MB200 - no start after spring swap

C

Clypto

New Member
#1
#1
I got a Massimo MB200 with a 196cc, ordered a stage 1 to install on it. Header, timing key and jet change were swapped and I had no issues. I wanted to check some tutorials for the lash settings prior to spring install but couldnt find anything solid. So it was the last thing and its been a hassle.

Installed 18lb springs - tried I/E at 003 and 004 but it was a hard pull, found somewhere to set at I 006 E 008 and I was able to pull the cord.

The issue is it pops really loud now, I see smoke out the carb air filter and smell gas. I emptied the bowl and that go me no where. Currently Im unsure what to do besides put the stock springs back in - anyone shed some light maybe?
 
B

BrownStainRacing

Well-Known Member
#2
#2
Clypto said:
I got a Massimo MB200 with a 196cc, ordered a stage 1 to install on it. Header, timing key and jet change were swapped and I had no issues. I wanted to check some tutorials for the lash settings prior to spring install but couldnt find anything solid. So it was the last thing and its been a hassle.

Installed 18lb springs - tried I/E at 003 and 004 but it was a hard pull, found somewhere to set at I 006 E 008 and I was able to pull the cord.

The issue is it pops really loud now, I see smoke out the carb air filter and smell gas. I emptied the bowl and that go me no where. Currently Im unsure what to do besides put the stock springs back in - anyone shed some light maybe?
Click to expand...
Sounds like you are setting the lash before the compression release.

.003" works good.

With sparkplug removed

Roll the engine over clockwise from flywheel side.

Watch the exhaust rocker
You will see it go down a lil bit and come back up.

Watch the keyway in crank on pto side
Turn crank til the keyway is lined up with the cylinder.

Now set both valves at .003"

If it's still hard to pull, put stock timing key back in.
 
C

Clypto

New Member
#3
#3
The left valve drops then comes back up and right before the right valve goes down is where I am stopping as I thought this was TDC. Hopefully I am thinking that is correct.

What is PTO, is that the side with the puller? I took it off to turn the engine easier.
 
VeritableFox

VeritableFox

Active Member
#4
#4
Clypto said:
The left valve drops then comes back up and right before the right valve goes down is where I am stopping as I thought this was TDC. Hopefully I am thinking that is correct.

What is PTO, is that the side with the puller? I took it off to turn the engine easier.
Click to expand...
PTO is Power Take Off, the side the clutch goes on opposite the flywheel.
 
Harquebus

Harquebus

Well-Known Member
#5
#5
Clypto said:
The left valve drops then comes back up and right before the right valve goes down is where I am stopping as I thought this was TDC....
Click to expand...
Left valve is the Exhaust valve and the right valve is the Intake valve. This is easily verified by noting that the intake valve is on the same side as the carburetor. Better to call them what they are to mitigate any confusion.

With sparkplug removed, you can insert a wooden pencil (eraser end first) into the plug hole and use the pencil as a gauge to determine piston position and TDC. Hold the pencil firmly against the top of the piston at all times and rotate the flywheel clockwise until both valves are at rest on the compression stroke (and the pencil is as far out as it can go).

On the intake stroke, the intake valve rocker moves to drop the valve and let in air. As you rotate the engine around the piston (and pencil) will come up and the intake valve will close... BINGO, that's where you want it: TDC on the compression stroke.
 
C

Clypto

New Member
#6
#6
I ended up putting stock springs back in, redoing everything and the engine turns over smooth like it was. Unsure why springs cause it, if there was something I missed or what but the bike it back up now.

Thank you for the helpful replies.
 
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