1989 sportster building pressure in oil tank

I have a compressor and the last time I used it, it was doing something similar. I haven't tried anything on it yet but I think there are two possibilities (Either it needs oil ) (It may need some air pumped into the tank to get it to build up pressure.) Either those two or the pressure switch is bad. The switches usually are very tough so not likely that but as a last resort I would try a new one. I do think lack of pressure would likely be the oil is low. I think the oil makes a seal around the piston and that causes it to build pressure. If it will still blow up a tire there should be enough pressure to turn the relay switch off. Mine will still blow up a tire so not sure if it is a pressure problem. May need pressure put into the valve on the tank and if there is one I will try that today.

Check for a pinched/blocked vent line.
Possible bad piston rings and over pressurizing the crank case (compression blow-by).
Overfilling the oil tank. Check with engine hot.
Also, it could be just a aged/dried up/ cracked o-ring.

check if it has a PCV VALVE OR BREATHER . EITHER WAY IT APPEARS TO HAVE BLOCKAGE . EVENTUALLY THUS WILL DAMAGE THE CRANKSHAFT SEALS AND CAUSE OIL LEAKS .

Your oiltank should have 3 hoses on it,one is SEND (brings oil into the engine),RETURN (brings oil back into the tank) and OVERFLOW (if there's too much oil in your tank it will drain through this). Check the overflow hose (the one not connected to the engine) for obstruction. If you want to check your oilpump pull the dipstick out,start the engine and use a flashlight to look into the oiltank.If you see oil pumping back into the oiltank through the return it's working.Check your oil level while you're at it,there may be too much in it.

My 1986 Silverado 3/4 ton started that and I chased it, and chased it. Remember the KISS theory! Start with the fuel filter, because that what it ended up being. Can't explain why exactly, but when discussing it with other mechanics we came up with maybe some form of wax that would melt above a certain temperature. When the fuel filter fixed the problem, I removed the tanks and steam cleaned them and replaced, no more problems starting other than my chock needing adjusted every so often.

If the tank cap is loose, you need to get a new seal or simply replace the entire cap. There are two marks on the dipstick. The upper mark is "FULL HOT" and the lower mark is "FULL COLD". Do not add oil to the tank when the oil is cold. As long as there is oil on the stick, ride the bike until it comes to operating temp and then add any oil if it needs any. This is a common mistake on the Sportsters. If you bring the oil up to the top mark when cold, it'll expand and blow the tank cap out and make a big mess. Do not overfill the tank but if the tank cap is loose, replace it.

Good Luck
steve

You'll lneed to test for 3 things:
Spark at the plug
Fuel, making it to the cyliinder
Compression, above the minimum spec.

Sometimes when engines have been rebuilt, they have really poor compression as they try to start for a few minutes of cranking. If you have good oil pressure, check compression, if low add a tablespoon of oil to each cylinder to build compression, as soon as it starts it will begin to seat and seal itself, as well as provide ample lubrication.

For Fuel and Spark, just normal diagnostics, based upon your description, I won't mention doublechecking now that it has been cranked a bit.

WD40 can be sprayed into the intake while cranking to get one lubed a bit and to start to idle, it will stall when you stop spraying, indicating a shortage of fuel.

good luck

well this isnt really my area but my dad used to build harleys and if im thinking right they have an oil tank ? and a filter on the lines, it might be chrome it will generally be a cylinder shape.

in the image it looks to be at the front of the bikes engine.

here is an image i googled.

http://www.harleydavidsonmaintenance.com/images/sportster-oil-filter.jpg

hope this helps if not send an email and ill ask my dad [email protected]

check crank shaft for damage, check PCV valve for proper operation, check that pulley sleeve is smooth with no abrasive areas that would chew up a seal, if needed try a speedy sleeve repair kit...

go an buythe tranny for it an put it on or pay someone to do it