Hi, I've had my little savage since May as a commuter bike and with the long term goal of passing her on to Mrs Toom once she finally takes her test.
She's a low mileage 1986 model bought having stood for four years.

After a lot of diagnostics on a weird carb problem ( it stuck open every other time you opened the throttle and emptied the fuel tank through the air box) which after a complete carb rebuild still wouldn't go. I ended up replacing with a new flat sided Mikuni built by  Allens performance in Nottingham and a replacement push pull throttle off a HD sportster she was good as new and runs like a dream 99% of the time.

Only other casualty of standing was replacement starter motor after the old one died.

Whenever it's very wet she seems to get very temperamental and on new years day in the rain emitted a stream of 5-7 backfires then lost all power and conked out at the top of a hill.

Oddly this has happened before always when wet.

I left her for 20 minutes whilst having a cig then bumped her in 3rd down the hill, had a splutter of life and then started off the starter. Managed to get two more miles in the deluge running lumpy as hell and as normal the next day everything was fine.

Anyone experienced anything similar?  Could it be something as simple as water getting sacked through the intake to the carb causing a bit of starvation?  Is this normal?

Oh.......Welcome to the site.

I have to assume the problem is electrical.
an old wiring harness, aged connectors, and minimal waterproofing.
I'd think I'd start her up and hose her down progressively till you found the problem.
Key areas of concern... kickstand switch, primary wiring, decomp controller (over the carb, has been known to fill up with water)

Toom wrote on 02/27/15 at 03:21:07:


The backfires and poor running when wet are most likely electrical.  The front tire throws a lot of water at the front of the engine, up under the fuel tank, and at the kick stand safety switch down at your foot.  The electrical connectors are not sealed well, and it sounds to me like the ignition system is getting weak when wet.

As other said previously - start the bike and carefully start to get the parts wet.....try a spray bottle of water to be more precise in where the water goes.  Don't just spray the whole bike all at once - start at the bottom and spray water on the kick stand safety, then work your way up the bike carefully trying to see what causes the bike to lose the ignition.  Spray some water on the spark plug cap, wire, coil, etc. and get each part wet one at a time.  Also try the left handlebar control where the engine stop switch is located.  

I would also suggest you take the tank off, pull the electrical connectors apart and look for corrosion.  Clean any off that you find, and then use a dialectric grease to seal and protect the connectors.  Look at the decompression controller - the seal in the housing can go bad and let water inside.    

Isn't there some sort of goop that we can put inside all of the connectors to keep the water out? Being a motorcycle, and more exposed to the weather, it may be a good idea. I just can't think of what it's called right now.

Oh wait....dielectric grease!  That's it! Could be a fix for a finnicky "doesn't run well when wet" bike.

Check the tech section about the head plug leak.  That might be where your oil is coming from.

Sputtering and dieing, sounds like an electric problem,.. but, just FYI...
Rain, equals humidity, and you will get rich condition pops and blats from the exhaust, because the air has less oxygen...  That part is normal...

You don't have an open air filter do you?... ...