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Post by scott56 on Jul 31, 2024 21:03:27 GMT
I have a 79 superdream and took it out for a short ride ( about 9 miles), I had to cokes it back home by holding 2000 rpm or it would stall. The bike starts and runs really good when cold but when it gets warmed up it starts to miss fier as if the petrol had been turned off?. I tried to drain the float bowls and the left hand one had very little fuel in it, but I could still see fuel in the tube?.
Does anyone have any ideas, I’m really stumped lol
atb
peter
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bazzer
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Post by bazzer on Aug 1, 2024 6:03:14 GMT
Hi Peter. Whilst no expert, I had a similar dry bowl issue and it was blocked jets etc. now I know only too well the pain of taking the carbs off. There has been some discussion on here of a product called ‘sea foam’. Worth having a look to see if that’s an easy fix for you. 👍
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bazzer
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Post by bazzer on Aug 1, 2024 6:26:49 GMT
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Post by scott56 on Aug 1, 2024 13:50:53 GMT
Hi Bazzer thanks for your reply, this is really a strange one it only happens when the engine is quite hot, it’s fine when starting from cold. I have taken the carbs off the bike to see if I can find anything that stands out, all I’ve found is that the float hight is probably to high ( about 17mm ) I think it’s supposed to be around 15.5mm. Also the fuel tap could be partially blocked with the sealing washer!!!. I’ve ordered a couple of service kits for the carbs as I noticed that one of the mixture screws was damaged. I’m also going to put the carbs in my ultrasonic cleaner for a good bath lol.
Atb
Peter
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Post by scott56 on Aug 1, 2024 13:51:46 GMT
Hi Bazzer thanks for your reply, this is really a strange one it only happens when the engine is quite hot, it’s fine when starting from cold. I have taken the carbs off the bike to see if I can find anything that stands out, all I’ve found is that the float hight is probably to high ( about 17mm ) I think it’s supposed to be around 15.5mm. Also the fuel tap could be partially blocked with the sealing washer!!!. I’ve ordered a couple of service kits for the carbs as I noticed that one of the mixture screws was damaged. I’m also going to put the carbs in my ultrasonic cleaner for a good bath lol.
Atb
Peter
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Post by scott56 on Aug 1, 2024 13:53:16 GMT
Hi Bazzer thanks for your reply, this is really a strange one it only happens when the engine is quite hot, it’s fine when starting from cold. I have taken the carbs off the bike to see if I can find anything that stands out, all I’ve found is that the float hight is probably to high ( about 17mm ) I think it’s supposed to be around 15.5mm. Also the fuel tap could be partially blocked with the sealing washer!!!. I’ve ordered a couple of service kits for the carbs as I noticed that one of the mixture screws was damaged. I’m also going to put the carbs in my ultrasonic cleaner for a good bath lol.
Atb
Peter
That Sea foam sounds like the old RedX we used years ago lol.
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Post by scott56 on Aug 1, 2024 18:09:26 GMT
Don’t know how I managed that, I only posted one thread lol
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bazzer
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Post by bazzer on Aug 2, 2024 13:04:09 GMT
Hi Peter. The new kit and ultrasonic should sort it. I believe the sea foam is ‘magic’ 😊. Redex never seemed to work for me.
If it wasn’t for the carbs, electrics, brakes and oil seals. These would be a doddle to work on 😂😂.
When something does go right though it’s a fab feeling. I’m just over halfway through mine and starting to enjoy it again. Mainly due to the help off people on here or I probably would have set fire to my SD by now 😊
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Post by scott56 on Aug 2, 2024 15:39:13 GMT
This is probably the best thing I’ve ever done, joining this forum lol. I may have found the main cause of my problems with lean running. On removing the carbs I noticed how easily the carbs came out, as specially from the air box rubbers. On closer inspection I found that although the clamps were tight up against earth other, they weren’t tight on the rear carb stubs. Also a telltale smell of fuel around that area. So maybe I’ve actually found the culprit lol.
I will keep you all posted ok.
atb
peter
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Post by peakdreamer on Aug 2, 2024 16:57:31 GMT
When you've coaxed it back hot take the plugs out [before starting it again] and have a look what colour they are.
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Post by scott56 on Aug 5, 2024 23:47:36 GMT
The last time I checked the colour of the plugs, they were very light grey which indicates lean running. Does the Superdream have a known problem with the Air box rubbers shrinking?. I think that the main problem was the the clamps were fully tightened but the rubbers were still slack!!!!.
atb
peter
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willy3pigs
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Post by willy3pigs on Aug 6, 2024 5:19:51 GMT
Are they the correct rubbers? Are they perhaps rubbers from a 400 on a 250..
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daveh
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Posts: 409
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Post by daveh on Aug 6, 2024 19:39:27 GMT
The last time I checked the colour of the plugs, they were very light grey which indicates lean running. Does the Superdream have a known problem with the Air box rubbers shrinking?. I think that the main problem was the the clamps were fully tightened but the rubbers were still slack!!!!. atb peter The rubbers do tend to harden over the years which means they don't seal up so well, particularly on inlet side. You can either source new ones (expensive for inlet manifold) or try and softened the rubber. There's plenty of YouTube content of different ways to soften engine rubbers with varying success. I have put a post on what I did on the 'tips' section. After the time since I posted that the rubbers have hardened again, but it did enable me to get a good seal on fitting. As a note the Superdreams are set up to run quite lean. Some have change the jets (not me) to run a bit richer. My plugs tend to be a light tan colour not white/ grey. Have you adjusted the mixture screws? |
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Post by scott56 on Aug 6, 2024 22:17:06 GMT
Hi all, the air box rubbers appear to be the correct ones also they are quite soft and not hard at all. In fact when I attempted to remove the carbs they actually fell out!!!!!!. I wasn’t able to adjust the mixture on the left carb as some clown had broken it off, now just waiting for a set of repair kits lol. The spark plugs we’re almost white, but this I put down to leaking carb rubbers. I know one thing as soon as she’s running well I will be selling her🫠🫠🫠🫠🫠
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Post by scott56 on Aug 12, 2024 18:37:28 GMT
Just an update on my progress with my 250n carburettor’s, I’ve managed to get them back in with a bit of a struggle ( easier to take out lol). I’m also going to replace the petrol tap as it appeared to be leaking, and no filter fitted?. I did actually end up in AE at my local Hospital due to a medication problem so I don’t no when I’ll get to finish this.
Atb
Peter
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