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roysicotte

oil questions for an 05 yz450f

6 posts in this topic

this may sound like a stupid question but it makes sense to me. Should I have oil in the case that surrounds the generator and flywheel? My problem is that I lost spark today and went to check the generator and there was no oil in that casing. Now the bike hasn't been ran in 5 hours. so with no oil in that case I checked the dip stick located by the top of the left radiator. The oil came gushing out the dip stick hole like it was under pressure even though the bike wasn't ran for 5 hours prior to checking this.  any ideas would be great. I'm puzzled. I just put a new cam chain, cam chain guides, crank and rod, all 5 valves with spring kits, new jug with head and rings, flywheel, and generator.

 

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Sounds like it could be a problem with the oil return being blocked to me but I don't even know if it is a passage in a cover or an external line on the 05.

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Read: http://www.thumpertalk.com/topic/746100-first-4-strokehelp-please/#entry7615908

 

If you ever have oil coming out the dip stick hole in the frame head, you have over filled the bike.  That simple.  It's a common mistake people who aren't familiar with dry sump systems make.  When the bike sits for a few days, the oil in the "tank" in the frame migrates back to the crankcase sump.  They see no oil on dip stick and add some; over filled.

 

Or, they drain the frame and not the sump, or the sump and not the frame, refill with the "right" amount; overfilled again.

 

And yes, oil belongs in with the stator.  Note that that is where the oil fill is.

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Read: http://www.thumpertalk.com/topic/746100-first-4-strokehelp-please/#entry7615908

 

If you ever have oil coming out the dip stick hole in the frame head, you have over filled the bike.  That simple.  It's a common mistake people who aren't familiar with dry sump systems make.  When the bike sits for a few days, the oil in the "tank" in the frame migrates back to the crankcase sump.  They see no oil on dip stick and add some; over filled.

 

 

That was my first thought but then I read the post as saying that there was no oil at all in the sump even after 5 hours not running but the 'tank' still being pressurised and, possibly no top up having been done since the engine was re-assembled.

 

The overfilling gotcha with a dry sump is even worse on a Voxan. They hold a lot more oil (not oil in frame but a tank) than a YZ450. Refilling after an oil change has to be done in two stages. You can't just put the nominal capacity in straight away. only 2 litres of oil at first then turn over with the kill switch off, then start and idle for 2 minutes before putting in another1500 cc. Finally idle for another two minutes and check the level.

 

Just the level check caught out more than one UK magazine tester who ended up with oil blown out of the breather, as even 2 minutes of idling wasn't usually enough. Better to get it up to operating temperature and the cooling fan kicking in first to be certain.

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That was my first thought but then I read the post as saying that there was no oil at all in the sump even after 5 hours not running but the 'tank' still being pressurised and, possibly no top up having been done since the engine was re-assembled.

 

5 hours isn't enough for a significant amount of oil to run down to the sump if the pump is healthy.  The tank isn't "pressurized", either, just filled above the level of the dip stick port.  Remember that the steel YZ450's oil capacity was specified as 1.0 liters without a filter change compared to 1.5L for the 426.  The actual volume of the frame tank was never reduced, just the dip stick was moved down to the side of the head gusset plate rather than the top of the top tube.  You can still add as much as an additional half liter of oil more than the spec'd 1L without causing any real problems with the system except for the fact that the oil will run from the dip stick hole if opened because there is still that much space for the oil in the tank before it starts to be forced back into the sump for lack of room.

 

If the return pump were weak, it wouldn't have that much oil in the frame; there would be an excess in the sump all the time if that were true.

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OK. I didn't know about the 'spare' capacity on the 450.

 

The Voxan system was much more inclined to act like a gusher, than just run, if overfilled and the dip stick taken out before it had a chance to drain down.

 

Presumably the OP will have found that the level has dropped by now.

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