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Author Topic: EVO Performance & Top End Rebuild  (Read 580 times)

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August 22, 2020, 11:03:11 AM
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Ernie


My bike is pinging at high RPM's and using oil. It doesn't smoke, but it can use a little TLC.
1998  Low Rider EVO motor
10.5 Wiseco pistons
.500 lift cam , not sure of duration
Stock ignition
CV carb w/ yost upgrades
SE slash cut pipes
It seems to run hot and on a highway ride if you open it up , once above 4000 RPM it pings. on hotter days, above 90 deg. it will ping a little on take off.
I've retarded the timing, fattened up jetting, no help.
the only thing that seems to work is octane booster, which I don't like using. to me it's a band aid.
Should I lower compression ? Different ignition maybe ?
Your thoughts and recommendations are appreciated !

August 22, 2020, 12:05:37 PM
Reply #1
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HDBitchin

Administrator
Welcome to the forum!

I agree that octane booster is a bandaid.

On the subject of octane I would ask what octane are you running?

I have a stock 1995 Evo and the owners manual says the motor is designed for using 87 octane which I actually run in the cooler weather and it runs fine on that octane. For about 8 months of the year I will use 87 octane. In the hot 4 months of summer here in the Phoenix area I will run 91 octane. Running the higher octane in the summer heat will ensure that I don't have any pinging.

From what you wrote it sounds like you have added more fuel and running lean is not your issue.

Another thing that might be an easy fix is to run some fuel treatment in the motor. Any carbon build up inside the motor might be inviting the pinging. Carbon buildup can form on the tops of pistons, causing pre-ignition, rough idling and poor throttle response. I use the below linked product on about every 10th tank of gas that I buy...

Quickshot premium fuel additive

This product will clean any carbon buildup that you might have.

Heat control might help. Make sure that you have the proper oil level as the oil plays an important part of the V-Twin's cooling and further to that, adding an oil cooler might be just enough of a means of cooling the motor further to get the pinging to go away.
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August 22, 2020, 05:08:32 PM
Reply #2
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HDBitchin

Administrator
Besides my last post here is some more general thinking on the issue that you might want to be mindful of.

Pre-Ignition or Detonation (Knocks or Pings)
1. Fuel octane rating too low.
2. Faulty spark plugs.
3. Incorrect spark plug for the kind of service.
4. Excessive carbon deposit on piston head or in combustion chamber.
5. Ignition timing advanced due to faulty sensor inputs (TMAP and/or CKP).
6. Ignition timing advanced due to ECM or sensors (CKP, ET or TMAP) defective.
7. Intake manifold vacuum leak.
HDBitchin aka Tank
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When shopping for anything look for Made in the USA and save American jobs and families


August 22, 2020, 05:18:16 PM
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Ernie


 Thanks for the response. I guess what my real question is, does anyone have a piston recommendation for EVO's ?
 Cast or hypereutectic choices that you were happy with ?
 Are there any new choices ?
 I've been out of the loop for awhile .
 I saw  Wiseco and S&S . 
 Which is better ?
I want 9.5 compression Hyperuetectic ideally .
I have stock heads and 500 lift cam .
Stock ignition , SE slash cuts , and a CV carb . I'll Probably install an S&S Super E that I have .
SO FAR !  LOL

August 23, 2020, 07:59:30 AM
Reply #4
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HDBitchin

Administrator
I have a stock Evo so I can’t provide an opinion. Maybe some of our more experienced engine builders like @maniacmac and @bc45 can comment.
HDBitchin aka Tank
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When shopping for anything look for Made in the USA and save American jobs and families


August 24, 2020, 06:28:22 AM
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bc45

Global Moderator
Sorry I have never been inside or built a evo motor. So I dont have any recomendations on pistons. Please keep.us informed on what you use.

March 15, 2021, 05:26:14 PM
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Ernie


Hi all, been a while since I added anything, so here goes !
I tore the top end apart, and found a piece of piston missing, at the thinner area, where the exhaust valve relief is cut out. After doing some research, the only thing that I can come up with is tight ring gap. Keith Black pistons, it seems to be a problem with the design where ring gap needs to be checked a little closer. So, my fault.
Anyway, I installed .030" oversize Wiseco forged pistons with a 10:1 compression ratio , ( after gapping rings ). I then did a little port work and replaced the exhaust valves, as they were pitted due to detonation. I used Kibble White valves, nice valves! I also installed an EV46 cam.
This all was back in October. I fired her up, and she sounds fantastic! I've put about 500 miles on her so far, and absolutely no complaints. Lots of power, and very responsive. I can't wait for temps to climb above 60 for more enjoyable rides.
Everyone, have a great summer and stay healthy !             Ernie   
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March 15, 2021, 05:51:19 PM
Reply #7
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HDBitchin

Administrator
Thanks for the followup @Ernie

Sounds like a great outcome.
HDBitchin aka Tank
AMA Member- Click Here to Join
When shopping for anything look for Made in the USA and save American jobs and families


March 16, 2021, 09:36:06 PM
Reply #8
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bc45

Global Moderator
 Thanks for posting what you found and what you did. Great to hear that it is running awesome.

March 17, 2021, 12:09:11 PM
Reply #9
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WantMore

Supporting Member
Good followup @Ernie

Karma (HDB Rep) given.
Smoke em if you got em


 




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