A65 SPITFIRE KICK BACK

[Servodyne]

the timing is spot on the mark and advances perfectly.

Hi. Just to be clear, when you say the timing is spot on the mark and advances perfectly, do you mean it advances perfectly up to the timing mark?
If it starts advancing after the timing mark It'll be way too advanced and will give you the potential of a broken ankle you describe.
The timing will only be spot on the mark is when the engine is doing 5000rpm.

[Mike Farmer]

 

Sudden thought and I may have missed something in the posts.

Do you have proper air filters on it. If not it may be worth a try--it should richen the start mixture just a tad.

Mike

[johnjag]

Hi all and particularly Mike Farmer. Mike I think your idea is a good one but I cannot try to start the bike at the moment due to an injured back. This was caused not by the bike kicking back but just stooping slightly while I was spraying the rear shocker covers! Oh the joys of old age. Will let you all know when I have a result. Thanks again for all your inputs.  John.

[johnjag]

Hi - yes the ignition advances perfectly up to the line. I had thought about air filters but didn't think it would make enough difference but I am willing to try anything. As soon as my backs ok I will start experimenting again and let you know. John.

[Servodyne]

Sorry to harp on about the timing, but when you set the timing marks on the Electrex rotor and stator, what advance did you set it at? It may just be worth checking that the timing marks are still in the right place at 34 deg BTDC.

[Mike Farmer]

 
You could always break all the conventional rules and time it fully retarded, About 1 degree past TDC. If it still kicks back its then definitely fuel.

Mike

[johnjag]

Hi Servodyne & Mike. The timing was set using the crankshaft locking tool to find TDC and a timing disc and pointer to set at 34 BTDC and the markers on the Elextrec lined up. The adjustment screw being bang in the middle. I have since retarded it as far as it will go on the adjustment slot to no avail. I will actually time it retarded as suggested and see what happens. My back is almost ok now so this weekend should see further investigation. Thank you all yet again for your tremendous help. John.

[Servodyne]

Hi John
The crankshaft locking tool sets the pistons at 34 deg BTDC. You should be able to set the markers on the electrex in this position.
If you are using a timing disc to further advance the electrex before setting the markers it will far too advanced.
Jim

[johnjag]

Hi Servodyne - sorry I should have said I am going to set it with the locking tool I have just purchased. It was originaly set using a TDC tool through the plug hole. However I am glad you replied because I thought the crank tool did set it at TDC, wow that would have made it worse.

[johnjag]

Hi all - I have now checked the timing with the crankshaft timing tool (arrived this morning) and while hoping beyond hope that I would find the timing was out by using this tool, IT WAS SPOT ON! So I am now more than ever thinking it is carb related and I have put a separate post on regarding which pancake air filters I should use, centre fixing or offset. Does anyone reading this know? Will keep you updated.
John.

[Mike Farmer]

 

I expect that you will have already checked this but just in case: These symptoms will appear if you have any water in your petrol and they will also appear if you have oil in the fuel. Because oil has a much higher flash point than petrol it wont burn in a cold engine so will radically weaken the mixture. (2 strokes are designed around this feature)

Sorry to be boring.

Mike

[johnjag]

Mike - the last thing you are is boring, you have been very helpful to me over this problem. The petrol is brand new Esso premium brand who everyone seems to think as well as being higher octane, it has no ethanol. So no problem there I think. Between us all we will get to the bottom of this problem, this is what these forums are all about.
Regards John.

[johnjag]

Sorry for the delay in progress but as soon as my back was better, I have now got bloody flu!
John.

[johnjag]

At last I am reasonably fit again. So finally fitted the air filters and as previously mentioned I have fitted a choke and upped the size of pilot jets. As long as I don't touch the throttle the bike now starts instantly on tickover and sounds lovely. As long as it rides ok (after I have painted the tank and side panels) that will do for me, so I am not going to risk a bad ankle by trying to start it with a whiff of throttle, just for the sake of it (unless I get braver at a later date).
Again thanks for all your input, it was much appreciated.
John.

[Mike Farmer]

 

Sounds good to me and very pleased for you. Incidently I always try to set that side of things up so that it starts with the throttle fully closed.

Mike