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Post by jim150 on Jan 1, 2011 20:46:25 GMT -5
does anyone have a spec or suggestion for fork oil in the 250B roketa? Mine has a serious vibration at cruising speed and beyond. workiing on getting the front wheel balanced and the head bearings are tight.
I havent ever changed the fork oil and i imagine the stuff that came from china is a step better than wok oil.
also anyone know the quantity for each fork??
Jim
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Post by Bluefront on Jan 2, 2011 9:45:38 GMT -5
Good question.....the manual for my Xingyue doesn't mention the quantity of fork oil either.
On mine the axle needs to be removed to get access to the drain plugs.
Anybody......?
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Post by chaz12 on Jan 2, 2011 19:34:41 GMT -5
I add bearing grease too mine. I would not put oil on it, because oil runs down and will get your tire slick. Any bearing grease will work. It cost around $5 and will last along time. I use the same grease for my axles also.
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Post by chaz12 on Jan 2, 2011 19:50:14 GMT -5
Now on the forks boot, there is a small hole.. I added oil there, but it did not help hold boots level or nothing. Eventually the rubber boots fell apart. Had to replace them. Oil in the forks( 2 forks) now I never thought of taking them apart to see if one could get oil in them. Why? Thought is was sealed and on roketa.com the sale the fork unit assembled. So if I ever had a problem with the forks, I would just order knew ones.
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Post by jim150 on Jan 4, 2011 9:27:53 GMT -5
I think people are missing the point here.
The forks have oil in them just like any motorcycle. If they didn't contain oil the front end would bounce endlessly on the springs. the oil is there to dampen the rebound of the fork. the heavier the oil the slower the rebound, the thinner the faster.
I believe I need to slow mine down and wondered if anyone has changed theirs and what weight they used.
Jim
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Post by trigger on Jan 7, 2011 9:22:26 GMT -5
Hi Jim,
I used 5W the last change on my 250B. It worked good, but I plan on increasing the vis. to 10W for a little better front end control. Just use a good quality lube and measure what you remove and put the same amount back in.
5W Maxima
10W PJ1
The OEM is probably ready to come out.
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Post by trigger on Jan 7, 2011 9:28:18 GMT -5
PS. a quart will be good for many changes.
My log said I put in 85CC per leg.
Cheers,
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Post by thepope97 on Jan 7, 2011 10:11:48 GMT -5
I have an Automoto and changed the fork oil with 90 cc of 20 weight .I also added a 1 1/2 inch spacer inside the forks above the spring. It made a huge difference.Much better now . Good luck !
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Post by haywire17 on Jan 7, 2011 23:04:38 GMT -5
Here is what I used in my Vog 260 It is a take off of the Yamaha YP 250, these measurements are from the YP 250 service manual
hope this helps you
joe k
8. Fill:
Fork oil
Oil quantity:
0.142 L
Recommended oil:
Fork oil 15 WT or equivalent
9. After filling up, slowly pump the fork up and
down to distribute the fork oil.
10. Measure:
Oil level a
Out of specification Adjust.
Oil level:
80 mm
(from the top of the inner tube
fully compressed and without
the fork spring)
Hold the fork in an upright position
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Post by earthman on Jan 8, 2011 2:25:45 GMT -5
hi folks
has anyone a picture of what is going on here.
yes I am the type that needs a visual aid, no giggles please
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Post by Bluefront on Jan 8, 2011 4:43:48 GMT -5
Simple.....there's oil in each front fork leg that gets dirty, and should be changed from time-to-time. Here's where to put the oil.......that top plug unscrews.  Be careful removing the plug....there's some spring tension on it. To drain the oil, either remove the whole fork leg and dump out the oil, or remove the front axle to get to a little drain plug on the bottom of each leg. I've always used ATF, but a person could experiment with different weight oils. There's no grease in these fork legs, just the fork oil. |
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Post by WarrenS on Jan 8, 2011 12:35:25 GMT -5
Here is what I used in my Vog 260 It is a take off of the Yamaha YP 250, these measurements are from the YP 250 service manual hope this helps you joe k 8. Fill: Fork oil Oil quantity: 0.142 L Recommended oil: Fork oil 15 WT or equivalent 9. After filling up, slowly pump the fork up and down to distribute the fork oil. 10. Measure: Oil level a Out of specification Adjust. Oil level: 80 mm (from the top of the inner tube fully compressed and without the fork spring) Hold the fork in an upright position The engine may be a copy of the Yamaha but the body is a copy of the Suzuki Burgman. So the fork capacity could be anybody's guess. The burgmancalls for 284ml(9.6 US oz) per leg of #10 weight fork oil. The level (without spring): 96mm (3.78 in). The Morphous uses 10W fork oil 5.04 us oz and level is 3.58 in. Oil cannot be compressed but air can. More oil will limit the amount the fork can be compressed and too much air will let them bottom out. |
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Post by Fokus on Jan 8, 2011 17:25:59 GMT -5
Here is what I used in my Vog 260 It is a take off of the Yamaha YP 250, these measurements are from the YP 250 service manual hope this helps you joe k 8. Fill: Fork oil Oil quantity: 0.142 L Recommended oil: Fork oil 15 WT or equivalent 9. After filling up, slowly pump the fork up and down to distribute the fork oil. 10. Measure: Oil level a Out of specification Adjust. Oil level: 80 mm (from the top of the inner tube fully compressed and without the fork spring) Hold the fork in an upright position The engine may be a copy of the Yamaha but the body is a copy of the Suzuki Burgman. So the fork capacity could be anybody's guess. The burgmancalls for 284ml(9.6 US oz) per leg of #10 weight fork oil. The level (without spring): 96mm (3.78 in). The Morphous uses 10W fork oil 5.04 us oz and level is 3.58 in. Oil cannot be compressed but air can. More oil will limit the amount the fork can be compressed and too much air will let them bottom out. All substances, gases, solids, and liquids, including water, are compressible. Some substances just require more pressure per change in volume to compress than others. The numerical value of the compressibility depends both on the temperature and on the pressure too. That is how hard you have to squeeze at one pressure to obtain a certain fractional decrease in the volume is different than at some other pressure. The same for two different temperatures. Under most "normal" lab conditions however solids and liquids are usually considered to be incompressible. Technically speaking, water can be compressed, but very little even at high pressures. For practical design purposes, water is considered an incompressible fluid, that is, its density does not change with pressure. The reason anything is compressible is due to how close the atoms are packed together. If you think about air, it is highly compressible because there is considerable spacing between the atoms, so it is relatively easy to force the atoms closer together. When you have a liquid, the atoms are much closer together and considerable pressure is required to make them any closer. Solids will compress some as well, but it takes significant pressure. Temperature also plays a factor in density (and thus compressibility), just ask your chemistry teacher about the ideal gas law. I am not sure what your book was using a "water compression system", but hydraulic systems are used almost everywhere to transmit power across a system. What a hydraulic system does is put a liquid (usual an oil of some type) under pressure, route that pressurized liquid through pipes or hoses, and releases the pressure at a place where work needs to be done, usually through a motor or cylinder that transfers the pressure into work. You might want to research on hydraulic systems (hydraulic lifts, hydraulic elevators, etc.) to get a better understanding on how energy can be transferred around in a hydraulic system. |
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Post by chaz12 on Jan 10, 2011 16:38:51 GMT -5
Like I said, if you got the forks apart, you might not be able to get them back together. They may be compressed on by a machine. I would suggest not oiling them. I never worried about that part of my forks, but rather concentrated on the rubber dusters or boots.
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Post by Fokus on Jan 11, 2011 0:30:03 GMT -5
Checking the level of fork oil on a scooter requires draining the oil and refilling with the correct amount. A good indication of a low oil condition is soft front suspension damping or bottoming out on rough terrain. An easy way to test the fork damping ability is to tap the front brake at 10 miles per hour several times. Pay attention to the amount of dive in the front and how fast it recovers. If there is excess dive and slow recovery, the fork oil needs to be checked.
(1) Raise the scooter enough to allow the front forks to extend fully. Remove the top fork tube cap nut, keeping in mind the forks are spring-loaded and even with the forks extended, there will still be some compression. Do one fork at a time.
(2) Remove the lower fork tube drain plug. Allow the oil to drain completely. Install the drain plug and tighten it with a wrench.
( 3) Fill the fork tube through the top acoording to your manual with of 7-15 weight transmission fluid. Install the top fork tube cap and tighten securely with a wrench. Do the same procedure to the opposite side. If amount is not known measure the amount drained and fill back accordingly.
(4) Test ride and adjust if not pleased with the results.
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Post by Bluefront on Jan 11, 2011 4:29:03 GMT -5
Fork oil does get dirty over time, depending on riding conditions. Dirt bikes need to have the fork oil changed every season (at least). The crap that comes out of these bikes, doesn't even look like oil.
On street bikes, the change interval can be extended. But given the Chinese habit of using questionable oils, it would benefit a scooter rider to install a better grade fork oil as a part of a thorough PDI. Finding out the correct quantity to use is the big problem.....
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Post by lshigham on Jan 11, 2011 13:44:48 GMT -5
Blue, you could measure what comes out for a rough guide.
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Post by jim150 on Jan 11, 2011 14:28:29 GMT -5
Thanks to all who have contributed to this!!!!! ;D
I am thinking of starting with the 15w and moving on from there.
I usually use a baby bottle to measure the amount to go back in the forks, so i will probably try to get a reading on what comes out of each leg and average the two. Should be a good starting point for the fill with the 15W.
I like the idea of the scaper for a custom preload setting. I have used that in the past on motorcycle forks. Progressive suspension even recomends that method when you purchase their aftermarket fork springs. I have also heard of people cutting an inch or two of the fork springs off and then putting in the spacer to adjust the preload as well.
No reason these bikes shouldn't be customizable in this arena as well. I'm kind of sick of the "pogo" effect of my forks.
I will try to get this done this week. I won't be able to do a test until the darn snow melts though.
Jim
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