yz85 trike?

[hondahaulic]

Im starting to get an idea for a trike conversion project. I have a 2002 yz85 dirtbike that i almost never ride anymore but its in pretty good shape. The 2 stroke 85's really seem to rip for their size, And thats why im thinking it would make an awesome trike conversion.
I dont want to just start hacking away on the yz85's frame and end up with a useless non-finished project down the road so if i do this, im thinking that i'll buy another used yz85 frame and make a roller, and when the roller is complete transfer everything i need from the dirtbike over to the new roller.
For making the roller, I would probably try to get a blaster or maybe a 200x swingarm and axle attached to the new frame. Im guessing i would have to make a new lower, wider subframe for it but that shouldnt be too hard and it will help that the yz85 already has a removeable subframe. For the frontend, Im thinking i could use a frontend from a 250r or 200x, or maybe if i could come up with a way to make new tripples i could use the dirtbikes inverts.
Am i forgetting about any major obstacle, and does this seem do-able? and, will the 85cc 2 stroke still rip in a trike or will it feel underpowered? Im around 6'2" 170lbs and the completely stock dirtbike still has plenty of power for me right now.

[tecat-z]

On hard level ground it would probably accelerate pretty well once under way. However lots of clutch would have to be used to get moving in high drag conditions, such as sand and mud. Even 250's sometimes need a lot of revs and clutch to pull away in loose deep sand. Small engines don't generate enough torque. Excessive weight would be your worst enemy in this situation. Jason Hall built a cr85 powered atc that frekin rips for his son. But again it was built as light as possible and his boy is light as well.

[TwoHundredEx]

If you were going to be building the bike from scratch I would say go with atleast a 125cc, but since you already have that engine, I'd go for it.

Now with that said, I would think that it would be a little underpowered because of the extra drag created by 3 heavier wheels and tires, heavier axle etc. since those bikes are quick because they're light. But I'd imagine that if you can keep it in the powerband most of the time, and do some minor mods, it could still be pretty quick.

[RedRider_AK]

I agree with what people on here are saying. I think that the 85 in a trike frame with 3 ATV tires might just be too heavy and it will dampen down the acceleration a lot. I have a YZ80 and it straight rapes when you get on the gas and start slamming through the gears, but that's because it's only spinning one tire and the whole bike weighs about 140 lbs.

Sticking that same engine into a trike frame (custom job, 200X?) would probably slow it down a lot... If you put a kid on it, he'd probably be able to race competitively (assuming the suspension and such was good), I saw a Quad magazine where they took an RM85 motor and stuck it into a Cobra ECX70 mini-quad chassis. The kid was doing adult sized doubles and tabletops on it but he couldn't have weighed more than 80 lbs.

[Vealmonkey]

I would be curious of the horsepower of the yz85 as compared to an atc90. I don't think an atc90 was rated at over 10 horsepower. And they worked ok. What are you trying to do with the trike? You can probably have custom sprockets made to tailor the gearing anyway you want. And you can atc70 wheels and tires or even go kart tires, you don't have to run 22x11-8's.
It might not be the fastest, but I'm sure you could make it work.

[oldskool83]

80's and 85's got like 17hp i belive...thats what i keep thinking. remeber rears ago there was a tiger 80 and a KX60 trike. i think if you use lightend parts the thing will fly....after all people use to put CR80 motors in blaster because they were faster.

[scooterroo]

would be a cool mini trike like that kx cionversion that was on here a bit back. i seriously have been wanting to get me a kx 80 and convert it to make myself a mini-me t3 to go side and side with my others, plus give the kid a kickass trike unlike any others. or a zuki, definately would be soemthing different then the norm. if yah got the bike already, i say do it.

[hondahaulic]

if i wasnt as big as i am or maybe had a younger cibling or something interested in trikes i would probably do this for sure... but maybe i should wait for a good deal on a little bigger bike if i want to do this.

[RedRider_AK]

but maybe i should wait for a good deal on a little bigger bike if i want to do this.

I think that a CR125 or YZ125 would make an awesome mini-trike engine. They're barely bigger than a YZ85 motor and put out a little more power, especially the newer liquid-cooled varieties. Put that engine, into either a custom built mini frame (chromoly-steel ) or a 200X chassis and you'll have a fun little zinger to ride around on. Maybe you could even find someone willing to give you detailed photos of a Tiger 80 that you could base the design off of. I would personally love to have a little 2-stroke "pit trike", like a bigger version of an ATC70, to bomb around on. Plus, you could scare the crap out of anyone with a mini-trike that goes 60 mph or so...