Hi all, I've come to the conclusion that my bike may have been ported in the past. Earlier this week I got to ride a 93 Kdx200 (mines an 89), and the 93 didn't perform nearly as well as mine does. Mine seemed to have more bottom end and alot more over-rev. I know that both bikes are jetted correctly for the 0* weather we've been having, so I think I can rule that out. And I don't think sprocket size will have a this much effect on bottom and top end power. Does anyone have the specs of the port dimensions? I plan on putting a new top end in it soon, so I can check them out then. Thanks
Is my bike ported?
- Thread starter TransAm77
- Start date
jaguar
~SPONSOR~
PM your porting specs to me next time you get it apart and I'll reply with my bikes stock specs.
dirt bike dave
Sponsoring Member
- May 3, 2000
- 5,349
- 3
I've read stock ignition timing on the '89 is 1 degree retarded from the '90+ bikes, which improves power.
My buddy's old '89 always ran a little stronger up top than my old '90 with similar mods.
Hard to say that your bike is ported just because it runs better than your friend's, as there are other factors. Gearing can certainly make a difference. Maybe his silencer is clogged, his rings are worn, or something else.
My buddy's old '89 always ran a little stronger up top than my old '90 with similar mods.
Hard to say that your bike is ported just because it runs better than your friend's, as there are other factors. Gearing can certainly make a difference. Maybe his silencer is clogged, his rings are worn, or something else.
- Thread starter
- #5
Thanks for the replies.
I didn't know that the 89 ran better than the others of that generation. I'll get the port specs when I tear it down (waiting on my next paycheck).
The guy I bought it off of said it was ported before, but I didn't believe him. Since he said that he was tearing the bike down for a complete rebuild, but the way it was torn down, it looked like he knew nothing about bikes. He had the whole bottom end ripped appart and in a 5 gallon bucket. Half the bolts were in their wrong places and most of them needed to be replaced.
I didn't know that the 89 ran better than the others of that generation. I'll get the port specs when I tear it down (waiting on my next paycheck).
The guy I bought it off of said it was ported before, but I didn't believe him. Since he said that he was tearing the bike down for a complete rebuild, but the way it was torn down, it looked like he knew nothing about bikes. He had the whole bottom end ripped appart and in a 5 gallon bucket. Half the bolts were in their wrong places and most of them needed to be replaced.
jaguar
~SPONSOR~
I just tore into mine and here's what I found:
30mm from top of cylinder to top of main exhaust port
31mm from cylinder top to top of side exhaust ports
46mm from cylinder top to top of side intake ports
47mm from cylinder top to top of main intake port
30mm from top of cylinder to top of main exhaust port
31mm from cylinder top to top of side exhaust ports
46mm from cylinder top to top of side intake ports
47mm from cylinder top to top of main intake port
