Fork oil change 83 heritage special... 7.5 ounces??

[section8joe]

I'm changing the oil for first time since I've had the bike. I searched throughout the forum and I just want to make sure I'm adding the proper amount of oil. I going to be adding 7.5 ounces. I just wanted to make sure this the right amount for my 83 heritage special.

From XSLeo

Tom if you think fork oil don't get hot try running a few miles of bumpy road and stop to feel the forks.
In the manuals they speced different weights of oil for the forks. The early years used 30w motor oil, then they speced 10w30 oil. The later years speced fork oil.
The weight of the oil controls the speed at which the forks move. A thinner oil = faster, thicker = slower.
The cost of trying a few different oils won't be much. So experiment some. I tried several oils. 10w30, 5w20, Regular ATF. I plan on trying some different fork oils sometime but the ATF works fine.
Ok, to change the oil look down at the bottom of the forks, you will find the drain screws. Outside each fork. Phillips head bolt. Remove the bolt, pump the forks up and down to pump out the old oil.
Now up at the top of the fork where they go through the upper tree, loosen the clamp bolt. It releases the tension of the tree on the fork tube. Now you remove the fork cap in the top of the fork tube. Different years had different caps. Yours might be a 17 mm Allen head or a big nut not sure on the size.
I built a 17 mm tool for my caps. Get a metric bolt with a 17 mm head and a nut. Use a few flat washers and a lock washer. Now tighten the nut very tight on the bolt. Put the bolt in the cap and use a wrench on the nut to loosen the caps.
Remember to put the drian screws in before filling.
With the caps out, springs out, forks compressed just pour 7.5 ounces in each fork. Or a bit more and draw the extra out. so you have the 6 inches down as described earlier. Put the springs and caps back, Tighten the clamp bolts.
You might want to flush the forks before the new oil. I used Kerosene. Remove the caps and springs as descibed, pour in 8 ounces or so of the cleaner of your choise, Pump the forks to speard the cleaner around, drain, do repeat till the cleaner comes out clean. I then flush it once with oil to get the cleanr out, let drain over night, then do the fresh oil.
Leo

 

[5twins]

I use 7 but I suppose 7.5 would be OK too. To check it, measure the oil level from the tops of the tubes, springs removed, forks compressed fully. You don't want the level any less than 6". I originally went to 7 ounces after checking the levels with the stock amount (about 6 ounces). They were at about 9" down which I felt was too low. The forks also make a funky squishing sound when pumped with the stock amount. 7 ounces brought the levels up to about 7". From that, one could deduce that each half ounce of oil raises the level about an inch. So, 7.5 ounces should put it at about 6" from the tube tops. You should also try to make the level in each tube the same. Even though you are adding the exact same amount of oil to each leg, the levels may end up different depending on how well the old oil was drained from each leg.

 

[jetmechmarty]

This is what I do:

Use 15wt (US3) Fork Oil set to 130mm Oil Level (Fork Spring out, chrome tube at bottom of stroke) Oil Level Tuning Range is 110-150mm in general.

This is the top of the oil level to the top of the tube. Keep in mind that the oil will not compress and the air will. So, if the air space is less, it will be more difficult to bottom out the forks. Also, keep in mind that less air space will make the forks less compliant. You may want to adjust the level until they feel right to you. That may be much different than what feels right to me. Also, the viscosity makes a difference too.

 

[5twins]

Be aware that if you put too much oil in there, you can blow the seals upon hitting a big bump. That's why most recommendations are for about a 6" oil level at the least. 110mm is about 4 3/8". If you try that and the seals pop, please let us know, would you?

 

[section8joe]

Thanks for the replies. I added 7oz not 7.5. I was just a little hesitant because the service manual calls for a lot less then 7.5 oz. it raining cats and dogs here so I haven't had a chance to take it for a ride but the front end seems a lot more firm.

 

[EvenmoreXS]

This is what I do:


This is the top of the oil level to the top of the tube. Keep in mind that the oil will not compress and the air will. So, if the air space is less, it will be more difficult to bottom out the forks. Also, keep in mind that less air space will make the forks less compliant. You may want to adjust the level until they feel right to you. That may be much different than what feels right to me. Also, the viscosity makes a difference too.

Hey Jet, off topic, but I thought Id mention this to you. I wont be able to make it but maybe you can make a showing for us here on xs650.com

http://vjmc.org/

Vintage Jap bike rally in Helen in 2 weeks. Just a fyi.

Sorry to jump the thread. I will be watching though, my fork seals came in last week. Gonna jump on em soon.

 

[jetmechmarty]

Hey Jet, off topic, but I thought Id mention this to you. I wont be able to make it but maybe you can make a showing for us here on xs650.com

http://vjmc.org/

Vintage Jap bike rally in Helen in 2 weeks. Just a fyi.

Sorry to jump the thread. I will be watching though, my fork seals came in last week. Gonna jump on em soon.

Thanks for the heads up! I can probably get there in about 30 min on my trusty 650. I will certainly swing by for a look.

 

[angus67]

I have 8oz of atf in each leg. Im pretty rough on it. my driveway is rutted and washboarded, have not blown yet.
I plan on going to 15wt fork oil soon though. front is too squishy.
On another forum im on, marauder intruder group, A debate was running about using atf. not one of them suggested it. Could this be because of newer designs?

 

[5twins]

Maybe because it's not fork oil? Fork oil is specially formulated to use and work in forks. Let me ask you this - would you put ATF in your motor? Would you put motor oil in your automatic transmission? Would you put fork oil in either of those two places? It seems guys will put just about anything in their forks, short of pissing in there, lol. I don't understand it.

ATF is only about a 5 or 7 wt. The factory speced 10wt. REAL fork oil will probably work fine for you.

 

[XSLeo]

ATF has been used in forks for a long time. It works well. I use it in mine.
The early bikes speced 30w engine oil. A bit later they speced 10w30 engine oil. They didn't start specing 10w fork oil till late 78.
I think it has a lot to do with the size of the hoiles in the damper rods. The oil flows through the holes. To change the rate the oil flows you change the weight of the oil or the size of the holes.
Over the years Yamaha tried several combinations of oils and holes sizes.
The cost of oil to experement with different oils is not much. Try a few different ones yourself.
I set the level with the 6 inches down method. I start by putting in 8 ounces of oil and drwai ng off to get to 6 inches down. Pulling back out about an ounce. So the 7 to 7.5 is a good start.
Leo

 

[5twins]

A simple little fork oil leveling tool can be made from some brass tubing and a syringe. Mine is a bit fancy as a machinist buddy made the sliding stop w/ set screw for me but just a pair of needlenose vice grips lightly clamped on the tube at the height you desire serves the same purpose .....

 

[jd750ace]

I do the fork oil tool with a piece of tubing and needle nose vice grips. Don't get much cheaper than that. The reason no manufacturers use ATF anymore is because they started to understand that a fork had more in common with an engine than hydraulics. ATF is NOT graded by viscocity index, and retaining lubricity is not an important factor either. It's biggest attributes are transmitting heat and high detergency. For the latter reason, I use it to flush my fork tubes before putting in fork oil. As ATF breaks down, forks become ratchety as the lubricity goes away, and they become soft as the viscocity falls. Lots of people still run it, but it's not for me.
Fork oil for me, thank you.

 

[angus67]

this is why im switching. just sayin'