Im going nuts--PW50

[FROSTY]

I pulled the non runner PW50 out from under the house.
I pulled the exhaust and carb out and gave em a huck out--fuels flowing fine.
Pulled the switch block off and cleaned all the contacts.
Shortened the spark plug ht lead--replaced the plug and the plug cap.--Tightened up the contact to the coil--cleaned up all the joins in the wiring.
with the plug resting on the cylinder head---BIG FAT SPARK
put the plug back in thinkin yep shes gonna fire up--BUT NO
Plug out -a tiny bit damp --Rested back on head -NO FRIGGIN SPARK
what have I friggin missed

[hospitalfood]

try a new plug, sometimes they are cunty.
then threaten the bike with death by fire, or get info from somebody with a big brain.

[FROSTY]

-sorry--done that-2 different plugs

[riffer]

How about the lead? Bending it at a particular angle could be causing a crack in the lead to open up...

[imdying]

When you try it the first time, does it even try to fire? Any chuffing at all, or does it just turn over mutely?

[Taz]

Has yours got the 3 position Off/Run/Start switch on the R/H handlebar? Will only start in the start position and will only run in the run position. Oh and will turn off in the off position.:2thumbsup Just a thought.

[skidMark]

you say it had a big fat hefty spark.....well what did ya change since then....

could maybe be a kiddy kill switch somewhere..sometimes on back of bike...they can wriggle loose, but sorry i am unsure whether the pw 50 has one...

i would be inclined to go with anthrax's post.... in regards to the killswith...

[westie]

Your lead/plug cap could be arcing out. Try it in the dark and have someone look for a spark down the lead or plug cap

[Sketchy_Racer]

Its a two stroke you need three things

Compression
Fuel
Spark

So you fairly confident you have fuel and spark, whats up with the compression?

Could have broken reeds? Or a damaged piston/rings

Have you had the barrel off to have a look?

[Motu]

Its a two stroke you need three things

Compression
Fuel
Spark



For a 2 stroke there is a 4th requirement - crankcase compression....and suction.You can have compression in the combustion chamber - but can it suck fuel into the crankcase and pump it up into the cyl?

I'd go for the ign switch first Frosty,as Anthrax says...it will only start in start,not in run.I can talk,I have a PW50 that loses spark too....I suspect the CDI stuff,but can't be bothered sorting it out as my kids are too big for it now.

[lb99]

-sorry--done that-2 different plugs

I have a workshop manual if its any good for wiring diagrams ect.. I could scan it to a cd if you want.


PM me before you torch it I need parts

[lb99]

......can't be bothered sorting it out as my kids are too big for it now.

PM me before you torch it I need parts

[Sketchy_Racer]

For a 2 stroke there is a 4th requirement - crankcase compression....and suction.You can have compression in the combustion chamber - but can it suck fuel into the crankcase and pump it up into the cyl?

I'd go for the ign switch first Frosty,as Anthrax says...it will only start in start,not in run.I can talk,I have a PW50 that loses spark too....I suspect the CDI stuff,but can't be bothered sorting it out as my kids are too big for it now.

Yes that is true, but even without you will still get some sort of a fire generally.

From a simple fire at least you know your getting some sort of spark and some amount of fuel.

[Conquiztador]

Frosty.

1. Try a third plug (yep I know, you have already tried two. Been there.)
2. If any spark at all, even just a little, use "Start Ya Bastard". You might get her going and the magneto clears out the crap that is there?
3. If no spark, then take magneto cover off. Clean and check.
4. Check all connections. If she has been sitting under the house for ages, then the current that has just gone through the system when you first kicked over might be enuf to cause poor connections.
5. You might have a wire shorting to earth??
6. Swap plug lead.
7. If still no go (and you have disconnected any kill sitches) then sadly you are up for a CDI I think...

Good Luck.

[FROSTY]

Sorry guys I Kinda downed tools before large hitting device got used
Ill try to amswer all your replies.
1) fuel is fresh as is oil
2) 2 plugs--tested on conveniently positioned (right next to bench) PW80
Ie--plugs fitted to PW80--both have fat spark.
3)I cut 15mm from plug lead and swapped plug cap from said PW80--fat spark still in 80 NONE in 50.
4)All wires checked for continuity
5)Attempted to get spark with switch in off/run/start position then again with switch bipassed.-no spark.
6) using the pissed off mechanic theory I bounced CDI off gargre wall
Plugged back in checked all wire connections again--
Plug resting on head -SPARK
7) refit plug in engine -Kick it over-no go --kick again and again etc--NO go
Remove plug--tadd wet n oily sofit NEW plug and test kick with NEW plug resting on Head--NO FRIGGIN SPARK
SLAM gargre door storminside in a huff
Im leanin towards CDI

[Conquiztador]

CDI it is. BUT normally what happens in them is that the soldering gets loose. I have successfully opened a few and fixed them by simply re-soldering all the joints on the small PC board inside. Some of them are not made to be opened. But if you carefully cut them with a hacksaw blade you can get inside. And really, what is there to loose??

Good Luck.

[westie]

I know a company who fix igniters. I think you are calling them cdi?
Any hoo they are in wheuapai if you want to try them drop me a line. Probably cheaper to get secondhand tho

[FROSTY]

Im lucky--I can get a CDI/coil and a switchblock for $60.00 so Ill go with that option

[Ozzy27]

Hi,
Frosty Pw50' s are known for stator coils failing. The symptons you describe are exactly what will happen if you have low output from the charge coil(Stator).
Check the resistance of the coil and the voltage output. The normal failure is an internal short from insulation breaking down. Which will often not show up on a resistance Check.
Good luck
Chris:crazy: