Author Topic: Pushrod question - problems starting new engine  (Read 9031 times)

Offline a101960

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Re: Pushrod question - problems starting new engine
« Reply #75 on: 22.02. 2011 22:00 »
Trev, I gleaned that bit of information from Brian Pollit of lighting spares. There is or was an article on the Lightning Spares web site about how he rebuilt his A10. Called 70,000 miles on a BSA A10. You can click on the link below to read the complete article.

Quote
"How many times have you set the timing then tightened up the magneto nut and found when you recheck, that the timing is slightly out? My solution to this is to elongate the three fixing holes in an arc around the armature. This can be done by placing one leg of a set of spring dividers in the end of the armature and, using the other end scribe an arc on either side of each hole. Using a round file elongate each hole either side by about 1/16'' keeping between the scribed lines. You should then mount the magneto in position with the studs in the centre of the elongated holes. Time the bike as normal and if, when you check, the timing it is out, all you need to do is loosen the fixing nuts and rotate the magneto in whichever direction necessary, to give perfect timing, then retighten the fixing nuts, after checking that the magneto and timing pinions mesh correctly".


Timing
"The engine is timed at 13/32 before TDC. To ensure that the timing is always spot on I put some timing marks on the engine. This is done in the following way:- With the outer timing cover removed, bring the engine to its correct firing position before top dead centre. This varies for each model. Then with a centre punch, make corresponding marks on the timed breather which turns at engine speed and its surrounding boss in the inner timing cover. The breather is hardened so you will have to use a sharp punch. Now, when you want to time the ignition you just line up these two marks and set your magneto."

http://www.lightning-spares.co.uk/index.htm

This is a verbatim extract from that article. If I remember correctly the article was also published in the Star Magazine.

John

Online bsa-bill

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Re: Pushrod question - problems starting new engine
« Reply #76 on: 22.02. 2011 22:33 »
The pinion on the end of the crank has half as many teeth as the camshaft pinion, this allows the camshaft to turn at half engine speed and also the Magneto,(magneto pinion has same number of teeth as the camshaft pinion - note this does not apply to the idler pinion which has extra teeth so that it does not mesh with the same teeth on the camshaft pinion every time it revolves (evens out load and wear) )

It has to be this way or the A7/10 range would be two strokes *smiley4*

Making marks to align for ignition timing only works provided you do not remove the magneto pinion, fair enough if you are for some reason changing the camshaft
All the best - Bill
1961 Flash - stock, reliable, steady, fantastic for shopping
1959 Rocket Gold Flash - blinged and tarted up  would have seizure if taken to  Tesco

Offline trevinoz

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Re: Pushrod question - problems starting new engine
« Reply #77 on: 23.02. 2011 21:18 »
There you go, John.
                                You can't believe everything that you read.
    Trev.

Offline RichardL

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Re: Pushrod question - problems starting new engine
« Reply #78 on: 23.02. 2011 22:21 »
Besides, the problem with timing is not determining the distance BTDC of the the piston, that's easy. If you want that translated to angle, that info is somewhere here in the forum, thanks to Richard (Orabanda), as I recall. The problems (unless you have slotted the mag base) are having to remove the timing cover and, then, tightening down on the mag taper without losing position. After gawd knows how many attempts, I ultimately got to a comfort zone in tightening down the taper, but removing the timing cover is, for me, a reality to live with.

Richard L.
Plan on signing up for the world-wide 2017 DISTINGUISHED GENTLEMAN'S RIDE on September 30, 2018. Watch website at https://www.gentlemansride.com for details.

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Re: Pushrod question - problems starting new engine
« Reply #79 on: 23.02. 2011 22:33 »
Yes slotting the magneto holes is an attractive proposition, incorporated with a micro adjuster would be heaven for many I think.
I know it has been done, just the thought of all that filing really although there just has to be a power tool to do that (hasn't come to Aldi yet though) *smiley4*
All the best - Bill
1961 Flash - stock, reliable, steady, fantastic for shopping
1959 Rocket Gold Flash - blinged and tarted up  would have seizure if taken to  Tesco

Offline RichardL

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Not a pushrod question! Now we talkin' mag slots.
« Reply #80 on: 24.02. 2011 05:49 »
I suppose the best way would be by using a chuck on a vertical mill rotary table.  Sadly,  I don't have one of those in the garage. I've forgotten how others did it. OK,  how about a wooden stand with a hole in it and sitting on a drill-press table.  Clamp the stand to the table so the mag bolt circle is under the chuck holding a milling bit.  Run the chuck down and turn the mag by hand.  Hey,  it might work.  Doubter!

Ricchard L.
Plan on signing up for the world-wide 2017 DISTINGUISHED GENTLEMAN'S RIDE on September 30, 2018. Watch website at https://www.gentlemansride.com for details.

Online bsa-bill

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Re: Pushrod question - problems starting new engine
« Reply #81 on: 24.02. 2011 11:24 »
Let me know how you get on Richard ( before I ruin mine  >:D)

Thinking about though, the answer is to take it to our local engineering shop, depends upon what price you put on skinned knuckles
All the best - Bill
1961 Flash - stock, reliable, steady, fantastic for shopping
1959 Rocket Gold Flash - blinged and tarted up  would have seizure if taken to  Tesco

Offline RichardL

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Re: Pushrod question - problems starting new engine
« Reply #82 on: 24.02. 2011 13:05 »
No immediate plans. Just daydreaming.
Plan on signing up for the world-wide 2017 DISTINGUISHED GENTLEMAN'S RIDE on September 30, 2018. Watch website at https://www.gentlemansride.com for details.

Offline Duncan R

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Re: Pushrod question - problems starting new engine
« Reply #83 on: 01.03. 2011 13:13 »
Got it back together this morning after grinding in the valves and fitting new valve springs and it started on both cylinders 3rd kick! And also starts first kick after a carb tickle

its popping and banging a bit and seems like it is running out of fuel, so just need to check the fuel flow now. I fitted a metal banjo bolt to the concentric and I noticed it crushed the gauze filter a bit,so that is a possible cause of the restricted fuel flow.

I had a feeling it was going to run, after getting the head on and turning it over by hand the valve sequence seemed a lot different from the last time, I have no idea what I could have done so wrong on the previous assembly? Maybe a misplaced push rod?
Anglo - Indian A7SS (Actually is a 650)
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BMW R80GS
BMW R1100GS

Offline Duncan R

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Re: Pushrod question - problems starting new engine
« Reply #84 on: 01.03. 2011 19:16 »
Oh well, that was short lived, warming it up to set the carb and went down on one - sodding pushrod came out of the rocker!
So off with the rocker box again - this has got to be the worst engine I have worked on *problem*
Anglo - Indian A7SS (Actually is a 650)
Kawasaki ZZR 1100
BMW R80GS
BMW R1100GS

Offline trevinoz

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Re: Pushrod question - problems starting new engine
« Reply #85 on: 01.03. 2011 20:18 »
Patience Duncan, patience.
                                          Look at it as a learning experience.
You probably thought that we loved our A type BSAs but we all want to inflict the frustration on as many others as possible!
On a lighter note, are you using the comb to install the pushrods? Always a good idea to shine a light into the rocker box as well to ensure that the rods are in their cups and not riding on the rim.
Trev.

Offline Duncan R

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Re: Pushrod question - problems starting new engine
« Reply #86 on: 01.03. 2011 20:43 »
Hi Trev,

I used the comb, and it was far easier then last time (must have learnt something *smile*) set all the tappets and spun engine by hand several times and rechecked, can't see how it came out ? I was trying to jiggle  it back in but the rod would not go under the rocker , even with the adjuster taken right out,I need to get some decent lighting as well. Any way least I know the bike runs on both cylinders and the oil system is working properly- sounded quite nice.

I will get there in the end - but give me a DOHC  16V four any day *smile*

Cheers
Duncan
Anglo - Indian A7SS (Actually is a 650)
Kawasaki ZZR 1100
BMW R80GS
BMW R1100GS

Offline trevinoz

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Re: Pushrod question - problems starting new engine
« Reply #87 on: 01.03. 2011 20:50 »
Maybe a Bantam? No pushrods there!
  Trev.

Offline Duncan R

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Re: Pushrod question - problems starting new engine
« Reply #88 on: 01.03. 2011 20:56 »
Now there's a thought !
Anglo - Indian A7SS (Actually is a 650)
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Offline nigeldtr

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Re: Pushrod question - problems starting new engine
« Reply #89 on: 01.03. 2011 22:12 »
Hi Duncan,

Sorry to hear about all the problems. Always good to have two or three  builds on the go, when you get cheesed off with one you can go and get cheesed off on the other - somehow seems to help. Anyway, I use the comb but always ruins the seal with the gasket sealant sticking to it. I also get my Son to shine a torch in from the front and he makes sure the rockers are in the cups from his side while I fiddle around at the back - worked so far!

Good luck!

Nigel
1951 Golden Flash (engine now rebuilt) 1953 M21 a pain to start and 1961 GF that is turning into a black hole!