Jump to content
Sign in to follow this  

pinging and fuel

Recommended Posts

After the rebuild I hear this metalic sound from the engine at 1/2 throttle,it comes even if just running on open road(no load).First thought was power valve rattling as it seems to happen when the valve would be opening.all this is happening when I have a slight gurgle in the throttle response like its running rich in that spot.It seems to go away if I go full throttle and isn't there going slower,my fear is that it pinging and will ruin my engine.What I was wondering is if trying octane boost would be effective in eliminating pinging or is it a waste of money.I would try it and if it goes away then I would repair whats causing it,I'm thinking the head needs squish band adjusted.I had the head opened up to accomodate a 68.5mm piston and the machine shop ran the cutter over the squish area,didn't look like much,just to clean it up but he might have raised the squish too much.

Share this post


Link to post
Share on other sites

the additive is crap, irrc the best stuff raises the octane rating 0.3 ron (negligable). can you get some aircraft fuel? maybe just a little race fuel from a friend or maybe a shop around you has an open can theyll give $5 worth or something? having said all that, pinging ussually happens under a load, not cruising like you describe. maybe piston slap? are you sure the bore is the right size and the piston is as well? or it could just be the PV

Share this post


Link to post
Share on other sites

bore is new and piston is new,bought together and I checked clearance before installed,to me it sounded like power valve too as when its happening if I give her more throttle it goes away.Today I checked the timing and found I had her a tad advanced but not by much,I adjusted her just slightly retard and will give her a try today.

Share this post


Link to post
Share on other sites
bore is new and piston is new,bought together and I checked clearance before installed,to me it sounded like power valve too as when its happening if I give her more throttle it goes away.Today I checked the timing and found I had her a tad advanced but not by much,I adjusted her just slightly retard and will give her a try today.

was going to mention that too. just because the bore and piston are new doesnt mean there wasnt a mistake made, but you measured, so it should be good there.

Share this post


Link to post
Share on other sites

Timing retarded got rid of the ping but killed my bottom end,although mid to high was awesome.Put the timing back to stock which is still slightly retard from before but haven't tried it yet.Think I would rather live with the ping and keep the bottem end,or maybe its time to ditch the pc pipe and get a gnarly.Guess I just got to find a happy medium between the 2.Trail riding with the timing retarded is great but sand pit riding it sucks.

Share this post


Link to post
Share on other sites

Trust me, Sacrifice the bottom end power over ping, You do not want that thing pinging and detonating. For the price it'll cost you for a new top end you could pull your cylinder off right now and send it to eric gore and the head and have him set it up for whatever pump you want with all the porting in the world for bottom end cheaper.

Share this post


Link to post
Share on other sites

fiddled with the timing some more and got her a small amount advanced and put the 48pilot back in and its very close to what I had before but now there is no pinging.With the timing retarded she had very smooth power but the low end suffered,for open trails with little tight stuff it would have been awesome.If there was only a way to hook a thumb screw to the stator plate so it was adjustable like the idle screw,that would be awesome.Tight trails advance it and open areas retard it with the twist of a screw.Hmmm may have to patent something there.

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:

Sign in to follow this  

  • Similar Content

    • By jace kornegay
      I have a problem with my stage 2 exhaust cam on my rmz whenever I kick it over the exhaust cam likes to stop at the lift unless I put it at tdc or kick it really slow it runs fine when it starts and I have played around with the shims right now all the valves are shimed and I have checked the timing everything’s to spec it just gets stuck at the exhuast I’m pretty sure it’s something to do with too much compression I probally will end upbuying stock cams but wanted to see if anyone knows how to fix this first
    • By frontline510
      I recently acquired a 1990 KDX200. The bike runs reasonably well for it's age. The first ride over 30 min the gearbox oil started overflowing into the airbox (overflow hose is routed to airbox). The oil that overflowed and the oil in the gearbox are an odd shade of dark forest green. The oil appeared to be overfilled slightly which explains the overflow. What I don't understand is the weird dark blueish greenish gray color of the oil.  I believe the PO used motul 10w40 ester gearbox oil because he gave me a half used gallon. I use Motul 710 2t oil which is blue, and run green coolant in the radiator. I drained the gearbox oil and there was a nice little clump of dark gray metalic paste on the magnetic drain plug, which should explain the gray hue. What I do not understand is the greenish blue hue. Anyone know what in the heck is going on with this old horse?
      The pic shows a sample of my drained oil. When held up to the light it turns more of a green color. Oil still feels slick as can be.

    • By 2strokeKyle
      I am wondering how a kx125 will do at at Glaims. I am 14 years old 5 foot 4 inches  and 100 pounds. I will have a paddle tyre in the back too. 
       
    • By Snox90
      will a clutch basket from a 98kx250 fit a 96kx250? How about the carb also?
    • By Kaelan Frost
      I have a new cylinder that i bought to rebuild my 1993 kawasaki kx250 with, because the old cylinder was destroyed. The guy said the cylinder is overbored a little but never gave us numbers. The new one i bought came with a piston thats been used and i would like to replace. I believe the piston that came with the cylinder is the correct size, but it very well could be off and i have no way of knowing. So how do i properly measure the cylinder bore, and how do i use this measurement to find what size piston I need to get?
       
      thanks,
      Kaelan
×