Spluttering and missing

Hi All,

I use my ST70 on a daily basis to get to and from work. The last month or so it has started to splutter a little and missfire occasionally. Along with this the top speed has dropped down, or is certainly much harder to achieve, and it struggles a little more on the few hills I have to negotiate, not that it has ever been great with these.

It feels to me like a mixture or spark issue, but then I don't know a great deal about these things. I cleaned the carb out and that didn't do much. Could it be the points need resetting as I havent done these for a long time? New plug maybe? I just wanted to gether a few notes before setting off on tackling this one.

Cheers
Ben

I would:
- fit a new spark plug
- re-set points and check condition
- clean carb (and new gaskets)
- check condensor
- check earthing of coil
- check head gasket
(in that order)

Thanks for that Waynus.

An interesting development yesterday. I rode home from work, and for the first time in a while it was pouring down with rain (hard to believe for England I know), within a matter of seconds in the rain the bike started to splutter and I had to keep the revs really low and constant to keep it going for a minute or so, before if died and I had to pull to the side of the rode. I had to call a friend with a van and get a lift home.

I woke up this morning and it was not raining and the floor was dry, so I decided to see if the bike would run again in this weather. It took a bit of starting, but once going it got me to work as normal, with just the odd miss and splutter that has been happening over the last month. This leads me to believe it is the gasket from the carb to the manifold??

On the downside to it having worked again today I am now at work praying it doesn’t rain could be another interesting ride home.

Not sure why the wet weather would lead you to suspect its an air leak?
More likely to effect electrical function really,try the suggestions already given (plug cap/HT lead insulation etc?)

Chief wrote:More likely to effect electrical function really,try the suggestions already given (plug cap/HT lead insulation etc?)

My thoughts exactely!