In a drag race i was just wondeing because my friend has a 400 ex.And i might be getting a 86 250r for a 1000 this weekend.His has a white brothers pipe and kn air filter.The 250r comes with a DG pipe and a filter.Thanks for any replies.[img]i/expressions/face-icon-small-smile.gif[/img][img]i/expressions/face-icon-small-wink.gif[/img][img]i/expressions/face-icon-small-sad.gif[/img]

 

the 400ex will get slaughtered unless you can't keep the front end down on the atc.

 

Thanks for the info[img]i/expressions/face-icon-small-smile.gif[/img]

 

I agree, the trike just weighs a lot less and the 250 is no joke

 

Well, I have both and it will depend on the condition of the 250R and it's level of modification.

A stock 400EX with it's throttle adjusted properly is not much slower than a mint ATC250R. However, many ATC250R's today are in less than mint shape.

Most people have not ridden a bone stock R, and many of those that have forget how mild they were in stock form.

A piped atc250R with other modifications will change the story substantially (although I wouldn't put my money on a DG piped R being much faster than stock & the filter won't make any difference at all on a stock/piped only engine).

If you can keep the front in check on a properly modified 250R, it should be able to take the 400EX pretty easily.

Good luck on your race.

 

Atc250r: Excellent post, very true.

 

I don't know what stock atc250r you guy where riding but mine did about 72-75 mph stock. You would be lucky to get a stock 400ex to go 69 mph going downhill.

In a drag, a 2-3 mph difference is huge.

 

72-75 true MPH is unrealistic. A simple gearing calculation will show that, unless you have a special 250R that will turn more RPM than a normal one.

Also, I thought we were talking acceleration, not top speed. People tend to confuse the two. I can gear an ATC250R to do 100mph - but it may take a while & a great distance to get there.

As far as stock ATC's. Mine was a bone stock low hour unit. Now it is only bored .040 and has a pipe & that's it.

I've raced my own bikes & have seen numerous sand drags between ATCs in various states of tune and stand by my comments.

 

The racing I was taking about was asphalt, the 85-86 atc 250r ran 70+ mph easy, hell the trx250r stock ran 70-72 and it is heavier and less aerodynamic.

As per the gearing, a stock atc 250r running stock gearing 13/39 with stock tires reving to 8500 rpm (very conservative) will go 71.97 mph according to the chart. This is not taking into account the tire growth that would make the gearing slighlty higher and a rev limiter somewhere in the 9000s (if it has one). I have an 85 atc 250r engine in my trx and it revs to about 9200 - 9500 with the mods I have and pretty tall gearing (15/36).

 

ATC250R if its in good shape