Jump to content

NC700S ABS error code 23 - problem with sensor air gap?


Guest szerwony

Recommended Posts

Guest szerwony

Hi.

In march I bought NC700S with little (as I thought that time) ABS problem. It stops working on almost every ride - sometimes at the very begginning, but sometimes even after 5-10 kilometers. I managed to read error code and it states 23. When reffering to service manual, which I found on the internet, it says that it's a problem with rear pulser ring or its sensor. First troubleshooting step is to check sensor air gap. Manual says it should be 0.54 – 1.14 mm. What I found, is that on my bike rear sensor is about 1.5 mm from pulser ring (front sensor has proper air gap). As the air gap can't be adjusted, how is it possible that it is too far? Do anyone know how can I fix it? While riding, before error comes out, ABS pump turns on very often when using rear brake, even when I barely brake. When I push brakes more, then it stops pulsing.

 

Here I uploaded some photos of rear wheel: https://imgur.com/a/YfbA2xF

Maybe someone will be able to help me fixing it?

 

Link to post
embee

One possible cause is that the rear wheel bearings have been replaced (not uncommon) and they have fitted the chain side one first fully home in the recess, then fitted the disc side and spacer up to it. This puts the wheel offset towards the chain side, increasing the ABS sensor gap.

The disc side should be fitted first fully home, this controls the positioning of the wheel/disc/ABS ring relative to the swingarm and therefore the caliper and ABS sensor. Then the spacer and chain side bearing are fitted until it makes contact with the disc side bearing.

Half a mm is the sort of distance I'd expect from doing it in the wrong order (depth of bearing recess).

 

5ce5b7d65af84_NCrearwheelbearings.jpg.0f77d2965ea57a3e114715a9dda6abe8.jpg

Edited by embee
  • Thanks 4
Link to post
Guest szerwony

Thanks! I think I will have to bring bike to service to get it done, because I won't try to take off rear wheel by myself. Anyway, I also found one point on pulser ring, where air gap is something about 2 mm, so it looks like it's also deformated.

Link to post
Andy m

While I think Murray is spot on, there is a potentially cruder solution. 

 

The ABS sensor is a standard BOSCH looking type. It's designed for mounting using a sprung bush on a car. The butterfly flange round the barrel is some sort of press fit. Check if it does move. 

 

I just had a look on Fowlers website. £293 for a ****ing ABS sensor. I know the OE price and decimal point is in the wrong place. Don't use more than your fingers to see if it'll move. 

 

Andy

Link to post
Guest szerwony

Andy, I am not sure what do you mean (sorry, I'm Polish :ahappy:), but I checked sensor and it doesn't move. It's even stuck, I cant get it out after unscrewing it.

 

I thought some about Murray solution and came up with one question. If the brake disc is in good place, then if I move pulsar ring to be closer, brake disc won't fit. Am I thinking right? If pulsar ring is too far, then shouldn't brake disc be also too far? They are both connected.

Link to post
MikeBike
11 hours ago, szerwony said:

Andy, I am not sure what do you mean (sorry, I'm Polish :ahappy:), but I checked sensor and it doesn't move. It's even stuck, I cant get it out after unscrewing it.

 

I thought some about Murray solution and came up with one question. If the brake disc is in good place, then if I move pulsar ring to be closer, brake disc won't fit. Am I thinking right? If pulsar ring is too far, then shouldn't brake disc be also too far? They are both connected.

As I understand it Murray (embee) said that the whole wheel may be offset. So when corrected both brake disk and sensor would move over 0.5mm. So now both would not be in the correct position. Maybe this also explains why, when you push hard on the brakes, the ABS stops pulsing. The brakes move the disc and sensor ring back towards where they should be, just a little bit, just enough for the sensor to work.

Moving the sensor is IMHO making two things wrong. Mummy always said two wrongs don't make a right. :-)

If you do this then next time the wheel is off and someoen puts it back on correctly then it the sensor may then be too close or foul the sensor ring.

Getting the wheel off and new bearings inserted correctly isn't a big job.

Edited by MikeBike
  • Like 2
Link to post
Guest szerwony

I think that brake disc is in correct position, it fits between braking pads perfectly. Also when pushing hard on the brakes, disc doesn't move. Even if it was moving, it wouldn't be able to move pulser ring closer to sensor as both discs are screwed to the wheel with the same screws.

I am afraid that that if the pulser ring was closer to the sensor, then brake disc won't fit. I don't know how this could happen.

 

8 hours ago, MikeBike said:

Maybe this also explains why, when you push hard on the brakes, the ABS stops pulsing.

It doesn't stop pulsing in 100% when I push hard on brakes, it just becomes barely noticeable, but it's still pulsing. Sometimes when I try to start braking, pumping is so strong that it almost blocks ability to push down brakes (fortunately not very often, in most times it just resists a little bit). So when ABS error comes up, I know about it immidiately without looking at ABS indicator - I just feel that I can brake normally.

Link to post
3 hours ago, szerwony said:

I think that brake disc is in correct position, it fits between braking pads perfectly.

I think that it will always fit perfectly since caliper floats horizontally

  • Like 1
  • Thanks 1
Link to post
Andy m

Runout on the pole wheel will be interpreted as deceleration and hence cycling of the modulator. If you fix the air gap this may or may not go away. 

 

The float on calliper is "after" the bracket the sensor mounts to, so IMHO is not a factor. The bearing issues raised earlier makes sense, moving the whole assembly in relation to the axle spacers. 

 

Andy

Link to post
Guest szerwony
12 hours ago, wendeg said:

I think that it will always fit perfectly since caliper floats horizontally

Yes, but if both disc were moved 0.5 mm to the right, then caliper would bend braking disc or it won't fit.

 

12 hours ago, Andy m said:

The float on calliper is "after" the bracket the sensor mounts to, so IMHO is not a factor. The bearing issues raised earlier makes sense, moving the whole assembly in relation to the axle spacers. 

But I'm not sure, if there is option to regulate calliper distance. If there is, then moving whole wheel to the right won't be a problem.

Link to post
embee

As the others say, the caliper slides on pins to align the fixed pad with the inside face of the brake disc, wherever it is, and the brake piston pushes the moving pad against the outer face of the disc. Within a certain range the caliper will align itself with wherever the disc sits.

You are only talking about half a mm or so of error on the ABS sensor to pole-wheel distance. That's enough to upset the ABS system but the brake will accommodate that range of movement easily. It can cope with a pad when new and when completely worn out, maybe 4mm or similar.

The disc and pole-wheel are fixed rigidly to the wheel. The bearings fit in a fixed place relative to the swingarm and caliper mounting bracket (and ABS sensor). If the bearings are in the wrong place in the wheel, the pole-wheel will be in the wrong place relative to the sensor.

  • Like 1
  • Thanks 2
Link to post
Guest szerwony

Now I understand, thanks :ahappy:

 

Yesterday I accidentaly met someone with the same Honda as mine. He let me to take pictures of his bike, so I can compare. Here is the result: https://imgur.com/a/XxYkWiO

I marked with red circle the differences I see. In my Honda, the ring seems to be wider than his. Is this a bearing, about which are you talking?

Link to post
outrunner

Has it always done this, or has it just started? Have you had the rear wheel off and inadvertently swapped the spacers around?

 

 

Andy.

  • Like 1
Link to post
Andy m
11 hours ago, szerwony said:

Now I understand, thanks :ahappy:

 

Yesterday I accidentaly met someone with the same Honda as mine. He let me to take pictures of his bike, so I can compare. Here is the result: https://imgur.com/a/XxYkWiO

I marked with red circle the differences I see. In my Honda, the ring seems to be wider than his. Is this a bearing, about which are you talking?

Yes

 

Also, look at the brake calliper. Yours has the inner pad very close to the disc and a huge gap for the outer pad to slide on the pin. His has both pads able to slide. 

 

If it has done a few miles like this I would suggest fitting new pads while you have it in bits. Your inner pad is potentially worn or glazed because the bearing movement has actually taken up pretty much all the calliper travel. If you keep the old pads, once fixed, work it as hard as you can for a few days, you want the surface of that inner pad cleared off. Do not let the grease monkeys use a grinder or file, bits of the tool left in the pad will ruin the disc. 

 

Andy

Link to post
embee
14 hours ago, szerwony said:

Now I understand, thanks :ahappy:

 

Yesterday I accidentaly met someone with the same Honda as mine. He let me to take pictures of his bike, so I can compare. Here is the result: https://imgur.com/a/XxYkWiO

I marked with red circle the differences I see. In my Honda, the ring seems to be wider than his. Is this a bearing, about which are you talking?

The ring you can see is the spacer which fits between the wheel bearing (inboard of the seal) and the caliper/swingarm. If you can see more of this spacer it indicates that the bearing is nearer the outside face of the wheel, in other words the bearing is probably not fully home in the recess. This is why Honda specify the order in which the bearings are fitted, the disc side first and fully in to the bottom of the recess in order to get the distance to the caliper correct, then fit the chain side bearing until it just reached the spacer tube. The chain side bearing recess will be slightly deeper in order that it goes down to the spacer tube without bottoming out in the recess. 

 

Your pictures support the theory that the bearings are not in the wheel correctly.

 

To correct it you really need to remove the bearings and start again, at which point it's wise to fit new bearings, they are not expensive if you get them from a bearing supplier, for example https://www.bearingsrus.co.uk/bearings/deep-groove-ball-bearing/metric-deep-groove-ball-bearing/6204-2rs-skf or https://simplybearings.co.uk/shop/p6275/SKF-62042RSH-Rubber-Sealed-Deep-Groove-Ball-Bearing-20x47x14mm/product_info.html

 Note you want a 6204  2RS (= 2 x rubber seals), not shielded ("ZZ") and not a C3 grade.

Unfortunately putting any significant load axially through the actual bearing elements (the balls) risks damaging the raceways, especially any hammer type blows, so they must be fitted correctly. The outer part must be pressed or drifted in with force directly applied to the outer race, it must not be knocked in by the inner part.

 

If you have a spot on the ring which is a bigger gap then it suggests it is slightly bent, quite possibly accidentally by someone when fitting new bearings. The ring can easily be straightened carefully.

Edited by embee
  • Like 1
Link to post
Guest szerwony

Thank you all for tips! I think I will try to find a mechanic who will have time to do it. Also this may explain why braking disc is unevenly worn.

Link to post
  • 2 weeks later...
Guest szerwony

Today I visited mechanic. He took off the wheel and checked everything. He told that it can't be a problem with bearings or distances that I marked on previous photos. He told to replace sensor as it must be the problem. Sensor also looked a little bit scratched.

 

I compared again photos of my Honda and another one which I accidentally met, and saw another difference. His sensor is much longer than mine and this is what may be causing the problem. I don't know how it could get shorter, but it is. Here I compared them: https://imgur.com/a/yYOgN5p

Maybe the problem isn't in the wheel mounting, but in sensor?

Link to post

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...