Predator 420 Valve Lash Adjustment

[Benkonvl]

I have a predator 420 with a Mikuni 34mm carburetor, Billet flywheel, Billet rod, Flattop piston, Super X265 camshaft, 1.3 stamp rocker arms, Torque converter. I keep breaking pull starts, it’s really hard to pull and start it the compression is too high so I’m thinking it’s the valve lash. What would I set it at with this kind of build? Thanks in advance!

 

[BrownStainRacing]

.003" is always a safe place to start. Make sure the exhaust lobe is OFF the compression release before setting exhaust valve lash.

I have a predator 420 with a Mikuni 34mm carburetor, Billet flywheel, Billet rod, Flattop piston, Super X265 camshaft, 1.3 stamp rocker arms, Torque converter. I keep breaking pull starts, it’s really hard to pull and start it the compression is too high so I’m thinking it’s the valve lash. What would I set it at with this kind of build? Thanks in advance!

 

[Benkonvl]

.003" is always a safe place to start. Make sure the exhaust lobe is OFF the compression release before setting exhaust valve lash.

Is there a video or something on YouTube I can find explaining how to make sure the exhaust lobe is off the compression or is it easy to explain? Sorry I kinda “ bought not built ” my bike so I’m learning everyday

 

[BrownStainRacing]

I'm not a fan of " bought not built", you jus don't know what kinda goofy mess somebody has done.

Jus a quick check, turn ignition switch to off and pull the rope a few times. If it's still hard to pull, it's valve lash or comp release issue. If it's easy to pull, its a timing issue. We can fix that too,

Valve lash adjustment, it's fairly easy, I can walk you thur it.

Take off blower housing, valve cover and take out sparkplug.

By hand, turn the flywheel cw while watching rockers.

TDC is between intake valve closing and exhaust valve opening, DO NOT SET VALVE LASH HERE

When intake rocker comes back up to top, watch exhaust rocker, keep turning flywheel til you see the exhaust rocker starts to go down jus a bit, then it wants to come back up to top. That lil bump is the comp release, turn the flywheel a lil more. Both rockers will be loose, check lash here and see where they are at, make a note for future.

After you have confirmed they are .003". Turn flywheel a few revolutions cw and double check lash again, using the same method.