bye bye maxim x power

well I know its been a while but I blew my maxim x up today while passing a car I probly hit around 10k rpm then when I let off the throttle I heard a bunch of crunching and the motor was off. the piston rod went right through the motor on both sides and I don't think the cause of this was my valve clearences bigfits

 

probaly the 10K rpm

 

10K is redline on an X, and 11k on the FZ750 (they share engines for the most part).
Broken rods happen for a lot of reasons.

 

yeah I never go past 10k but ive been downshifting doing it all the time lately also its a mystery motor so idk what its been through

 

but yeah well time to see how long the aircooled xj700 will go till a rod breaks

 

i read somewhere a long time ago that the red line of a engine is determined by valve float and the piston breaking the sound barrier setting up shock waves that destroy the rod bearings.
it would take way too much math for me, so i just took their word for it

 

hmm sounds right

 

i wanna hear what bigfits has to say about it all

 

Bigfitz hasn't said anything around here in months, so I'll chime in instead. Have you checked your brake shoes? Delamination probably didn't contribute to your issue, but it is still serious. Too bad I never am...

 

PS am i reading you right, and you still have a 700? at least you've got something to ride. Too bad, but you gotta look for the bright side!

 

The X-motors are known for throwing rods occasionally, more than one has met its demise in that manner.

 

what are the reasons they through rods and is the aircooled motor more bulletproof?

 

Don't know the answer to that Josh, just seen it mentioned periodically on this website going way back when (even had some pictures of holed cases). The redline on the X motors is actually slightly higher than on the air cooled 700's (by 500 rpms), but that is not the cause. Could be operator error, could be engineering error, could be casting error (a bunch of bad rods or bearings got out). In my memory I can't recall anyone breaking a rod or launching a piston on any of the air-cooled motors; occasionally you'll read about pistons getting holed due to overheating, but never letting go a rod, and the air-cooled engines are MUCH more common than the X motors (at least in XJ-series bikes), so if it was an issue, the same percentage of air-cooled engines puking their guts would be something you'd hear about on a weekly basis.

The X motor was a newer engine design than the tried-and-true air-cooled engines, so it may be something along the lines of what Polock mentioned above (design oversight) or bad materials. Would be interesting to learn whether the FZ's suffered the same issues, or whether it had been corrected as time went by.