PREDATOR Wont go pass 4500 RPM??

Mini420

Mini420

New Member
#1
#1
Why wont my predator spin pass 4500 RPM???:confused:

It will go to 5500 or so when i lift the tire up, but when im riding it stays around 4500:eek:

MODS:
Exhaust, Air Filter, #90 JET with E-Tube, 15" rear tire:wink:


Could this be because im running a 13 tooth clutch and 75 tooth rear sprocket??

OR

Wrong jet and E-tube??


Im gonna back track and put the stock air box back on and go from there


Please help
 
Last edited:
Oldsalt

Oldsalt

Well-Known Member
#2
#2
Unless you popped for some better internal parts it will soon be limited to zero RPM. Also, and most importantly, the removal of the governor and mindless quest for RPM could have a decidedly grave ending. Flywheel explosion. If you really gotta do this thing the very least you can do is kinda tuck your scrotum and etc. over to the left when riding at top RPM. If that looks uncool to be doing in front of your girlfriend simply scoot over to the left after you are under way for your record breaking run. That way maybe you will only loose a leg.
 
Mini420

Mini420

New Member
#3
#3
Oldsalt said:
Unless you popped for some better internal parts it will soon be limited to zero RPM. Also, and most importantly, the removal of the governor and mindless quest for RPM could have a decidedly grave ending. Flywheel explosion. If you really gotta do this thing the very least you can do is kinda tuck your scrotum and etc. over to the left when riding at top RPM. If that looks uncool to be doing in front of your girlfriend simply scoot over to the left after you are under way for your record breaking run. That way maybe you will only loose a leg.
Click to expand...
WTF.. shouldnt assume, u dont kno wat i have or wat i plan to do.

Alot less judging and more help would be great, Thanks Salt:thumbsup:
 
texasfabguy

texasfabguy

New Member
#4
#4
I won't assume anything,I'll just go off the mods you have told us about.

After doing the putting your data into the "whyismyshitsoslow" program,it came up with your tire is to tall for your gearing or you need more horsepower.
 
Mini420

Mini420

New Member
#5
#5
texasfabguy said:
I won't assume anything,I'll just go off the mods you have told us about.

After doing the putting your data into the "whyismyshitsoslow" program,it came up with your tire is to tall for your gearing or you need more horsepower.
Click to expand...
HAHAHA i like that, where can i get that program?

So basically i need a smaller rear sprocket??:smile:
 
hal_armour

hal_armour

New Member
#6
#6
Min, maybe you could add more upgrade info for us all. When I read 4500 rpm, I know there is a governor mod happening somewhere. then I look for what other mods, maybe a different cam or springs so I can offer some solid technical help, then when the mods you list do not include parts that can handle 4500 rpm .... specifically a flywheel and rod, then I think (probably like most others) that maybe they were not listed because they were not yet intalled. My point is without you telling us that you added billet parts we rightly or wrongly guessed.
I help lot's of guys here and so does Oldsalt, but we both know the liability issue if we provide support for governor modded engines without proper precautions.
So please let us know the complete list of your upgrades, I will for sure help you out and I cannot speak for Oldsalt, but to me he is a solid guy and will likely offer some technical help once he gets clarification on what you have.
I too was concerned about you and your engine facing disaster, I think that is what our brotherhood is all about. We are all human, we care, but when we are missing info we sometimes guess.

Wanna try your post again ?
 
TomH

TomH

New Member
#7
#7
I will go with oldsalt on this one, spin until your hearts content. sing soprano when she blows, and don't forget to try to sue the maker after she blows up. You don't need a good flywheel and rod, just get stiffer springs and a bigger carb, don't forget to mill the head too.:laugh:
 
Mini420

Mini420

New Member
#8
#8
hal_armour said:
Min, maybe you could add more upgrade info for us all. When I read 4500 rpm, I know there is a governor mod happening somewhere. then I look for what other mods, maybe a different cam or springs so I can offer some solid technical help, then when the mods you list do not include parts that can handle 4500 rpm .... specifically a flywheel and rod, then I think (probably like most others) that maybe they were not listed because they were not yet intalled. My point is without you telling us that you added billet parts we rightly or wrongly guessed.
I help lot's of guys here and so does Oldsalt, but we both know the liability issue if we provide support for governor modded engines without proper precautions.
So please let us know the complete list of your upgrades, I will for sure help you out and I cannot speak for Oldsalt, but to me he is a solid guy and will likely offer some technical help once he gets clarification on what you have.
I too was concerned about you and your engine facing disaster, I think that is what our brotherhood is all about. We are all human, we care, but when we are missing info we sometimes guess.

Wanna try your post again ?
Click to expand...
I understand totally.

I think my post is comming off the wrong way.....

Im not trying to rev it to 7000 or anything. I have 2 motors with the same mods, but my second minis' set up has a 13 tooth clutch instead of a 12 and the rear is a 75.

I jus cant tell if its because of the different gear setups or if its a bad motor?? Beacause my other mini feels way stronger and it only has a pipe.
 
texasfabguy

texasfabguy

New Member
#9
#9
I will tell you this,one reason to run the billet rod is the bearing. The stock rod is to soft for high rpm 's .billet rods have an automotive type bearing that will support high rpm and the stock rod will seize on the crank. When that happens the rod will snap and jam into the block and the flywheel will stop suddenly. If that happens the flywheel will either shear the key or split. Next thing is the stock flywheel is made from crap we all take to the scrap yard and gets melted down (you know all that junk we thought was no good to be safe anymore) then it gets sent to china by boat to make the cheapest new crap we buy here.
Also the billet flywheel will let your motor rev quicker because they are lighter.
None of it is a wast of money,in fact it could save you some...or a leg or a by stander...

Now for the gears....
Speed Calculator For Go Karts and Mini Bikes
This should help you figure it out.
 
vwfan79

vwfan79

Active Member
#10
#10
Your running a 5.77 gear ratio on the new setup compared to a 5.50 on the other setup, so IMO that shouldn't cause the engine to rev that much less. Does the engine bog or anything at 4500 or just won't go any higher?
 
Mini420

Mini420

New Member
#11
#11
vwfan79 said:
Your running a 5.77 gear ratio on the new setup compared to a 5.50 on the other setup, so IMO that shouldn't cause the engine to rev that much less. Does the engine bog or anything at 4500 or just won't go any higher?
Click to expand...
Finally, thank u vw for understanding wat im asking:thumbsup:

It seems like a slight bog or like its getting too much air from the filter or too much gas or something like that.
 
vwfan79

vwfan79

Active Member
#12
#12
You can change back to the stock e tube to lean the mixture out, if that doesn't help then you can try a larger main jet to richen the mixture. If these things don't help then its probably not a fuel air problem. :shrug:
 
Mini420

Mini420

New Member
#13
#13
vwfan79 said:
You can change back to the stock e tube to lean the mixture out, if that doesn't help then you can try a larger main jet to richen the mixture. If these things don't help then its probably not a fuel air problem. :shrug:
Click to expand...
yep, jus tried swapping the stock jet and air box back on......NO DIFFERENCE:censure:

I also swapped to a 12 tooth clutch and no difference.


Im really leanning towards the rear sprocket being the issue.
 
vwfan79

vwfan79

Active Member
#14
#14
You talking about 10t so it could be, but the final gear ratio isn't that different so it shouldn't make that much difference.

What does the other motor spin?
 
Mini420

Mini420

New Member
#15
#15
vwfan79 said:
You talking about 10t so it could be, but the final gear ratio isn't that different so it shouldn't make that much difference.

What does the other motor spin?
Click to expand...
im on 12 tooth.

The other motor will go pass 4500, but when i tried the filter kit on there,it also didnt go pass 4500.

Im almost convinced the CA predators will not work with a #90 jet,ive tried 3 motors now and they all didnt run right.

Now everything is back to stock on the motovox frame and it still hovers around 4500.............it has to be the rear sprocket:hammer:

My doodle with jus a pipe kicks this ones ass bigg time??
 
tundrabeagle3

tundrabeagle3

Member
#18
#18
With that small tire and a 6.25: 1 ratio it should rev up to 4900 rpms. The exhaust pipe makes a difference in acceleration. I got about 200-300 rpms more with my intake and exhaust. My jet is a 90 from OldMiniBikes but it looks like a 92 jet. I would also check if the throttle is opening the carb all the way.
 
vwfan79

vwfan79

Active Member
#19
#19
I know this sounds like a lot of work but might be worth it, swap engines from bike to bike to see if it still does it. If the same problem happens on the new bike you know for sure its the gearing, if not you know its another issue. I'm still leaning towards and air/fuel issue, I don't see that small of a difference in gearing making that much of a difference in RPMs. But I could be wrong, wouldn't be the first time won't be the last.
 
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