Right..to add to my last post ref starting issues..my struggle continues....(bike decelarated whet to acellerate and engine died - unable to start since)

I have now replaced the pistion rings - Compression has been considerably improved...

I put the bike back together and attempted to start - nothing -

I put small amount of fuel into the plug chamber and tried - nothing.

Removed plug and checked it against the engine casing - has spark..

Checked all wiring - earths all intact.

Questions...

I have a spark - from this can I summise the CDI unit is operational (HT and CDI are one in the same unit)..is there a way to check the CDI unit ?

I neglected to change the base gasket - it appeared to be in fairly good nick, but if it isn't doing it's job properly could the engine be sucking air into the chamber under compression messing with the fuel mixture??

Fuel seems to be getting into the carb, as repeated kick starting of the bike made fuel leak from it - although strangely even after all the kicking, the plug chamber didn't seem to have much/any fuel in it.

As I have been messing with the carb (dismantled it to clean and check) and have moved the mixture/idle screws..what is the best setting for me to reset them (i.e screwed all the way in/2 turns out etc)

I really am beginning to feel that perhaps the bike has had it's time, but since it simply died while being ridden I can't help but think that it really is something really simple i'm over looking....

Any suggestions, pointers, hand of god cures would be sincerely appreciated....

Thanks

Simon, March 2010

Sorted .....

Bike now up and running....
The problem(s) were: -

1. Fuel tap - faulty - constantly flowing fuel
2. Reeds - Faulty - bent petal
3. Piston wear (low compression)

The main faulty was the piston, the fuel tap and reeds were found to be faulty during fault finding..

I originally purchased new piston rings, but they did not seat correctly and acted more like oversized rings, too big for the chamber..

I purchased a complete new head kit from beedspeed.com (49.99) - included new piston, rings and barrel...took 15 minutes to fit and now runs perfectly...bike struggled to start using the electric start before replacing the head, now fires almost instantly...

Thanks for the help given and hope that the info above may be useful to others who have the same problems

Simon, April 2010

REEDS.....

Just read a very interesting forum where someone had the exact same problem...

He changed everything from Stator to CDI and it did not solve the issue...

Looked at his reeds and saw one of the petals was raised...reversed them and hey-presto !!

Now...on mine the lower end of the engine is flooding with fuel when kicking and fuel seems to be flowing freely into it...The reed DOES have a slightly raised petal that isn't sitting flush, so I will reverse them tomorrow....

You never know !!!!!!!!!!

Simon, April 2010

Thanks for the last Adam,

Despite waiting for new parts, I couldn't resist working on the bike again today...I've got it back together using a temporary base gasket & managed to repair the cylinder stud (cut about 3mm of the end where it was x-threaded) and even freed the valve in the fuel tap so that now works (still replacing it with a new one when it arrives though)...

Here are a few more questions if you don't mind...
I've been reading up on the ignition system and understand the Stator to coil to plug flow works (by the way checked the woodruff key as you suggested, was a bit corroded but is intact and engine seems to spark when the piston is near top dead centre).....

Now, Although I have a spark (that will ignite fuel oustide the chamber when the bike is kicked - I held the plug at the plug chamber opening while my son turned it over and it ignited) - it will not ignite fuel when screwed in.

When tested the spark is wirey and orange white in colour - Is this spark good enough to ignite fuel within the chamber ?? - I thought a good strong spark was blue in colour...

If this spark is too weak what could the problem be ?...(faulty coil/cdi unit or perhaps Stator)..I know that the CDI and Stator create the voltage required to create the spark - perhaps there is an electronic breakdown/malfunctioning component so not creating the correct voltage.

Does the condition of the battery effect starting if using the kickstart ?

Also, I am going to earth the CDI to another part of the bike just to make sure the current earthing point isn't bad

Sorry to keep bombarding you with my problems, but I keep running things over in my head (I do keep coming back to the same conclusion - CDI fault !!)

Any way - Enjoy Easter...Thanks again

Simon, April 2010

right i dont know the xact torque seting a si just know how tight to do them through years of doing it i would suggest using a 1/4 " ratchet and do it up with one hand until you feel its pretty tight they are only a 6mm thread and will break or strip easily as you know :)
the woodruff key is sandwiched between the crankshaft and the groove in the centre of the magneto on the right hand side of the engine basically it keeps the magneto in the right posistion as there is a high point on the outside of th magneto that triggers the pulse coil at a bit before top dead centre and sends a signal to the cdi coil which makes the plug spark so if the magneto and crank are not in the right place the spark will be at the wrong time.tka the right hand cover off and have a look in there you will see the rounds bit that turns when you kick the engine over thats the magneto.ok good lcuk with your ungoing problems !

adam bike doctor, April 2010

Thanks for getting back Adam....

Right, i'll let you know where i'm at...

After changing the piston rings (what a job !!), put all back together and nothing (except improved compression)- checked spark, fuel etc - still nothing..

I have checked the reed valve and all seemed fine there..

Interesting what you said about the base gasket being metal, I was wondering this as looking on-line they are metal for air cooled bikes, as mine is, but mine was/is paper (for liquid cooled bike)...and you are quite correct it is now leaking from the crank side...

I also appear to have a problem with the fuel tap on the tank, the pressure valve is not working, so fuel constantly flows - now flooding the carb...

I've also managed to cross thread a cylinder bolt (ahhhh...and i thought things couldn't get any worse..lol !!)

This is my plan of action from here on....

I'm ordering a new fuel tap, cylinder bolt & base gasket (a metal one)...fitting and trying again from there...

It will probably be after easter when the parts arrive so I'll leave it alone until then...

If this fails, as i'v been messing with the piston etc, I will most likely buy a complete barrel and piston kit..I've seen them on eBay for £50.00 plus delivery, includes piston, rings, gaskets and head so that doesn't sound too bad..I suppose if I wasn't such a skinflint i'd have got this kit first rather than just the piston rings !!.

Just a few Q's though...
1. What torq settings should the Cylinder bolts be ?
2. You mentioned the woodruff key .. were is it located ?

Thanks again Adam..and I'll certainly keep you informed with any progress (if made)

All the best

Simon, March 2010

ok simon i didnt see your first post as i have not been on her for a few days,the cdi/coil is one unit yes and if it has a good blue spark then its ok.
the fuel air mixture goes in as a vapour somthis should not wet the inside of the crankcase to heavily so thats fine
the mixture screw is set 2.5 turns out from being all the way in on this bike if it has a dellorto carb if its a weber carb then i think its 1.5 turns out.
the base basket will affect the pre compression of the crankcase as the piston comes downwards and tranfers the new gases up the transfer ports so if its leaking it will be a bit of colour but saying thet if you have not bent it it should be ok as it should be an aluminium one and providing the head nuts are tight enough.
i would check the following in the order given:
1,check the reed valves petals for any cracks or broken parts and see if its closing up ok and not staying open due to a bent petal you may need to turnt the petal around.
2,check the crankseals for leakages you will see oily deposits from the seals if they are leaking check the transmission side first its the one that leaks most.
3,check the woodruff key is ok and not broken as the ignition timing will be out if it is you may need a puller to get it off dont use a hammer it will ruin it.
4,make sure you can blow through the exhaust ok with your mouth a blocked exhaust will stop it running if its really bad.
let me know what you find out

adam bike doctor, March 2010