Friendly chap with huge kickstart foot required!

Phil Baker

Well Known and Active Forum User
Non-VOC Member
Hi all

I have recently acquired a Comet and cannot get the !@*** to start. I have checked the valve timing with a degree disc (learnt from a mate that the marks on the pinions only line up about twice in the average lifetime). The ATD springs are old and tired - like me after kicking the thing to Kent and back - and I have removed and shortened them but still not happy so I'll be ordering new ones tomorrow. If there are any knowledgeable Comet owners near Basingstoke then I would be happy to hear from you - phil@pgbf.freeserve.co.uk.

Thanks

Phil
 

timetraveller

Well Known and Active Forum User
VOC Member
Is there a good healthy blue spark at the plug when it is kicked over? Have you put in fresh petrol and not months/years old stuff? If the ignition timing is correct, on the correct stroke, then have you checked that the inlet and exhaust valves are just 'rocking' when at TDC one full turn of the engine earlier or later? How good is the compresson? You should be able to stand on the kick starter. If all that is correct then get a tow start, a push start or find a long hill. It will start, it just seems that it wont.
 

Bill Thomas

Well Known and Active Forum User
VOC Member
Hello Phil, My bikes , Sometimes play up after winter breaks, Like Norman says the petrol breaksdown after 3 months,If it's been longer drain the tank and carb, And fill with top spec' petrol, Once a spark plug has been wet, Put it in the bin !! This year after one of our friends on the forum said try Easy Start , From Halfords, I did, And it started third kick !! I am too old to do the running down the road trick, My engines are all in race trim, So a bit harder to start than soft motors. Good Luck Bill.
 

davidd

Well Known and Active Forum User
VOC Member
Phil,

You mentioned the valve timing, which I assume was ok, but you did not mention the ignition timing. Timetraveller and Bill both have good suggestions. Did this bike run well when you bought it? Then it is more likely a fuel quality or mag issue.

If you have never seen the bike run then you have to start further back and check the carb, gas tank, mag, plugs, wires, points, etc, just to be sure. If you have a mate with car rollers then that is the ticket for something that you have never seen run. You can pull the plug and run it on the rollers to see if the oil is circulating and check the spark at the same time. With rollers you can also start the bike at full advance, i.e. with weak springs. Note: the ATD is more important and difficult to sort than most owners think.

If you get it started then you can do a leak down test once it is warm and learn a lot about the engine condition and get a base line as well.

If you describe your starting procedure you may solicit some additional comments.

David
 

Martyn Goodwin

Well Known and Active Forum User
Non-VOC Member
Phil,

A few things.

first - be aware that through over zealous use of the kick starter you WILL bend the kickstart lever and eventually it will make contact with the exhaust. You should be pushing it down and through- not jumping on it.
second - despite the temptation you should not start or try to start it while its on the rear stand - possible result may be broken rear wheel lugs on the RFM
Third - The ignition advance at the time of (attempting) starting is critical. If without any adavance at all it is at TDC or AFTER TDC then it will be almost impossible to kick start - but roll starting will work. Conversely if it is at 10 degrees or more BTDC then kick back through the kick starter is highly possible resulting at best in a sore foot and still no starting. It is my understanding that the sweet spot for starting (with the kick starter) is between 4 and 6 degrees BTDC.

This assumes you have checked the fuel, spark plug and valves - and have not made the mistake of setting the timing on the exhaust stroke (like I once tried to do!) The TDC you want is when both inlet and exhaust valves are firmly closed.

Martyn
 

Howard

Well Known and Active Forum User
VOC Member
Phil,

We still don't know the most important things, if we're going to help.

Was it running when you acquired it?
If not , wny not?
If it was, what have you done that could have caused non startng?

H
 

clevtrev

Well Known and Active Forum User
VOC Member
Now if you`d have had a Twin, you could have used one of these, and then called for assistance.

There should be a picture here.


Trev photo.jpg

Picture added. TT.
 
Last edited by a moderator:

Phil Baker

Well Known and Active Forum User
Non-VOC Member
OK, gentlemen, thankyou all for your replies - I've only just realised how this site works (sorry!). The continuing story - the bike did not run when I bought it 3 weeks ago but I was assured that it was running 2-3 tears (misprint, should have been years but I think you'll understand the mistake) ago.... Having checked everything possible in terms of valve timing, ignition timing, mag, spark plug, amount of oil on the garage floor etc there was nothing else for it but to remove the head. So, I read the book and eventually wheeled away the front end - interesting experience!! Removed the head and took it over to Stumpy's place because over the course of the years I have given away, loaned out and generally lost all my valve removal/grinding stuff and the cause of the problem may have become clearer as the inlet valve was so tight that it had to be tapped out with a hammer; the rocker didn't rock a lot, the exhaust valve was a very old one and the inlet valve had been reshaped (on a lathe by the look of it) with a single chamfer. Neither valve had been ground in at all. SO, WHOEVER PUT THAT HEAD TOGETHER - YOU KNOW WHO YOU ARE - you should be ashamed of yourself!!!! With many ongoing thanks to Norman Stumpy Lord who has been and is being a huge help and to Hugo Myatt for the e-mails!! I'll keep you all posted.
 

Phil Baker

Well Known and Active Forum User
Non-VOC Member
You'll doubtless be fascinated by the latest development............... Stumpy suggested that I take off the barrel and piston to make sure that the bore is OK............. how many circlips are fitted to hold the gudgeon pin in place ......... you're going to guess at TWO, aren't you?

Well, words really do fail me this time. ONE $£&&&+@*** circlip has been used, just the one and no more. Thank goodness the dear old beast did not start up or it would probably have wrecked the engine.

I went to see Clever Trevor in his cave of swarf and he is a true engineer! He supplied me with all the bits I needed to refit the head... or so I thought until Stumpy had spent an hour gently reaming out the exhaust valve guide to take the new valve. Just as he was making the final pass with the reamer for a perfect fit................... the LINER ?$!! WHAT? Yes, the liner of the valve guide came free and raised itself up in front of us. Now the head is off for a little holiday on Hayling Island with the aforementioned Clever Trevor.

I really would like to meet the individual who has perpetrated these evils on a Vincent......


Phil
 
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