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Posted by: mywifesquad
I wonder if you could just preload the bearings correctly and not use a tube inside? I havnt seen this rear end, mine is the old style with ball bearings. I would think it would be like the front wheel bearings on a car. Tighten to seat the bearings and then back off about 1/8 to 1/4 turn. Is there a grease zerk on the rear end anywhere to fill the cavity with grease?
Posted by: mywifesquad
Originally posted by: windtrader
Mind you I am not a motorcycle frame engineer but going off basic physics the spacer is needed in this application given the way it is designed. It could be modified with the addition of load bearing washers to take the load off the bearing centers.
The whole 150 axle is designed with the load coming from the nut on the wheel onto a n outer sleeve that then presses against the inner bearing race. This occurs on both sides except one side has a splined brake rotor and the other a sprocket. Both just pass the load through on the sleeves. There is only one set of axle nuts on one side that keep the load locked into all these moving parts. There can be not slop or movement in any of these for obvious reasons and as you can expect there can be quite a load on these components.
Since the load carries all the way through, it seems there needs to be support between these bearings. If it is not there then over time, the lateral load from the other components will incrementally keep pressing inward on the inner bearing race and then cause the bearing to fail. A proper length and diameter spacer sleeve allows the full load to be passed through the bearings without placing any extra lateral load on them, thus keeping the inner and outer race and bearing cage and bearing properly aligned.
If a large washer was used to spread the load from the outer spacer sleeves onto the full face of the bearing face (cover inner and outer race), this might work as well; although, I've not analyzed it fully.
The reason it works differently here than in a typical single bearing design is the single bearing is pressed into some housing that provides even load bearing on the back side of the full bearing and races. The outer bearing side is usually covered with a large washer or some other part that is wide enough to cover both inner and outer bearing races. This eliminates any possibility of uneven lateral loading of the bearing.
Im guessing you have never repacked front wheel bearings on a car? There are tapered bearings and no spacer. I understand what you are saying but its been working on cars for decades.
Posted by: mywifesquad
Ive been thinking about the tapered bearings and a spacer some more. I have never seen a spacer used on tapered bearings. The only places I have seen spacers in between bearings is when ball bearings are used. I have seen them used on every motorcycle hub wheel that uses ball bearings.
I think if this was just put together and torqued correctly it would be fine. If the spacer isnt the perfect length it will either be too tight or too lose. Neither one will be good for bearing life.
Posted by: mywifesquad
Originally posted by: outofline
Am I wrong but the inner race is not backed up against the axle anywhere (like a car bearing would be backed up against the spindle) and this is where the spacer is playing a part. I have not looked inside mine just guessing!
Now Im confused. Is the spacer to keep the races apart? Or to control the preload on the tapered bearings?
Posted by: billl2099
If I were you I would tighten the nuts down as hard as I could and see what happens. If the sleeve is the right one, your axle will be tightened up as it should be.
i see you never taken a class in torque, you do not want to tighten the nuts down as hard as you can, if you do you will stretch the treads on the nuts causing premature nut failure, their is a torque valve for each and every nut and bolt on your atv , if the manual does not call out a specific torque valve for that particular nut or bolt there should be a torque value table that shows what the torque valve is for that size bolt or nut. this is very important you do not want to over torque, i can't tell you what the torque valve on your axle nuts are but what i would do is loosen them up then apply blue or red loc tite and retighten them making sure they are tight but not over torque
Posted by: outofline
You could be hearing the chain slap the swing arm, Is your chain too lose? I kind of gotten use to the chain slap noise! Also both of my 150's have a rattle in the muffler, the insides are not built to tight so they rattle but that is just that a rattle!
Posted by: outofline
Yes you can adjust the chain, there are two bolts on the rear axle and one on the rear brake that needs to be loosened then with a hammer you can tap that tab on the axle around (I believe down) to spin the axle around which tightens the chain. I had to remove the lower guard (4 Bolts) to get to the two nuts on the bolts (you will see what I'm talking about). They will take some wrenching from time to time but we have had fun on them! Be sure to oil your air filter and change the original crank case oil out! Also put slime in the tires, I have plugged several holes caused by nails before I slimmed!
You can see some Modifications on my web site that will help ya out! www.myjetmotos.8k.com
Posted by: outofline
Ya when it tighter the slap is much less, I'm not an expert of lubes perhaps there are others on here that are or pretend they are. Just find a good chain lube and keep it lubed!
Posted by: outofline
Here is the Jetmoto Chain Slap sounds: Chain Slap Video
Windtrader that videoegg site worked pretty slick!
Posted by: outofline
Fixed it, didn't know you had to make it public!
Posted by: outofline
I wonder if this problem was just with the second batch or just a few? Mine are from the first and I know I have not heard any of this noise from mine, Yet! But my axle nuts have not came lose! I just wish Jet would own up to problems and say hay we found this may be a problem so here is replacement sleeve so we don't have to replace everyones bearings!
The wife on her 150 and I may go out riding today up in the mountains before it snows, may be our last ride this year but hope not!
Posted by: outofline
Ya know, I was working on my 150 yesterday and saw the 150's set up is different then the 250's and the 150 will not make the chain slap noise that we have experienced with the 250's as heard in my video. So I was wrong with my initial chain slap noise statement post for the 150. There is quite a bit of distant that it would take a very loose chain to hit any thing of the 150. Looks as if Jet did a good job in that respect because I know a lot of other Chinese 150's suffered from the chain rubbing the frame and wearing holes.
I have been working on eliminating rattles on my 150's, I tore the muffler apart and RTV'ed the arrestor (I think it's called) into the end caps and solved that rattle but I still have two rattles I just can't locate and it's driving me nuts!
Posted by: outofline
Am I wrong but the inner race is not backed up against the axle anywhere (like a car bearing would be backed up against the spindle) and this is where the spacer is playing a part. I have not looked inside mine just guessing!
Posted by: outofline
Where they are talking about ID is the important size it seems this must be the case as it will ride right on the axle! and against the inner race!?
Posted by: windtrader
Here are a couple of links to videos I took of a rear end problem in the newest batch of JM 150. It is a clanking, popping, pinging sound that start out coming from the rear. It did not start until I tightened the large axle nuts after they loosened up after a ride or two. The next ride out the problem started.
LM is aware of the problem. It turned out to be the spacer sleeve that goes on the axle between the two bearings in the rear end is too short causing the bearings to get crushed when you crank the axle nuts down.
If this is your problem, it's a quick and fast fix: new sleeve, bearing and seals.
bad bearing
bad bearing
Posted by: windtrader
If you got it from Raceway recently it is under warranty. They can advise you how best to get you back in the dirt. They'll likely help you isolate the problem and advise you on next steps.
I'm less than 30 minutes from Jetmoto HQ so I have rung them up and dropped in to get parts. It was one of the deciding factors when I chose them. I can break down and be going the next day. Hard to beat even from Big 4 quads.
Posted by: windtrader
@wings36,
Make sure you get n direct contact with Raceway on how to proceed. Meanwhile, it seems you have the same problem as I did and others. These nuts should be VERY tight. If either are loose, you have a problem, although not necessary directly creating the bad bearing issue. What you need to do is to crank the inner nut down hard, I believe clockwise if you are facing from the side the nuts are on. There is a spacer sleeve that maintains the proper distance between the axle bearings and keeps them from crushing. If the spacer is too short, like in my case, then the bearing got crushed and loosened up the nuts. Yours may have been tightened as shipped but if the spacer was short, then undue pressure was put on the bearings which cause the failure and the loosening of the axle and nuts.
If I were you I would tighten the nuts down as hard as I could and see what happens. If the sleeve is the right one, your axle will be tightened up as it should be. If the sound gets worse, then you know you have a bad spacer.
Good luck and don't worry - your problem will get fixed.
Posted by: windtrader
It's about 1/4" too short and is not giving any support to the bearings at all.
Bingo! Exact problem I had. You can replace the sleeve your self, just find a piece of pipe that just slides over the axle and is cut to the length of the bearing carrier. The inside diameter is the critical dimension and length. The outside dimension is less important as a thicker pipe just adds weight. Jetmoto has a length of pipe the proper dimensions as I was the one to be the gopher and get it for them when the problem occurred on mine a couple weeks back.
Ideally you can use a bearing puller to extract the bearings and seals which are separate pieces. If you are careful the seals should be fine but get new ones to be safe.
On another topic - Since your quad is new, make sure to go over every bolt/nut you can get a wrench on and make sure it is snug. It'll take a few trips to feel that you got them all but listen very closely for any kind of rattling, clinking, clanking, knocking sounds and chase it down to take care of it. My 150 is nearly silent now and running good, knock on wood.
Posted by: windtrader
I wonder if this problem was just with the second batch or just a few? Mine are from the first and I know I have not heard any of this noise from mine, Yet! But my axle nuts have not came lose! I just wish Jet would own up to problems and say hay we found this may be a problem so here is replacement sleeve so we don't have to replace everyones bearings!
It seems the problem is with the latest (August) batch of 150's and if you have not had a problem yet, you are probably alright. It would show up pretty quickly as there is quite a bit of side pressure applied doing normal riding and if the sleeve was too short the bearings would have gotten hammered without the sleeve for support.
I thought the same thing - why not just send out notices and fixes when common problems arise. It certainly is the best thing to do but nobody does it. The only time this occurs is when an official recall is ordered and that is usually because of some serious safety issue. ATVs by nature are safety hazard so I think they have generally higher exception anyway. But it is just basic business 101 to just serve out the parts when a failure occurs as it costs the mfg the least amt of money. Either you pay more up front for better inherent build and parts quality or you pay less and suffer more flaws and earlier failures. The basic thing is if you send the fix to 100% of the sold units it costs alot more than to just those who have and report the problem within the warranty period. How many actually got short sleeves? Let's say 50%. It is sure cheaper to just send those fixes out. What if another 20% don't ride enough and get the problem until after the warranty expires. Now the mfg only has to fix 30%. If you were the mfg you would do the same thing. If you wanted to have less of these issues, then you sell a better quality product at a higher price to a different target market. Just pure, plain, simple capitalism at work. We made an informed decision and are experiencing exactly what should be happening. Hang in there! :-)
Posted by: windtrader
Measure the diameter of the axle then call to a couple of the local metal suppliers. If you have a scrap metal recycler, that's even better. Remember the ID is more important than the OD. It'll cost you more in gas than the tubing. You are really looking for tubing rather than pipe, although either would work. When you make cut it make sure it is long enough to keep the bearings from pressing too much against the carrier. Mine is a tad longer so one of the bearings does not seat all the way in but it is fine. I'd rather they not get crushed. Good luck.
Posted by: windtrader
Originally posted by: mywifesquad
I wonder if you could just preload the bearings correctly and not use a tube inside? I havnt seen this rear end, mine is the old style with ball bearings. I would think it would be like the front wheel bearings on a car. Tighten to seat the bearings and then back off about 1/8 to 1/4 turn. Is there a grease zerk on the rear end anywhere to fill the cavity with grease?
Mind you I am not a motorcycle frame engineer but going off basic physics the spacer is needed in this application given the way it is designed. It could be modified with the addition of load bearing washers to take the load off the bearing centers.
The whole 150 axle is designed with the load coming from the nut on the wheel onto a n outer sleeve that then presses against the inner bearing race. This occurs on both sides except one side has a splined brake rotor and the other a sprocket. Both just pass the load through on the sleeves. There is only one set of axle nuts on one side that keep the load locked into all these moving parts. There can be not slop or movement in any of these for obvious reasons and as you can expect there can be quite a load on these components.
Since the load carries all the way through, it seems there needs to be support between these bearings. If it is not there then over time, the lateral load from the other components will incrementally keep pressing inward on the inner bearing race and then cause the bearing to fail. A proper length and diameter spacer sleeve allows the full load to be passed through the bearings without placing any extra lateral load on them, thus keeping the inner and outer race and bearing cage and bearing properly aligned.
If a large washer was used to spread the load from the outer spacer sleeves onto the full face of the bearing face (cover inner and outer race), this might work as well; although, I've not analyzed it fully.
The reason it works differently here than in a typical single bearing design is the single bearing is pressed into some housing that provides even load bearing on the back side of the full bearing and races. The outer bearing side is usually covered with a large washer or some other part that is wide enough to cover both inner and outer bearing races. This eliminates any possibility of uneven lateral loading of the bearing.
Posted by: wings36
Hi everyone!
I'm new to the forum and have a question. I just received a new Jetmoto 150 over the weekend from Raceway, put it together, ran it all of Saturday and everything seemed great. On Sunday it aquired a stange noise which seems to be coming from the rear. It's kinda like a poping noise almost a crunch. It doesn't happen all of the time. Usually when slowing down or speeding up. Sometimes when slowing down to take corners. It seems to be possibly coming from the chain or the chain tension arm. It's just so hard to pinpoint. Everything seems to solid and bolts are all tight. Anyone have this problem and know what it is?
Thanks!
Posted by: wings36
Thanks for the response outofline!
You may be right about the chain. Just in the 2 days that my family has used it, the chain has loosened up considerably. And it could be slapping the swing arm. Is there anyway to tighten the chain?
I also was wondering if the chain slips a tooth or engages rough at certain times to cause the noice. When you hear the noice it causes you to raise an eyebrow and wonder if there is something seriously wrong.
Has yours always done this?
(Oh, by the way outofline, your posts have been a big help on my decision to order this quad. I'm very happy with it.... other than the noise
Any other suggestions?
Thanks again!!
Posted by: wings36
Did you notice the sound go away when you tightened the chain?
Have you lubricated the chain, and if so, what do you use?
Posted by: wings36
Thanks outofline for the info. I'll be checking the chain tonight to see if it could possibly be hitting the swing arm.
This sound is sort of a bang or slap. It doesn't happen continuously, only here and there, but enough to take notice. If anyone else has another thought on what it could be I'd love to here it. (just in case it's not the chain versus the swing arm)
Thanks
Posted by: wings36
Thanks!!
I'll have to look into this and see if it's a problem. I haven't tightened the axle nuts, has anyone had this problem without tightening these nuts?
Posted by: wings36
outofline, I get an error message on your video. Says it's private ?!?!?
Posted by: wings36
windtrader,
I put the 150 up on blocks and spun the tires and got it to make a sound close to yours. So I would guess that this is the problem!!
So what was involved in fixing this? Did you get the parts from Raceway?
(This is the first atv I've owned, so I'm not very fimiliar with them) Sorry
Thanks
Posted by: wings36
Thanks for all your help windtrader! I'll be contacting Raceway tonight.
Posted by: wings36
For some clarity on the axle nuts-
There are 2 large nuts on the rear left side of the axle right next to eachother. One was tight closest to the tire and the other was loose. Should the one that is loose be tightened towards the axle carrier or tightened against the other nut. I would imagine towards the carrier, and when it's tightened towards the carrier, this is what causes the bushings to be crushed?
Posted by: wings36
Does anyone know which way these nuts should be tightened?
Posted by: wings36
Thanks windtrader,
I tightened the inner nut clockwise until it was very tight. This made the sound way worse and sounded exactly like yours. It also made the wheels harder to turn. There is now a gap between the 2 nuts. I would imagine this gap should not be there!?!?!?
I'm waiting on a call back from Raceway. I'll let you know how it goes.
Thanks again!
Posted by: wings36
Well, I took the axle carrier off last night and one of the bearings is bad. The sleeve between the two bearings rattles around in the carrier. It's about 1/4" too short and is not giving any support to the bearings at all.
I spoke with raceway before I took the rear end apart and they said they would be sending out new bearings asap but they were not sure about a sleeve problem. They were going to contact Jetmoto about the sleve.
I should be able to make my own sleeve/spacer - should it be tight against the bushings with no play? Also - I haven't removed the bearings yet and I see that they have a rubber seal on them. Are these seals part of the bushings or are they seperate? Also, will Raceway send these (if seperate) with the bearings or do I have to ask for them?
So far, everything is going smooth. I'm hoping to have it back in the dirt for the kidos by the weekend.
Posted by: wings36
Yeah, it's quite a problem that should have been addressed.
I just got done talking to John at Raceway. He's getting the bearings (with seals) shipped out asap. He said he'll be talking to Jetmotto later on today about the sleeve/spacer. I'll post what I find out later incase anyone's interested.
***Have fun outofline !!!***
Posted by: wings36
Update:
I talked to John at Raceway about the spacer/sleeve. It is suppose to be 5.188" in length. Mine is about 5". To get a new one will take about 3 weeks. I'd like to make one myself but to find pipe with the same I.D. is difficult. I can get standard 1" or 1.25" plumbing pipe which neither one matches the I.D. of what I need.
Windtrader, can you tell me what you used?
Thanks
Posted by: wings36
Thanks for everything windtrader, you've been a big help.
