Questions about changing fork oil - QingQi QM250-2D (Sport-Naked version)

[Tordo]

Hello everyone ..!

Some time ago I did my introduction here: http://www.mychinamoto.com/forums/showthread.php?4481-Greetings-from-Argentina-!

Today I come to bother you with a question; after 8600 km of joy with no mayor problems.

The inverted forks of my motorcyle started to dive when braking hard and have a little stiction too.



It's time to change fork oil..!

I know my bike QM250-2D forks aren't equal to the Qingqi motard version QM250GY-B, and do not take the same amount of fork oil (330ml in the motard version)

Here in Argentina there's no one who has changed the fork oil, that's why I wanted to ask MychinaMoto forum experts, which I think some of them are contacted with Qingqi factory (Crazycarl and other ... Thanks in advance!)

I emailed Qingqi myself in order to know oil type (Shell Tellus hydraulic fluid?) and capacity of the forks, but no one aswered me... still waiting!

As a passing comment I want to tell you that yesterday I changed the factory original rear brake pads (lasted 8600 Km) After sporty driving riding 90% in the city (Buenos Aires city), 85% with pillion rider (my wife). I'll be posting soon so you know what brake pads must be used in this certain model, and others too.

Thank you very much for everything, hope to be useful if you need me, I'll be here.

Tordo.

[Zorge]

Hello again!

Here's what I would do. If the forks are not began to leak, simply measure how much fluid you let out. Maybe even the factory does not fill enough fluid, but it's better that, than not to have any idea how much to fill.

Since forks on your bike and supermotard seems to be different only by their length, maybe you could use a little math. If you know the length of the fork and the amount of fluid on the supermotard, and you know the length of your motorcycle forks, you could easily to calculate the right amount of fluid in your forks. Or, maybe in this equation, instead fork length, you could use it's travel.

I'd start with any fork fluid with viscosity 10.

[998S]

Be careful that fork oil is different then motoroil, looks to me you mention motor oil.

More precise it will be to measure the level from the top of the fork.
You can use a small strip of white paper, a measure stick or fabricate a hose with syringe.
This level (probably in the range of 60-120mm) can then be used as a reference for refilling, and finding the correct level if you will not get any reply from the factory.

If the airpocket above the oil is too small, your fork will not use the whole travel, so you will need to release some.
If the airpocket is too large, you will use the whole travel too easy.

I agree with Zorge, start with a viscosity of 10, if you feel the fork is too still, you can reduce it to 5, or mix a bit for any other viscosity.

[Tordo]

Sorry for the delay in my response, I was busy with so much work and other things that didn'tallow me to answer them quickly.

Thank you Zorge and 998S..! I really appreciate your answers, they were very helpful, I must say that any factory hasn't answered my mails (BetamotorArg, China Qingqi, Qingqi Colombia... I'll try again...)


I found out that a member of "Betaclub Argentina" forum that has the same bike that I, changed the original hydraulic fluid: the right fork incredibly came with 100 Cm3 and the other 180 Cm3!!! He ended up adding 160 Cm3 in both forks, but when I drove his bike, I didn't like the feeling of that forks... Something must have been wrong, Too much stiction and very rigid. He poured an "Ipone" fork fluid 20 (made in france)

I'll send a PM to CrazyCarl to see if he could help me find the exact measurement of the hydraulic fluid, maybe Qingqi will respond him... I know... Im a Stubborn guy.. I don't want to dissasemble the forks without knowing the exact amount of fork oil. But if I have no choice...

Here I show pictures of a short trip to "Lujan" (75 Km from Buenos Aires) we've made the other day. From right to left: My Beta Chrono 2.5, a Brazilian Honda CBX 250 "Twister" and a Gilera SMX 400 "Touring" (Xingyue XY400GY-2)





Thanks again folks!

Tordo.

[Zorge]

Oh, T-shirts and sunshine - it's summer time on the southern hemisphere...

Here's plan No.2: ask Krasi if he can ask a specialist for suspension from his neighborhood ( http://www.mychinamoto.com/forums/sh...V-Raptor-owner ), to give you some simple tips on how to appoint the proper amount of suspension fluid in upside-down fork.

IMO, 160 cc seems to be too little for your bike's fork.

[MJH]

Consider the variance in the other guys forks, it was 60cc and then consider that the factory may have the filling controlled, a pump that is set to offer the correct amount 140cc? If they are filling one and an air pocket prevented it from taking all the 140cc, they then stopped and began to fill the other the first got 100cc and the second got 180cc? That or they just eyeball them, that's kind of an unreliable methods and would bring about lots of variances and inaccurate levels. .


I never filled a fork so I am not sure, do they have to be messed with to get the fluid level accurate, tapped on or moved up and down?


Seems if the balance is off then that would causes sticking and also too much travel, one having too much and the other not enough.

[ChinaV]

Consider this... most factories know nothing about the specs. They purchase these forks from an outside supplier and they are already assembled. I have asked many companies in China for specs on things like fork oil, valve clearances, etc. and rarely have gotten an educated reply.

Cheers!
ChinaV

[Krasi]

Oh, T-shirts and sunshine - it's summer time on the southern hemisphere...

Here's plan No.2: ask Krasi if he can ask a specialist for suspension from his neighborhood ( http://www.mychinamoto.com/forums/sh...V-Raptor-owner ), to give you some simple tips on how to appoint the proper amount of suspension fluid in upside-down fork.

IMO, 160 cc seems to be too little for your bike's fork.

No need to ask anyone. USD forks of my GasGas get filled to about 90mm below edge when fully compressed without spring. Manual says 100-110mm, but I need them stiffer (because I'm fat, OK? ).

[MJH]

It seems that the QM125-D, QM200-D and QM250-D share many of the same parts? Probably not all the parts though as their has to be some differences with each engine, but the body parts and frames seems they are all the same. http://www.baltmotors.ru/motocycles/street_250


So then you could broaden your question to include distributors selling the other models.


Balt has an owners manual, in Russian though and a part book too for the QM-D bikes.
http://www.baltmotors.ru/prices/cons...ogs/street.pdf


http://www.baltmotors.ru/technics/ma...street_250.pdf


Sinnis also sells the QM125-D
http://sinnismotorcycles.com/contact.php


I think somebody must have an idea of what the capacity and viscosity should be.


You can also try the factory for Pioneer, they seem to be more receptive to queries.
http://www.xfmotor.com.cn/en/contact.html

[998S]

Something must have been wrong, Too much stiction and very rigid. He poured an "Ipone" fork fluid 20 (made in france)

Your problem is the 20, this is far too thick and makes your fork damping to harsh.
Replace it with a 10 and you will be most likely good to go.
Oh man, i miss the warm summer.

E.