Cam upgrade Andrew's 23
Tourer
Joined: Jul 2021
Posts: 388
Likes: 255
From: Florida
Is your carburetor stock. is the air filter dirty/restricted. Start there it's inexpensive and easy. My bike has stock ignition and a cam /big bore runs fine. I'm running a mikuni. But a stock modified CV work great .
Seasoned HDF Member
Joined: Jul 2014
Posts: 8,608
Likes: 3,375
From: Cental, MI
Both the motor and exhaust generate heat. They need to balance in such a manner that CHT and EGT are balanced to there own optimum number. Say 300 F for the heads and 600F for the pipes. The pipes are smaller and typically have heat shields where the heads and rest of the motor has more surface area to radiate heat.. Anyway too retarded and fuel burns in the exhaust pipe. Too much advance and more mixture is burned in the motor.. It's temp will increase and motor radiate more heat... CHT goes up.
Retard yer timing...tell me the First Symptom!!!
Remember...the Thread concerns (supposedly) nothing but a Cam Change!!
Last edited by Racepres; Aug 5, 2025 at 07:11 PM.
Seasoned HDF Member
Joined: Dec 2005
Posts: 19,930
Likes: 8,033
From: poway
Yeah, the heat goes up... Like I wrote. Overall heat may go down if too far advanced in the first place. If the OP simply marked the timing plate an did not set it, the timing could be anywhere.. The cup notch may be in a different place..
My bobber ran too much timing and the motor would overheat. You could feel it.. It crisped a crank seal. I don't have the dyno runs but with 3 pulls you could see the motor overheating from too much timing. Power dropped off with each pull.
HDF Community Team
Joined: Dec 2005
Posts: 5,423
Likes: 2,621
From: NC USA
@Toneloco Two things would cause that, as mentioned the timing may be high. Even if you marked the plate to the cover, changing a cam/gear will through it off.
The cam turns backward so turn the timing plate clockwise to advance timing or counter-clockwise to retard timing.
Did you replace the carb to manifold gasket? Air intake will make them run hot too.
The cam turns backward so turn the timing plate clockwise to advance timing or counter-clockwise to retard timing.
Did you replace the carb to manifold gasket? Air intake will make them run hot too.
Seasoned HDF Member
Joined: Jul 2014
Posts: 8,608
Likes: 3,375
From: Cental, MI
@Toneloco Two things would cause that, as mentioned the timing may be high. Even if you marked the plate to the cover, changing a cam/gear will through it off.
The cam turns backward so turn the timing plate clockwise to advance timing or counter-clockwise to retard timing.
Did you replace the carb to manifold gasket? Air intake will make them run hot too.
The cam turns backward so turn the timing plate clockwise to advance timing or counter-clockwise to retard timing.
Did you replace the carb to manifold gasket? Air intake will make them run hot too.
Personal experience shows me. Retarded timing makes more Heat, than Advanced.. Too much advance, should reveal itself in starter Kick-back, and Pre-ignition.. I guess if Ignored..more heat will result, just before you hole a Piston ...ie, The original symptom was ignored!
Thread Starter
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Advanced
Joined: Jun 2025
Posts: 90
Likes: 9
The 23 is a fairly mild cam designed to work with a relatively stock 80" Evo. You can run it with your stock ignition just fine, however, if you want to maximise performance and have your timing / rpm limit adjusted to get the most out of your modifications - an aftermarket ignition would be a nice addition. You can always put it on the shopping list for later.
If you are running noticably hotter after swapping out the cam sounds like you might be running the motor lean. Have you bumped up your jet sizes to account for the new cam?
What do your spark plugs look like?
If you are running noticably hotter after swapping out the cam sounds like you might be running the motor lean. Have you bumped up your jet sizes to account for the new cam?
What do your spark plugs look like?
Road Master
Joined: Sep 2013
Posts: 1,054
Likes: 441
From: Tejas
Easy enough to find out
Griz
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