1988 Kdx 200

[csdwarf]

Hi, i just bought a nice compression gauge the other day to test compression on my snowmobiles to see if i should rebuild them this summer.


i decided to compression test my dirtbikes.

My KDX test 150PSI of compression.

This doesnt seem to bad, but I would rather rebuild it then run it and do damage.


the bike runs amazingly, and starts so well, first kick in like 30-40 degree weather.

It wont be ridden a lot because its my backup bike, but my dad might be riding it some.

What should compression be? and how low can the compression go before I should rebuild?


thanks!

 

[julien_d]

150 should be fine for an aircooled KDX. My 89 has a usable range of 119 - 185psi. I am around 160 with a freshly re-plated cylinder and new top end. I would expect an aircooled model to be a bit lower than that.

 

[csdwarf]

I figured it was probably fine because of how fantastic it runs, but i am having a bad experience with my dad running his ktm 125sx for too long without a rebuild.


scored cylinder, and when he took it apart the bike was still running alright. he only had like 120 psi of compression! should be like 170 or more!!

my ktm 250 exc was just broken in and it test 250 psi of compression. and will run as low as 150.