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Discussion Starter #1
I have noticed my 09 has an issue with spark knock. I have a 95 and sold my 03 and neither one of them had the issue like my 09. I think I need to back off the advance on the spark. Is this possible on the TW or is it set from factory? If I lug it at all, or try to take off on a hill it complains.
 

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I am pretty sure it is set. Mine were doing that when I first got them but it was because of the DG pipes. Rejetting fixed it. Maybe your main jet is glogged. I pretty sure mine was a lean problem.
BTW we are talking about flying up to see you in ALaska.
 

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Effective timing can change slightly with a loose cam chain adjuster. Perhaps pull cam gear cover and crankcase inspection port off in order to inspect timing marks and chain tensioner? With chain tight the correct witness marks should all align, if loose timing can drift up to about 1/2 a cam tooth. If chain appears at all loose pull the auto-tensioner and inspect/clean/wind up and release for a test,etc...

This assumes the problem is indeed a pre-ignition issue and not old fuel or carberation related.
 

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Fuel in this mixture has two jobs:

1. Explode and turn the crank..

2. Cool the piston crown and cylinder walls etc. [Remember evaporation cools the surface]

So some part of the fuel that is pushed into the cylinder actually cools it a bit. When you go lean what happens is that with every progressive stroke the cylinder / piston etc gets hotter as the cooling effect of fuel is less due to a lean mixture

Thereby you can get Hot-Spots in the cylinder / Piston and as the fuel air mixture is compressed this Hot spot can lead to a pre-ignition, and a very lean mixture can take the damage further and sometimes hole the piston

A slight increase to richer in mix may help (adjust the screw).

But it could be anything.. including you are in-fact loading the little motor a bit much.
 

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Camshaft timing is controlled by the chain.

For spark timing, the initial advance is set when made and then further advance is by the CDI.

There is no adjustment for the initial spark timing. At higher RPMs Tom Bauer can change the timing advance curve in the CDI or you can buy an Igni Tech CDI with adjustable spark timing you can change with your laptop.
 

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I would try 95 octane if enriching the carb doesn't work and your timing lines up correctly. I had a car I increased compression on, cam change etc. It loved Valero gas. Everything else would ping and it was running rich.
 

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Discussion Starter #8
When the crew arrives at Moab I will have one of you guru's check it out for me. I have never messed with the needle or screws on the carb.
 
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