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Post by nigelsm2 on Nov 6, 2015 0:33:54 GMT
I have 3 bikes 2 x 400s & 1 x 250 they all start up on the left hand side & run on 1 cylinder for about 20 secs give a little backfire then run on both, i have rebuilt & cleaned the carbs more times than i wish to remember but still they do it, once they are running they are faultless so i put up with it, i have tryed everything sugested on here plus changing CDI units,coils,plugs & redoing earth cables, they dont change but i still love them all.....
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Post by stevie on Nov 6, 2015 10:15:06 GMT
Mine does it as well
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ian
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Post by ian on Nov 6, 2015 20:16:20 GMT
My 250 does it too. Also, the length of time I have to churn the starter is proportional to how long since it was last used. Next day is instant, next week takes several minute & next month might flatten the battery. I don't worry about it much, but I've been using the 400 for a few weeks, so I better give it a run soon!
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Post by bojer on Nov 6, 2015 21:12:13 GMT
My 250 does it too. Also, the length of time I have to churn the starter is proportional to how long since it was last used. Next day is instant, next week takes several minute & next month might flatten the battery. I don't worry about it much, but I've been using the 400 for a few weeks, so I better give it a run soon! My NA is exactly like this , leave it two weeks and it just churns away not even firing for 30 secs or so before it coughs into life whereas my N will start first touch of the button or one or two kicks . |
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ian
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Post by ian on Nov 6, 2015 21:23:48 GMT
If you ever fix it, let me know what you did  |
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Post by bojer on Nov 6, 2015 22:14:50 GMT
If you ever fix it, let me know what you did Suspect yet another carb clean out needed ?  , tried leaving the fuel switched on for a few minutes before starting , holding the choke pulled out to make sure its got full choke , swopped spark plugs around , richened/weakened the idle mix, new manifold o rings - all had the same result , nothing changed ! If I run it the next day it will start straight up no messing about at all . When I get round to cleaning up my spare carbs I might swap them over to see if it makes any odds , its running with a different stator than it did have , no change there . As the carbs are generally behaving themselves and not flooding etc I'll live with it as a "characteristic" for the moment I think Ian  . |
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Post by Somersetdreamer on Nov 6, 2015 22:24:24 GMT
If I use bike every day it starts up on the button, after a week of not using it takes a little longer to start & sometimes starts on 1 & after a few seconds the other cuts in, having carbs balanced made it much better, best cure .….. Ride it every day |
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Post by retrobarmy1 on Nov 28, 2015 16:47:33 GMT
Do you leave these bikes on the sidestand? If so, the fuel may syphon back to the left carb. Try using the centrestand and see if it still happens.
mike
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ian
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Post by ian on Nov 28, 2015 20:17:46 GMT
Not me, I might park it up on the side stand when out on it, but in the garage, it's always on the centre stand. I had thought it was low compression on mine, but I've never checked it recently. As Rich says, if I use it everyday it's fine |
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Post by mikef on Dec 12, 2015 10:14:50 GMT
Hi All.
I have an idea, of a possible cause of this problem. It is only an idea I haven't tried it yet.
The float needles may be sticking in the float valve housing and preventing fuel from filling the float bowls.
When the bike is stopped the float bowls are full of fuel and the needles cut off any further fuel supply, if the bike is then left for a few weeks before re-starting the fuel in the float bowls gradually evaporates. In theory the floats and needles will then drop down.
It is just possible that one or both carburettor float needles could stick in the closed position until vibration frees it off.
A possible test for this idea would be to tap the float bowls prior to attempting to start the engine, or turning off the fuel supply before the bike is stopped for the last time to drain the fuel bowls so that the floats will be in the down position when the bike is next started.
Just an idea, what do you think?
Mike.
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Post by bojer on Dec 12, 2015 10:33:39 GMT
Possible and seems logical but my "fix" was yet another carb clean ! T'was the jet "beneath" the main jet with multiple holes than needed cleaning - once done it started straight up.
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Post by ian on Dec 12, 2015 19:01:49 GMT
Next time I use my 250 I'll test the float valve theory - should be easy enough. If that doesn't work, I'll try cleaning that pesky jet. It would be nice to get it like my 400NA - for all it's other problems, I can leave it 12 minutes or 12 months & it starts in milliseconds.
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Post by bojer on Dec 12, 2015 20:44:37 GMT
Went out to my NA today and again it started up on one after 10 seconds of cranking  - really thought the carb clean had sorted it as when I fitted the carbs back on it fired up straight off despite not being run for a week or two ......... Maybe it is the floats and with it all squeaky clean that first time it was ok , when it starts on one the other side pops a few times before chiming in properly. I'd believe it was old fuel but my N starts up straight off regardless of time with the same fuel etc  . |
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Post by ian on Dec 12, 2015 21:09:31 GMT
Bu99er, that must've been disappointing. Maybe I won't rush to pull my carbs off..........
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Post by bojer on Dec 12, 2015 21:13:23 GMT
No sorry Ian not the cure I thought it was , needed cleaning out regardless but not confident it's the fix for the issue now  |
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, tried leaving the fuel switched on for a few minutes before starting , holding the choke pulled out to make sure its got full choke , swopped spark plugs around , richened/weakened the idle mix, new manifold o rings - all had the same result , nothing changed !
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- really thought the carb clean had sorted it as when I fitted the carbs back on it fired up straight off despite not being run for a week or two .........
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