KX Riders

Maintenance & Technical => KX500 Original => Topic started by: jonny500 on October 30, 2010, 07:38:36 AM

Title: BEST K5 CON ROD
Post by: jonny500 on October 30, 2010, 07:38:36 AM
i have heard stories of the k5 breaking con rods. i currently have a bent one. my questions are have any of you guys bent or snapped one, what do you recomend, what do the guys running high compression engines use. i am not a pro rider or anything but i work my bikes hard even the 500 hence i have a destroyed engine, i would like anyone and everyone to have there say on this so i can make the best choice. thanks in advance
john
Title: Re: BEST K5 CON ROD
Post by: martinfan30 on October 30, 2010, 08:57:35 AM
I really am a fan of OEM internals...
Title: Re: BEST K5 CON ROD
Post by: jonny500 on October 30, 2010, 09:14:10 AM
oem are the same as prox, all conrods are forged?
Title: Re: BEST K5 CON ROD
Post by: kwakman on October 30, 2010, 10:18:39 AM
i dont think they are all forged.vesrah are, I think hotrods are, but have been known to fail, wiseco are forged, and I think the kwak rod is too.dont think prox are but not certain.
Title: Re: BEST K5 CON ROD
Post by: don46 on October 30, 2010, 12:31:48 PM
high HP over time will break KX rods, I'm spraying nitrous and using a Titanium Rod. Not sure where to get another one, the one I have  I got off ebay.
Title: Re: BEST K5 CON ROD
Post by: sandblaster on October 30, 2010, 04:40:32 PM
high HP over time will break KX rods, I'm spraying nitrous and using a Titanium Rod. Not sure where to get another one, the one I have  I got off ebay.

I'd like to get my hands on a Titanium rod that was junk and reverse engineer it and make a set of prints so I could see about having some made.
If you have one laying around I would be happy to make the plans, send you a copy as well as send the rod back.
Just a thought....
(http://i644.photobucket.com/albums/uu165/oemcycle/RODANDPISTON.jpg)
Title: Re: BEST K5 CON ROD
Post by: gortex on October 30, 2010, 05:47:04 PM
Getting my motor rebuild with a Cr500 rod to hold up to the increased hp we going for. Meant to be one of the strongest rod around.
Title: Re: BEST K5 CON ROD
Post by: RoostDaddy on October 31, 2010, 05:02:56 AM
Getting my motor rebuild with a Cr500 rod to hold up to the increased hp we going for. Meant to be one of the strongest rod around.
what year rod are you going to use, I believe honda has two different lengths, between the years on the 5's.  Also, what brand?
Title: Re: BEST K5 CON ROD
Post by: kwakman on October 31, 2010, 09:28:47 AM
I dont think the cr rod is any stronger than the kx rod, if you were making them they would just be the same quality for each app surely? Does any one know the length/s of the cr rod, centre of small end to centre of big end? I believe kx rod is 14.5cm...
Title: Re: BEST K5 CON ROD
Post by: don46 on October 31, 2010, 11:48:02 AM
Getting my motor rebuild with a Cr500 rod to hold up to the increased hp we going for. Meant to be one of the strongest rod around.
what year rod are you going to use, I believe honda has two different lengths, between the years on the 5's.  Also, what brand?

You are absolutely correct, although one is like a pre 87ish and the other is like 87 on. The pre 87 are almost unobtainable, or so I was told, and it was shorter that the current rod, I have both and could measure them. I think the reason that Honda has less rod issues is due to the shorter stroke. I have a motor built with the Honda rod and piston, a true 560, and for a trail bike it would probably be great the thing will pull a truck but doesn't rev quick, I also used a 87 cylinder, the thinking was that the huge bore wouldn't be affected by the center KIPs. There are some guys now having 90-91mm KX pistons so I may put the KX rod back in and get one and try it.
Title: Re: BEST K5 CON ROD
Post by: RoostDaddy on November 01, 2010, 09:17:11 AM
Don, from what I have seen the '85-'86  has a "short" rod length of 178.45mm and the '87-'01 has a "long" rod length of 183.6mm
 I have also seen KX pistons ranging from 89-91mm using the Wossner piston.
Title: Re: BEST K5 CON ROD
Post by: kaw rider on November 01, 2010, 11:50:27 AM
jason   those must be outside to outside measurement.
Title: Re: BEST K5 CON ROD
Post by: RoostDaddy on November 02, 2010, 09:28:08 AM
jason   those must be outside to outside measurement.
yeah, I'm pretty sure that was overall length.  It's not my measurements, just what I've found, so they may not be 100% accurate.  If someone knows for sure, Post-Up.