DRZ500 Concept ...

Well Gentilemen ... Here I go again ... with alot of thought and research ... I believe the DRZ can be increased to 500cc and be made as reliable as the original 475cc concept ... I recently had the opportunity to have a athena big bore cylinder in my hands and did some measurements ... using the athena cylinder with the wider water jackets and thicker cylinder skirt ... will allow upto a 97mm piston and keep the same wall thickness as big boring to 94.5mm on a stock cylinder ... also ... the headgasket sealing area left after boring will be greater than big boring a stock cylinder to 94.5 (which we already know works) ... that coupled with the hotrods stroker crank will give a 499.6 displacement ... the only issue remaining will be to add weight to the counter balancer to offset the extra weight of the 97mm piston ... The cost to gain the extra 25cc will be higher because of the premium paid for the athena cylinder and buying the custom piston from thumper racing ... another idea is to contact JE pistons as they will build custom pistons in (4) lots ... Anyway ... I thought I would thow the concept out there ... Winter is just begining ... and I 'm always thinking of a project to keep me amused ... what do you guys think ....

do it.

and then let me have one. hehe.

500cc wouldnt that require a 43mm (or larger) carb? and what kind of cams would it need to fully utilize the bore?

That would be a lot of cash for the bang LOL. I have spent a lot and that sound crazy. But if you do it let US know.

HOLY BIG THUMPIN MADNESS...... :D Please do it and report!!! :worthy:

I am all ears... keep me posted.

cool winter project:thumbsup: :worthy::D

:worthy: wow that would be awesome. but kinda expensive too. expensively awesome! :D

500cc and some tweeking from Eddie, could it be a 70HP DRZ!???


Make sure to log your progress so we all can learn for you.

Oh, and pics!

That's one sled Eddie would do all the building on. I have one of his old bikes ot's the most reliable damn machine I have ever ridden. I don't think it will ever need a valve shimming. I ain't never seen such motor perfection as when he puts one together. Damn shame a friggen electrical part made the SM he built for DR seem like a bad bike . I know the guy he don't build bad bikes. If anything he may be the best damn builder I've seen in 44 years. pdawg:thumbsup:

that should work.

the only down side i see is that is a lot of piston to be moving that fast.

that should work.

the only down side i see is that is a lot of piston to be moving that fast.

Yeah ... I thought of that ... then I took a look at KTM's stroke vs Peak power/RPM ... coupled with the fact that the 475 stroker makes peak power at about 8k rpm ... erased the concern out of my mind ... over rev ability ....

well just have to see ...

I am hoping that some one on the forum would have a scared athena cylinder kicking around ... the guy that has the 470 big bore might be willing to donate the 97mm thumper racing piston ... I would donate the cost of the big bore and replate ... I'm sure eddie has a bike kicking around his shop for doner/dyno time ... Just thrown it out there ... You guys like thinking out of the box ... I'm just providing the spark ... what do you think

whick ktm are you talking about?

i think the power peak will be lower than the 475 for sure.

with my new programable ignition set up i could lower the rev limiter 9500 or so and it will live fine.

that should work.

the only down side i see is that is a lot of piston to be moving that fast.

No joke. 97mm is a pretty massive slug of metal to be hauling around, especially with the longer stroke he'd be adding. Maybe if he gets a forged piston it could reduce that effect enough to where it wouldn't be as big of a deal.

i just checked my dyno files.ktm 525 makes peak power at 7500 rpm and the 625 ktm at 6500.

You guys don't have little kids do you??

Who do you think is typing for eddie. He relays what to say while he works on the bikes.

You guys don't have little kids do you??

my youngest is 7.

i dont get your point?:worthy:

my youngest is 7.

i dont get your point?:worthy:

I think he means ... do we let them ride our hopped up toys ...

Eddie ... I was refering to the 72mm stroke on the 525 ... you illistrated the point listing the peak hp on the dynographs

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