The cheater MX85 argument. I might be changing my mind.

[quallman1234]

Yep, I got several basket case TF125s for around that price.
Good points:
About $200 to rebuild if the barrel only needed a hone, including piston, rings and little end.
Bad points:
No porting and no power (9hp factory claim) for that price. Crank costs bigger money.

They are cheap and available but they are not bolt in competitive.


If it ain't smokin' - it's broken.

~300$, for everything would be about what you will get one for. Thats how much i paid for one i brought a couple of years back.
They definitely are quite a underperforming engine standard. Not close to a stock fxr!

[aircooled]

std 05 & 06 cr85 engine's with pipe, 20.5hp

std 2010 yz85 engine, pipe, 21.3hp, had a v/force reed block.

cr85's were in nf4/nx4 frames, yz is in a tz frame. easy to ride with power from 8500--12000rpm

24hp with std ignition, 28mm carb,squished head, porting & pipe. power from 9000--13000.

reliable & cheap to run, pretty fast around a kart track & great on the big tracks.

[F5 Dave]

On your local dyno? What type? Thanks

[Drew]

If those numbers are anywhere near accurate, it's a pretty good indicator that the MX85 route should be a popular one. If they are admitted to the class.

Reckon I'll just get one and hope.

[mr bucketracer]

~300$, for everything would be about what you will get one for. Thats how much i paid for one i brought a couple of years back.
They definitely are quite a underperforming engine standard. Not close to a stock fxr!

if the botton ends fine in 4 hours i can make them have 20hp, the one i made at 17-19 only had 18hp on a dyno jet but 1 hour on it they had over 21hp and that was a 100 , never done a 125 but easy with 125 mx chambers now days .. hard to make a chamber work on a 100 in the day

[RMS eng]

If those numbers are anywhere near accurate, it's a pretty good indicator that the MX85 route should be a popular one. If they are admitted to the class.

Reckon I'll just get one and hope.

shit if they let in 85 mx motors thet have to let in the Honda CRF150R motor,then i can sell Jasons CBR150 motor as the CRF is lighter and a lot less work to fit in the RS125 frame,

[scott411]

shit if they let in 85 mx motors thet have to let in the Honda CRF150R motor,then i can sell Jasons CBR150 motor as the CRF is lighter and a lot less work to fit in the RS125 frame,

Why? they are not cheap and abundant like MX85's are?

[Sketchy_Racer]

shit if they let in 85 mx motors thet have to let in the Honda CRF150R motor,then i can sell Jasons CBR150 motor as the CRF is lighter and a lot less work to fit in the RS125 frame,

4 strokes are currently already well catered for with a large amount of performance options. That is why 90% of bucket grids are 4Ts now

[Mental Trousers]

4 strokes are currently already well catered for with a large amount of performance options. That is why 90% of bucket grids are 4Ts now

... and that's why an option for 2T's is needed. Redressing that imbalance should be one of, if not THE, main goal.

[RMS eng]

4 strokes are currently already well catered for with a large amount of performance options. That is why 90% of bucket grids are 4Ts now

there are lots of TS KE GP motor around people just have to look,no 85 mx motor for sale on trade me lots of bikes at around 2K i think if you paid much less than that they will be junk like most old 85 mx motors,they all ways blow up just like the late model KTM 85 s.looked on ebay there are over 12 CRF150R motor for $1000.00 to $1400.00 same as a 85 ,how much is it to get 22 hp from a FXR150.

[Sketchy_Racer]

there are lots of TS KE GP motor around people just have to look,no 85 mx motor for sale on trade me lots of bikes at around 2K i think if you paid much less than that they will be junk like most old 85 mx motors,they all ways blow up just like the late model KTM 85 s.looked on ebay there are over 12 CRF150R motor for $1000.00 to $1400.00 same as a 85 ,how much is it to get 22 hp from a FXR150.

There's also a lot of DR125s, GN125s, XL125s and GL145 motors around too, so maybe we should ban the FXRs and CBRs as clearly they are too expensive and not needed and there are plenty of other motors.

Sorry for being cynical but that is along the lines of suggesting a TF and GP motors. KE motors are rare as rocking horse...

Apparently it can't be hard to get "22HP" from an FXR as there are a large amount of guys with motors at that level floating around.

This discussion is not about the 150 MX engines, it's about the 85 2Ts and the primary objective of them is to get more 2Ts back in the feild.

[F5 Dave]

shit if they let in 85 mx motors thet have to let in the Honda CRF150R motor,then i can sell Jasons CBR150 motor as the CRF is lighter and a lot less work to fit in the RS125 frame,

That logic does not follow.

I understand that nationally they've separated 85s & 150s in the US due to the performance disparity.

[richban]

That logic does not follow.

I understand that nationally they've separated 85s & 150s in the US due to the performance disparity.

Yeah 4 strokes are better. No one on this site could tune an 85 to make the same power.

[quallman1234]

if the botton ends fine in 4 hours i can make them have 20hp, the one i made at 17-19 only had 18hp on a dyno jet but 1 hour on it they had over 21hp and that was a 100 , never done a 125 but easy with 125 mx chambers now days .. hard to make a chamber work on a 100 in the day

Yeah but not everyone is you. Or can send it to you. Some people just want a modern reliable 2 stroke engine they can easily get parts for, to bolt in which has reasonable power in comparison to a stock fxr.

How i have experienced it thus far, is that a stock FXR150 with a carb and a pipe/pipe mod. Is as fast as a stock RM85, however the RM85 is a ton harder to ride.
The 85 still has better peak power. But the power under the curve is greater on the FXR. It ends up very similar.

[RMS eng]

That logic does not follow.

I understand that nationally they've separated 85s & 150s in the US due to the performance disparity.

who gives a .what they do i the US,i think they all race in the same class here,the 250s in the MX champs do.if you open the door for any MX motors look out.Dave do you have a stock pile of 85 motors, your looking to make a killing on.