Bloody bike conked out!

[rich]

Thought I'd pop out for a quick spin on the LC this evening as a wind down before work tomorrow. Fired up ok, rode it up the road and it did the usual spluttering through first and second. However it didn't clear like normal but started bogging. Then it went onto one cylinder and I struggled to keep it running. Then it stopped all together Tried kicking it and nothing except a single backfire. Pushed it back (luckily mostly downhill) and whipped the plugs out. Nothing abnormal looking but am only getting a very weak intermittent spark on both sides. There's plenty of fuel in it and it ran absolutely fine last time I rode it a couple of weeks ago. I gave the CDI connections under the seat a wiggle but nothing. So, I have covered it up in disgrace for now until I can go over it with a multimeter. It's running Standard F2 ignition and a Dyna coil. Any ideas?

[db8888]

same happen to my rd350lc last Saturday coming back from castle combe stuck some new plugs in and it was fine done a 100 miles since the plugs that came out looked ok and have only done a few miles
modern fuel and old ignition system maybe ...........

[db8888]

did you check the spark with the plug caps off and just from the leads if the plug is no-good it wont earth properly and would show a weak spark

[rich]

No, just checked the plugs with HT caps still fitted and with the thread resting against the head bolts.

[db8888]

wont hurt to try without the caps both at the same time

[Eyrey1]

HAVE YOU another coil to try ?

[rich]

Jun 29, 2014 22:46:29 GMT 1 Eyrey1 said:

HAVE YOU another coil to try ?

Only the stock one but this Dyna coil is brand new and only done about 600 miles. I was thinking though, I am using resistor plugs (BR9ES) in conjuction with TWO resistor caps - one at the coil end and one at the plug end of each HT lead. This can't be doing anything for the strength of the spark. So, I am going to buy some non resistor caps for the coil end and also some straight B9ES plugs first.

[steve h]

Even with a dyna coil, the spark is not like a bolt of lightening. And yes do change your plugs for non resisted ones.
Have read that using both resisted plugs and resistor plug caps can have a detrimental effect upon the ignition coil.

[rich]

All sorted now Tried kicking it from stone cold, fired up on one side for a few seconds then died and wouldn't restart. First thing I did was check the stator and Dyna ignition coil resistances - all checked out ok. Then I replaced the ht caps at the coil end with non resistor type and swapped the plugs for a pair of new B9ES. Nice strong spark again from both plugs. Refitted tank and she fired up as normal, happy days

So, I can only assume that I had a weakened spark from too much resistance in the ht leads and resistor plugs and they had fouled during cold running.