Possible timing issues

Sauer_35

Sauer_35

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Like most people I’ve upgraded a Predator 212, Governor delete, new valve springs, Mikuni carb, and exhaust. While riding the engine will rev upwards of 6700rmp. I’ve had zero issues with this motor, but was worried about the stock flywheel coming apart and stabbing me in the back. I replaced the stock flywheel with a billet with 8 degrees built in timing advance. I used the stock woodruff key. Since I’ve done this, and changed nothing else I’ve had an issue getting the kart started. I choke it and have to give it throttle for it to start and let it warm up for a good 30 seconds before I take the choke off. Once it’s warm it’s run fine, but I never had this problem before the flywheel swap. To be honest I don’t think it runs as well as it did before the flywheel swap, but I haven’t done the work to confirm for sure, it’s just feel while riding. Before I start tearing into it does anyone have some wisdom to impart?
 
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Master Hack

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You chaged several things including the carb. It's not hard to start, you're just not giving what it wants. First thing l thought was jetting. Actually the first thing l thought was whiskey and wimmin, then l thought jetting.
Have you gone through that ritual? Or did you just take a carb outta the box and bolt it on? Is it a real Mikuni or is it a amazon/ebay Mikuinison?
 
Sauer_35

Sauer_35

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Master Hack said:
You chaged several things including the carb. It's not hard to start, you're just not giving what it wants. First thing l thought was jetting. Actually the first thing l thought was whiskey and wimmin, then l thought jetting.
Have you gone through that ritual? Or did you just take a carb outta the box and bolt it on? Is it a real Mikuni or is it a amazon/ebay Mikuinison?
Click to expand...
No I had the carb on, tuned and running for about 3 months prior to the flywheel. The engine ran fine with all the modifications, expect the flywheel. The addition of the flywheel is where all the issues started. It ran like a top before I swapped flywheels
 
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panchothedog

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What did you set the air gap ( distance between flywheel magnet and ignition
coil ) at. All of the billet flywheels have a much stronger magnet and need to be gapped quite a bit larger. Also, did you lap it to the crankshaft. Are you sure it's the right one ( taper). The hemi and the non hemi use completely different flywheels due to different crankshaft taper. I've put ARC billet flywheels on six different predators ( 212, 224, and 301) and never experienced anything like what you are describing. Go back and recheck everything. You've done something wrong along the way.
 
Sauer_35

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panchothedog said:
What did you set the air gap ( distance between flywheel magnet and ignition
coil ) at. All of the billet flywheels have a much stronger magnet and need to be gapped quite a bit larger. Also, did you lap it to the crankshaft. Are you sure it's the right one ( taper). The hemi and the non hemi use completely different flywheels due to different crankshaft taper. I've put ARC billet flywheels on six different predators ( 212, 224, and 301) and never experienced anything like what you are describing. Go back and recheck everything. You've done something wrong along the way.
Click to expand...
I’ll do just that, but here is what I did do: it is for a non-hemi, which I have, I did lap it and I set the air gap at .040.

It’s just weird to me that once I get it start, having to give it a a little throttle while cranking it, then once it’s warm it starts every pull.
 
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panchothedog

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FWIW, I gap all of mine at .045" to .050". I doubt that's the issue. 4 of my engines are running rejetted stock style carburetors. The other two are Makuni style. One is the real deal, 24mm flat slide. The other is a 22mm Chikuni imitation. On both of those karts the throttle needs to be held about 1/2 the way open for them to start. But they start easy, as long as someone is holding it open.I guess the same as yours. I've never messed with the jets in either of them. On the other ones (the stock carb ones) after lots of modifications, cam, milled and ported head, springs changed ect , I have found it necessary to enlarge (drill out ) the pilot jet. I am thinking maybe you should give that a try. Taking them from .016" to .020" really made a difference. Both in starting ease, and hole shot ( acceleration ). Don't know if there is any correlation in sizes between the two types of carburators, but enlarging your pilot jet by .003" or .004" sure seems like it's worth a try.
 
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panchothedog

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Question. Are you still running the stock predator rod. That is a very high rpm range for the stocker. They won't hurt you when they let go ( like the flywheel
can ) but it stands a good chance of ruining the crank and.the block.
 
Sauer_35

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Yes I haven’t upgraded the rod. I’ll run it this way until it goes and I’ll put a 420 on it. Everything I’ve got can be swapped over to my kids go kart. I haven’t done the Governor delete for him yet.
 
Sauer_35

Sauer_35

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I played with the carb adjustments today and it started on the second pull. I’ll go back and check it again when it cools off to see if it’s repeatable.
 
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