Topic: Quick way to tell if the cam is 180 off on 350 twin?

[singedebile]

Hi,

This poor 350 has been to too many shops, too many cooks in the kitchen...

any quick way to double check the cam is in correctly before I bend a valve? would the bike run at all with the cam upside down?

Thanks for the help!

[tbpmusic]

The bike wouldn't run and you would bend valves.
Before setting the cam timing, there is no compression/exhaust stroke, there's only TDC.
Since 180 degree twins tend to "run by" at the top of the compression stroke, Honda designed the cam to be installed in the "off stroke" position, making it easier for one guy to do.
There is a little pin on the end of the cam, the advancer keys into it.
When cam timing, that pin should be pointing straight down.
When doing valve lash/ignition timing at TDC of the compression stroke, that pin will point straight up.

Hope this helps,

[singedebile]

thanks!

I was asking because a friend of mine had his motor blown up by a guy that put the cam in backwards, so the bike was "running"...  the buy blew up the motor doing a wheelie in front of my friend. A certain shop in philly that may have had a TV show and will remain nameless. Poor guy had to walk his bike home after paying him $1500.

[trueblue]

YOU CAN'T HAVE A CAM 180 OUT and anyone that tells you you can is a dumbarse with no idea on the basic principals of engine operation.

The cam turns at half crankshaft speed, so if you think the cam is 180 out turn the crank through one full revolution and your cam will be in the correct position. 

[singedebile]

hahahha good to know,

curious how this other mechanic managed to bend a valve, I had wrongly assumed that with a cam 180 off and the 350 being an interference motor? This might have been the culprit, as you would really really really have to mess up your clearances to bend a valve otherwise.

Now to continue the troubleshooting on this nice little 350.

[trueblue]

You can bend a valve by being a couple of teeth out, that is highly feasible.  If the bike was running, then bent a valve it had nothing to do with the cam position.  More likely he over-revved it and floated a valve.

What is actually wrong with your bike?