Fork Chatter

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AllanP
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Fork Chatter

Post by AllanP » Sat Feb 25, 2017 12:20 am

Just passed the 620 mile-1000km mark today and taking the bike into the dealer for its first service on Monday. I'll be mentioning the tank pressure problem I posted about earlier, the big gap on one of the pannier lids and also clonky front forks.

When slowing down to a stop, the front forks rattle as I decelerate from about 10/15 mph to a standstill. It feels almost like the ABS cycling but I'm nowhere near breaking front wheel traction. They also feel a bit rough on some road surfaces which would not bother a 990 or any other modern bike I know. They work well at speed but there is definitely a rough edge to the ride at some intermediate speeds, has any one else experienced this?

Fueling is superb, handling is slower and heaver than a 990 on tight twisties, but excellent and much more stable on fast bends which is what I was hoping for. It looks like it'll be comfortable enough for long days in the saddle and I like the wind protection. I do most of my riding in central Texas, ride year round and I wanted something which would keep the weight of my chest and arms, be free or turbulence but deliver enough breeze to help with cooling, and its looking good.

I plan a 5-day trip to Big Bend on it in two weeks time. A lot of 80mph cruising down the roads to get me out there then some of the best bike roads I've ever ridden on. I'll have a better idea of what this bike is all about after that :mrgreen:

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Re: Fork Chatter

Post by DaveNZ » Sat Feb 25, 2017 9:16 am

Try a firmer setting Allan, and see if you still get any chatter, does the chatter you describe happen at the top of the fork stroke, like topped out. some times with soft suspension the speed of the suspension compressing and extending can feel flimsy, firm them up a little until its more bedded in.
2016 1290GT-remus link and muffler, 2010 Black 1200 Multistrada full Termi system with mapping, 2005 SMR 640, full Titanium system, Mikuni flatside racing carb, 2 sets of wheels, 18 litre tank, and a nice soft seat.

AllanP
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Re: Fork Chatter

Post by AllanP » Sat Feb 25, 2017 4:08 pm

Thanks. The chattering only happens when the forks are under compression while braking to a standstill and only then at low speeds as I come to a stop.

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Re: Fork Chatter

Post by DaveNZ » Sat Feb 25, 2017 6:17 pm

AllanP wrote:Thanks. The chattering only happens when the forks are under compression while braking to a standstill and only then at low speeds as I come to a stop.
OK, try a firmer setting, and also just check that its not your disc under soft braking, transferring the feeling up through the fork, new braking systems need good firm (hard) bedding in, or they can get surface spots that grip on the brake pads more so, and give a fine pulse. if you can, do some heavy braking from good speed, but be careful, firm up the suspension first tho, as you don't want the forks diving hard under good braking.
2016 1290GT-remus link and muffler, 2010 Black 1200 Multistrada full Termi system with mapping, 2005 SMR 640, full Titanium system, Mikuni flatside racing carb, 2 sets of wheels, 18 litre tank, and a nice soft seat.

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Re: Fork Chatter

Post by AllanP » Sat Feb 25, 2017 8:47 pm

I have gradually been gradually increasing the braking force and have done a few quite hard stops from 70 mph down to about 30mph. Not enough to get the ABS working (at least I couldn't detect it) and the brakes are great and so is the suspension and stability.

The problem only shows itself at very low speed with low braking forces. Its not clear to me why I should harden up the suspension or avoid fork dive when braking, when it seems to be set up well?

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Re: Fork Chatter

Post by AllanP » Sat Feb 25, 2017 10:23 pm

Hi DaveNZ. Just after I posted my last reply, I realized why you suggested preventing the forks diving when testing the chatter on my front brake. This I suppose will isolate possible fork related causes from brake system related causes.

I'll try the following and and post the results:
1) Warm the brakes up then brake as normal using both brakes at the same time to make sure the problem is still there.
2) Increase pre-load to the max and try again.

In view of the fact that the brakes are linked I'll then try the following with normal pre-load and then with max preload
a) brake only with the front brake
b) only with the rear brake
c) switch off the ABS

I'll post the results.

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Re: Fork Chatter

Post by JDS1290SDr » Sat Feb 25, 2017 11:42 pm

Could this just be the brake pads rubbing on the disks? The 1290 SDRs are well known for this.
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Re: Fork Chatter

Post by DaveNZ » Sun Feb 26, 2017 9:06 am

JDS1290SDr wrote:Could this just be the brake pads rubbing on the disks? The 1290 SDRs are well known for this.
Yip thats what i was thinking, my multistrada does it, who ever owned and ran that bike in, didn't bed the disc's in hard and fast, now they are pulsing pieces of shit. I did 690Ks on my GT today, when the pace upped on the way home, i switched to Sport power and Sport suspension setting, the GT is more at home in these settings. Hope you get it sorted Allan.
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Re: Fork Chatter

Post by AllanP » Tue Feb 28, 2017 12:13 am

DaveNZ wrote:
JDS1290SDr wrote:Could this just be the brake pads rubbing on the disks? The 1290 SDRs are well known for this.
Yip thats what i was thinking, my multistrada does it, who ever owned and ran that bike in, didn't bed the disc's in hard and fast, now they are pulsing pieces of shit. I did 690Ks on my GT today, when the pace upped on the way home, i switched to Sport power and Sport suspension setting, the GT is more at home in these settings. Hope you get it sorted Allan.
Thanks Dave.
I took it for a ride today and checked the things you suggested but first I have to say that the problem was a little less evident today than earlier.

I started by checking the bike with the 1 rider, sport damping and engine control I do most of my riding in. The chatter was still there although mild and only by the time I had decelerated to walking pace breaking quite gently.

I next rode the bike with max pre-load but no difference.
I then put it back to my normal sport setting and tried braking with the front brake only - chatter
Then rear brake only - no chatter.

I have 1000kms on it and it goes into the dealer to be serviced soon but I think I'll follow your suggestion about braking a bit harder. Its only really evident now a almost walking pace and light braking.

Tonight I'll take it for its first night ride. I once bought a new Yamaha Fazer 1000 but didn't check the lights and the first time I switched them on far from home, they were pointing at the sky :o I couldn't see enough in the dark to find the adjustment screws and had to ride the thing miles to home like that. I did a dumb thing, but I'll be a bit more careful this time :)

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Re: Fork Chatter

Post by DaveNZ » Tue Feb 28, 2017 2:39 am

The lights on the GT are fantastic, they light up the full width of the road, and the cornering lights work really well on those narrow country roads. On previous bikes I've had Allan, I've put a smear of grease between the brake pad back and the brake piston, just so the pad can move freely if needed, striction can cause a horrible noise and sometimes a shudder, i haven't had to do this on the M50s that the Superdukes have tho.
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Re: Fork Chatter

Post by Bruce Wayne » Tue Feb 28, 2017 4:12 am

Sounds like it is build up like the others have suggested. I've had this on other bikes in the past. Your best bet is to find a long stretch of road so you can run through this process. Basically get up to as high a speed as you're able to do comfortably/legally and break HARD down to about 10MPH, speed up straight away and repeat the process. After three goes of hard breaking, cruise along, staying off the brakes until they've had a chance to cool - don't pull up until then. Hopefully that will clear it up straight away - good luck!

Dave - good to see you over here. I'm migrating across from the Aprilia site so we can leave the Caponord forum alone :)

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Re: Fork Chatter

Post by DaveNZ » Tue Feb 28, 2017 4:29 am

Nice to see you here also Bruce, theres gradually building a few numbers on here, and knowledgable guys who have had multiple makes of bikes. I liked being on the Capo site from time to time, theres some really good friendly guys on there, who don't mind other bikes and their riders, i Hope Brisbanonord joins here, he's such a character. :D
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Re: Fork Chatter

Post by AllanP » Thu Aug 03, 2017 7:08 pm

An interesting development here.

I've got 5500miles/8800kms on my 2016 and what I described as fork chatter/clonking still persists. Two weeks ago I got a call from KTM USA Customer Service asking me what I thought of the local dealer service I'd received and if there were any problems with the bike they could help me with. I told them the dealer service had been very good and there were only two unresolved problems. One is a small oil weep from the front forks the other is the crude clunking and chattering sound from the forks I get when I hit a bump or apply the front brake on a rough road, or when applying the front brake just before I come to a standstill.

The customer service lady asked if I would like her to call my dealer to see if she could help but she clearly didn't know anything about motorcycles so I asked if she could put me through to a technical person at the suspension maker WP. The reason I wanted to speak with a WP person was that I first need to establish if this is something that's broken or its just a characteristic of the bike. So she put me through to someone at WP but this guy told me that the semi-active suspension is handled ONLY by the KTM factory and WP technicians don't support it. At that point I began losing interest and we finished our call. Two days later however, my dealer called to tell me that KTM had contacted him and were sending him a new right hand fork damping cartridge to be installed under warranty!

This has been done many times for the KTM-SA but I've never heard of it being done on a SD-GT. Yesterday I took the bike in to have the new cartridge installed only to be told that KTM have sent them one for the Super Adventure and it won't fit the GT because the suspension travel is much shorter. The dealer will ask KTM to swap it for a GT length cartridge. This is a pity because I leave for a 3-4 week ride on Tuesday and I would have loved to have the new one in before I go. On the other hand, perhaps there might finally be a solution and that's a good thing.

It has occurred to me that perhaps the KTM USA people assumed that this was a SA cartridge problem because there have been so many of them and they don't actually have a solution for the GT (I did tell the KTM USA and the WP person that it was a GT). It will be a month before I get back and find out but I wanted to post this for any other GT riders who are not happy with their forks and I'll let you know what happens.

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Re: Fork Chatter

Post by Aussie Dave » Sun Aug 06, 2017 9:06 am

Cheers all......I just had both front disc's replaced under warranty after 8,000kms usage(one had warped out of spec and was grabbing/pulsing at the end of the braking roll). Can't say it had anything to do with what Allan is working on, but it is nice to be back to new with straight Brembo disc's and new Brembo 'road' compound pads (the KTM pads are identical but almost twice the price ;) ....so thanks to my local front desk service guys for saving me some $$.. ;) ).

I've not noticed any chatter......but I'm a WUS rider anyway, and probably haven't pushed the GT hard enough to find fault with the WP units......but the warped disc's are easily noticed as you pull up at traffic lights in city traffic.....you get the grabbing/pulsing feel as you put your landing gear down..... :lol:

If that is an issue for anyone - the other Dave (in New Zealand!) has found that the Racetec disc rotor's (err, turns out they are prob Brembo 'Serie Oro' 320x5mm) are thicker (5mm vs 4.5 oem)......so this could be the big fix once warranty stops.. ;)

Don't feel cursed by this......it's a big issue on all Brembo shod iron horses (Ducati MS1200 has the exact same issue.......and many many other brands use Brembo rotors.......but I have heard there is a more expensive version of Brembo brake disc's......but i have no first hand knowledge or info on this...... :roll:

Oddly enough, I put 37,000kms onto my beautiful red Aprilia Caponord 1200TP before I test rode a 1290GT.... and it had no problem with it's Brembo calipers and brake rotors.....it weighed 30kg more than a Gt but had 50hp less....... :lol: ......can't recall the O/D of the rotors, maybe they were smaller than 320mm and not prone to warping..... :| ......prob never know the answer to this one...... :roll:
Last edited by Aussie Dave on Mon Aug 07, 2017 7:20 am, edited 2 times in total.
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Re: Fork Chatter

Post by AllanP » Mon Aug 07, 2017 4:05 am

That's a great outcome Dave.

These are my third Brembo brakes. 990SD, Triumph Street Triple-R and now the SD-GT and so far no issues with them but any kind of brake issue would bug the hell out of me and I'd have to get it fixed.

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Re: Fork Chatter

Post by AllanP » Sat Oct 28, 2017 1:02 am

There have been several threads on the board concerning fork issues (knocking, harsh, stiff, chatter etc) including this one. I took my first ride today on my 2016 SD-GT after KTM replaced the internals of both front forks legs except for the springs, tightened the head bearings (again) and replaced the weeping fork seals. I thought you might be interested in the outcome.

From the first day I bought it, the front forks on my bike made clunking noises and a kind of "chattering" which you could feel through the bars when braking to a standstill. They ironed out large individual bumps quite well in all three damping modes, but could not cope with a rapid series of bumps particularly when braking hard. This caused a harsh hammering feedback through the bars and a feeling like the front forks had locked up. I don't think the forks had actually locked up, but they had lost most of their compliance which gave me the feeling that front tire contact was compromised. Straight-line or trail braking was pretty scary going downhill or on wet roads.

The bike was in the dealers for a long time but the important thing is that the suspension is now significantly better than it was when the bike was new. I did 150m/240km on its first trip after the rebuild today, not far but I did make a point of taking it to roads where it had really struggled in the past. The suspension is quiet and compliant in all three damping modes and I think I can finally understand what is a characteristic of this generation of KTM semi-active suspension rather than a fault. This is the first day out and I didn't ride it hard but it's a vast improvement over the way the bike was when I bought it.

Not far today, but the black ring round the lower fork legs at the top of their stroke is back.:D

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Re: Fork Chatter

Post by Striff » Mon Oct 30, 2017 5:14 am

AllanP wrote:There have been several threads on the board concerning fork issues (knocking, harsh, stiff, chatter etc) including this one. I took my first ride today on my 2016 SD-GT after KTM replaced the internals of both front forks legs except for the springs, tightened the head bearings (again) and replaced the weeping fork seals. I thought you might be interested in the outcome.

From the first day I bought it, the front forks on my bike made clunking noises and a kind of "chattering" which you could feel through the bars when braking to a standstill. They ironed out large individual bumps quite well in all three damping modes, but could not cope with a rapid series of bumps particularly when braking hard. This caused a harsh hammering feedback through the bars and a feeling like the front forks had locked up. I don't think the forks had actually locked up, but they had lost most of their compliance which gave me the feeling that front tire contact was compromised. Straight-line or trail braking was pretty scary going downhill or on wet roads.

The bike was in the dealers for a long time but the important thing is that the suspension is now significantly better than it was when the bike was new. I did 150m/240km on its first trip after the rebuild today, not far but I did make a point of taking it to roads where it had really struggled in the past. The suspension is quiet and compliant in all three damping modes and I think I can finally understand what is a characteristic of this generation of KTM semi-active suspension rather than a fault. This is the first day out and I didn't ride it hard but it's a vast improvement over the way the bike was when I bought it.

Not far today, but the black ring round the lower fork legs at the top of their stroke is back.:D
Not sure if the same issue, but I just recently got a SDR 2017, and noticed chattering when braking at lower speeds.

It also had the power parts wavey type discs fitted.

Thanks to a post on another forum it was suggested the casting of where the disc butts up against the wheel is not the best and to file the wheel where the horizonal meets the vertical part of the wheel.

So I took off my discs as much as I could with leaving the wheel still on, could not notice any imperfections but still went ahead with a small file and filed lightly, did this on both sides of the wheel.

I wasn't expecting any results but the chattering is completely gone, braking at slow speeds no longer produces any chattering what so ever!

Which reminds me, must go back and let the other forum posters know as well.


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