Wonder if the threads on the cam sprockets/cams were coated with a film of oil possibly allowing them to loosen? I'd definitely remove the bolts and use contact cleaner on both threaded surfaces bolts/cam sprocket bolt holes then run the red thread locker.

Looking over the dyno results, it's easy to see the drop off of hp / torque in the upper rev range. And in the dirt that translates to running out of breath so to speak. I need that upper end hp/torque. I enjoy your use of the word radical tho!

 

I am not surprised by the drop off. It occurs pretty much the same place the stock drop will be - around 8600 rpm, the point of max horsepower. The KLX250 engine - in spite of what the tach may show as a red line - has tuning that has the horsepower peak at around 8600 rpm. It will take some work; cams, hi-comp piston, head work, carburetion to get it higher. The dyno stuff does show the ability to overrev though, a good thing off road. The red line is just plain way too optimistic, up shifting around 8500 is better than trying to rev out further in most cases.

Your evaluation of top speeds makes some sense, my 650 maxed around 100, showing about 108 on the speedo. Never tried with the 250, but I think KLXter is running an SF which has a 39T rear sprocket versus the S having a 42. I know with a 15-39 my bike cruised at 60 in 5th easily. So maybe 100 is possible with a well tuned SF model. But I don't know.

Did you find the big bore to actually push up the true hp peak rpm or did you do the carb/pipe at the same time and aren't sure? Did it actually push the power peak up or no? Not that I'm looking for a lot of revs, power is power. If in the middle that's just that much more usable in general.

I know punching out the 650 didn't do much on top, but boy what a boost in the middle. It wasn't a higher compression piston though, it was a stock Vulcan 1500 piston adding around 27cc displacement to the bike, but again what a boost. That's why I'm taking a chance with the AHL 299cc kit. Maybe send the stock cylinder out to BB and do a 330 or 351. It would be fun to have close to DRz400 performance due to power/weight considerations with the big bore KLX.

 

I think oil film might have been a factor with the LockTite not doing the job as well as expected.

 

Well, lets not abide any "rewriting of history"..

My KLX250S and Scootr KLX250S are running identical mods (MCM, lidless, full FMF exhaust, the lidless CVK setup for full exhaust) and both have done over 100 mph indicated on level ground with no wind assist on my runs and perhaps small tailwind with Scootr's, using stock sprockets, near sea level. Here is the thread - https://www.kawasakiforums.com/forum...ndition-43883/

Whether or not 100 mph indicated is something different is immaterial to the fact that they will go 100 + mph indicated, with stock sprockets..

There is no abnormal drop off of TRQ with the MCM versus stock cam timings. The MCM TRQ curve follows the stock cam timing curve perfectly above 6500 rpm.. It is about 1/2 lb ft under the stock timing curve the whole way from 6500 rpm on up.. And to be accurate, this is actually within the margin of error for a dyno run. - the MCM may not have any TRQ deficit above 6500 at all..

The MCM reshapes the TRQ curve below 6500 rpm with big increases while maintaining the shape above..

Here is that thread - https://www.kawasakiforums.com/forum...timings-44296/

 

If you guys were anywhere near in line with each other the draft can add up to 10 mph. I learned that in bicycling. on one down hill I would run 45 mph, in a draft with another rider we hit 52 mph Not to mention watching flat track. Adds some speed to both riders. But regardless, not being there and with the modifications, I won't argue the point myself.

You are running the stock 14-42 then, right? I know going to a 15-39 definitely steps up the road capability.

 

Ahh.. Scootr lives in Wichita Kansas... I've never met him in person... Both bikes are stock 14-42.. l

 

Oh, the way it was phrased, looked like he was with you with possibly a tail wind.

Either way, no argument here.

 

Being a borderline savant at second-guessing myself, all this talk of cam gear bolts working loose required me to go back in a look at mine... just in case. Good news is that mine are still tight many miles after doing the MCM *grin While I had all the bodywork off, I took the opportunity to install a new Edge 2 tail light kit that arrived for Xmas... huge improvement over the styling of the stock bits!

 

Abrams, your bike is "full tilt stage 1" also.. ever get her near 100mph?

 

Oh hell no.....LOL

I'm too mortal to get above about 60mph.. not to mention geared 14/49 and knobbied for deep sand.

My old Versys is pretty comfy around 80mph, and I had a '92 naked GS500 that I remember getting up to 105mph indicated on a long gradual downhill (but that was 20 years ago, so I may have been dreaming *grin).

KLX is too light for me to get comfortable much above the posted limits...