprockets from a 70 will fit that motor, since you don't have a front sprocket I would start with a 14 tooth on the front and run the stock back one with 420 chain for stock tires, the gearing is a bit high for stock tires but you will have plenty of motor to start with, as you get adjusted to the motor you may want to change the gearing to suit your riding

Will any kill switch work?

[86trizinger]

Yeah any switch should work. I have a a little dirt bike push button switch on mine to keep it simple. If you want a headlight plan on a switch with a headlight switch on it. Same thing if you want electric start.

[parker88]

Quick question guys...would a 2007 honda crf 80 motor fit in a atc 70?

[biggyb12]

No thats an upright motor 70's are lay down check this site out has everything you'd ever need to know about building a 70 http://www.glamisdunes.com/invision/index.php?showforum=50

[parker88]

biggyb12, Thanx for the link