GB250 Handling peculiarity.

[TrickyMicky]

Greetings one and all.  I have owned my GB250 Clubman for just over 1 year now, and most times it is a joy to ride, BUT, very now and then it develops a peculiar feeling as though there was a gyroscope running, meaning that it is not that keen to change line without being forced by more body movement than normal.  It only does this now and again, and it only lasts for about a minute.  It went for its Ministry of Transport yearly safety inspection about 6 weeks ag and passed with flying colours, and since then I have crawled all over it checking nuts & bolts, steering head bearings, wheel bearings, swinging arm, tyre pressures, and cannot find anything amiss.  I'm stumped, unless there could be an invisible tyre problem.  Any help folks???  Thanks, Mike.

[xbally]

Just seen this. I don't profess to be any kind of expert but having owned and ridden many motor bikes for nearly 50 years now the 2 worst handling problems I've  had were 1) caused by a worn front (old style Avon roadrunner tyre on a Superdream) which pitched and rolled nearly throwing me off when I was riding up a rutted / potholed country lane on the way to work in the 90's. (2) The other time was in the early noughties when I had a full tankslapper on a 600 Hornet at speed and I believe this could have been caused by the front wheel bearing not being fully located in its housing after powdercoating. Fortunately for me I managed to regain control more by luck than any riding skill and was able to slowly reduce the speed gradually. This probably isn't much help but may provide food for thought and I'm sure other more knowledgeable posters will be along soon with comments and advice. You seem to have covered all the usual areas for potential faults. Both my bikes were as far as I was aware in good useable condition and IIRC  had passed their previous MOT's without anything adverse being flagged up.

[Moto63]

Yes I would tend to agree with Martin with his first encounter. Dodgy front tyre, is it an old tyre? Was the tyre already fitted to the bike when you bought it? If so the compound may have hardened up through lack of use, especially if you’re not riding the bike often. I’d go with changing the tyre. Again like Martin, I don’t claim to be a tyre expert but have definitely suffered certain issues over the years through old tyres that have gone hard through being stood.
Hope this helps... best of luck with it 🤞
Cheers, Michael

[TrickyMicky]

Thanks for all the tips fellas. Now they tell me that confession is good for the soul, so, hopefully you will understand when I tell you that even with just under 60 years of motorcycling, it is easy to miss the bleeding' obvious!  I purchased the bike with 8500 miles on the clock, which I thought for a 35 year old bike was a dream. Having crawled all over it I found nothing wrong, even being impressed by the fact that the tyres were hardly used, having still got all the little pimply bits on. Conti 'Go's' as it happens.  When I mentioned the problem to the man who fits my tyres and rebuilds my wheels, his first reaction was "How old are they?".  "Check the date marking" he said. "What date marking" I replied.  Following his instructions, I slowly turned the wheel to find a marking that indicated that the tyres were 11 1/2 years old! WHOOPS!  Am now just waiting to have new Avon Roadriders and Michelin tubes fitted.  Will report hopefully good news. Mike.

[TrickyMicky]

GB250 handling update. So, having castrated the piggy bank, new Michelin tubes and Avon Roadrider tyres have been fitted, along with new rear chain and sprockets. Wheel bearings and swinging arm bushes all checked, all good.  Went out for a 100 mile Round trip on quiet roads to settle the tyres and chain.  20 miles from home and the bastard did not want to go round corners again, plus now, it was not too keen on holding a straight line.  Into the garage, placed on centre stand, sat my arse on the pillion part of the seat to raise the front wheel, and just very lightly using fingertips on the bar end weights, it was possible to detect a detent in the straight ahead position.  New steering head bearings now await fitting.  In the past, I have had bikes  with shagged bearings, but as they never handled that well even when perfect, I never experienced this degree of deterioration on the handling department. Every day is a learning day eh?  Stay Safe. Mike.

[iansoady]

A few years ago I bought a Guzzi V50. Riding it home I thought I'd made a terrible mistake as it refused to go into bends and once forced over didn't want to get up again. I discovered that the head bearings had been tightened down by someone with far more strength than knowledge.

Fortunately when adjusted correctly there was no brinelling and the handling returned to what I expected. I bought the bike off a young lad (who actually worked for triumph in Hinckley) so hope he wasn't on the engineering side........

[Itsme]

I have been chasing a bit of handling oddity on my Inazuma and now have more or less sorted it, just waiting for new tyres to be fitted as the ones on the bike are 9 years old. I have come to the following conclusions; tyre pressures and road surface can affect old tyres as can wind strength and direction. Riding position can affect handling and putting weight through one foot or the other on the footpegs can stabilise a bike which seems to be wandering.

However what you are describing almost sounds like occasional mechanical interference, e.g. something catching on something else and physically preventing the forks from turning in. I once had a steering lock pin that worked loose and prevented the forks from turning fully to the left whilst riding, that was a very scary moment. Have you checked things like cable runs, any brackets that run close to the forks etc? I would give a bit of thought to what could impact on the forks or wheel as they turn and have a look at that stuff.

Hopefully you will sort it soon as the GB250 is a cracking looking bike.

Ian