Save your money on the oil cooler stuff and put it towards a good after market ignition
Never had any heat issues on any of the evo's i owend. Run 1 or 2 step colder plugs than stock. Also put a good fuel valve in it like a pingel. Wouldbe nice to know what was done to it.
Most guys with the evo's shaved the heads some to bump up comp and installed the ev27 cam back then.

 

This.

If you're pinging, your advance is off. No other add-in solution will do anything permanent, and carrying around mixing your gas at each stop is a disaster in the making.

Fix it right, fix it once.

 

So I go with my gut and pull 2 degrees at a time till it stops pinging and run that for now . Then replace ignition wit something programible when I can afford to do so.

 

I did that once... on my Deuce. It worked fabulously.

 

How did you pull 2 degrees on the stock Deuce ignition?

 

That little cover with the two screws comes off revealing the "points" plate which has two screws riding in slots that can be turned clockwise or counter clockwise.

 

Mine didn't have stock ignition. It had a Crane Cams ignition. But adjustment is the same - see Stiggy's post above.

 

Gotcha.. So the ignition wasn't stock on your case so you weren't running the stock advance curve.. You simply had too much timing and retarding worked.

Adjustment is not the same.. One requires twisting a ****. Other requires turning a plate.

IMO setting the timing on a EVO is a PITA unless you have a good aftermarket ignition.. Then you can set it statically.

 

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" If you're pinging, your advance is off. "

No disrespect intended but when a motor detonates it doesnt always mean the ign timing/adv curve is way off base or wrong esp when it's stock ecm thats not been touched as the OP already stated.

And if timing is still stock in op's stock ecm (which should be the case) its not a good idea perf wise to bandaid fix the detonation by taking the easy way out retarding the timing the 3-4-5+ deg required to stop the detonation on lower grade 91 octane fuel hurting overall perf & mpg in the process too.

Thats because retarding ign timing can:

* INCREASE ENGINE & OIL TEMP ,ESP AN AIR COOLED BIKE MOTOR.

* REDUCE PWR & TRQ.

* MAKE THROTTLE RESPONSE LESS CRISP/LESS TRQ'Y FEELING.

* REDUCE FUEL MILEAGE.

That's why i rec going after heat and carbon buildup that are often significant factors in detonation in an air cooled hd v-twin (esp in warmer temps as long as current timing curve isnt out of line/way too much timing thats maybe coming in too quick which shouldnt be the case with the OP's bike having the stock ECM which is a key point.

And OP also stated the motor dosent ping or detonate till it heats up which falls in line with cleaning comb chambers and cooling oil/motor with the 2 cooling mods i rec being a good place to start esp when they will give his bike so many benefits right off the bat in mult ways and not just improve the detonation situation.

Air cooled HD motors do in fact become much more sensitive to detonating (esp in warmer temp) even with proper timing curve and when you address the issue of the excessive heat they produce significantly reducing oil/engine temp along with also doing a good combustion chamber cleaning using a helthy dose of techron (concentrated version) that will often stop the detonation & or greatly reduce it that will be challange to do on the lower grade 91octane fuel he's running.

But the OP has a few issues that can make that harder to stop detonation on his bike with 1st being only 91 octane fuel (vs higher octane 93) avail in his area along with his bike also having a fairly fresh top end rbld where he dosn't know if compression is still stock or has been raised let alone if it has stock or aftermarket cams too.

Now that has a big affect on the motors cyl pressure that has a lot to do with dictating the octane requirement and lets face it,on avg larger disp air cooled hd v-twins need 93 octane fuel to not detonate or at least to significantly reduce it (esp in warmer temp) & he's trying to stop the detonation with lower 91 octane fuel with unknown compression and cam setup that may have higher cyl pressure requruing 93 or bit higher octane requirement to begin with.

But cleaning the comb chambers of excess carbon along with getting the oil & motor to run a lower more reasonable temp is never a bad thing that will only improve the bike/riding experience in mult ways .

How could anyone not like better engine perf (motor retains more pwr/trq/throttle response /reduces or stop detonation/sig higher oil pressure with less valve/engine noise) along with rider comfort improved due too less engine heat hitting them.

Now that should put a smile on anyone's face when their bike/motor retains more pwr & trq etc along with a bit less heat hitting then from the motor too every minute & mile they ride the bike for the rest of the time they own it is money well spent IMHO.

So there is really a lot more to be gained by installing the 2 cooling mods and carbon cleaning i rec the op do then just reducing & or stopping the detonation which will be a challenge when using lower grade 91 octane fuel to begin with along with unknown compression and cam combo that directly affect cyl pressure & octane requirement.

But retarding timing would be the last resort i'd only do if the motor was still detonating enough to be an issue post getting the oil & motor to run cooler using the 2 cooling mods i rec along with cleaning carbon from comb chambers using chevron's concentrated version of techron @ 1.5oz per gal of fuel too that i found to be a more effective dose i use with good results vs the 1oz per gal fuel dose rec elsewhere in this thread i found to be less effective.

Scott

 

No disrespect taken at all. None meant on my part either.

Given that the top end was recently rebuilt was part of the reason I dismissed carbon build-up. That said, my comment was meant more directly against adding an octane booster at each fillup.