505 head shakey, shakey

Hey guys, my 09' 505s front end seems very nervous when throwing steering input at it at high speeds.

This weekend I hope to soften the compression some more and slow that rebound down.

Where are some of you guys at?

Solution: steering stabilizer. I got the mounts and swapped the Scott's stabilizer over from my XR650R. I've never even ridden my 505 without it. I put the stabilizer on before my first time out on the bike.

This chassis is nervous at high speed. That is a trade off since it turns so good. So the high speed instablity is inherent in the design. Doesn't matter if it is a 505 or a 530, it will shake sooner or later. A stabilizer is a must for anything resembling high speed with this KTM chassis IMO.

another place to look at is the rear sag, if its not right it screws the front up.

Solution: steering stabilizer. I got the mounts and swapped the Scott's stabilizer over from my XR650R. I've never even ridden my 505 without it. I put the stabilizer on before my first time out on the bike.

This chassis is nervous at high speed. That is a trade off since it turns so good. So the high speed instablity is inherent in the design. Doesn't matter if it is a 505 or a 530, it will shake sooner or later. A stabilizer is a must for anything resembling high speed with this KTM chassis IMO.

+1:thumbsup:

The very first thing I noticed on my 505 was how well it carved. I played with the sag/compression/rebound and I never was able to find a sweet spot for speed and it felt unstable. I threw on a Scotts stabilizer and now have the best of both worlds... I'd never ride a Katoom without one now. I ride the girlfriends 09 250 XCF-W without a stabilizer once in a while, and it scares the hell out of me riding it like I would with my 505. Yeah, it's a 250, but basically the same chassis

I noticed a signifigant reduction in 'head shake' at high speed after I re-sprung the shock to achieve proper sag measurements on my 08' 505XC-F.

Solution: steering stabilizer. I got the mounts and swapped the Scott's stabilizer over from my XR650R. I've never even ridden my 505 without it. I put the stabilizer on before my first time out on the bike.

This chassis is nervous at high speed. That is a trade off since it turns so good. So the high speed instablity is inherent in the design. Doesn't matter if it is a 505 or a 530, it will shake sooner or later. A stabilizer is a must for anything resembling high speed with this KTM chassis IMO.

:banghead: I did the SAME EXACT thing, Took off 650 and never rode mine without it either.:worthy: My bike never gets the shakes. I have heard from others that the 505 has headshake but I would'nt know, SCOTTS:thumbsup: :lol:

Thanks guys for the input. I have the rider sag set, being a lighter rider it looks like the stock spring is going to work out.

I really dont want to pop for the $500 stabilizer, but considering the animal I may have to for this high speed business.

Anybody have any thoughts on lengthing the wheel base, via smaller rear sprocket. I currently have a 50 on it now. Maybe this will assist in taming it down a bit??

I guess I could just slow down, but that sucks!!

I am hoping to bring the gps out this weekend to get an idea of the top speed of this beast.

Anyone know what I might expect???

Thanks guys for the input. I have the rider sag set, being a lighter rider it looks like the stock spring is going to work out.

I really dont want to pop for the $500 stabilizer, but considering the animal I may have to for this high speed business.

Anybody have any thoughts on lengthing the wheel base, via smaller rear sprocket. I currently have a 50 on it now. Maybe this will assist in taming it down a bit??

I guess I could just slow down, but that sucks!!

I am hoping to bring the gps out this weekend to get an idea of the top speed of this beast.

Anyone know what I might expect???

I'm running a stabilizer and a rear 50 tooth. Clocked 68 mph but not pinned for long. I have since switched back to the 48 tooth. Haven't ridin it yet since the gear change but gonna try it out this weekend!:lol:

I was going to say more like 96 to 98 mph pinned in 5th with a 50 tooth rear on a 505 xcf. 5th gear is insanely fast on the xcf. I raced a guy downhill in the sand who was on a yzf450 with a 49 tooth rear who said his top gps speed was 92mph (no idea if that's right) and I was faster than him with my 50 tooth rear setup by quite a ways. So if he was right about his top speed I guess ours to be anywhere between 96 to even 100mph. Again no verification here but I can promise you it's the fastest I have ever rode on a dirtbike. Let us know the results, I may be way off on the numbers but it's fast no matter what, as fast as you would want to go off road anyway.

PS I now have a scotts but have been to the dunes twice without it and yes it feels quite unstable at high speeds, just pull back and squeeze those knees. I am looking forward to the dunes with the stabilizer.

68 mph ??? must be a mistake! I have a 50t and im with Andrew, close to 100.

That guy with the YZF was on crack. Even with a 49 that bike is nowhere near a 100mph bike. Maybe 80mph. Maybe.

With stock gearing (14:52), the XCF is good (on paper anyway) for 97.3 mph at 11,000rpm. If you bump that up to a 14:50, you get 101.1.

A stock 4spd 505 SXF (like mine) is good for 86.0 mph with the insanely tall 14:48 stock rear sprockets. Throw the 52 tooth rear that the 450 comes with (and most feel that the 505 should have) and you knock that down to 79.4 mph.

Remember that these are all numbers in a perfect world. The faster you go the more inherent wheelspin and air drag you suffer from limiting top speed. Theoretically the gearing on my XR650R will get me to 112.6, but on the loose gravel road I was running down I could only get to 103 on GPS due to wheel spin and drag (I just couldn't quite hit the rev limiter due to some worn out valves either).

Spreadsheets don't come out quite right when you paste them into a post, but you can get the idea below.

Bike 505 SXF 505 XCF

Primary Drive Gears 29 74 29 74

Transmission Gears 1 17 32 16 34

2 19 30 19 31

3 21 28 20 26

4 23 26 23 25

5 n/a n/a 26 24

6 n/a n/a n/a n/a

Sprockets (F/R) 14 48 14 52

Redline 11000 11000

Final Drive Ratios (each gear) and top speed (mph) in gear 1 1: 6.45 51.7 1: 7.89 42.2

2 1: 5.41 61.6 1: 6.06 55.0

3 1: 4.57 72.9 1: 4.83 69.1

4 1: 3.88 86.0 1: 4.04 82.6

5 n/a n/a n/a 1: 3.43 97.3

6

'07 KTM 505 SX-F

Stock C/S sprocket, 52 tooth rear...

128 Kilometers per Hour = 79.53551260637874 Miles per Hour

Pretty much exactly what Eastreich said....

Hit the rev limiter at that speed and got a little busy up front :p

Not a problem with a stabilizer now....

'07 KTM 505 SX-F

Stock C/S sprocket, 52 tooth rear...

128 Kilometers per Hour = 79.53551260637874 Miles per Hour

Pretty much exactly what Eastreich said....

Hit the rev limiter at that speed and got a little busy up front :p

Not a problem with a stabilizer now....

My spreadsheet doesn't account for tire "growth" at speed, so the number would be a hair (.13551260637874) low!:ride:

Well on gps I achieved 93 mph, which is really pretty amazing considering the rear ice tire weighs in over 15lbs and the front tire is pretty hefty as well.

I would say eastreich your numbers are real close or right on.

What a day on the ice!!, just awesome and also laid down some sweet helmet cam videos.

I also dialed in the suspension a bit more and it really calmed the front end down to a reasonable amount of back talk.

Thanks for all of the input guys

Set the rear Sag to 115mm or greater.

Set the adjustable triple tree from 20mm offset to 18mm, both adjustments will lengthen the Trail which will help make more stable at speed. Worked great on my 08 505XCF.

Cheers,

William

Santa Cruz, Ca

No head shake @94 mph GPS verified but I have never ridden my 505 without the stabilizer either..It is geared stock and I usually ride at 5500 ft. or higher..I would guess a few more mph at sea level though.

No head shake @94 mph GPS verified but I have never ridden my 505 without the stabilizer either..It is geared stock and I usually ride at 5500 ft. or higher..I would guess a few more mph at sea level though.

I would doubt that. The 505 makes more than enough power that any loss due to altitude has no effect on the top speed. I can still hit the rev limiter in top gear at 6500 feet where I ride or at 2000 feet in the So Cal desert.

If you can find a way to limit wheelspin on the dirt, then you may get some more speed. Or just run 'er down the pavement and replace the tire when you are done!:p

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