Author Topic: Well what a disastrous rebuild this has been  (Read 12628 times)

Offline bikerboy

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Re: Well what a disastrous rebuild this has been
« Reply #45 on: 05.05. 2013 16:58 »
manosound

I think the original difficult to kick thing was the wet sumping.

Now it is not so bad. It has standard SR pistons in about 8.5:1 and it kicks over lovely with no plugs in. I think that is more me being a bit of a girl than anything wrong with the bike I am seriously considering trying to tow start it once I get the damned mag back on.

BTW whats the recommended ignition timing setting now with the new fuel. I did look it up before I timed it last time and cant remember now.

Its a SR with a 357 cam in it

Offline bikerboy

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Re: Well what a disastrous rebuild this has been
« Reply #46 on: 05.05. 2013 21:20 »
Right progess at last.

Refitted the mag, retimed it at 5/16 btdc. Kicked it over until my heart near gave out and got sweet FA.

Swapped the leads just in case I had timed on the wrong stroke and still got sweet FA.

Eventually decided that it had to be fuel so in pure frustration whacked a squirt of easy start up each carb. 2nd kick got a misfire which is the first sign of life it has ever shown me.

Then thought "oh yes I have not put the leads back on the sides I believe they should be ok.

Swapped the leads gave it another whack of easy start and it actually fired about 8 times on the left hand side. So now I have to try to work out just why its not getting any fuel to the cylinders. I am not to worried that the right hand side never really fired it might not have had enough easy start in that carb its harder to reach.

It has twin carbs both 930 concentrics that I stripped and cleaned before I fitted them. At least I feel a bit better now it has done something.

Offline RichardL

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Re: Well what a disastrous rebuild this has been
« Reply #47 on: 06.05. 2013 15:19 »
Sounds of hope. Think of it as preparing for your future as an American football place kicker.
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 muskrat

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Re: Well what a disastrous rebuild this has been
« Reply #48 on: 06.05. 2013 20:45 »
G'day Bikerboy. So now we turn our attention to the carbs. Do a search in Amal & Carburation section for float height and pilot jets. Have a good look at the Amal site http://amalcarb.co.uk/optimising-mark-1-concentric-fuel-levels  and  http://amalcarb.co.uk/rebuilding-mark-1-concentric-carburetter
Note the different pilot jet types.
Cheers
'51 A7 plunger, '57 A7SS now A10CR, '76 XT500, '77 AG175 '83 CB1100F, '81 CB900F project.
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Offline bikerboy

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Re: Well what a disastrous rebuild this has been
« Reply #49 on: 06.05. 2013 21:49 »
muskrat

Good advice but these carbs were last used on my 650 plunger (which had twin carbs) albeit a long time ago, so the jetting should be pretty much ok. At least now I know its definitely fuel which is progress of sorts. The only thing I can think of is that I did not pay enough attention when I stripped them down and rebuilt them. One thing I have done which gave me a bit of a surprise. When I get a bang or it tries to fire it always seems to be the left hand cylinder which is trying.

I took both misxure screws out and blew them out. The left hand one under the air pressure pushed fuel out of the tickler but the right hand one forced fuel out of one of the holes on the back of the carb nothing from the tickler. Without being an amal expert common sense tells me they should both act the same when the same test is carried out on them. My only other observation is that (as always) I never bothered with chokes they are both blanked off. After stripping the carbs if I still get no joy I might try blocking the air vents a bit to see what that produces.

I did speak to a guy at the Kempton auto jumble who is supplying replacement carbs http://brillbikeparts.co.uk/tech.html he seems to think they are pretty special I wonder if anybody else off here has tried them and what comments they have. The price is pretty reasonable at £84 each.

Online muskrat

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Re: Well what a disastrous rebuild this has been
« Reply #50 on: 06.05. 2013 23:25 »
 I have a pair of those on my '57 A10 cafe. They only come in left hand so choke and pilot adjustments are hard on the right one. With a pair, the throttle springs are too hard. Once jetted right (30 odd different needles) and balanced they are great.
Concentrics are easier to tune.
Cheers
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Online WozzA

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Re: Well what a disastrous rebuild this has been
« Reply #51 on: 07.05. 2013 00:24 »
I THOUGHT my electrics were spot on too...  new plugs & leads, good spark on each plug out of the bike...
After 2 weeks of kicking, checking timing,  Mag & pionts 20 odd times, enough swearing to book my place in purgatory, I replaced the new leads & plugs with another new set of both ...
Imaging my supprise when it started 2nd kick...   *rant*

Stick with it bikerboy, you'll get there..
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Offline bikerboy

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Re: Well what a disastrous rebuild this has been
« Reply #52 on: 27.05. 2013 20:07 »
Wahoo we have lift off  *smile*

All that messing about and I should have followed my instincts from the very beginning.

For those that have followed this thread from the beginning one of my first observations was that the bike was difficult to kick over and just never sounded right when I did kick it over. AFTER stripping the carbs again to check the pilot jets I decided to go back to basics. I stripped the timing side back completely because I decided to start with the valve timing. On very close inspection I noticed that the dot on the pinion wheel was in the wrong place ???? I removed it and compared it with another pinion wheel and noticed a very faint mark where it should be but a very distinct dot in another place completely. I changed the pinion wheel and retimed the valves. I knew instantly I was in the right track because now the ignition timing was now a mile out and when I kicked it over it was a hell of a lot easier to kick and this faint whoomph noise that concerned me had disappeared.

Retimed the ignition (without taking the rocker covers off) so I had no idea what stroke it was on but within 3 kicks the big bang told me to change the HT leads over and bingo the roar of an A10 echoed around my garage. I did not run it for long because the timing cover was still off but it ran long enough for me to see the oil returning to the tank nicely.

Having moved everything out of the way on that side of the garage to save splashing it in oil, a quick tickle and it burst into life first kick and revved nice and cleanly. God knows what muppet put a centre mark on the pinion wheel maybe it was a strobe mark or something but all that messing about because of it.

Still got to put the timing cover and that back on but it sounds fantastic, god bless goldie silencers  *smile* *smile* *smile*

Offline bikerboy

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Re: Well what a disastrous rebuild this has been
« Reply #53 on: 27.05. 2013 20:09 »
Oh and full marks to muskrat his first comment was "is the valve timing right"

Online Triton Thrasher

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Re: Well what a disastrous rebuild this has been
« Reply #54 on: 27.05. 2013 20:47 »
Somebody's home made mark, I would guess.

Online muskrat

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Re: Well what a disastrous rebuild this has been
« Reply #55 on: 27.05. 2013 21:35 »
 Great to hear bikerboy, you will now be able to service her blindfolded. *smile*
Lucky it didn't bend a valve, the "hard to kick over" might have been one just kissing a piston.
 Now for miles of smiles.
Cheers
'51 A7 plunger, '57 A7SS now A10CR, '76 XT500, '77 AG175 '83 CB1100F, '81 CB900F project.
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Offline bikerboy

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Re: Well what a disastrous rebuild this has been
« Reply #56 on: 27.05. 2013 22:07 »
Lucky it didn't bend a valve, the "hard to kick over" might have been one just kissing a piston.
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Don't say that for gods sake as I have a slight miss on the left cylinder. To be honest I think I would have heard that kicking it over with the plugs out.

Unfortunately I am working away again the rest of the week so it will be next week before the timing case is back on and I can tweak the carbs etc. Hoping to get rid of the misfire but I think its an air leak. For some reason when I put the carbs back and bolted them up on the left hand slide was sticking big time so I loosened the body to see if it was distortion or not. I am hoping that when I tighten it up the miss will go but until I get the timing case back on I cant really check that out to much and I need a new gasket for that.

I will also stick a compression test on it because that will automatically show up a bent valve.

BTW did I tell you it sounds effing marvellous  *smile* *smile* *smile* *smile* *smile* *smile*

Offline RichardL

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Re: Well what a disastrous rebuild this has been
« Reply #57 on: 28.05. 2013 14:31 »
Taking nothing away from Muskrat, a doff of the hat should go to BSA-BILL as well, who just about nailed the exact circumstance.

Truly hoping for all's well with the valves. I don't recall if you mentioned your compression ratio, but I assume 7:1 is less likely to clink than, say, 9:1. Here is yet another place where, I think, Musky and others will have the exact answer versus my supposin's.

Richard L.
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Re: Well what a disastrous rebuild this has been
« Reply #58 on: 28.05. 2013 16:31 »
Heres hoping , after all the crap you've gone through  you deserve a break as well as a medal for perseverance , good luck ,by the way my "goldie" silencer ( contradiction in terms really )roars beautifully too and sounds great on the overun with the siamese pipes ! Cheers BobH.
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Re: Well what a disastrous rebuild this has been
« Reply #59 on: 28.05. 2013 20:23 »
We don't really get "breaks." The valve hit the piston and is bent, or it didn't and isn't.

My experience is that compression felt through the kickstarter disappears on one cylinder when a valve is bent and that cylinder does not fire at all at low revs.