Flywheel key, jetting changes

[Larky]

When installing the 4 degree timing advance flywheel key, should I expect any carb jetting changes? Or if it was good before the install will it remain the same?

[JohnC]

I added the 4 degree key to my Brozz. I made no changes to the carb for that mod. Should be good to go.


John

[Bill Hilly]

Originally Posted by JohnC

I added the 4 degree key to my Brozz. I made no changes to the carb for that mod. Should be good to go.


John

I have a Brozz 250, and am currently running a 16 /42 sprocket combination, which is just a hair higher gearing than the stock 17/46 . I seldom hit above 7000 rpm with this combo. Would an advance key be of any use for me? Would it cost me any low end? What kind of performance do these keys add?. My bike is stock, except for the gearing, and exhaust mods, and rejetting of the carb Thanks

[JohnC]

I have done the 4 degree key and a port and polish on the head. Both were done at the same time. There is a noticeable improvement in throttle response. But what I have not done is anything with the exhaust. I am leery of the ebay exhaust because of the increased volume. I think that is where the real gain will come though.

So until I do the exhaust I do not expect I am seeing the power improvements that are possible. I may do the cat delete and see what that does. And thinking about gutting the stock muffler and putting a larger pipe in it. Or maybe the slip on muffler and leave the stock header (w/o the cat).

I kind of like the look of the stock exhaust. And I don't want to make it too loud.



I don't know if any of that helps because I'm obviously not done with this process.


John

[Megadan]

Generally speaking, advancing the timing should not require any jetting changes. That being said, advancing the timing can expose a jetting issue, especially at idle and low rpm. So, as long as your carb setup is good, you shouldn't need to adjust anything.

[Megadan]

Originally Posted by Bill Hilly

I have a Brozz 250, and am currently running a 16 /42 sprocket combination, which is just a hair higher gearing than the stock 17/46 . I seldom hit above 7000 rpm with this combo. Would an advance key be of any use for me? Would it cost me any low end? What kind of performance do these keys add?. My bike is stock, except for the gearing, and exhaust mods, and rejetting of the carb Thanks

The key advances timing across the entire rpm range, so there is an improvement pretty much across the board. If anything the most noticeable improvement is in the lower and mid rpms.

[Bill Hilly]

Originally Posted by Megadan

The key advances timing across the entire rpm range, so there is an improvement pretty much across the board. If anything the most noticeable improvement is in the lower and mid rpms.

Does anyone have a link for the advancement key? Are they all 4 degree?, or are there ones with more, or less advance? I have a wheel puller. Is that and common tools all I need? Thanks

[JFOlivier]

This advanced timing key thing? is there no other way to advance yout ignition timing without moving the flywheel, in the dark ages we used to do that by moving the ignition contacts or points as we used to call them to adjust the timing. I hear mention of the stator from time to time is this the fixed part of the magneto under the flwheel or maybe rotor.

[Bill Hilly]

Originally Posted by JFOlivier

This advanced timing key thing? is there no other way to advance yout ignition timing without moving the flywheel, in the dark ages we used to do that by moving the ignition contacts or points as we used to call them to adjust the timing. I hear mention of the stator from time to time is this the fixed part of the magneto under the flwheel or maybe rotor.

I have saw small engines were the ignition components were mounted on a plate under the magneto, and the plate had slotted screw holes, and reference marks that allowed one to adjust ignition timing.

[franque]

Since these are electronic ignitions, the only easy ways to change timing are to either move the pickup sensor or move the flywheel with an offset key. I've heard of programmable CDIs, but I'm not aware of anything for these that is known reliable. A mechanical advance can be a bit safer, because it keeps you from accidentally going too far.

[JerryHawk250]

Originally Posted by Bill Hilly

Does anyone have a link for the advancement key? Are they all 4 degree?, or are there ones with more, or less advance? I have a wheel puller. Is that and common tools all I need? Thanks

Here you go. https://www.adaracing.com/timing-adj...ee-honda-crf50

[Bill Hilly]

Originally Posted by JerryHawk250

Here you go. https://www.adaracing.com/timing-adj...ee-honda-crf50

Thanks Jerry... Are these keys weaker due to their shape, and more likely to sheer? As I have mentioned before my motor is internally stock. I have gutted the cat, derestricted the muffler, and changed both the pilot, and main jets on the stock carb. I probably will get a pod filter.. Should I get the 4 degree, or the 2 degree key?

[JerryHawk250]

Originally Posted by Bill Hilly

Thanks Jerry... Are these keys weaker due to their shape, and more likely to sheer? As I have mentioned before my motor is internally stock. I have gutted the cat, derestricted the muffler, and changed both the pilot, and main jets on the stock carb. I probably will get a pod filter.. Should I get the 4 degree, or the 2 degree key?

I've had no issues with them. Get the 4 Degree key.

[alex_in_az]

Originally Posted by JerryHawk250

I've had no issues with them. Get the 4 Degree key.

same here, and I've ridden mine pretty hard

[Badluck]

Is the shaft tapered on the flywheel side? If it is, they key is just there for timing purposes. If you can accurately install it, you should be able to advance or retard the ignition timing to whatever you'd like, but you could easily get into diminishing returns.