Topic: twin CB350 newb!

[zef933]

hey all you folks who are smarter and wiser than i!

i just got a CB350twin and i know you are all mostly 4cylinder guys but i thought i would see if you could help me out with my twin.  i havent been able to find any enthusiast site with troublshooting ideas of anything about it.

i used to have a cb550/4 so iam not a total loser! hahahaha

i dont think iam getting spark and want to check out the coil to see if it is getting electricity and then if it is sending it down to the plugs.  how would i go about doing that!?  i have a good basic mechanical understanding and used to work on my 550 but electrical is def something iam quite weak at!  thanks in advance!

[kirkn]

http://www.hondatwins.net/forum/index.php

The best site for Honda CB350 twins.

As for troubleshooting, the coil should get twelve volts when the key is turned on and handlebar kill switch is in RUN position.  From there, current flows thru the coil to the points.  Current flows to ground when the points are closed and current flow stops when the points open.  Stopping current flow is what sparks the plug.

So, with points open, you should see 12 volts at the points.  With points shut, that drops to zero.  This 'drop to zero' confirms that the points are actually touching when closed and not corroded etc.

Beyond those few checks, a couple new (or at least a confirmed good) plugs wouldn't go amiss either.

Good luck, Welcome aboard, post some pictures of your new ride if you get the chance, and enjoy!

Kirk

[zef933]

hey kirk, i really appreciate your post.  i love it when someone takes the time to spell things out. 

i just found some local dudes here in PDX oregon and i will probably sort things out with them.  i will for sure try and get some pics up!

[mrblasty]

The Honda twins like a nice strong battery.  Every time I've worked on one that was brought to me dead the battery was weak and the points needed to be cleaned up a little.  Good Luck.

[kirkn]

+1

9.5 times out of 10, a strong battery and 10 seconds with the points file gets you spark on 'em.

[rchrdms]

You can try holding the spark plug lead just an 1/8 of an inch from the engine
head and see what kind of spark it has. It should be a fat, blue arc. A weak spark
may mean trouble with a coil or points. You should rule out the battery and alternator too.

[zef933]

well i took the sparkplug out, put in the plugwire and then held the plug up against the cylhead fins... i didnt see any spark.  so now i guess i need to check the points but its been over two years since i have fiddled with points so that might be a bit of an adventure! hahahahaha

[kirkn]

Two quick checks first (just in case you didn't do this already):

make sure you're trying that spark check with a GOOD plug - either grab one from a running machine (even your lawnmower or weedeater - anything that sparks) or try the plug in a vehicle that you KNOW runs (your mower, etc).  That's the only way to positively rule out the plug itself.

secondly - sometimes just laying the plug against the fins isn't good enough, especially if there's corrosion there.  Ya gotta sometimes scratch it around a bit to make sure you've got a good connection.


Otherwise, it's on to the points...

Kirk

[zef933]

yeah ill check out the points for sure....to be continued!  i will for sure let you know how it goes and if and when it fires up.

[Alan F.]

http://www.hondatwins.net/forum/index.php

The best site for Honda CB350 twins.

As for troubleshooting, the coil should get twelve volts when the key is turned on and handlebar kill switch is in RUN position.  From there, current flows thru the coil to the points.  Current flows to ground when the points are closed and current flow stops when the points open.  Stopping current flow is what sparks the plug.

So, with points open, you should see 12 volts at the points.  With points shut, that drops to zero.  This 'drop to zero' confirms that the points are actually touching when closed and not corroded etc.

Beyond those few checks, a couple new (or at least a confirmed good) plugs wouldn't go amiss either.

Good luck, Welcome aboard, post some pictures of your new ride if you get the chance, and enjoy!

Kirk

www.hondatwins.com is also quite good.