av gas

[toalco-kdx]

im pretty sure my bike is predetonating, its a 2000 kdx 220, i ahve a fmf pipe and silencer, and had it ported for mid- topend. it sounds like someone is hitting my pipe with a hammer or like marbles are in my pipe, like someone else described it as. it does this at idle. i just finished cleaning my powervalve, there was quite a bit of carbon, could that make it ping like it is?

i was thinking about getting av gas. i live about 1/4 mile from a airport so i hav pretty easy access to it. is there any concerns about what i should look for if i buy some? is there different kinds? what would work best in my bike? i ride mostly at the mx track or in gravel pits.

the pinging just started after i put my bike back together after cleaning the powervalve, and i cleaned the valve becuase i had suddenly ran out of low end power.

i dont know much about fuels so anything would help me alot.

 

[bigred455]

You want av gas 100LL it will be blue. After my motor work she was a knocking down low just like yours.You are saying it did not detonate before you cleaned the exhaust valves? doesn't make sense. My bike was fat with the av stock main 165 it was real lazy blubbery I stepped down to a 162 it cleaned it right up but sometimes you can here a miss or a very slight sputter when you are on it heavy,so 160 main I settled on. I moved the clip to the 3rd from the 2nd richer just to play it safe.It was not clean at all real dull sounding and power dropped, So I moved it to the 1 st Wasn't sure if it was better than the second so I am running it in the 2nd stock. The pilot I am caught in between stock 52 or a 50. The main jet with the av gas needed to go leaner The mid woke up from just changing the main. Just because my bike ran richer with the av don't assume yours is going to. You will find that jetting is easier with av fuel than pump crap.

 

[toalco-kdx]

im confused about the pinging too. it NEVER pinged. before i took apart the engine i put a 155 main inplace of the 152 and that increased the mid, still no bottom end though and still no pinging. then i took apart the engine, cleaned the valves, used the SAME gaskets that were in before, i guess there might be an airleak . but the gaskets looked fine and there were no tears thats why i reused them. they looked like they were new. the egine started up 2nd kick and ran fine, but i noticed the pinging. any ideas?

i dont really know much about jetting. i didnt really understand the specs u told me u were running. i think ill try the av gas. what about all the lead? what does that do? i buy premium gas and im pretty sure its unleaded.

 

[toalco-kdx]

oh and i dont even know if the bottom end is back because something is wrong with my transmission.

 

[CaptainObvious]

toalco-kdx,

It sounds like you have more problems with your bike than the fuel you are using.

First off, never reuse gaskets. Once they are compressed and sealed they can’t seal as they were originally designed. Why go through the hassle of tearing apart a motor, only to put it together incorrectly.

Secondly, before you start chasing your engine problems with different types of fuel you need to KNOW how to jet your bike properly. Do a search; there are many simple “how-to’s” right here on DRN.

Third, fix your transmission.

BTW, detonation by too low of an octane seldom (if ever) occurs in the lower rpm range. The cylinder pressure and heat simply do not exist to cause octane related knocking/pinging. If the bike is pinning it likely is something other than the fuel you are using. You can run 150 octane and the problem might not go away. Worst case, it will mask the real problem.

 

[canyncarvr]

Some reading for you:

http://dirtrider.net/forums3/showthread.php?s=&threadid=5277&perpage=20&display=&pagenumber=1