Built predator only hits 7500rpm

130 is lean on a 22 mikuni, much less a 26. Also try an NGK plug, I have had a couple autolites foul. It is also easier to read an NGK.

I agree with not free revving either, good way to find the weakest link.
 
That was suggested earlier.

I know Arc has a bulletin on their website on this. I can't recall if there is an ohms reading for checking this with the change to their flywheels.
A coil is fairly cheap to simply replace and check if makes difference.

As has been suggested several times, ignition timing could be slipped as well.
Really cheap and simple to check key.

Better still, know where the timing is by either degree wheel, or in the hole method.

Knowing where the cam degrees in is also always good information.

Sometimes you can get away with just assembling some parts, but most times a small thing can louse up the whole deal.
 
125 is too small bogs on top end like the 135 130 seems to be the sweet spot right now with no bogging but it can barley go past 6800rpm under load. And my rod clearance is fine doesn’t hit anywhere. I’m just mind boggled trying to figure out why it hits a wall at 7k
Rod bearing too crank journal Clearance ?
Not rod too block .
By now it woulda probably let go , so might be a mute point .
 
Hey I have a predator that’s fully decked but it only has one issue. I have 32-28 valves ported and polished 14cc chamber with a 26mm mikuni and 36lb springs with all billet parts flywheel side cover valve cover flattop piston and a .308 grind cam with champion rocker arms fully vented with oil catch can but it only hits 7500rpm no load and sounds like it’s hitting a rev limiter and is just maxing out won’t go higher it’s build to go 10k only thing that is stock on this is the spark coil which I heard some of them have rev limiters
If it sounds like its hitin a rev limiter .
Then the valves are floating , the spark if failing in some way or its over rich flooding it out .
Possibly not enough fuel flow but that should show as on and off not a constant stutter .
 
Are you actually checking any of things suggested with a feeler gage? A lot of guys are trying to help but for example you said "it looks like you have space in the springs" or "coil looks good and is not hitting". All these things need to be to spec. A gap of .010 on the coil can have a large affect on performance.
 
Are you actually checking any of things suggested with a feeler gage? A lot of guys are trying to help but for example you said "it looks like you have space in the springs" or "coil looks good and is not hitting". All these things need to be to spec. A gap of .010 on the coil can have a large affect on performance.
I’m confused on what you mean by check the coil with a feeler gage, where am I supposed to measure. I put my valve on max lift and my spring still has a lot more room till coil bind.
 
How about the retainer too the valve guide ?
Like install height? Maybe my install height is too low and makes me 32mm valve float early, I ordered 40lb duel springs I’m gonna see if that helps the heavy valves
 
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I’m confused on what you mean by check the coil with a feeler gage, where am I supposed to measure. I put my valve on max lift and my spring still has a lot more room till coil bind.
The gap between coil and flywheel. On a factory predator the coil gap will be much less than one that is modified. I believe you should be running somewhere close to .050.
.055 gap on coil not .035
.080 piston to valve
.030 piston to head
 
The gap between coil and flywheel. On a factory predator the coil gap will be much less than one that is modified. I believe you should be running somewhere close to .050.
.055 gap on coil not .035
.080 piston to valve
.030 piston to head
How do I measure pistion to valve and pistion to head
 
How often do you change it? As far as I know the things that turn oil white are methanol or water (condensation).
 
How do I measure pistion to valve and pistion to head
Piston to head is measured with head off. You measure how much the piston is “in the hole” at top dead center then add thickness of head gasket.
Piston to valve requires a gauge to do properly. Valve should be fully open or at “max lift” then measure distance to piston. You do that with head on torqued to spec. There are good YouTube videos by Jody at ARC explaining a lot of specs in detail.
 
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