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Author Topic: Rear Bearings  (Read 76012 times)

JScott

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Rear Bearings
« on: May 26, 2010, 12:00:25 PM »

Hi,
I have just bought a XY250 STXE, after 25 miles and only 4 days, all those miles done on road and at no more than 30 MPH, my rear bearings have gone.  Although I am getting a repair done on warranty I was wondering if this is a common problem and are there any upgrades for the standard ones.  The quad is a 2010 model.
Also does anybody knows of a repair manual for this bike, I have been given some with the bike but none go into service intervals, what each service requires. 
Any other tips gladly recieved and also any other owners in the suffolk area know of any good shops for spares and mods.
Any decent ready fit exhuasts for a few more hp and also enginge cooling.
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Johnny

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Re: Rear Bearings
« Reply #1 on: May 26, 2010, 10:20:29 PM »

Hi and welcome,

It is not uncommon for the bearings to go on the 250STXE, I would suggest that you change your bearings to SKF (although these are now made in China as well, however the quality is better). It is not a difficult job to do yourself. If you plan on doing it yourself, let me know and I will give you the SKF part numbers for the bearings. It is a good idea to replace the bearings with sealed bearings, that way you will not have to keep pumping grease into them.

To the best of my knowledge, there is no work shop manual available. I have written to Shineray a couple of times, to no avail. I change oil at the following intervals; before first motor start (straight after delivery, the chinese oil is a little suspect  ;D) then at 300, 500, 1000 and then contrary to what a lot have said ::), every 2000 k, if you use a good oil (mineral and not synthetic in accordance with the hand book) it will not be necessary to change oil more often (besides it being a waste of money). Make sure you run your quad in properly (keep the speed down for the first 1000k). In terms of what each service requires, there are only things like checking brake pads and discs, clutch free play, lights etc. These should all be checked at regular intervals anyway. Make sure that all your nuts and bolts are tight (loktite helps) I have changed all my nuts and bolts for stainless steel, that way they are not going to rust like the original. The chinese steel is not up to our standards, so if you are not carefull the original screws are likely to break relatively easily.

You will not gain any great increase in hp by simply changeing the exhaust. You will gain a little more speed by changing the sprocket ratios (but not a lot).  You will also improve the cooling by changing the main jet in your carbi and perhaps an open air cleaner (sports air cleaner).  You will also need to re-adjust your valves, they are normaly set too tight at the factory (that way they run quiet) this is not much good for cooling the engine, you also run the risk of burning the valves. So at you first oil change, adjust your valves.

For any additional tips, have a look at some of the other posts I have written.

I hope you enjoy getting your hands dirty, cos that is what you are in for with these quads, and besides they are a lot of fun.

If I can be of any more help, let me know. Cheers and have fun

Johnny
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benton1576

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Re: Rear Bearings
« Reply #2 on: May 27, 2010, 06:04:21 AM »

just to say, any advise johnny gives you is worth gold! he has helped me out from day 1 and been absolutely correct in everything he has ever told me. ;D

 ive managed to get an extra 15km out of my quad so far by changing the air filter and rear sprocket. still got loads to do to get what i want out of it. rejetting my carb, cutting restricter out of exhaust pipe and upgrading my chain. i suggest you run the quad in before changing anything. think of it like a car, you cant tune a brand new car until youve run the engine in properly. just take it easy, i know how tempting it is to wanna get these things screaming along but i could cost you dearly if you dont give the engine time to wear in properly.

Mark
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Johnny

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Re: Rear Bearings
« Reply #3 on: May 27, 2010, 08:02:21 AM »

Gee Mark, golly gosh now I've gone all red  ;) Thanks for the vote of confidence, I'm only to glad to be able to help.  I'm sure there will come a time when I need help.

Cheers Johnny  ;D
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JScott

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Re: Rear Bearings
« Reply #4 on: June 29, 2010, 11:46:43 AM »

Hi thanks for all the great advice, have quad back and all is well I think.  There seems to be an oil build up under the chain pooling in the metal guard under neath the rear axle, is this normal? Is it a self oiling system.
Also my quad works fine except when you open up the throttle fully it caughs and splutters while moving as soon as this has started I have eased off (will sit at 30 mph happily).  When stationary have tried opening the thorttle fully and quad cuts out. Any ideas?
Silly question time is the chole open or closed when fully to the left?  I cant hear any change in the idle speed in either position.

Cheers
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Johnny

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Re: Rear Bearings
« Reply #5 on: June 30, 2010, 03:11:32 AM »

Hi,

Sounds like you are running too rich or you have the choke closed. The choke is closed when your choke lever is to the left.  You will not notice any any change in the revs because the choke is not connected to the throttle valve. You are only choking the air supply (making the fuel air mixture richer).

Cheers Johnny
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JScott

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Re: Rear Bearings
« Reply #6 on: August 11, 2010, 06:47:52 AM »

Hi

Johnny what were those details for the skf bearings mine are on the way out again.  Lots of freeplay in chain and wheel movement going to try an upgrade to these if this doesn't work think quad may have to go still not even done 200 miles and thats all on tarmac roads at no faster than 30mph. 

Upon further inspection I don't think it is the bearings but the chain is very loose.  The chain tensioner is pushing the chain into the underside of the swingarm, I have disconnected the tensioner and now the chain is very loose, if i were to remove a link or two would this work?  Tried tightening it but still seems slack  
« Last Edit: August 11, 2010, 09:55:28 AM by JScott »
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Johnny

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Re: Rear Bearings
« Reply #7 on: August 12, 2010, 02:54:10 AM »

It sounds like the chain has stretched, which is not uncommon with these quads. Either take a link or two out or a new chain. You are better of with a new good quality chain, they don't stretch as much. Make sure that when you adjust the chain, you are sat on the quad, otherwise you will find that the chain is too tight. Put your chain tensioner back on (by the way, repalce the roller with a better quality roller, the original are only an injection molded plastic, get somebody to turn you one out of high impact plastic). Make sure your sprocket is nice and tight, you may need to undo the kock nuts and put a liberal amount of loktite on the threads (the nuts are a 41mm spanner).  I think I have covered everything, let me know if you need more help.

Cheers Johnny  ;D
« Last Edit: August 12, 2010, 02:58:55 AM by Johnny »
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Johnny

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Re: Rear Bearings
« Reply #8 on: August 12, 2010, 03:11:03 AM »

Nearly forgot,

The bearing numbers are as follows:

2 x 61907 or 6907 ZZ or 2Rs

the seals are:

2 x 40x55x8 or 40x55x7 You will need to measure the depth of the original seals to see which ones they are.

Cheers Johnny  ;D
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JScott

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Re: Rear Bearings
« Reply #9 on: August 27, 2010, 05:57:29 AM »

Hi,

Thanks for the advise, quad is going too much hassle to be honest cant get 50 miles out of it without having to fix it.  Got myself a real bike and already managed to ride it futher and it's cheaper on insurance road tax, personally think it's more fun all round. 
Thank you again

Happy quadding
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gas5995

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Re: Rear Bearings
« Reply #10 on: September 02, 2010, 04:49:54 AM »

Hi and welcome,

It is not uncommon for the bearings to go on the 250STXE, I would suggest that you change your bearings to SKF (although these are now made in China as well, however the quality is better). It is not a difficult job to do yourself. If you plan on doing it yourself, let me know and I will give you the SKF part numbers for the bearings. It is a good idea to replace the bearings with sealed bearings, that way you will not have to keep pumping grease into them.

To the best of my knowledge, there is no work shop manual available. I have written to Shineray a couple of times, to no avail. I change oil at the following intervals; before first motor start (straight after delivery, the chinese oil is a little suspect  ;D) then at 300, 500, 1000 and then contrary to what a lot have said ::), every 2000 k, if you use a good oil (mineral and not synthetic in accordance with the hand book) it will not be necessary to change oil more often (besides it being a waste of money). Make sure you run your quad in properly (keep the speed down for the first 1000k). In terms of what each service requires, there are only things like checking brake pads and discs, clutch free play, lights etc. These should all be checked at regular intervals anyway. Make sure that all your nuts and bolts are tight (loktite helps) I have changed all my nuts and bolts for stainless steel, that way they are not going to rust like the original. The chinese steel is not up to our standards, so if you are not carefull the original screws are likely to break relatively easily.

You will not gain any great increase in hp by simply changeing the exhaust. You will gain a little more speed by changing the sprocket ratios (but not a lot).  You will also improve the cooling by changing the main jet in your carbi and perhaps an open air cleaner (sports air cleaner).  You will also need to re-adjust your valves, they are normaly set too tight at the factory (that way they run quiet) this is not much good for cooling the engine, you also run the risk of burning the valves. So at you first oil change, adjust your valves.

For any additional tips, have a look at some of the other posts I have written.

I hope you enjoy getting your hands dirty, cos that is what you are in for with these quads, and besides they are a lot of fun.

If I can be of any more help, let me know. Cheers and have fun

Johnny
hi there can you tell me Johnny how is the clearence of the valves
thanks anyway
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Johnny

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Re: Rear Bearings
« Reply #11 on: September 02, 2010, 10:16:32 PM »

Hi and welcome,

Depends on what quad you are driving, I have the 250STXE and have set the exhast valve at 0.9mm and intake at 0.6mm and this works well for me. Some have set the valves at ex. 0.15 and in. 0.10, but I think these settings are too big(the valves will rattle like crazy). You will need to try and see.

Cheers Johnny  ;D
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Paulo

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Re: Rear Bearings
« Reply #12 on: March 25, 2011, 10:00:15 AM »

Hy Johnny

Can you tell me what rear sprocket do you sujest for my ATV its the same motor of the shienray STIXE

Best regards

Paulo
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Johnny

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Re: Rear Bearings
« Reply #13 on: March 28, 2011, 02:37:23 AM »

Hi I'm using a 40 tooth sprocket which a readily available on ebay and they don't cost a lot. It is possible to use a 37 tooth sprocket, however, what you gain in speed is lost in power i.e., you lose torque.

Cheers Johnny  ;D
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Paulo

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Re: Rear Bearings
« Reply #14 on: March 28, 2011, 05:18:55 AM »

Hi Johnny

But does it lose a lot of torque power with a 40 sprocket, or just a bit in 4th gear, because I dont now if its only because its a new ATV but in 2nd and 3rd gear it has a lot of power, in half acellaration it seems that already in full power.


I use more my atv in off road so do you think its better to put a 37 tooth sprocket?  ::)

Cheers Paulo
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