Dont know the amount of fork oil that is

The amount for the forks is 386ml or 13.5 ounces per side.

2003 Suzuki VL 1500 Intruder LC fork oil capacity - Fixya

https://www.fixya.com > motorcycles > t24541779-much...

Buy a clymer or haynes manual

Depending on bike it's normal between 420-470 per fork with the springs removed or set air gap between 105-110 mm with fork level gauge.

The fork oil does not have anything to do with the kind of engine do you have, 2t or 4t. Doesn't matter.
You need to replace the fork oil, you need to know the year of the fork. means, you need to know if it's a bladder or non bladder fork.
oil height of the bladder fork is approx. 70mm, non bladder forks run about 100mm oil level.
oil amount is about 530-600cc per leg

Front fork leg oil level (from the top of the inner tube, with the inner tube fully compressed and without the fork spring) 135 mm

To replace the front fork oil first support the motorcycle so the front end is off the floor and the forks are fully extended. Remember that the FLSTC and FLSTF models have a preloaded fork spring and that the fork tube plug is under spring pressure.Then you remove the fork tube caps. And then you drain the fork oil. ON FXSTD models, your remove the drain screws and washers from each fork and drain the fork oil this way. ON ALL MODELS EXCEPT the FXSTD, remove and discard the drain screws and washers from each fork and drain the fork oil and then you install new drain screws and washers. ON FXSTD models, apply LOCTITE THREADLOCKER 243 (blue) to the drain screws and tighten them to 12-18 inlbs (1.4-2.0 Nm). ON ALL MODELS EXCEPT FXSTD, tighten the drain screws to 52-78 in-lbs (5.9-8.9 Nm).THEN fill the fork with Harley-Davidson TYPE E FORK OIL (Part No. HD-99884-80).Either by installing oz or cc's of fluid if the forks were left in the frame or by measuring the amount of oil in the tubes in inches or mm if the forks were removed from the frame and disassembled. In the latter case the oil level is measured from the top of the fork tube with the spring removed and the fork fully compressed.

MODELs FLSTC, FLSTN use 13.4 OZ 395 cc4.41 inches 112.0 mm
MODEL FLSTF uses 13.4 OZ 397 cc5.04 inches128.0 mm
MODELs FXST, FXSTB, FXSTC use 12.5 OZ370 cc 6.69 inches170.0 mm
MODEL FXSTD uses 11.6 OZ343 cc 7.48 inches190.0 mm

FINALLY tighten the fork tube caps to 40-60 ft-lbs (54.2-81.3 Nm).

2004 Touring Fork Oil Requirements

FORK MODEL TYPE and AMOUNT in OZ. ML IN. MM

Left FORK - All models except Road KingCartridge10.0 oz 295ML 4.21INCH 107mm

Road King Conventional 11.1oz 328ml 5.24inch 133mm



Right All modelsConventional11.1 oz 328ml 5.24inch 133mm



WARNING

Fork oil level in cartridge type forks is carefully measured from top of tube after pumping damper rod. Anydeviation from instructions can result in incorrect amount of fork oil. Incorrect amount of fork oil can adversely affect handling and lead to loss of vehicle control, which could result in death or serious injury.

The recommended weight is Suzuki SAE 10W fork oil. The amount for the forks is 386ml or 13.5 ounces per side.

I’m happy to help further over the phone at https://www.6ya.com/expert/al_e83b1941f9c0f302

Well, when you take off the fork make sure you empty it first before anything else then make sure that the fork pressure spring is released before changing the seals. The fork oil amount should be no more than 200 cc or no less than 190 cc

its 120 mm or 4.7 inches from the top of the fork
Some measure the oil quantity and fill the fork up, some fill the fork up and measure the oil level. The most correct method is to measure the level, I guess, but many guys measure in quantity.. both ways work well.