1960 a10 superocket hard starting

[wole]

Hi all my superocket is a pig to start. In the past someone  I think has rebuilt it with a racing mag and proberly high lift cam and hc pistons. I am going to measure the lift of cam. When I have this measurement can the cam be identifiyed?. Also what cr pistons would give me Easy starting.thanks wole

[KiwiGF]

Does it not fire? Or is it just very had to kick it over?

My a10 gf is easy to kick over with a 356 cam and 7.25 cr Pistons.

I've kicked over an original a10 gf with 6.5cr and 334 cam and in comparison to mine could hardly feel the compression it was so easy to kick over!

[wole]

Hi it is fairly hard to kick over as I am 67 on full advance it kicks back. if slightly retarded it will not fire. I just have to kick it over on full advance until it does start

[Bsareg]

Sounds like a weak mag. Do you have a good spark when retarded?

[RichardL]

Could be the mag, but spark strength is easy to check. Also, could be that ol' devil pilot jet gunked up. My guess is that the first few kicks are not a problem but it gets harder as exhaustion sets in.

What's the plan for measuriing lift, dial indiacator on the end of the rocker arm?

Richard L.

[RichardL]

Here are the cam profiles: http://atlanticgreen.com/images/356-357.jpg

[Topdad]

have you checked the timing .if so what was the figure btdc. my cr is 8.25 ,spitfire cam whilst good comp not that hard to crank ,I'm nearly 67 ( jan ) ( *whistle*date can be provided for any donations ) 

[muskrat]

G'day wole.
Are you 100% sure the timing is correct? With manual advance/retard loose wire = advanced, tight wire = retard.
Cheers
Topdad beat me to it.

[wole]

Hi I have set timing to the Manuel. Which I believe is 3/8 Btdc fully advanced

[chaterlea25]

Hi,
+ 1 on all the previous suggestions,
As you are losing spark strength when you retard the mag, one or two pointers that may help
Very few mag guys have the proper strength magnetiser to remagnetise the mag once its assembled
Some were also fitting sub standard capacitors that are not up to the job ??
Check the points for blackening ? clean them and see if starting improves ?
I think you will find that 3/8in. BTDC is a bit too much with the fuel we have to cope with now a days
I would bring it back to nearer 5/16in.

I have a Super Rocket in a similar state of tune, manual mag etc, I found it runs and starts better at 35 degrees before TDC (if my memory is correct??)

John

[RichardL]

Never having had to (gotten to?) start a manual.advance bike, I made the assumption that if the timing can be advanced to the point of kickback, it could be retarded to the right spot for starting. Wouldn't this make the setting of timing at full advance less critical, since it can be backed off manually?

Richard L.

[Bsareg]

Auto timed mags open the points when the armature is around max magnetic flux density,   on manual mags retarding  ignition brings points away from the most efficient fluxes density causing reduction of ht voltage at the plug

[Triton Thrasher]

With manual advance/retard loose wire = advanced, tight wire = retard.

Should be, but it's not impossible to have the opposite.

[wole]

Yes I agree with richard. I can adjust the timing to where ever needed.but if I retard it even slightly it does not fire

[Bsareg]

Retard your ignition and look at the colour of the spark, should be blue with an audible  snap. A pink spark will be useless under cylinder compresstion