predator 212 engine help

[jimboslice]

https://youtu.be/yDJSYw_WKFQ

so my engine starts up fine every time. When i start to rev it past a quarter of max rpms, it starts to bog up pike as if it’s skipping a beat.
my upgrades include:
billet rod
billet flywheel
18 pound springs
air filter upgrade
mod 2 cam
governor removed

thing i have tried to resolve the issue:
cleaned carburetor
checked valve lash
replaced all gaskets

what am i missing here?

also when i take the bike out in the rain, she stalls after riding for 20 minutes, is that because the air filter for the gas tank is getting wet?

 

[mckutzy]

Did you rejet the carb?? Typically you'll need to when you have a new filter intake...

 

[jimboslice]

sorry forgot to mention i rejetted at 0.38

 

[mckutzy]

What does the plug show after a run? Sounds like you may have to re jet to a smaller size...

Typically what is also done when these types of upgrades are done...is a free flowing exhaust...

 

[itsid]

sounds like the governor is trying to slow the engine speed down.
but that can't be it, right?

Almost like a defective ignition coil...
have you dropped or hit it when installing the flywheel?
then it might be worth testing a new one (say from a friends engine)
And also make sure the coilgap is set correctly and it's tightly bolted to the engine,
so it can't rattle loose

Talking of the flywheel
... have you installed an offset flywheel key?
If so, reinstall the original straight key!

The ARC flywheel comes with a 8° advanced timing pre'installed'
and thus adding an offset timing key makes a terrible running engine.
(never heard one with a known 16° combined advance... but if that at all runs it should sound somewhat similar I guess)

Also what's worth checking if rejetting and higher flow exhaust don't help
is double checking all alignments
cam to crank is sometimes overlooked or misread;
checking the lifters on the cam and the pushrods on the lifter
and when you check valve lash
make perfectly sure the engine is at TDC in the compression stroke
and the pushrods are nicely seated in the rocker arms
ideally with the side cover still off so that you can check the cam lobes against the lifters,
to be extra certain )

'sid

 

[jimboslice]

thanks for the reply Sid, some very good advice here

I never dropped the ignition coil, but I'll definitely check that out
no offset flywheel key, just the original because I know the flywheel already has advanced timing
I'll have to double check that valve lash I don't think it was at TDC when I set it

My gut tells me it has something do do with the air/gas mixture and that I may have to use different sized jet

 

[jimboslice]

ok so I completely removed the exhaust header and it seems like it fixes the issue. I think if I changed the jet it would work with my current exhaust? but for now maybe I should find a wider exhaust header.

 

[JTSpeedDemon]

Yeah, try a non-restrictive header, run it for a while in varying circumstances, and then let us know how it goes.