The Shakedown

[kavb]

Took the G/S for a blast around the M25 this evening as part of her running period since arriving in UK. She's riding lovely and started 2nd push of the button despite being laid up all week. Couple of questions/observations as a first airhead owner:

Think she's best at 60mph on the motorway.

At 70 the steering gets a little shakey (more prominent under acceleration). Nothing too frightening but is this normal? I'm running TKC80s.

Hit 85mph and she started to stutter. I probably have no business at these speeds anyway but had to give it a go. My first thought was fuel starvation from float level, what do you think?

Speedo reads 8-10mph over GPS, presumably thats normal?

When starting the bike do you leave it to warm up on the choke or move straight off?

Not being old skool this is my first bike with a fuel tap, and I keep forgetting to switch it to off. Do people just leave it on or is this a big no no. What the implication, carb floats get stuck and empties your tank?

Any responses appreciated.

Many thanks.

Billy

 

[redsoul]

I am probably the worst person on here to give you advice as what i know about airheads you could write on the back of a postage stamp lol.
Saying that there are posts about issues with those tyres and stability at speed.There are also posts about stability with the high front mudguard at speed.Alot of people use a metal bracket in cunjunction with the mudguard to make it more rigid.

 

[Timpo]

I will not use my R100GS over 70mph with the TKC80 tyres fitted..... I have done it twice and it gave me bit of a shock........ and I'm used to bikes moving around below me!
60-70mph does me fine and at that speed I'm enjoying the ride.....

Timpo.

 

[metropolis2k]

Agree with the blokes above. What I know about airheads will fit on half a postage stamp but TKC80s are well known for being interesting at high speeds and I think the high front mudguard will only accentuate things. Gonna face the same issue with my '85 Tenere when she's up and running but I'll get lynched if I swap it for a smaller supermoto one (even if it's just temporarily!)

 

[Beemerboff]

Float levels, or blocked in line filters, taps or carb orifices can cause the problem.

Try a dose of "injection cleaner" in the tank before you start pulling things apart.

And if you plan on fast road riding get some decent 90/10 road tires and just accept that you will have to go a little slower when you are off road - Distanzas are excellent on road and surprisingly good off.

 

[Rob Farmer]

A g/s should go straight up to a ton and sit happily at 80 MPH. It sounds as though you have a carb issue.

TKC's are terrible tyres for road use. The best tyres for the g/s are the ones designed for it Metzler enduro's 1 & 2. Have the advantage of being cheap and still available.

Mono G/s aren't that stable at the best of times. Put a set of panniers on and run at high speed and it doesn't take much to get them unstable - I've had a few scary moments with the one's I've had.

Your speedo error sounds about right.

Always turn the fuel off. They have a habit of dumping fuel every now and again if you leave the taps on.

 

[VAL. H.]

I will not use my R100GS over 70mph with the TKC80 tyres fitted..... I have done it twice and it gave me bit of a shock........ and I'm used to bikes moving around below me!
60-70mph does me fine and at that speed I'm enjoying the ride.....

Timpo.

A g/s should go straight up to a ton and sit happily at 80 MPH. It sounds as though you have a carb issue.

TKC's are terrible tyres for road use. The best tyres for the g/s are the ones designed for it Metzler enduro's 1 & 2. Have the advantage of being cheap and still available.

Mono G/s aren't that stable at the best of times. Put a set of panniers on and run at high speed and it doesn't take much to get them unstable - I've had a few scary moments with the one's I've had.

Your speedo error sounds about right.

Always turn the fuel off. They have a habit of dumping fuel every now and again if you leave the taps on.

As said above the airheads are not as stable on TKC's as the bigger oilheads. My 1200 will push on up to 120 ish without loosing stability. Though this is not something you want to do much as they are speed rated to 99mph.

The biggest issue with TKC's, is running the correct pressure. They do not need anywhare near the same pressure as conventional road tyres. You should be running (solo) 27psi in the front and 35psi in the Rear.When carrying passengers or fully loaded up the pressures by 2-3psi.

Riding on TKC's should be done with a confident and relaxed attitude. Loose grip on the bars, letting the bike have it's head. Holding on tight to the bars and trying to force the steering whilst riding on the road can offten proove to be quite unnerving and can easily put off a rider new to TKC's for good.

As Rob said, the g/s is not the best handeling bike out there. Especially when compared to modern bikes with no fule tap, as they will have significantly better, more predictable handeling than the old g/s, with part of this due to the bigger, narrower 21" front wheel.

Ridden with confidence and respect, the TKC's will work as well as any other tyre, in all weathers. However, never forget, you are riding on one third of the contact patch of a normal road tyre.

Who want's to be riding such a pleasurable old girl at 70 plus anyway? Enjoy the view why not.


Val.

 

[bumpmuncher]

Have you got both fuel taps open

 

[Rob Farmer]

Have you got both fuel taps open

They only have one..

 

[cookie]

my g/s gets pretty unstable above 70mph on TKCs, and to a slightly lesser extent, the original metzeler enduros. on the other hand, the light quick steering is what makes it such a hoot at lower speeds

i have been running them at whatever continental specify, which IIRC is way above what is suggested above. i'll try lowering it a bit and see how it goes.

ps. they may be dubious, but perfectly tolerable, in a straight line, but are unbelievably tenacious in corners

 

[Devon]

I find the high front mudguard starts flapping about and destabalises the front end above 70mph.

 

[(RIP) Proff]

I'm a WUSS can't ride on TKC's owing to excessive Sphincter Splutter..
I still use the original style tyres as fitted from 1980.
Metzler Enduro 1 front.
Metzler Enduro 2 rear.
Green lane perfectly OK and cruise @ 75/80 2 up....
Also IMHO handle superbly on tarmac......
IF you have difficulty finding any [only made once a year now] I always have a pair in stock here..
Available for what they will cost me to replace when they are AVAILABLE AGAIN..
Which is £125 the pair at today's quote....

 

[cookie]

I find the high front mudguard starts flapping about and destabalises the front end above 70mph.

that is probably a major cause. i have the high guard and a fork brace.

 

[John Roberts]

... Always turn the fuel off. They have a habit of dumping fuel every now and again if you leave the taps on.

If I park mine on too much of a slope the left hand carb will very ocasionally leak/drip, so I turn the fuel off and to remind myself to turn it back on again on my return I leave the handle of the fuel filler in the upright position so that I don't run out of fuel a hundred yards down the road.

Incidentally I only use the left hand fuel cock so that if I do run out of fuel I will still have what fuel that is left in the right hand side of the tank as a final final reserve. I could then use that by opening the right hand cock. It isn't much, but it might get me out of trouble one day... OK I know you only have the one cock (FUEL cock, that is ) but it might be of interest to others with two.

 

[VAL. H.]

I find the high front mudguard starts flapping about and destabalises the front end above 70mph.

I fitted an alli moto cross stabeliser to Jill's 100GS hi mudguard which seems to tame the front well.

She's been riding on TKC's for three years with no probs other than a gentle weave on the motorways when the bike's loaded. She recently passed the RoSPA test and the examiner said she was braver than him to be riding on TKC's.

my g/s gets pretty unstable above 70mph on TKCs, and to a slightly lesser extent, the original metzeler enduros. on the other hand, the light quick steering is what makes it such a hoot at lower speeds

i have been running them at whatever continental specify, which IIRC is way above what is suggested above. i'll try lowering it a bit and see how it goes.

ps. they may be dubious, but perfectly tolerable, in a straight line, but are unbelievably tenacious in corners

You're holding on too tight

The lower pressures gives the tyres more flexiblity, allowing more tread to make better contact with the road.

I've done 45'000 (all be it on the 1200GS which is considerably heavier) or more in all weathers loaded and solo. Boots still touch the ground and best of all they tell you when you're pushing too hard.

I get excellent milage out of them, they are a good price and I see no reason to stop using them. I think they make the bike look that bit better too.

Relax and ride


Val.

 

[MickDB1]

If its any help
I believe everything that Val says on the subject of TKcs is bang on with what I think
I can get up to 94mph on tkcs with GPS not speedo but it does become a little
F in ell and it was only for a speed test with cross winds as well
bit daft above 80 true speed I think and thats on either high or low mudgard on a r100gs and same on me PD
HTHY

 

[Kenny]

I fitted new TKC's to my R100gs and they were bloody awful above 70 mph ( did a big thread on them about a year ago ). Tried everything/settings etc but still they were s***e compared to other tyres I'd had fitted.

I'd never recommend TKC80's for an airhead now - unless you stay below 70mph.

 

[ChasF]

Strange this instability as mine seems fine. Rarely go much over 70/75 but have ocassionally whizzed up to 85mph and never really noticed any difference. This is a 100GS with high mudguard, 1.5 bar in the front tyre and a Technoflex rear shock

 

[Rob Farmer]

Strange this instability as mine seems fine. Rarely go much over 70/75 but have ocassionally whizzed up to 85mph and never really noticed any difference. This is a 100GS with high mudguard, 1.5 bar in the front tyre and a Technoflex rear shock

Thats because you have the superior Paralever. If you had the early, unstable at high speed, g/s I'm sure you would be telling us a different tale

 

[cookie]

You're holding on too tight

i'm not.