Head shake

[GJP-SP1]

I’m getting a few miles under my Foggy Stealth now and it’s had it’s first service and I’m generally very happy with it. But as I’m increasing my pace of riding I’ve been finding that the bike shakes it’s head quite a lot particularly when hitting bumps at speed and have had a few real tank slappers. I’m wondering whether this is a characteristic of the bike or whether it just needs the suspension setting up for my weight and riding style. Anyone have any comments to make?

[martin G10]

Hi,
I’d say suspension settings, the standard suspension is a bit over sprung to cope with heavier riders and with the low weight of the bike it tends to kick off bumps, as you said ! I took my six to Maxton Engineering with 300mls on it to have it improved, it now has SD25 fork cartridges (I could have chosen a revalving and new springs) and RT10 rear shock absorber, It’s better with softer springs (midcorner I tried, on/off the throttle, running over white lines then cats eyes, it’s very good, I’ve also raised the rear ride height 12mm) but still doesn’t have the the unsprung mass, less unsprung weight to work against is the next step, lighter tyres is the cheapest option (19″ road tyres are around 2kg lighter than flat track) lighter wheels are expensive. I’ve swopped my rear mitas for a 130 to improve the profile on the 3″rim and building a set of 19″ wheels using 19×3 KTM tubeless rims (they use a gasket to seal the spokes), bulldog stainless spokes and CCM hubs, it’s a work in progress, the Spitfire frame, swingarm and geometry are fantastic , all a matter of my own opinion.
regards martin

[ian]

Hi Gjp-SP1, Picked my Foggy Spitfire flat tracker up in May 21 fitted with marzocchi forks. When I rode it I was having the same trouble as you shaking and bouncing all over the road to the point I was getting blurred vision. It appeared as though the suspension was set up too hard so I wound it back to its softest setting but it was still too hard. When I contacted the factory to book the service I raised this problem and asked if softer springs could be fitted and was told no, the springs should be right. I decided to wait until the first service to see if the mechanic had any ideas to soften the suspension and again asked if there was any softer springs, he confirmed that they don’t fit softer springs. The mechanic altered the settings on the bike and said try that see how that works, unfortunately no different and like you as you increase the speed it gets worse. Contacted the factory and was told that Carl Foggerty had done a lot of work on the suspension and it should be right for the bike and there was nothing more they could do to solve this problem. They suggested taking it to a suspension specialist which I did, he worked on the bike with me getting on and off it as he made alterations and measurements. He said the forks were not compatible for the bike and he couldn’t set it properly because he couldn’t wind back the damping enough to compensate for the spring. He set the bike up so it was level (equal weight on each wheel). He said it was the best he could do and it would probably be still hard on the front. Haven’t had chance to try it out due to illness. Have you managed to solve this problem if so what did you do. Has anyone else had this problem.

Thanks and regards Ian

[GJP-SP1]

Ian, I have not done anything about the issue as yet but I’m intending to have a suspension specialist have a go at setting it up and am seriously considering changing the tyres from flat tracker to sports as suggested by Martin. However it’s now unlikely that I’ll be doing this until next spring.

Regards

Geoff

[ian]

Hi Geoff, Thanks for getting back. Let me know how you get on or any advice would be welcome. I do think the springs are too strong in the front forks with it being a light weight bike. I’ll let you if there any improvement on mine when i get chance to get out on it.

Best of luck

Ian

[Martin]

Don’t know if this is any help but I’ve had the same issue with my Foggy FT and have had the first service done and discussed it at the time with Ben, the mechanic. He backed the suspension off at the front for me and I didn’t notice much difference. I then put it back myself to where it was and notched it up even a little more and again, I didn’t notice a right lot of difference.

I’m 5′ 10″ tall and weigh c 11 stns 7 lbs and have come to the conclusion that it’s me and my riding style. I am used to adventure style bikes where sitting upright seems to be the order of the day and you can’t reasonably do it on the FT, as it lets the bars bounce all over the place. I find that when I lean forward a little and put more weight on the bars (not as aggressively as on a sportsbike), I seem to be able to eliminate the wriggly head, and have not managed to induce a tank slapper since!

[ian]

Thanks for the info. Not been out on my bike since it was set up by the suspension specialist but when i do i’ll post an update whether it be good bad or indifferent. I suspect that the front forks/springs are too heavy for the bike and there is not enough wined back on the damping to compensate for the heavy springs.

[Martin]

. . . . . and finally, I read on the internet (!!!!!!) that if the rear shock is too hard, it will try to overtake the front end in certain circumstances causing the tank slappers I am all too familiar with. So, as I had tried almost everything else, I thought I’d give it a go and backed the rear shock preload right off to the point where the spring was next to being loose and hey presto, I’m much more relaxed on the bike and try as I might, can’t induce the tank slappers/death wobbles!!!!

[martin G10]

Hi, GjP,Ian,Martin
There are other suspension posts with JM , Andy and myself for Marzocchi forks.
Foggy set his bike up for himself at approx 75kg , then CCM added large preload spacers in the forks and a heavier rear spring to accommodate heavier riders, your forks are probably topping out and the tyre loosing contact with the ground , I thought the forks felt over sprung and under damped (soft springs did bottem out on the brakes, rear was over sprung with 950nm for me at 85kg), JM had his forks sorted with altered spacer and a revalve , I took my Six to Maxton for a full suspension job , both ends of the bike need balanced suspension or one end is forced to do all the work.
regards martin

[ian]

The first suspension specialist I mention previously failed to solve the problem. A friend recommended Mike Shanley of MS Race Developments Ltd based in Middlesbrough. He quickly diagnosed the problem as a too soft a rear spring which he changed to a stronger spring and cured the problem. Anybody with a suspension problem in north east area, Mike Shanley is the man to see. Now the bike is a joy to ride.

[peteproud]

I had a similar problem with my Foggy S fitted with ohlins front and rear, far to hard right from the word go.

Backed eveything off at the front , still horrible.

Not sure where you are located but after spending roughly 1 hour at FTR Suspension who are based in Sutton in Cambridgeshire, they worked their magic and have transformed how the bike handles and feels.

[Author]

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