classic motorcycle forum
Motorcycle Discussions => British Bikes => Topic started by: DaveHall on July 19, 2007, 08:12:25 PM
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Does anyone have any advice on using lead free in T140's? I have been running my '76 Bonneville on lead-free for some years now although at very low mileage. I can't decide whether the performance has suffered or whether it is due to comparing it with my TT600! I wondered whether I should have altered the timing for the change in fuel.
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Modern day unleaded fuel is fine for a Bonneville, timing should be left as is, however it may be running a tad rich, so you may have to change the slides by 1/2 to weaken the mixture out, but if it is running fine leave well alone. Plugs should be black around the outside but a nice shade of light brown on the electrode.
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Thanks TBS. I found a problem with the needles in the carburattors which may explain some of my problems. The spring clips that hold the needles in position had come adrift. Do you know what is the correct position? My workshop manual says position 1 but I don't know if this means locate the clip in the top notch or bottom notch? Also the clips appear to be broken - do you know if they should be in one piece or is there supposed to be a split in them where they grip the needle?
Regards,
Dave.
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Clips will be fine, and if the manual says position 1 then you start at the top groove and go from there. This will give the weakest mixture as the needle will be restricting the needle jet. Position 2 will richen the mixture and 3 even more rich.
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Thanks again. That's the way I figured it too and it's running a lot better than it was. I have just read your correspondance with ChrisT140 which seems to answer all these carb related matters.
Regards,
Dave.