TRX90 Motor direct bolt in to ATC70/TRX70?

[unclejemima]

Ok, so I've actually got a 86 TRX70, but there is next to no info or forums on that quad, so I'll pretend I have an ATC70... (I do have a ATC125M 84&87, YTM225DX, ATC200M & 185S so don't worry, I like 3 wheels too!)

The ATC70/TRX70 have the same motor from what I understand, just the TRX is 12V CDI vs 6V Points for the ATC70, correct?

Would the TRX90 motor bolt direct in without mod? (exhaust, footpegs, ext., carb and so-on) or is it physically larger than the 70?

I know the ATC125M motor can fit, but it needs a bit of work to fit... plus its for my kids, and the 90 will be plenty of power (throttle will be limited for sure!) just our TRX70 motor is in need of a rebuild and I found a good deal on a TRX90 motor.

Thanks kindly,

[Jon Boy]

the 90 motors are the same overall size as the 125's. same work basicly, but then you could swap in the 125 after they outgrow the 90.

[Vealmonkey]

The 90 is NOT just a bolt in swap. They are close though. You will have to redrill the frame. Also I believe the chains are different sizes. I know on the atc90 and 110 engines, the chains are different and there is no place for the front head stock mount. If you pick up a lifan engine, they are a bolt in, but you will have to deal with the different electrical harness and hookups and the coils are different plus the cdi. Plus you can get the lifans in semi auto like the 70 or with manual clutch and there are a couple different shift patterns. It all depends on what you want.

[unclejemima]

Cool. But the TRX90 has a totally different bottom end of the ATC70 (what has the same bottom end as honda 50's) from what I understand...and the TRX90 would be similar in aritechture as the CT90/110's/ATC90/110/125's. Is this correct?

My TRX70 is CDI 12V already, so we are ok harness wise.

Might as well get a ATC125 motor if the work is the same to get a TRX90 motor in.

Thanks!

[jb2wheels]

I put a Loncin 125 in mine. It is semi-auto, e-start, 3sp + reverse.

The reverse is cool. I like it a lot more than I thought I would.

Having the starter on top of the engine is a PITA. When I build the ATC, it will be bottom start or just pull start conversion.

http://www.3wheelerworld.com/showthr...88#post1167488

[Jon Boy]

...Might as well get a ATC125 motor if the work is the same to get a TRX90 motor in.

or a TRX125 laydown motor (horizontal not the vertical) then you'll get reverse instead of the hi/low sub trans.

[KASEY]

hold on!!!!!! the trx 90 is the SAME AS A ATC70 MOTOR,, ITS NOT THE SAME GENERATION AS THE ATC90!!!!! IT WILL BOLT RIGHT IN... ANS ALL THE ACCESSORIES WILL BOLT ON TOO,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,

[Jon Boy]

cool, thanks for the correction Kasey.

[jb2wheels]

hold on!!!!!! the trx 90 is the SAME AS A ATC70 MOTOR

OUTSTANDING - I had no idea. I ASSumed it was like the old 90/110/125. Cool.

[unclejemima]

hold on!!!!!! the trx 90 is the SAME AS A ATC70 MOTOR,, ITS NOT THE SAME GENERATION AS THE ATC90!!!!! IT WILL BOLT RIGHT IN... ANS ALL THE ACCESSORIES WILL BOLT ON TOO,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,

Sorry to bring up an old thread...but are you sure???

If the TRX90 is really the same bolt pattern and drop in as the TRX/ATC 70, then why would all the Honda mini-bike guys (CT70/XR50/ZB50, ect.) be using the TRX90 motor if it is a direct bolt on as their motor is nearly identical to the TRX/ATC 70??

So Honda just "up-sized" the TRX70 motor to a 90cc (same bottom end)...not the re-used the ATC90/110 architecture?

Looking forward to your reply,