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xr400 retard the timing?

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I haven't heard of a way to retard the timing. May I ask why you want to?

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on a high compression engine, the timing could possible retarded to reverse pinging problems, predetionation, and could help get better fuel economy.

I heard someone mentioning about messing around in the CDI box but wanted to ask around here and see what anyone has to say

erik

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Retarding the timing would hurt fuel economy as it starts the ignition later in the combustion cycle shortening burn time.

The 400 is a fairly low compression engine that does not have pre-ignition problems on pump gas unless a piston of over 11:1 C/R is fitted. Stock, I believe, is about 9.3:1.

Pre-ignition can be caused by a spark plug heat range that is too hot, or carbon accumulations in the cylinder head and piston crown.

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Wouldn't retarding the timing also negate some of the benefits of going with a higher compression piston? I'd think (just IMO of course) the best solution would either be run a compression ratio that will run on pump gas, or run a high enough octane fuel for your compression ratio.

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you are correct, your wasting your time buying a high compression kit and then trying to retard the timing. However, if you purchase a bike with a HC kit, it might be good to run a colder plug and retard the timing 1-2 degrees to keep the bike from pinging from predetination. That is why i was curious if it could be done?

thanks

erik

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Alright, if you purchase a bike already in that condition it changes the situation a little bit. I was trying to figure out why you'd buy a high compression piston, then lower your power output, but now I see where you're going.

Not sure if you can do it or not however, someone else will have to answer that.

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there has to be a way to retard the timing a bit. i called dyna about their adjustable fs ignition boxes and they dont make them anymore according to the guy that answered the phone...

maybe using a 98 up box to retard it as it was an emissions box.

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The ignition control module on a 2003 is different than on a 1996 (according to Bike Bandit, these are the only years I checked). Might want to call Bike Bandit or Service Honda and ask if there is a difference. If the newer boxes do have the timing retarded a little bit, that could be another possible mod to do (put an older box on a new one and advance the timing).

Here's the part numbers if you want to check it out.

2003 XR400

2: MODULE, IGN CONT (CDI) 172049-001 $116.27

1996 XR400

2: MODULE, IGN CONT (CDI) Area Code A 172048-001 $167.56

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Does anyone have a newer used cdi xr400 igniton box for sale? 98 and newer to see if it will retard the timing?

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