Mine has a giant rear sprocket that actually fits OVER the original sprocket! I never counted, but it must have 60 teeth. So it would probably top out at 20mph, lol. But I'm 270 lbs, so I need the torque. UPDATE: Down to 240 lbs!

Man, it even still sounds like a 90! Very impressive! This seems like a really awesome swap, and just what my '74 needs. If you could post direct links to the engine and each of the parts you used, you'd be my hero! Btw, at least to my eye, that speedometer seems very, very off. You might want to check it, the cable, and the front hub.

i grew up in the 70s my dad was big on hunting in fishing,great memories of hanging on to the old man while he was laughing his ass of going thru rivers and trails....great little bike,my rupp mini bike would give it a run on the straight aways!!! lol

Nice build. It looks good, unlike a lot of the engine swap builds many people do.

I have a bone stock 1970 CT90. Stock engine, gearing, carburetor, exhaust, even the tires are original. Is been well used and the engine hasn't been rebuilt. Mine will just barely do 50 mph and I'm around 200 lbs. Something isn't right if yours isn't going faster than 35 mph.

Nice, good to see the 140 put into a later model CT. I have the 140cc manual on a 1965 CT200 and it runs great and bolts right up with only minor grinding. I suspect that muffler is really restrictive. I can get mine to about 55 MPH pretty easily with a 17t front sprocket and the power is solid through the powerband. Looking forward to future videos.

I think your speedo cable is broken, so its slipping somewhere. Consider changing the front sprocket on the engine for a larger one

Nice conversion.. I have a C90 which needs a transplant. PS Rev matching will make your downshifting smoother lol

These are cult bikes! I bought a ct90 and spent the first 2 weeks learning all about it. I'm now officially in the cult. lol 😊

I am about to do the same thing. In Norton, Ohio. See you at vintage days!

just saw this video. the 4v 190cc gets all the clicks, but the $$$$ is insane. the 140cc is the way to go, you can buy 3 of them for the cost of a 190 engine.

The hi lo gearbox is a gem in the originals

good for you. i hope you have fun.

I had a 1969 honda trail 90 as a kid....so much fun!

i know this is an older video but a parts list would be nice

Did you change the sprockets?

I need to do this on my '64 Trail 90! The engine (pushrods in 64 and 65!) is stuck and rusted beyond repair, and the electrical system is spaghetti. I dont have a headlight, so I dont care about that (until I get lost in the woods at dusk).

Just got a 69 ct90 with the 140 in it. First gear is too jumpy taking off, so I use 2nd gear. Engine revs out at 38 mph. How many tooth rear sprocket would you suggest to get it up to around 50 mph?

Figuring out the footpegs is my problem. I've got the atc125.. it bolts in nicely but the ct90 fp bar will definitely not fit.

I have a 69 CT90 and just got a piranha 140 semi. Did you have to drill the top engine mount for it to work with the original engine mount bolt? How did you get the DrATV mount to work? Mine doesnt seem to line up on one side... On later videos I see you have the factory skid plate on. Did you have to modify it in any way? Are those pitbike pegs the straight ones or the upsweep ones they sell? Sorry for all the questions, just trying to figure everything out before i start my swap!

Where did you get the new ignition switch?

What do you mean ugly, it need TLC, we rebuilt a yellow 1969 ct90 trail K1 with 1200 miles on it. Top speed with the original 90cc 7 HP is 50 miles per hour on the flat with an adult on it. In addition our gear box has a low gear setting for off road. I suggest you also rebuild the front shocks.

What do you think is better engine an original honda 90cc or these 140 lifans and pirannas?

Your speedometer is either toast or the cable...Your going way faster then indicated...Sounds like high gears... so yeah speedometer or cable...

Do the original bash bars not fit with the 140?

I just finished doing the same swap on my CT 90. I used a 140 with a manual clutch. Did you have to modify your exhaust pipe? I had to change the end on mine and the angle. I also had issues with the crank case vent and had to grind on the frame . Did you have to do that?

How do you start this? Choke up or down? Gas lever up or down (On or Reserve position?)

Did you have to weld in the bracket from dratv to help hold the engine or is it bolt on. I've a '73 Honda CT90 Mars Orange. Sounds nice! 👍👀

Has to be stuck in low gear right

Very Cool I have my fathers 1964 Honda S90 that he put into Storage indoors in 1965 and the bike is complete and all original i was hoping to use OEM parts to convert it to a semi Automatic Clutch because i have a Disability in my left hand that makes operating a Lever Clutch very difficult my plans are to do a semi restoration to make the bike a Rider but because of the history i would like to use OEM and Period Correct parts unfortunately i found out that the Honda Semi Auto Clutch will not fit inside my case like a Monkey bike uses ? my Engine was refreshed with new Rings ,gaskets and other parts not too many years ago by a Uncle who was a retired Mechanic and a Engineer who tore it down because the kick starter had sheared off part of the Mechanism because kids used to play on the Motorcycle when it was in Storage so i don’t beleive i will need to do a Motor Swap which is a nice cost savings Unfortunately the last few years parts for these motors have been going up because of World demand and the Internet although the positive is there are a lot of parts available and in some cases the Clone Engine parts are a good fit as well maybe not the quality of a Honda part but can work in a pinch

What aftermarket throttle did you use?

That ugly. adventure cub is beautiful ,& will get to places the high end BMW’ cannot get too.You can also get away with riding & parking in places you shouldn’t ,cops tend to find them inoffensive & turn a blind eye to them .The Australian post office used them & they call them postie bikes & delivered mail on them I have only seen one or two of them here in the UK .We mostly just got the standard step thru Honda Cubs with double seat & leg shields c 50 ,C 70 & C 90 & now the 125 Honda Super cub that is not good as it has become too high tech & not as owner friendly .

I just got a 64 CT200 trail 90 for free.. i wanna up power it im curious if the Piranha will flt in the same?

How did you mount the original CT90 exhaust to the Piranha 140? I am in the middle of this swap, and the 140 has a totally different mounting surface and design to the original 90 motor. The Piranha is a 32mm hole. The 90 is more of a recess for the lip of the 90 exhaust to sit into. My guess, is that you actually have a 110 exhaust on there, not a 90. They are different diameter mounting faces.

Where did you buy the engine?

How much

Is this a reliable engine

How cheap is cheap?

Does still have low range?

Nick, did you use the PIRANHA 140CC BOTTOM ELECTRIC START SEMI-AUTO E-START ENGINE? It's a 4 speed

What is the exact bracket from dr atv?

Needs another gear.

WHAT A PILE...I RODE THOSE WHEN NEW...

*35???* &*WHAAAAAT?* *Sounds like it's in the 'Low' gear-range, because even a 'bone-stock' Trail-90 would easily reach 50-mph, even in the '60's era* *Something seriously weird is going on...!*

Wouldn’t take much to put her back to pretty

What's the max speed flat out with the new motor?