Author Topic: Well what a disastrous rebuild this has been  (Read 12624 times)

Offline Rich

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Re: Well what a disastrous rebuild this has been
« Reply #60 on: 28.05. 2013 20:48 »
Brilliant news Alan, nice to have met you, I was thinking of visiting you with my timing box to help sort it out, no need now.
I missed that crank on ebay see my "OOPS" post.
Please get that one of yours double checked for me as hoping I was wrong

Offline bikerboy

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Re: Well what a disastrous rebuild this has been
« Reply #61 on: 02.06. 2013 02:12 »
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
---------------------------------------------

Triton

Quite agree the slight miss was more of an air leak than anything I reckon but now the bloody thing wont start again  *sad2*

To be fair I have not had time to check it out but I will do this week some time. I started it 5 times last time and it started great and revved ok today it fired once I think. Oh well more checks  *conf*

wardleyrob

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Re: Well what a disastrous rebuild this has been
« Reply #62 on: 13.06. 2013 20:13 »
Hy bikerboy there is no need to strip your engine to cure the wet sumping. You can alter the spring in situ as like a65 lhave
Done it many times wardleyrob

adm edit: topic about oil retention ball mod >   http://www.a7a10.net/forum/index.php?topic=7246

Offline bikerboy

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Re: Well what a disastrous rebuild this has been
« Reply #63 on: 20.06. 2013 02:54 »
Well at last I got a bit of time and the damned thing is running and ticking over even if the tickover is less than perfect. It seems to be on the verge of cutting out all the time. It revs cleanly enough but it alos floods extremely easily if you tickle it to start it when it is hot.

I span it around the block (a very short block) and all seems fine oil is circulating fine etc but, yes there is always a BUT, my first observation is that screwing the mixture screws in and out makes virtually no difference whatsoever.

I have a half forgotten memory of this happening to me in the past but cannot remember what I did to cure it.

The bike has twin 930 concentrics on it.

Online muskrat

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Re: Well what a disastrous rebuild this has been
« Reply #64 on: 20.06. 2013 06:49 »
 Float/fuel height too high and blocked pilot jet/passageway. Are they Mk1 or Mk1.5 concentrics?
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 #65 on: 21.06. 2013 00:56 »
Hi muskrat

The float heights are fine I reset them and the carbs are mark 1. I have cleaned the pilot ways 3 times now and there seems to be a perfect air flow from the mixture screw to the 2 little holes inside the carb and to the hole in the back of the carb. Did the normal brake cleaner blocked the holes up and blew them out with an air line I am fairly sure they are clear

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Re: Well what a disastrous rebuild this has been
« Reply #66 on: 21.06. 2013 06:47 »
You don't mention the fuel side of the pilot system. If you take the bowl off there is a small threaded hole in the body that meets with a hole in the bowl that picks up fuel from the bottom of the bowl. The Mk1 has the pilot jet screwed in the threaded hole. The Mk1.5 has the treaded hole but the jet is under the brass plug and at the end of the air screw hole. If you take the air screw out you will see a brass jet at the back of the hole. A 16thou jet cleaner is needed to make sure it's OK.
Cheers
'51 A7 plunger, '57 A7SS now A10CR, '76 XT500, '77 AG175 '83 CB1100F, '81 CB900F project.
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Muskys Plunger A7

Offline bikerboy

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Re: Well what a disastrous rebuild this has been
« Reply #67 on: 23.06. 2013 02:00 »
Muskrat

They must be 1.5's then as the pilot jet is fixed. I did blow out clear to the float bowl and they all seemed fine. I have started it again today and just blasted it up the road and back. It starts ok now, it ticks over quite nicely and the engine seems smooth enough (even my 12 volt dynamo conversion has worked straight away :))

The oil is pumping nicely and I think I really need to take it out on the road and do at least 30 miles on it checking the plug colour etc at certain speeds and intervals. I have to say I am actually quite happy with 99.9% of it now that its running and am possibly hoping for a bit to much for the twin carb conversion etc to be perfect from the word go.

I still need a speedo and a rev counter tho :(

Online Triton Thrasher

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Re: Well what a disastrous rebuild this has been
« Reply #68 on: 23.06. 2013 07:56 »
Only very early Mk 1 carbs and two stroke versions had the jet in that threaded hole. Normal Mk 1s have a tiny brass bush for an idle jet, hidden behind the mixture screw.

Mk 1.5 has screwed in pilot and cold start jets, a Japanese-style cold start plunger and lever and no tickler.

Offline bikerboy

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Re: Well what a disastrous rebuild this has been
« Reply #69 on: 29.06. 2013 02:55 »
Yes I thought the 1.5 had a cold start a bit like the Mk2's.

Mine are obviously 1's for sure then. I aim to take it for MOT on Monday so that will give it a bit of a blast and if the worst comes to the worst I will buy a new set of carbs.

Offline bikerboy

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Re: Well what a disastrous rebuild this has been
« Reply #70 on: 01.07. 2013 23:42 »
Has anybody got a gallon of petrol and a box of matches  *sad2*

The saga continues. Took the bike out Sunday for the first time and it started 2nd kick and purred away wonderfully for about 20 miles. It then stopped when I was coming off the motorway and refused to start. Got it picked up by van and when I got it home it started straight away.

Took it for MOT today and after 20 miles was coming off the motorway again and bang it died and refused to start. Let it cool down for 45 minutes and it started straight away. Same thing on the way home after just over 20 miles.

Correct me if I am wrong but I am fairly sure this would be the magneto heating up and breaking down. Anybody disagree or have any other theories ? I did put new bearings, seal, insulators and points in the mag but other than that I just cleaned it up.

The good news is that when it is running it is absolutely lovely.

Online Topdad

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Re: Well what a disastrous rebuild this has been
« Reply #71 on: 02.07. 2013 10:55 »
Morning, first up , hide the matches and petrol! You've come so far with this and will sort it within the next few days. Could it be someting else ,how did it stop suddenly of with loss of power. Before condeming the mag check daft things like tank cap vent hole and the filters on the petrol taps , worth a look . Then if nothing else comes to mind send the mag to an expert and get it checked ,many recommended here by the guys ,best of luck BobH
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Offline Motoanimal

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Re: Well what a disastrous rebuild this has been
« Reply #72 on: 02.07. 2013 13:42 »
I second Topdad! Hide the matches!! What you are experiencing is all part of the fun(?) of the journey to finally discovering what the problem was and the warm fuzzy feeling you get from sorting it, or is that the matches?  *smile*

Do yourself a favour and send your magneto to Ken at Brightspark magnetos (www.brightsparkmagnetos.com)for him to test and if necessary give an estimate for repair. If nothing else it will eliminate it from your enquiries?

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Offline A10Boy

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Re: Well what a disastrous rebuild this has been
« Reply #73 on: 02.07. 2013 14:42 »
I would say this is definitely the mag. I had exactly the same on the AJS, fitted a Brightpark condensor and that sorted it.

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Andy

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Re: Well what a disastrous rebuild this has been
« Reply #74 on: 02.07. 2013 15:34 »
The only other thing besides magie to have similar affects is tight tappets. Gets to a certain temp and the valves prop open. About 20 miles will do it.
Cheers
'51 A7 plunger, '57 A7SS now A10CR, '76 XT500, '77 AG175 '83 CB1100F, '81 CB900F project.
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Muskys Plunger A7