Jump to content

2005 KX250 jet block gasket. OF course its different.

Recommended Posts

Been troubleshooting a strange issue that turned out to be the jet block gasket.  Couldn't get the motor to clean out and it was running very poorly up to about 1/4 throttle.  Strange thing is that the bike ran fine when parked about two weeks prior.  Not at all gradual.  The float bowl also started leaking over the same period of time.  I guess both rubber seals gave up at the same time. 

Problem is that the jet block gasket that I had on hand for a Keihin PWK is slightly different than the one I removed.  I can't find one exactly like it.  The difference is in the single o-ring that seals the pilot jet passage.  Everything else is the same but on the 2005 KX250 PWK the oring is a smaller diameter and is siamesed into the main jet block oring.  Theres not quite enough room to fit another oring, though the oring for the air screw is very close.

I ended up cutting the larger oring off of the new jet block gasket, cutting a portion out to leave a U shaped piece that butted up snugly against the main jet block gasket while fitting tightly within the recess in the jet block.  Seems to be working very well.  Bike is running great again.  I would like to find the correct jet block gasket but this improvisation is working for now.

Edited by turbo dan

Share this post


Link to post
Share on other sites

http://www.jetsrus.com/individual_parts/021_532_su.html

This is where I got them for my KDX.  Same part other than that one little single oring that branches off.  I have been googling very thoroughly with no luck for an exact match.  Lots of places have that one type.  No listings for the other one.

I have not yet contacted the guys that make the STIC jet block.  They sell the whole thing with their own oring on it.  I know they're making orings but I do not know if they'll sell them separately.  Their website calls this jet block the 19E type.  The commonly available jet block gasket is shown for the 19M type.  Their website shows the difference quite clearly.

http://www.sticsupertorque.com/

Share this post


Link to post
Share on other sites

Just spoke with the guy at stic super torque.  He does sell their oring separately.  Got one on the way, we'll see how it looks.  Its a thicker cross section than the stock oring as it is intended to be used with their jet block so it may or may not be directly compatible with the Keihin jet block.

Share this post


Link to post
Share on other sites

Looks good to me. It is a little thicker but I bet it works. I am not sure if I'll ever take the carb apart again though. The bike is running incredibly well with the modified replacement jet block gasket. Straight up rips. More mid top power than it ever had before. super crisp down low and anywhere below 1/8 throttle. It is hard to hold onto at times. My left hand actually did come off the bars coming out of one particular corner. You really have to hold on when these things are running right.

20170721_172934.jpg

  • Like 1

Share this post


Link to post
Share on other sites

I paid $20.  I also told him he should charge more.  Would still be an excellent deal at $30 or $35 considering the oring came with the tamper resistant torx bit to get those bastard screws out, as well as new screws with threadlocker. 

I'm sure he would rather sell everyone a jet block, which wouldn't be a bad idea since the needle jet in the stock block is also not sold separately from Keihin.  Between a leaky jet block oring and a worn needle jet you could be missing a bunch of power. 

  • Like 1

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:


×