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Worth turning YZ85 into trail bike?

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My older son is coming off his YZ85. He was an MX'er.

My next youngest is a trailrider. He just likes to plink around in the woods, not really interested in MX except for an occasional play ride day. He has an XR70 now, but he's too big for it.

My plan was to sell the YZ and buy the younger kid an XR100 or TTR125, but then I wondered if anyone has made a YZ85 into a play/trail bike with a bore/port job.

Anyone? Thanks.

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I've heard that it's hard to turn the yamaha 80/85's into woods bikes cause they don't have power valves. Your either full on the gas or your not to make power.

If the kid has good clutch control, then he should be fine, but he'll be bagging on the bike hard for most of the ride.

IF they are just flat trails, nothing technical, couple puddles etc, then even more so he will be fine.

People here have made 85 wood/trail bikes, it can be done.

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One of my good friends is just plain small. He's 5' tall and 130 lbs. He rides the the crap out of a yz 80 in the woods. No mods.

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5'0 130?

how old is he

im 5'9 130:bonk:

I'd say it depends on how good he is on the 85.

If hes comfortable with the clutch, and with 2-ts hell do fine im sure. Test him out on it before you sell it and if he wants a 4t woods bike., getem the 125 or 100.

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My son had one for years . We ported it for low end , v-force reeds, corrected jetting and installed a flywheel wght. It was a great bike

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We ran a YZ85 as a woods/trail/track bike for three years. Box stock, with an FMF TurbineCore II spark arrestor. Great bike. :thumbsup:

The rider was coming off an old Suzuki DS80, so he knew how do use a clutch. The first year he would just bump against the 'hit' in the powerband, then up shift.

The second year he started to get deeper into the powerband. Pretty soon he was a master at dumping the clutch coming out of corners and throwing tons of roost. A skill he still uses on his 125. :ride:

The February 2010 issue of Dirt Bike has an article on restoring a YZ85 for track & trail. They said the TurbineCore II helped calm the hit.

I say no problem; run the little YZ!

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Let me be clear this would be for a trail bike, not a woods racer.

That said, maybe I'll give Eric Gorr a call and see what he thinks. Sending the cylinder off for a big bore and port job to smooth the power would be about the same hassle as selling this one and buying a TTR.

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hey, this looks interesting whaat exactly can you do to the bike I dont have the dirt rider mag so if someone could elaborate on the subject that would be cool

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It's been brought up before that Gorr cuts down the cylinder effectively changing the port timing and taming the hit. It can be "undone" with an extra base gasket or two.

I really don't think that's necessary unless the rider is a novice though.

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Let me be clear this would be for a trail bike, not a woods racer.
:thumbsup:

Believe me, our YZ had been bought with the intent of being used as a trail bike; it was the rider who eventually ended up using it like a race bike! :lol: :lol: :lol:

As far as getting acquainted with the YZ, I would be more concerned about the 'height' of the bike than the powerband.

The YZ85 is a good bit taller than others (KX & RM85), and initially can be a difficult transition for a kid coming off a playbike.

Re; modding the cylinder. If the hit is a concern, I would save the $$ and teach clutch control.

It's a lost art in these days of broad, controllable 4-stroke power delivery, but it pays dividends in control, confidence, and safety. :ride:

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The big bore for that bike can really make it have some bottom.

The real issue is the pipe, it's hard to find one that truly works well for tighter woods stuff.

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hey, this looks interesting whaat exactly can you do to the bike I dont have the dirt rider mag so if someone could elaborate on the subject that would be cool
Basically, the Dirt Bike article, "Building a Budget YZ85", was about a $300 'garage find' that the writer reassembled for a 10-year-old who had outgrown his KLX110.

They didn't really modify the bike much. Aside from the TurbineCore silencer, they used an FMF pipe(!), then added a Stealthy flywheel weight to soften the hit.

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I believe I would stick with the yz 85 if you can. The TTR's and such have such awful suspension and chassis pieces. When we had the kids on them they damn near destroyed the TTR's from jumping.......nothing crazy, but the fork and shocks on these is from the 70's. Even as a novice I would rather have good suspension and work on dealing with a powerband hit.

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