still pinging

[whc]

My 400ex always ping when it gets hot, like half way thru a 2 hour harescramble, my engine is mildly modified as noted below, I have an over sized oil tank, keep the cooler clean am jettet with a 168 main and one up on the low speed, I have ran as high as 100 octane. the engine would ping even when stock. am I lunging it too much? do I need to go even bigger on the main? when I tear sown the engine there is always some carbon on the piston crown which leads to to believe I am rich enough. the time and ignition are stock. any thoughts> thanks Bill

[JOHNDOE83]

Yeah Id bump it up on the main a lil bit.

If your at 168-170 and pinging with 100 octane you may need as much as 185 main jet. Call me crazy but dont knock it till you try it.

Also try making the needle a lil bit richer, your probally getting most your heat from lean needle settings if you mostly trail ride.

[CJM]

What jets are you running, keihin, dynojet?

Id suggest a keihin 175 to start (go down from there till you reach a happy medium) and 3rd notch down on the needle (from the top-the flat end). I have the near the same setup as you and can ride all day with no problems. Im also at sea level.

[supertrooper90]

Im curious to hear some thoughts on this. I am running a very similar set up as you, and I have the same problem. about an hour into a harescramble I start to get a ping when lugging it. Doesnt seem to have any fade in power, but the pinging is there. Last harescramble i did was in may. I ran a 50/50 mix of 100/93 octane. didnt really help. I think im running a 175 or 178 kehin main in a 450r carb. the plug chop says im good even though most will disagree. (and I was a little reluctant myself)

[CJM]

For the record I and steve (honda400ex2003) have near the same setup. We are both at or near sea level and when he ran the 400ex carb he could run a 168, needle 2nd notch and 42 pilot on his 416. My 416 likes a 170 main, 3rd needle notch and 42 pilot (I could actually go up since it backfires slightly on deceleration tho). my plug chop is dead on too and I never ping, I also only run 93 octane.

I think that although the jet and plug chop might be ok, your not running it nearly as hard as you will be in a race. Might try going up a size or two in the main and see what happens. My buddys old 450r would ping on anything but 100, he got a new 450r and jetted it himself instead of letting the dealer. He can now run 93 pump no issues and he is slightly rich on the main by maybe 1 size.

Bottom line, Id try going up on the main and possibly messing with the needle.

[supertrooper90]

My head is ported and polished, and I'm not running a base gasket, but from all the stuff I read when I was building it, having the piston near zero deck height was supposed to keep this from happening.

[CJM]

Did you try upping the main 1 or 2 sizes-still does it if you did?

[supertrooper90]

I ordered an adjustable hrc needle for the 450r carb. I think it pings more in the needle range while im lugging it. I dont think it needs anymore fuel up top. And it didnt do it in the winter. It seems more heat related for me. Sorry for the hijack WHC Ill stop now.

[whc]

I have 170 to 180 jets on order should have them today and may also raise the needle One notch. will not be racing for a couple of weeks so may not know results right away. just as a note I am running the stock carb, also this winter I decreased my comp. by using a slightly thicker head gasket. still no change, well will be rejetting this week and will try to ride sunday. will repost later. Bill Carr

[JOHNDOE83]

Originally posted by supertrooper90
Im curious to hear some thoughts on this. I am running a very similar set up as you, and I have the same problem. about an hour into a harescramble I start to get a ping when lugging it. Doesnt seem to have any fade in power, but the pinging is there. Last harescramble i did was in may. I ran a 50/50 mix of 100/93 octane. didnt really help. I think im running a 175 or 178 kehin main in a 450r carb. the plug chop says im good even though most will disagree. (and I was a little reluctant myself)

can you get a pic of the plug chop?

removing the base gasket raises the compression but will also off set your timing, you may need, to adjust timing a lil bit

[leakyvoodoo]

i am running 48 with a 170 with 416 12.5.1 and sparks cam. on 93 all day long i do turn it off alot to cool it down. but no popping at all. i do suck some gas. i may get 4 or 5 hours on a tank. is that normal cjm. is your bike bad on gas also

[CJM]

Originally posted by leakyvoodoo
i am running 48 with a 170 with 416 12.5.1 and sparks cam. on 93 all day long i do turn it off alot to cool it down. but no popping at all. i do suck some gas. i may get 4 or 5 hours on a tank. is that normal cjm. is your bike bad on gas also

The more compression, the more power. Also way your riding (wide open or just cruising) can burn tons of gas, as does alot of smashing the throttle. Id say for your setup its pretty good, plug is what color mostly?

I can ride an entire day usually (6-8 or more hours) on 93 pump. But you gotta remember its not all out wide open throttle, sometimes I cruise, do some jumps, race around trails, or just hang out. Im usually on reserve in about 5-6 hours or so-depends on how I ride. 2 weeks ago I finally hit reserve and did ALOT of riding, we rode from like 11am till 8:30 on and off all day. My quad never pings-I do need to up the pilot b/c without a spark arrestor in the exhaust I pop on decel a bit and the air/fuel screw is 3 turns out already.

I am also running slightly rich with a 170 main vs prob a 168 would be perfect-but I prefer slightly rich as I wont have to change it based on conditions and temps. I ride it that way usually year round.

[honda400ex2003]

Originally posted by CJM
For the record I and steve (honda400ex2003) have near the same setup. We are both at or near sea level and when he ran the 400ex carb he could run a 168, needle 2nd notch and 42 pilot on his 416. My 416 likes a 170 main, 3rd needle notch and 42 pilot (I could actually go up since it backfires slightly on deceleration tho). my plug chop is dead on too and I never ping, I also only run 93 octane.



i also ran a 170 main in my 400ex carb. i only ran the 168 in my 450 carb.

some machines are quite different than others though. ive seen some as big as 180s and as low as 160s in 416s.

steve

[CJM]

Originally posted by honda400ex2003
i also ran a 170 main in my 400ex carb. i only ran the 168 in my 450 carb.

some machines are quite different than others though. ive seen some as big as 180s and as low as 160s in 416s.

steve

I think the elevation plays a huge role in it. Guy told us his stator was bad on his raptor 350, turns out it was probably fine-the idiot came from colorado and was jetted for it lol..