My 70 needs a stronger heart! 88 kit or stroker 108??

[90nut]

My PK 70 needs a heart. I Refuse to put a Lifan etc. In it! So, should I go with the trail bikes high end 88 kit? Comes with head and all that. Or will I see epic results with the stroker kit? I intend on on splitting the lower end no matter what path I take. I just want to retain as much old school, original coolness of this trike.

So, who's done it and how was it??!

[Joseph Farrow]

If it were mine.....I'd have to go with the 108 Stroker motor. Good for you for not wanting to use one of the Chinese motors.

[90nut]

Yea, that's all the atc 70 fb page people do. China China China engines, and stretched frame. �� I really wish I could get the same performance out of a re worked stock piece at a reasonable price. I'm a sucker for a period type build.

[Evan Hagenow]

I put a piranha 140 in my 84 and it is an animal. Ive barely ridden the thing and it wheelies in every gear. I did it for the manual clutch. The guy to talk to is Gordon Spangler on fb, he can hook you up with any kit you want and it will all be correct, along with a custom exhaust that is less restrictive than the stock exhaust. His website is www.hondaatc70com. Thats where I got most of my parts and is a great guy to deal with.
235910

[90nut]

Yea. No piranha. No China motors. In in for a stroke!

[jb2wheels]

I was really happy with the $100 88cc kit I got from DRATV on my TRX70. I used the stock head, carb, pipe, etc. Really woke up a tired engine.

[Ghostv2]

Yea. No piranha. No China motors. In in for a stroke!

That-a-boy! Old school race parts will always be worth more and have the coolness factor (even though I think these kits are all new repops). Plus you don't have to worry about something not fitting, mounts, exhaust, a kickstart, etc. And you still have that Honda reliability. Only real reason I'd want a Chinese motor is for the manual clutch.

You plan on upgrading to a CDI? Some people say it's great, some people don't have luck with them (my one friend being one of them).

[big specht]

You can do a manual clutch with a ct/sl 70 side case and basket and primary gears. Like any h/p upgrade it all comes down to what you want to spend and how much time you want to take in building it. I have a old Honda 70 motor that I put a custom sleeve in and a 110 big bore piston in with a ported sl head and old Honda race cam and a 200x carb and a button style rm ignition. It came out to 90cc and runs really good it don't have to torque of a stroker motor but it will hold its own with the bigger motor on top end. If I had it to do over again I would stroke it with the big bore.

[Ghostv2]

The ct and sl 70/90 cases and engine usually go for as much as a whole bike and are hard to find for the same reason we want one. If I could find one I'd do the sub trans delete on my 110 and do the conversion. But if you are lucky enough to find one cheap, snatch it up while you can.

[big specht]

I'm almost positive the 90's are different than the 70's.

[SSLS1]

Definately go for the 108cc stroker if you are going to tear into the motor anyway. The 88cc is not all that impressive for adults to ride on and will leave you wanting more quickly. Plus who knows how many miles are on that stock crank and bearings as these motors are over 30 yrs old. Would be wise to freshen up the bottom end with a nice stroker crank before running it hard like you will with the increased power. ;)

[90nut]

Yea, I wouldn't go to the effort of putting that nice new too end on a 30 yr old crank and bearings, I was just fishing for anyone that has actually ran one. I had an 88 kit, just the bigger bore, stock head etc, it was ok on my crf50 but the atc 70 has a bit more rolling resistance.

[Toaster556]

The other non-chinese option is a TRX90 engine. I have one converted to a full proper manual clutch with a 49.5 China crank and 52mm "race head" top end, and its brutally quick for what it is. The downside is the amount of Chinese pieces I needed to do the manual clutch conversion and the longer motor took some wiggling to fit it in my pit quad. Sometimes the motors are cheap, sometimes not.

But if you want to go off your cases, pony up for the 108 and put an HD clutch in it. My dad's 81 CT70 really woke up with a stock head 108 kit.

[YamaBoss]

Glad to see someone doesn't just throw a cheap Chinese motor in there trike. Good for you.

[RubberSalt]

Go big or go home ?