If I want to cure wet-sumping do I have to take the engine out to replace/refurbish the oil pump on my Dommi 99? Is a new pump the realistic answer? The engine has never been out of the frame from new, 44,000 miles ago. It seems that to cure jumping out of 1st gear will mean my removing the engine to get the gearbox out for a rebuild. Can the box be rebuilt in the frame?
You only need to remove th…
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Previously ian_cordes wrot…
Previously ian_cordes wrote:
You only need to remove the timing cover in order to access the oil pump.
The gearbox can pretty well be rebuilt in situ, although to remove the mainshaft you will have to strip out the drive side, including clutch, in order to remove the gearbox sprocket. The only thing you may have trouble removing with the box in the frame is the inner layshaft bearing.
It depends on what is causing it to jump out of gear. Mine was doing the same, which appeared to be caused by excessive end float on the layshaft. I cured it with a shim. See Old Brits website for good info.
Many thanks for your excellent info. Tom.
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Wet sumping is caused by o…
Wet sumping is caused by oil passing through the oil pump. There was an excellent article on servicing the oil pump recently in RoadHolder. If you replace the pump, be aware that there are variations. The late ones got much wider scavenge gears, and also in the 60s, a double speed worm drive. Single oil pumps are the other way round
To attend to the gearbox - remove the gearbox outer and inner covers, and also the primary drive. The gear cluster can be removed along with the main shaft, without removing the sleeve gear or for that matter the gearbox sprocket
Paul
Previously ian_cordes wrote:
You only need to remove the timing cover in order to access the oil pump.
The gearbox can pretty well be rebuilt in situ, although to remove the mainshaft you will have to strip out the drive side, including clutch, in order to remove the gearbox sprocket. The only thing you may have trouble removing with the box in the frame is the inner layshaft bearing.
It depends on what is causing it to jump out of gear. Mine was doing the same, which appeared to be caused by excessive end float on the layshaft. I cured it with a shim. See Old Brits website for good info.
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The article on refurbishin…
The article on refurbishing oil pumps can be found by checking out the archived Roadholders. Menu top left on this page.
Look for RH 327 February 2015 or possibly using this link below will get you there faster.
http://www.nortonownersclub.org/html/archive/rh/327/index.html#26
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Brilliant! Many thanks. Be…
Brilliant! Many thanks. Being able to get advice AND access the required Roadholder article is another reminder of what a great club this is. Riding the old Dommi again after many years in the shed makes me keen to stop the wet-sumping and get it to stay in 1st without having to use my foot for that purpose. See you at Sammy Miller's I hope.
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You only need to remove the timing cover in order to access the oil pump.
The gearbox can pretty well be rebuilt in situ, although to remove the mainshaft you will have to strip out the drive side, including clutch, in order to remove the gearbox sprocket. The only thing you may have trouble removing with the box in the frame is the inner layshaft bearing.
It depends on what is causing it to jump out of gear. Mine was doing the same, which appeared to be caused by excessive end float on the layshaft. I cured it with a shim. See Old Brits website for good info.