Why?

[Vincent]

Hi,
I though I would ask here before I put it in the hands of a professional...
I've restored a R65 GS: powder coated the frame, had some work done on the tank, new wiring loom, exhaust valves, timing chain tensionners, carbs overhaul, refurbished valeo stater. Everything works and lights up, engine turns over when I press the ignition buton but won't start. Fuel is reaching carbs, float chambers are filling, healthy sparks on both plugs, valves clearances correct, no oil leak... Would it have something to do with low compression? What are the signs and how should I go about it? what other checks should I do?
Many thanks
vince

 

[(RIP) Proff]

My 80g/s did this about 10 years ago, healthy spark when outside cylinders/// but no firing up..
Changed coil and that fixed it...
Seems the spark died under compression....
My 65g/s turns over for around 15 secs when cold before actually starting..
27 hp ,,, but when it has started once, it's perfect all day

 

[brassmonkey001]

It's not something simple like you've got the HT leads crossed over?

 

[Vincent]

Thanks Proff, I'll try changing the coil
HT leads are not crossed over, no...
I forgot to mention that I sort of get what seems to me like a high pitched sound from the cylinders when pressing the ignition. I remember getting that sound before but the bike started fine. I've changed the cylinder head gaskets and reassembled with correct torque. Could have something gone wrong when I put everything back together?

 

[Mike the Bike]

Did you disconnect the timing chain at any stage ? Maybe it's not now lined up properly, and sparks at the wrong times ?

 

[Kenny]

Take rocker covers off and turn over by hand...just to make sure all is moving as it should be.

 

[(RIP) pastyman]

Check the compressions . simple on an airhead
Check static timing
what about the carbs, chokes etc

 

[ghiribizzo]

You say "Fuel is reaching carbs, float chambers are filling, healthy sparks on both plugs" but is the fuel getting out the carbs into the cylinders?
Try taking the plugs out, if the fuel is getting through - after a period of churning away they should be wet if the motor is not starting.
The other way - a tin of damp start or even the old bodge of a can of lighter fluid. A quick squirt, plugs in, if it fires up in a cloud of smoke and quickly dies then there is maybe little getting out of the carbs.
Also try checking the voltage when the bike's cranking over. Will it fire up when there are jump leads on from a big battery, even though turning over just now.

 

[how much]

has it been stood for a long time?

could be blocked jets with old crusty unleaded



hm

 

[Vincent]

It starts!!

It starts!! Many thanks for your advise. I found what was the problem today... a bit embarrassed to say actually... what the hell! My throttle cables were connected onto the carburator's choke lever and vice versa so obviously... this project's been all about the learning experience.
Started first time though after standing for a year and a half. Reeving like mad but I'll get it tuned in and carbs synchronised by a professional cause I haven't got the tools and clearly not the knowledge.
Thank you all again. I'll be back...
Cheers
Vince

 

[ghiribizzo]

haha! Well done. At least, you'll not make that error again.

 

[steveo]

vincent....give me a shout if you need a hand, im just looking to buy some carb balancing kit myself for my g/s. i live in brighton and have a workshop on a farm near lewes for mucking about in ! steve

 

[Ogmios]

There's hope for us all.....

You got all the hard bits done and it fell foul of a basic error.
Fair Play to ya for all the bits you got right!

Balancing the carbs is relatively easy - given what you've done so far.
Get the kit, give it a go. It's basic stuff (meaning; i can do it )

 

[Kenny]

Takes balls to admit to that one

A true tosser

 

[brassmonkey001]

I was close, I knew he had his wires crossed somewhere...