Kickback

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Bevel bob
Posts: 833
Joined: Thu Apr 15, 2010 8:01 am
Location: Bromley Kent UK.

Re: Kickback

Postby Bevel bob » Sun May 24, 2020 5:13 am

I have a 250 Narrow case with the ADV retard unit that gives about 18 degrees adv that with the gearing equates to 36 degrees, I set my timing to give a few degrees static advance . with this amount it only kicks back rarely and I often start first kick. I now don't bother measuring the timing I just open or close up the points a couple of thou to get the mild kickback. The motor has a wild race cam and the 10 to one piston ,40mm inlet and 29mm SSI carb. and can pull up to 10000 revs ,its no pussycat. The carb needs plenty of flooding and once it starts it always 8 strokes for a while held on 1/4 throttle. I expect if I checked the plug would be dripping wet.I don't know what Ignition system you have ,but it needs to work like mine. If it does not I would change it. Some models have ridiculous systems that give far too much static advance. Just not practical. I also have a Pazon points booster that ensures a good strong spark. I do suspect you have a low fuel level. If you have reached the end of your point plate before getting the timing then you need to dismantle the timing gears and re-set . Do not kick over against compression,you will damage things, just ease the piston a few degrees over compression before you kick.

Ventodue
Posts: 627
Joined: Mon Mar 08, 2010 3:23 pm
Location: Montpellier, France

Re: Kickback

Postby Ventodue » Sun May 24, 2020 9:34 am

frankfast wrote:Bike is kicking back at the highest point of the kick starter. That's the only time it seems to ignite.


This is the bit that I don't understand, Frank. Set correctly, these bikes fire at the bottom of the kick start stroke. So how come you are getting a spark at the top? :?

frankfast
Posts: 140
Joined: Wed May 05, 2010 12:35 pm
Location: New York (upstate)

Re: Kickback

Postby frankfast » Sun May 24, 2020 10:41 am

Am I doing this wrong or is something else happening? Doesn't spark ignite BTDC which is when I'm getting kickback? I thought you want to kickstart the bike on the compression stroke.

frankfast
Posts: 140
Joined: Wed May 05, 2010 12:35 pm
Location: New York (upstate)

Re: Kickback

Postby frankfast » Sun May 24, 2020 11:03 am

Ventodue wrote:
frankfast wrote:Bike is kicking back at the highest point of the kick starter. That's the only time it seems to ignite.


This is the bit that I don't understand, Frank. Set correctly, these bikes fire at the bottom of the kick start stroke. So how come you are getting a spark at the top? :?


If you are correct, this would indicate that the timing is wrong, too far advanced? I have retarded the timing to varying degrees without success although kickback was eliminated. Two years ago the bike ran well and I've done nothing to change that except a new battery. This problem usually indicates ignition issues but I think, in this case, I'm beginning to suspect the carb. Kicking the bike multiple times with the enrichener in on position, the plug should be wet if it doesn't fire. It is not.

Bevel bob
Posts: 833
Joined: Thu Apr 15, 2010 8:01 am
Location: Bromley Kent UK.

Re: Kickback

Postby Bevel bob » Sun May 24, 2020 11:08 am

Have you got the bike back to front or upside down? :D

DBDBrian
Posts: 87
Joined: Mon Mar 30, 2015 11:29 pm

Re: Kickback

Postby DBDBrian » Sun May 24, 2020 12:25 pm

I have never started a 350 Ducati, so perhaps not qualified to comment, and I'm sure there are people on the forum with far more experience of Ducati's than me. But I have been starting BSA Goldstars for the best part of sixty years, and what you require to avoid kickback on a big single, is crankshaft momentum.
I understand this is perhaps difficult without a valve lifter. This is my procedure, prime the carburettor, this is obviously dependent on engine
temperature . (set the ignition timing which does not apply in you case) . The engine needs to be kicked onto compression, then eased just over TDC, then return the lever to the top position, the crankshaft then has almost two complete revolutions before ignition.
You must not pussy foot, kick in a manner that you are definitely expecting the engine to fire up.
This is obviously assuming that everything is mechanically correct with the machine.
HTH
Brian
Made in England

frankfast
Posts: 140
Joined: Wed May 05, 2010 12:35 pm
Location: New York (upstate)

Re: Kickback

Postby frankfast » Sun May 24, 2020 1:14 pm

That is basically what Ventodue said and it might be what I am doing wrong. Will try it but I suspect something else is wrong because I didn't have this problem when the bike last ran.

frankfast
Posts: 140
Joined: Wed May 05, 2010 12:35 pm
Location: New York (upstate)

Re: Kickback

Postby frankfast » Sun May 24, 2020 5:06 pm

I also have to admit that since my double knee replacement, I'm not able to give the kind of kick I used to be able to do. It would help if I had the compression release setup. The valve cover has the item at the top but the rest is missing. If anyone knows where I might get one, please let me know. Thanks for all the help guys.

DBDBrian
Posts: 87
Joined: Mon Mar 30, 2015 11:29 pm

Re: Kickback

Postby DBDBrian » Sun May 24, 2020 7:45 pm

Sorry to hear of your knee problems Frank, , definitely not conducive to kick starting a motorcycle, apologies for my Pussy foot comment. Regarding the valve lifter usage, it really only assists with getting the engine easily over TDC for the correct position of the crankshaft for starting, once this is established, the lifter is not used for the actual starting process, as said, the engine can now rotate for almost two complete revolutions before coming up on compression again, at which point it will hopefully fire up.
So I don't think a valve lifter would necessarily assist you with the actual kicking process.
Have you given any thought, as too a set of starter rollers, for the first start when everything is cold.

When starting my Goldie, the retard / advance adjustment sometimes require a bit of experiment, depending on the conditions, the result of which can sometimes be quite a sharp kickback, I am fortunate in that I am still able to fire it up, but for how much longer who knows, seventy six come the time this year. Things should be easier when I get my 200 SS rebuild completed.
Brian
Made in England

frankfast
Posts: 140
Joined: Wed May 05, 2010 12:35 pm
Location: New York (upstate)

Re: Kickback

Postby frankfast » Sun May 24, 2020 8:07 pm

[quote="DBDBrian"]Sorry to hear of your knee problems Frank, , definitely not conducive to kick starting a motorcycle, apologies for my Pussy foot comment. Regarding the valve lifter usage, it really only assists with getting the engine easily over TDC for the correct position of the crankshaft for starting, once this is established, the lifter is not used for the actual starting process, as said, the engine can now rotate for almost two complete revolutions before coming up on compression again, at which point it will hopefully fire up."


Maybe I'm missing something. If you don't kickstart until just after TDC, the spark plug has already ignited. You would have to get almost two complete revolutions of the crank on the kickstarting process for the plug to ignite again and start the machine. Maybe my knees are not capable of doing that. Isn't the compression release mechanism held open until the bike is started? That means the exhaust valve is partially open on the compression stroke making it easier to kickstart. I've never had a compression release so I'm not sure how they're used. If the exhaust valve is left open while kicking, maybe compression will close it.

If you're saying you're turning seventy six, you only have two years on me. Only us old fellas remember when these bikes were new. Don't know about you but I have no attraction for the new stuff.....but electric start was a great invention. :D
Last edited by frankfast on Sun May 24, 2020 8:50 pm, edited 1 time in total.


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