Attention Scallywags

[Dave20046]

Eat more pie.
I doubt any good fellow here exceeds 75mph but if in doubt, chin it and pin it.

https://www.youtube.com/watch?v=z3OQTU-kE2s

[Bibio]

ahhh the good old days...


why do you think the KH750 got the nickname the widow maker.


bikers today think that they are tank slappers... ermmm no as you very seldom walk away from real tank slappers.

[Seeker]

That was interesting. In the era this was filmed I had a Yamaha R5 350cc two stroke and on a local (deserted) bypass I made repeated runs and adjustments over the months to try and increase the top speed. I needed a new rear tyre and the one I wanted (as everyone did back then) was a Dunlop TT100 (K81) but the only tyre in stock was a Michelin something or other. Being a teenager and impatient, I had it fitted. Off to the bypass...the Yam had the stock "western" bars so the riding position was right hand pinning the throttle and left hand grabbing the left fork stanchion, chin on the tank. I hit the weave at an indicated 90mph and for the first time on a bike felt scared.
Since I was already flat on the tank I couldn't lie down any lower, I'd read that applying the front brake was not recommended so I gently applied the rear brake and eased off on the throttle and the weave stopped at about 70 mph. I ordered a TT100, dumped the Michelin and that cured the weave.

The video didn't mention it but the thinking at the time was that bikes had their centre of mass too far rearwards and needed more weight on the front wheel, which is why lying down often works, I suppose. In the video he said that carrying a pillion helped but with the Yamaha it meant that the front wheel often left the ground in first and second. Fun times.

[Craig380]

Originally Posted by Seeker

The video didn't mention it but the thinking at the time was that bikes had their centre of mass too far rearwards and needed more weight on the front wheel, which is why lying down often works, I suppose. In the video he said that carrying a pillion helped but with the Yamaha it meant that the front wheel often left the ground in first and second. Fun times.

There was a theory at the time that, depending on the bike's steering geometry and front/rear weight bias, having a treaded tyre like a TT100 on the front wheel could induce front-end shimmy that could lead to a proper wobble.

For some bikes (I remember the SOHC Honda 750 being one), a ribbed front tyre was recommended to avoid this.

[Dave20046]

Interesting my mate has one of the yellow Honda 750's , complete with ribbed tyre - I hadn't given it much thought. Centre of mass sounds very likely, there was a problem with (not that) old police bikes (think it was Pan euro) that when laden with police gear spat riders off around 100mph. A few cops were killed and the coroner made Honda look into it.

Originally Posted by Bibio

ahhh the good old days...


why do you think the KH750 got the nickname the widow maker.


bikers today think that they are tank slappers... ermmm no as you very seldom walk away from real tank slappers.

Must admit I forget wobble and weave differs from the back to front, front to back loss of traction pre high-side (which I believe is fixed by pinning it, this needs gentle slow down).
I'd been looking into what I've been getting on the bike and put down solely to suspension, the tyres are ****e I should probabably accelerate the purchase of replacements. Was glad I stumbled on this gem.

[Biker Biggles]

The Police Pan Euro issue was a strange one and I think they concluded it was something to with a combination of a traditional high speed weave and airflow problems around the blue light on a stalk they all carried. Either way they changed to BMWs soon after. Didnt the ambulance service have similar issues and "solved" it by banning higher speeds?

[Dave20046]

Not really a fix is it!

I feel the extra weight leathers would add would have helped this chap

https://youtu.be/uNwQK_HIHRU

[SV650rules]

I thought pan European police bike handling was something to do with the extra weight of police equipment and its distribution... I can see a zig zag pattern tyre could induce a weave, and why a ribbed tyre would be better.

[gadget]

All scary stuff there! Never had a wobble or a weave on any of my bikes ranging fro the 70's to present day!
Only ever had one 'tank slapper' and that was a proper tank slapper... not just a wobble, it came in so quick I didn't know what hit me, next thing I know I'm sliding down a section of dual carriageway and came to a halt literally a couple of feet from the central reservation. No immediate injuries to speak of just wrecked leathers, only thing I noticed a few minutes after was my right thumb was painful, it turned out it was dislocated from being bashed into the tank during the tank slapper, it had been so violent that the right steering stop had been broken allowing my thumb to get squashed into the tank.
Btw ... that was on my RD400E with ace bars, pretty scary stuff at the time tbh.

[daktulos]

Youtube is now recommending wobble and weave videos to me. if the original was missing one thing, it was Murray Walker.