crank reliability & crank alignment questions???

jminor

jminor

Vmax-4 Senior Member
so when you start to pound the torque to these things on the grass, how are these bottom ends holding up?
 

I believe you will be fine with 800 crank but with -92 750 there is trouble... Mine twist on loose snow.
 
Cranks

From what I remember back in the day on the 750's, Yamaha recommended welding the crank even if it was a simple mod such as putting on a set of quad pipes. This was no longer necessary when they introduced the 800's.
 
I know all that I was wondering how these things were holding up for the guys that are racing them and how many miles are being put on them in these extreme conditions.
 
JOSH, DON,T KNOW WHAT YOUR ASKING. lol !! I GUESS IF YOUR RUNNING UNDER 9000, THAT REALLY WOULD NOT BE EXTREME !! NOW IF YOUR RUNNING 10,200 AND FIRING AT 180, NOW THATS EXTREME !! AGAIN MY GUESS THESE CRANKS ARE ALL TRUED AND WELDED. !! ALL DEPEND ON WHAT RPM YOUR RUNNING AT !! 3:16 (tony)
 
Tony what I mean is what is the predicted time of failure for these bottom ends? My bottom end has around 8000 miles on it and now its going to be torqued to death on the potato fields of Jacobeys!! Take a skidoo for example you know around 6000 miles you will be completely redoing that bottom end. Is there a common mileage where these show enough fatigue that they require a tear down? BTW I will be spinning 8750 or so...:fishing: !!!!
 
Here is what I can tell you from my experiences:

I ran my 1992 Vmax-4 750 for more than 11,000 miles of hard trail use with the only non stock engine
component being the PSI 8350 rpm pipes with no issues, this engine is still alive in one of my buds ex race sleds.
Also I have put more than 9,000 miles on the 800cc Vmax-4 engine that replaced the above 750,
again the only non stock engine component was the PSI 8800 rpm pipes - this sled still runs like a champ!


Hope this helps.
 
LOOK AT THE MILES ON RULES VMAX4,s. LOOK BEING YOURS IS A 800, I DON,T FORSEE A PROBLEM FOR YA. THAN ON THE OTHER HAND, YOU GOT THE BEST CRANK, YOUR NOT RUNNING ALOT OF RPM, AND I HAVE NO IDEA WHAT THE TIMELINE FOR FAILURE IS. I GUESS IF YOUR RACING THAT CAN BE ANYTIME lol !! 3:16 (tony)
 
Crank

jminor said:
I know all that I was wondering how these things were holding up for the guys that are racing them and how many miles are being put on them in these extreme conditions.
Click to expand...

If ya know all that then whats the question? Its a loaded question to start with. How many miles will my crank last? Hmmmm, how hard was it ridden? Did ya use penzoil? Was it run lean most of its life? And on and on. It will last until it breaks, so run it and see what happens. Throw the juice to a weak bottom end and it will be like throwing a hand grenade under the hood. Don't worry about "blowin yer crank",,,,,,Josh.....LOL... I have a spare in case ya need it
 
Thank you Skinner for the input. I know there are no guarantees, I was merely making conversation and seeing if there was any patterns out there. I'll shut up now, take my toys and go home.:Flush:
 
HEY, WHEN YOU '' BLOW YOUR CRANK '' AT JACOBEYS, YOU CAN SAY , SEE THIS IS WHAT I WAS ASKING !!!! lol. THAN I,LL SAY NO !!! '' THATS RACING '' 3:16 (tony)
 
As long as you don't blow a nut when I scream past you!!!! LOL! Sorry I had to do it and will probably eat my words for saying it too! Hey, I've got to survive a couple of races before jacobeys by then I may just be a spectator, who knows, I do understand that racing is not the best thing for your hardware that much is obvious!
 
LOL!! I guess to clarify the original question even more was that to launch these on the dirt with studs that are about .5" or more over the lug and wicked gearing is going to put alot more force to the bottom end than anytime on a snowy surface would IMO so I wondered if there was any common problems amongst grass racers. That is all. When is Jacobeys again? Also, are there any other events in the NY area that would be worth me trying my luck at?
 
JACOBEYS IS FIRST SATURDAY IN NOVEMBER. ALOT OF RACES IN NY, I,LL POST DATES AS WE GET CLOSER. JOSH, YOU COME OUT AT 5000 ON CLAY WITH WICKED GEARING , I WOULD WORRIE ABOUT CHAINCASE MORE THAN CRANKSHAFT. 3:16 (tony)
 
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