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rm2fifty 01-21-2008 05:53 AM

2005 cr85
http://<a href="http://www.allthings...640_Large_.JPG[/IMG]i have a 2005 cr 85 that i replaced the crank on back in july 07. and yesterday when i pulled the top end apart the bearingon the rod end is no good again has about 1/8" of play up/down. i run amsoil dominator in this bike 50:1 i also have other bikes i run this in same ratio and no problems. now a little about the bike: FMF exhaust, vforce3,uni filter,tag top clamp,IMS tank,tire balls. maybe the crank was just ready to go or i got a bad little brother desert races this bike and does an average of 80 miles per race. i know thats a lot of wear on this bike but replacing the crank twice a year seems a bit much. or should i change the oil im mixing with the gas. if so what kind.

http://<a href="http://www.allthings...640_Large_.JPG[/IMG]

Jethro 01-21-2008 06:34 AM

Re: 2005 cr85
Was it a brand new crank (OEM or aftermarket?) or a reconditioned job?

I assume you're talking about the bottom bearing and not the top?

rm2fifty 01-21-2008 06:43 AM

Re: 2005 cr85
the first crank was oem the one that came with the bike. the second crank was brand new aftermarket made by hotrods. both times the crank went out it was the bottom bearing. first one siezed and now this one has alot of play and the piston is hitting the head/dome.

dhighlan 01-21-2008 09:29 AM

Re: 2005 cr85
If he is running the bike WOT all the time in the desert I would jet it accordingly (main and needle) and go with a lower ratio. Are you sure it is the lower rod bearing and not the case bearings? 2x a year is definitely too much. Did you do the crank (hotrod) if so you did do the case bearings at the same time right?

rm2fifty 01-21-2008 02:57 PM

Re: 2005 cr85
hi, yes i replaced the crank myself. i replaced the crank bearings and seals. i put all new gaskets and oil seals through out the entire engine. i figured since i had it apart i might as well replace everything as far as seals and bearings went. i wanted to do this right and i didnt cut any corners to prevent from taking this apart again.
i am positive the lower rod bearing is the problem, the crank itself does not move its the whole rod that moves. thanks

dhighlan 01-21-2008 03:08 PM

Re: 2005 cr85
Tough one to call but, if I had to guess he is on the main a lot in the desert and 50:1 can't handle that. Also make real sure you're not getting any debris in there through the air box as this will tear it up quick. The other thing is any air leak in the ignition side seal will cause problems in a hurry.
How does the piston look?

rm2fifty 01-21-2008 05:38 PM

Re: 2005 cr85
the piston looks good. i did a pressure check (plugged the exhaust port and pressurized the intake side with a PVC fitting w/gauge and a valve that i built), on the head and base gaskets, and on the crank ignition side, also the center case gasket. i didnt find any leaks. i am running a 150 main jet. i think stock was 140. needle on center clip. the elevation here is 5500'

rm2fifty 02-26-2008 09:35 PM

Re: 2005 cr85
since the last thread i posted i called hot rods and sent the crank back to them. they said i need to run a lower ratio like 32:1 instead of 50:1 and the guy from hotrods is sending me a new crank (warranty) which is great. But i already ordered a new complete bottom end kit from wiseco so i guess i have a spare. once again the 85 is running (32:1 ratio). thanks for all the advice you guys had it figured out from the start.

Thumper996 03-18-2008 07:20 PM

Re: 2005 cr85
Funny, i was reading you comments and hadn't got all the way to the last post yet and i was going to reply you are running the wrong ratio. Manual for the CR85 states 32:1 oil/Fuel ratio.

Something else you should know is Wiseco started a new special deal Jan1st that not everyone knows about. You can now buy a bottom end kit for the same price and the previous crank kit,

I just rebuilt our 85 and the new special kit was $158.00 from my Honda Dealer. Kit includes crank, crank seals, crank bearing, top rod bearing, right crankcase gasket, middle crankcase gasket, water pump gasket, and all other seals in the crankcase. oh and the intake and exhaust gaskets.

Heck of a deal.

2kHondaCR500R 03-18-2008 07:50 PM

Re: 2005 cr85
Run the oil at 32:1 for high rpm WOT running. Rejet as well.

rm2fifty 03-18-2008 11:22 PM

Re: 2005 cr85
thanks for the reply. yeah were going to run 32:1 in the 85. it funny how amsoil says you can run their dominator oil at 50:1. But i have found out this is not true for smaller engines that rev alot higher, i have run amsoil at 50:1 in my 2003 rm250 since 2003 and its running fine. i have rebuilt it once a year since 03 and the piston and power valve are usually very clean. But the RM doesnt rev as high as the 85 and i usually dont run WOT for extended periods. the cr85 did fine at 50:1 until we started racing it. im still using Amsoil but at 32:1 for the 85, i have gallons of the stuff.
i bought my wiseco bottom end kit for about $130.00 from Part Monster :rockout

2kHondaCR500R 03-18-2008 11:44 PM

Re: 2005 cr85
I never go by the general recommendations of a oil manufacturer over the engine manufacturer because they don't know if you're running a weed eater, or a high rpm race engine.

Just always remember the factory recommendations supersede anything else out there.

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