UV dye for oil leak?

[daniel4616]

All, I have had this oil leak for years now. It is always just a small amount and I drove it fine for a long time. Figure I should get to fixing it - but have no idea wheres its coming from. Most of the bike has small amount of oil on left side with kickstand down so it could be from anywhere. Anyone ever used the UV dyes? I just drained the tranny fluid as much as possible and it seems the little that is left in is somehow seeping out a bit. Seals were all replaced about 5 years ago - how long should they last?

[SoCal250]

Is it leaking just while sitting, or it more evident after riding?  Have you checked the tach drive o-ring?

Is the oil drain plug gasket in good shape?

Are you sure it's transmission oil and not 2-stroke oil? I had a weird thing happen on one of my bikes where the 2T oil tank supply line split. It had a small lengthwise split in it that could not been seen very well and it would just slowly seep oil which would run down to the bottom of the engine and down the kickstand.

[m in sc]

id look long and hard at the shift shaft seal. it gets hidden under a washer and a clip and easy to overlook. if the new seal was put in, it may still be leaking.. bad install, worn shaft, bad seal...



russ makes a good point, ive been bit by that on a different bike, but was pump housing leaking.

[Brad-Man]

Could be the neutral switch - is it cracked?

[mnein]

I've used the UV dye a time or two at work, works well. Believe it was from Amazon, kit had the dye and a UV flashlight supplied. Just need to make sure the oil is well mixed before it leaks out and you try to find it with the supplied flashlight.

[Robert58]

In HVAC business we use the UV dyes on hard to find refrigerant leaks.  It is designed to run with refrigeration oil which is one of the most highly refined oils out there. You could probably add a 1/2 oz or so to tranny , run it abit then get out your black light and an old Jimmi Hendrix Felt Black light poster and look for fluorescent yellow :)    It does work.

[daniel4616]

Im sure its tranny fluid, Bel Ray 80w red color. I use the SI7 2-stroke oil that is blue.

I did replace the tach o-ring when I thought that was the initial problem. It does seem to be a little more after it ran than just sitting. I also replaced the neutral switch, but I will double check that when I get home. I am willing to bet the oil drain plug gasket is not in good shape, I drained the oil from it a week ago and remember thinking to myself that I need to replace that. I hope it is that simple, but I will go back and double check the shift shaft seal before getting the UV kit

Thanks will update when I learn more - or if I get even more confused!

[quocle603]

I've done the baby powder test, but its always 100 percent effective. Smoke test is another way but I've never done it.

[SUPERTUNE]

Im sure its tranny fluid, Bel Ray 80w red color. I use the SI7 2-stroke oil that is blue.

I did replace the tach o-ring when I thought that was the initial problem. It does seem to be a little more after it ran than just sitting. I also replaced the neutral switch, but I will double check that when I get home. I am willing to bet the oil drain plug gasket is not in good shape, I drained the oil from it a week ago and remember thinking to myself that I need to replace that. I hope it is that simple, but I will go back and double check the shift shaft seal before getting the UV kit

Thanks will update when I learn more - or if I get even more confused!

There is 2 o-rings for the tach drive, the obvious is the housing o-ring, but there is a small one under a pressed in sleeve collar and shim washer, a real pain to get to sometimes because the collar corrodes in and is hard to get out.
Let me know if you need a drain gasket, I buy them in a 50 pack from Belmetric.com
https://www.belmetric.com/green-fiber-gaskets-c-11_93/g14-green-fiber-gasket-p-550.html
PM me your address and I'll send you one, like a $1 with postage, so when your in town you can buy lunch when we tune it up!
Do it now as I leave for the 2 stroke meet sat morning, or wait until I get back in 10 days.

Chuck

[IR8D8R]

I had an Alfa with a chronic oil leak. I had replaced all the likely gaskets and couldn't figure out where it was coming from.  I even pulled the engine and replaced the main seals. Consensus was maybe a warped casting somewhere...? A bit later I rebuilt the cylinder head and put everything back together tight. The problem got much worse but there was no obvious source of the leak. I always kept the engine meticulously clean but every time I drove it any distance it would have oil all over the front of the engine when I parked and a spot under the car in the morning.
After a while I got a little lazy and let some gunk build up on the engine. After doing an oil change and while I was doing some tuning I noticed a clean spot on the front of the head. Clean oil was seeping out of the metal! There was a casting flaw porosity that went all the way through 10mm of aluminum. It was totally invisible to the naked eye. Probably the alkaline hot tank had dissolved a bit of slag in the flaw when I rebuilt the head and it made the leak worse. You couldn't see anything but clean aluminum on either side. Only some probing with a die grinder revealed an area of crystallized metal in the head. It was in the timing chain gallery so oil wouldn't get to the spot until it slung off the chain and was hot enough to be thin and penetrate the porous area. Devcon F permanently fixed the leak. Can't even tell you how much effort went into solving that. 

IR8D8R

[quocle603]

I've been there, done that.