bikerbros2
New Member
1979 250N SUPERDREAM AND 1989 VFR750FL in Blackpool Lancashire
Posts: 18 
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Post by bikerbros2 on Nov 10, 2014 12:10:43 GMT
Hi, Anyone any ideas whats causing this problem. The superdream just stopped firing with no spark so I checked everything and put it down to the Stator windings being shot. I sent the unit off to BB Bikeshop and got a replacement, in the meantime I replaced the coil, HT Leads, plug caps and plugs (NOT SECOND HAND) and also replaced the ignition switch with a brand new one and also replaced the CDI Unit, checked all the wiring and the cut out switch, all is ok. When it fitted the stator back on and tried the bike it wont fire up for ages even though there is a spark on both leads that you could weld with its that strong. When it does fire up it wont rev for ages and then suddenly revs right up to the red line. I have cleaned the carb out and checked the float height, and balanced the carbs when I got it to run steady at 3000 revs so don't think its that side of things but who knows. The thing is that when I got the stator back from the repairers the pulse sensor pick up has 2 contacts in the middle of the sensor, the original I sent had one but it all looks as same as original, its not from the 400 as I know that's a different set up with 2 outer sensors. I also replaced the carb rubbers and done the WD40 test so its not dragging air in at engine side of carb.
Any ideas guys would be greatly appreciated, I have had superdreams before and never had this problem |
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stevegbr
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BIRMINGHAM
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Post by stevegbr on Nov 10, 2014 12:17:43 GMT
is the coil original or pattern, as other members have had trouble with pattern coils?
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Post by paddlesat16 on Nov 10, 2014 12:40:49 GMT
How did you get to the stator being at fault? Was the power down on the bike, did it pick up slowly not rev did you have weak spark at the plugs. I know the bike died with no spark in the end but faults can take a long time as components die/fail.
Correct diagnosis of the fault can sometimes be hard to find because you've changed so many components in one go and may have caused more problems or conditions. The stator having two pickups could mean nothing or mean everything?
Are your spark plugs gapped correctly if you have huge fat sparks open them up to the maximum size to get full benefit of the spark. Sometimes getting a bike to run right can be a battle. But slow methodical working and testing will see you right. Get yourself an electrical tester and test the new stator, is it working as it should etc the same with the plug leads, coil and plug caps. The haynes manual should give all the values you need and there are test matrix's on the site somewhere Rich put them on.
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bikerbros2
New Member
1979 250N SUPERDREAM AND 1989 VFR750FL in Blackpool Lancashire
Posts: 18
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Post by bikerbros2 on Nov 10, 2014 19:16:34 GMT
Thanks for the replies guys, I tested the resistance readings in the stator and found that the readings were all over the place and intermittent so it was the windings that were shot. and there was no spark even when I disconnected the plug cap and held the wire to the block.
I replaced the coil with an aftermarket one and that's seems fine but I did keep the old one so I might just put it back on and see if any difference.
One thing that I found today was that the NGK Spark plugs which I bought new from the local bike shop are breaking down when they get hot so I have replaced them and it started first time without the choke and runs through the entire rev range without a problem, just a very small blip from 1100 revs to 1300 revs.
The guy at my local shop told me that their are a lot of Chinese copy NGK plugs out there and they were caught out by them themselves with them failing completely after only 1500 miles.
Hopefully the bike will now be ok. its running better than I have been able to get it for ages with no misfires after 1300 revs. |
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stevegbr
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BIRMINGHAM
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Post by stevegbr on Nov 10, 2014 19:27:49 GMT
glad you got it sorted.  |
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Deleted
Deleted Member
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Post by Deleted on Nov 10, 2014 20:12:22 GMT
The Chinese NGK plugs are notorious for not working- was there a post somewhere on how to recognise the boxes? Puts you off buying plugs on Ebay for sure....
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Post by scania on Nov 10, 2014 22:26:08 GMT
Fair play that you got it up and going again, I would agree with the guy who said that's its bet not to disturb to many things at the one time when fault finding. That is when you found there was no spark, then it would have been best to just concentrate on the electrical system and not to go near the carbs. Its unlikely that both the carbs and the electrical would give up at the same time.
That's the way I go at fault finding.
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