Trouble starting...

[T.W.R]

have you tried pouring a small ( very small ) amount of oil into each cylinder then attempting to start the bike?

[magicmonkey]

have you tried pouring a small ( very small ) amount of oil into each cylinder then attempting to start the bike?

oil?? Really, what would that do?

[T.W.R]

oil?? Really, what would that do?

If the cylinders are down on compression via the rings the oil will temporarlily boost the compression ie: act as a seal on the top ring

[CookMySock]

Big hill time - someone will help you with it - tomorrow's saturday! You might have to shout them a pie for the use of their van/trailer.

No choke, select a gear so you get about 2-3,000 rpm, ignition on, and roll off down the hill. Just try small throttle openings. Don't forget helmet and gloves.

If you can't even make it backfire out the zorst, then you know it's time to stop punishing the starter and look elsewhere for the problem. Compression check, static timing, valve clearances etc.

Steve

[magicmonkey]

If the cylinders are down on compression via the rings the oil will temporarlily boost the compression ie: act as a seal on the top ring

ah ok, that make sense. That'll go on the list of things to do this weekend (which seems to be growing rapidly!)

[magicmonkey]

Big hill time - someone will help you with it - tomorrow's saturday! You might have to shout them a pie for the use of their van/trailer.

No choke, select a gear so you get about 2-3,000 rpm, ignition on, and roll off down the hill. Just try small throttle openings. Don't forget helmet and gloves.

If you can't even make it backfire out the zorst, then you know it's time to stop punishing the starter and look elsewhere for the problem. Compression check, static timing, valve clearances etc.

Steve

Thing is, I want to get the starting sorted, not just make the engine run (I know it'll run fine already) so bump starting it isn't going to do anything to fix the fault or narrow it down, unless I'm missing something off course and that's always a likelyhood!

[CookMySock]

Thing is, I want to get the starting sorted, not just make the engine run (I know it'll run fine already) so bump starting it isn't going to do anything to fix the fault or narrow it down, unless I'm missing something off course and that's always a likelyhood!

Yeah it is odd it doesn't just "go".

The hill thing is just to discover if its you, or it. If it goes, it's you. If it doesn't, its it.

And then you have your straight answer.

Steve

[T.W.R]

if you're going to bump start the bike: select 2nd gear, let the clutch out & roll the bike backwards till it takes up compression, pull the clutch in and start pushing, drop the clutch and have a bit of throttle and it'll fire up within 3bike lengths.

None of this down hill bollocks cause if it does fireup with a bang things can get messy if you aren't quick enough to clutch it, break & keep it running.

[bogan]

how easy/hard does it turn over, same as usual? and do you smell un burnt gas when its been turning over for a while, sounds like its probly mechanically ok, spark is ok, but not sure bout fuel. I'm assuming you haven't touched the timing chain or ignition advance.

EDIT, hang on, are you sure it runs fine when crash starting it, but just not good when electric starting it?

[magicmonkey]

how easy/hard does it turn over, same as usual? and do you smell un burnt gas when its been turning over for a while, sounds like its probly mechanically ok, spark is ok, but not sure bout fuel. I'm assuming you haven't touched the timing chain or ignition advance.

EDIT, hang on, are you sure it runs fine when crash starting it, but just not good when electric starting it?

I haven't crash started it, I do know that the engine is happy to idle though. I'm holding off on the crash starting idea fro the moment as I can't see it testing anything that I've touched but I might head onto that and crash start to get the engine warm (if it works that is :s)

[CookMySock]

None of this down hill bollocks cause if it does fireup with a bang things can get messy if you aren't quick enough to clutch it, break & keep it running.

It's only a little 250 inline four mate. If it kicks into life you leave the clutch out and let it have its' little purr and fart until it makes up its' mind.

Different story if it was a 2000cc vtwin with a supercharger on it - then you would want to watch it alright.

Steve

[T.W.R]

I've seen 80cc mx bikes make adults look stupid tring to bump start them so a 250/4 can easily make as much mess

I'd pay to see some bumping a 2lt V-twin with a supercharger

[kwaka_crasher]

I can't be bothered reading all the patchy information spread among all the posts, so did you set the float heights when you had the carbs apart?

[bogan]

I haven't crash started it, I do know that the engine is happy to idle though. I'm holding off on the crash starting idea fro the moment as I can't see it testing anything that I've touched but I might head onto that and crash start to get the engine warm (if it works that is :s)

I think I'm a little lost, how do you know its happy to idle if it wont start and you haven't crash started it?

[magicmonkey]

I think I'm a little lost, how do you know its happy to idle if it wont start and you haven't crash started it?

well, it would start but it was bloody hard to do, took ages to get it to catch properly and spring into life. So, I decided to check out the sparks, wound up changing the leads for ones actually meant for a bike (rather than the car leads it was using) and changed some o-rings on the carbs at the same time. Now there's no life at all, engine turns over but doesn't even fire one cylinder off let alone spark into life ...

As for the float heights, that's a job on tonights list. I'll post on how it goes but I have had a brief check while draining the bowls and it looked roughly ok at that point (earlier in the week, after the problems started)