2003 FS 650 extremely hard to start

You most definately feel it when you hit the rockers, you can open the valves if you want to, but there is a very noticable difference in the amount of force you need to use when turning the screws.

The screws should turn very very lightly with almost zero resistance, maybe your screw was already touching the valve to begin with and you wrongly assumed that that was the normal resistance for the screw when in fact it is already touching the valve. Hope this makes sense difficult to explain in English.

the easiest way to tell is to screw the other tappet out say exactly two turns.

NOW CAN YOU PLAY MORSE CODE WITH THE ROCKER ARM OR NOT.

if you can't then your questionable tappet is good. now adjust the original back in.

when the tappets are right you can't tap out a morse code - the tappets are too tight but you CAN get a little 'tick', 'tick' noise from it.

regards

Taffy

Thanks for your help so far guys.

I have ran out of time to look at the bike again tonight so i'll go for rocker cover back on and tappets set tomorrow.

Belgiquebasterd - If when i first turned the tapped adjuster screw and it was already in contact with the tappet, would this have held the valve open during normal engine cycle when it should have been closed? This would make perfect sense for my non-start scenario then would'nt it ?

Taffy - Thanks for that.

Guys,
So if we're to make a list of things to check in order for when the bike is very difficult to start, how would that list look like?
Got the same problem with my 2003 FE650E. No problem when running but a b.....d to start! :evil:

Thanks
Dariusz

Rocker cover sealed and refitted, tappets set - (so much easier now - i backed off all the adjusters and screwed down until contact, then backed off 1/6th of nut and locked. Inspection covers sealed and refitted, engine cranked over, sounds like its taking more effort to turn over than it did before, i'm guessing its making more compression than it did before with the correct valve clearances instead of being able to walk through the gaps that were there previously!

Its taking more effort to turn it over now, starter is now 'slipping' at certain points, i think this is that sprague thingme slipping like i read in a thread somewhere.

Observation - , whilst cranking and holding my hand over the exhaust my hand is blown away then sucked back to the exhaust end repeatedly.

Bike will still not start or splutter.

My fuel tank is still off, i will refit tomorrow night and try and see if it will fire up now.

I forgot to say - the suck/blow at the exhaust end was present prior to me taking the rockers off and setting the tappets.

have you touched your cam and the auto decomp at anytime in this? kick the engine over slowly and if it 'locks' on full compression then you have a weak ADC.

regards

Taffy

I can kick it over slowly but its a bit of a **** to do requiring a fair bit of effort.

The decompression setup on the exhaust valve was not touched, it does operate if i turn it by hand, however the cable is not attached at the cylinder head end as i do not have the fittings to attach it to the operating arm. Will this matter if i can still operate it manually?

I did'nt try to start it tonight as i was fitting my new fuel taps to the new large capacity fuel tank also extending one of my fuel hoses. Will try to start tomorrow with new tank fitted.

You have three decomp devices on the engine, first one is the manual lever on the handle bars, second one is the cable wich runs from the kickstart to the head (these both use the same small cam wich push on the right hand exhaust valve) and the last and most important one is a separate small (ADC auto decomp cam) cam wich sits on your camshaft wich is spring operated and opens one of the valves also, they changed the profile off this cam in 2005 or something like that. The new profile makes it easier to start the bike.


Here you can see part of it on the camshaft



Old style with a very worn out tip (part that opens the valve)



New style, the tip looks like a dutch clog






I only used my bike briefly with the mikuni carb, before I upgraded to the FCR carb but do remember that it was a real bitch to start with the mikuni, probably because it wasn't set up correctly, but never looked into it so can't help you there.

Don't take this the wrong way but when setting the valve you know that the piston has to be in a certain position? If you set the valves with the piston in the wrong position you'r bike will not start.

When trying to start it, if you still have the original 2003 sprague, motor and such don't even bother with it, try and get it to start well with the kick. The original (not rewound) SEM ignition needs a good kick to get it working, if I recall correctly it will only start working at 300rpm or something like that, so if you give it a halfassed kick it certainly won't work, the way I did is was placing my bike stand next to the bike stand up on it and then give it a good kick with my right leg.

Also make sure you put the engine just past compression point, let the kick return fully and then give it all you got! And don't forget to put your boots on, caus if she bites back it hurts

supermoto madness said:

Observation - , whilst cranking and holding my hand over the exhaust my hand is blown away then sucked back to the exhaust end repeatedly.

Click to expand...

This is weird, are you sure the engine was in the compression stroke when setting the valves?

Hi,

I had set the valves with the engine at t.d.c. and with the ignition marks on the flywheel in line with the top rotor cover screw hole as per the 'doc' instruct.on.

I have an s.e.m. igntion coil module which has been modded via taffy to work better with the electrix stator which i have fitted.

Carb is a dellorto phm 40, it has all standard sized jets in for the FS650. - I need to go back to the 'doc' to see if there is anything regarding setting the carb, i.e. base settings and number of turns on the screws etc.

Decomp system - You'll laugh at this :lol: - I have the lever on the handle bars but no cable attached, i have the kickstart to head cable but i don't have the fittings to connect it at the head end, to be honest i was not aware of the 3rd decomp arrangement i.e. the one on the camshaft itself, if i can operate the exhaust valve decompressor myself by holding it when i turn the bike over with the starter then won't that do?

Super bro....
I think wot ******* bro is getting at is there are two TDC's. one on compression stroke and one on exhaust/inlet stroke. Im being lazy by not rereading your threads but from memory you sed the cam lobes were pointing up? (TDC inlet/exhaust). If the lobes were pointing down its TDC compression. sorry if Im stating the obvious, its a quiet night at work.
You have obviously figured out that sucking in thru the exhaust is not helping the starting problem and the only way it can do that is if the exhaust valves are leaking (quite a lot if it sux up zorst and not down inlet) or open at the wrong time..

As for manual decompressing...... yes it will work, just not as convenient as ADC.

The tdc is used was the one where as soon as you turn the flywheel clockwise and move off from the timing marks at the top screw hole on rotor case, it starts to compress the springs and push on the valves.

Was i right or should i have used the other tdc where nothing happens after you move off clockwise on the flywheel?

I'm poised ready for a response like a coiled spring!

Yer bro..... uncoil that spring 360 degrees (or the crank 360deg). you should be able to rock your cam several degrees before the valves start moving...... safest way to check is to look at the cam lobes, the big lumpy bit should be pointing towards the piston, or away from the roller rockers. That should make a major difference to the way things work.
I shall keep a closer eye on here to see how you get on, so if this makes no sense let me know and I shall explain bettera. by the way.... which part of the world are you in maddness?

Aberdeenshire, uk mate

I wanted to know if i had set the clearances using the right t.d.c. or not.

I can't see how this matters anyway if i've set the clearances then that is them set and they will remain the same no matter which t.d.c. that they have been set at surely.

It seems the valve timing is wrong allowing the suck/blow at exhaust rather than an incorrect clearance.

The only other thing can see is the cam timing or positions are wrong, how do you sync the crank to the cam or do you not have to.

I used the 'doc' to set the clearances word by word.

Righto buddy, I try again (had a reply typed only to be logged off before submitting..... grrrr.)
In order.

Englund. nice.

From your info.... NO. wrong TDC.

Matters much. If you use the wrong TDC then your mota aint guna go son. And you are quite right, once set they wont heal themselves, so you DO need to set them correctly. What I think you have done is set the valve clearance between the rocker and the top of the cam lobe (or partway up the lobe anyway) BUT wot you need to do is set the clearance between the rocker and the bottom of the cam lobe. Remember your cam spins at half the speed of your crank (motor only fires once every two revolutions) hence the need to find TDC on compression stroke. (also needed for the next step).

If valve timing is wrong then you may well get a suck from exhaust BUT if your decompressor is stuck on or you have less than zero valve clearance (at TDC compression) then you will also get a suck from exhaust.

To check cam timing..... go to TDC compression and check cam sprocket marks are lined up ( check in doc for cam marks as they may differ over different models) you will have to take the rocker cover off to check marks on cam so also check that the cam lobes are pointing down at TDC compression (if they are pointing up then spin the crank 360deg).

Dont take this the wrong way...... but you set the clearances by your interpretation of the doc.... and its not always written in the plainist of the English language. (Now I'm gunna get s**t from Taffy. sorry mate no disrespect to your exelent pool of info).

Hope this helps Mr Madness.

Had the exact same problem a couple of years ago, couldn't understand **** what some more experienced people were saying:

this is how I picture a 4 stroke engine in my mind

stroke 1 sucking fuel in the cilinder stroke, wich means, the piston goes down, the cam pushes on the inlet valves wich then open making it possible for fuel coming from the carb being sucked into the cilinder by the vacuum created from the downward motion of the piston

stroke 2 compression stroke, all valves are closed, piston is coming up to top dead center thus compressing the fuel mixture.

stroke 3 boom stroke, spark plug gives a spark, mixture goes boom, piston goes down, exhaust valves start to open already if I'm not mistaking

Stroke 4 getting rid of the burnt gasses stroke, piston goed up to top dead center, cam pushes on tappets exhaust valves fully open, piston pushes the bunrt gasses out.

The stroke you want is the compression stroke, as you can see when you set the valves when the engine is on the 'getting rid of burnt gasses' stroke you'll set them wrong since the cam is pushing down on the tappets. Easiest way to find out wich one is the compression stroke is to take out the spark plug, put a spanner on the flywheel nut, turn the engine over by hand and watch the tappets, you'll be able to easily identify each stroke when you see the movement of the tappets.

Your explanation of getting a blow/suck scenario at the exhaust port is in my opinion the result of having set your valves at the wrong TDC.

About the doc, it's a wealth of information but you have to speak not only English but also Taffyish, wich can be hard sometimes.

Hope this helps and don't give up, when you get it started you'll be smiling like an idiot and pulling wheelies like Evil Knievel

Ok - There are 2 x t.d.c.'s.

Being bored this afternoon i decided to try setting the valves to the other t.d.c. - please check - i wound the flywheel round one complete revolution onward from the last t.d.c. until the flywheel marks lined up with same rotor case screwhole. I think this is the other t.d.c. - the piston was back at the top as before.

This then made my exhaust valves have a huge gap at the tappits, i adjusted them up, the inlets were nearly the same.

Now whilst cranking over it manages to turn the engine over easier now as it did before i started the forum diagnosis. - But still suck/blow from exhaust!

If i've tryed both t.d.c.'s and they both are still giving me this suck/blow scenario then is it time to burn the bike?! :angry:

Not at all Mr Madness. No matches needed yet. plenty more bored arvo's before then.

Yor huge gap after turning crank 360deg proves you had the wrong TDC to start with. We going forwards.
Now bak to checking the cam timing (it is also possable you have very bent zorst valves) if yor cam timing is well out.
But, easy things first, check yor decomps (any or all of them) to prove they are not holding the valve open. Then
Back to TDC compression...... and check with the DOC or a knowledgable fellow (my scoots a different year) as to the timing marks on the cam sprocket/ camshaft. If marks aligned correctly and decomp not holding valves open then you may need to look for bent valves.
Incidently, any sucking or blowing goin on at inlet?

Dont give up, keep asking questions.

My responces will be even slower shortly as my 12hrs(work) is almost up and there is a motorcycle needing to be put to good use.