dadof2

A linkless system does give a rising rate based on the shock angle, rear wheel travel and spring stiffness. The rising rate is near linear. The linkage system gives a rising rate which increases at a greater than linear rate as the spring compresses. Different sections of suspension can have different rising rates, This makes the suspension more effective over a wider range of travel. Using compression oil damping to give a rising rate effect has the drawback of putting a lot of energy into the shock oil which would cause overheating which is difficult to compensate for.

#17 Clearly Nigel you do not appreciate the difference between value and and affordability. The first part of my post concerns value, the latter affordability. I will probably book tickets in advance this year but I know of quite a few who are unable to do so, for reasons such as their working pattern is not known that far in advance. For example I only found out this morning that I would not be expected to work on 2 of the 3 days, however that could still change although unlikely.

With regard to #221 and #222 I feel I can sum it up with risking keyboard fatigue failure Res ipsa loquitor as the Beta engineers may say. Such failures are inevitable given the constant drive to make bikes lighter. The first time I saw the lower bearing housing stiffener on the outside of the headstock I suspected GG were building this area pretty close to the minimum strength limit. The upper and lower frame tubes are connected to the headstock bearing tube over a relatively short distance, similar to 348 montesas that also suffered from similar failures.

The comment containing the word pessimist was in response to Steve's previous post containing negative. I do not wish to partake in ACU bashing but there are some points worth making. It is not a voluntary organisation, it has paid staff and levies fees. In my view all the controlling bodies have failed to address some key issues, including Noise Land access The difficulties of running road trials as they are grouped with speed events. It is a pity that as yet no one has posted a breakdown of the costs that make up entry fees.

Oven cleaner and pressure wash works pretty well. Centre section does have to be cut apart. Lack of centre section packing is often why and older bike never quite runs as "softly" as a new one.

I had a 75/76 MAR for about 14 months and apart from a broken rear wheel spindle it was completely reliable. There are are number of solutions to this common problem, look on Ossa forum. I would say it was not quite as competitive as a Bulto of the same era, but should not be an issue at twinshock trials. I know a very small rider who also had one, he did OK on it but found a 200 montesa more suited to his size.

If you are a pessimist it makes you optimistic because things can only get better, on the other hand optimists who only look on the bright side are in for a nasty surprise some time.

When I first saw the shock on the side I did not like it. I felt it would be more likely to get bent if the bike was dropped, a bit like on old twin shocks. This has not proved to be the case. However I do know a couple of Jgas riders who found the inside of their heel rubbed on the linkage, and could get a bit sore on a long trial. There is easy enough metal on the linkage to slim it down a bit. My preference is still for a shock mounted centrally and as low as possible.

That -25 temp made me think back to the original bore / piston damage. Could the bike have been cold seized at some time? A cold seize usually occurs when the bike is worked hard (even very briefly) immediately after the bike is started in cold weather. The piston heats up fast and expands before the barrel has time to warm and expand. In some cases the effect is that the inside of the barrel expands inwards unevenly as it warms because it is constrained by the still cool outer barrel. I have known this to occur even at UK winter temps of about 5 to 6c so I would think it could easily happen at your much colder temperatures.

These "face cam" cush drives used to be common especially on single cylinder british 4 strokes. Some consider a primary chain (rather than a gear) also gives the gearbox an easier time and gives more grip. Wonder if any trials engine manufacturer has ever experimented with different drive cushioning systems to see which gives most grip at rear tyre?

Considering the financial risk the Penrith organisers are taking and the effort, time and skill involved then the ticket prices are perfectly reasonable and many would think that to see the best in the world close an absolute bargain compared to the F1 GP or premiership football. Having said the above I also agree with the poster who feels the cost of a family attending the event is too high. I believe there is a good argument for allowing a second parent and non earning children in at greatly discounted rates.

I apologise in advance for posting what would be more appropriate in a general or GG section but some of the comments cannot go unchallenged. What I have written is fact not bollocks. I cannot predict when a Pro gearbox will fail and that is why it would be foolish to enter a wager. What would be obvious if a statistical study were carried out is that a Pro gearbox is more likely to fail than any other current trials bike (perhaps except Ossa). Frequency of failure. I have not mentioned frequency (as in over a period of time). In the case of the riders I mentioned who have had 3 (possibly more) Pro gearbox failures both had a couple of failures in about 2004 / 2007, they then gave up on GG for several years. One tried a Pro again in about 2011 / 2012 and its gearbox failed. The other tried a Pro again late 2013 and its gearbox had to be rebuilt recently. I also point out that of all the Pro gearbox failures I have known only 2 have occurred during a trial and in both cases the bikes could be ridden back to the start field. I am quite happy to accept that ND and Balidlocks have been more fortunate with their gearboxes but I expect they will in return accept what I say is accurate. I also point out that I am not commercially involved with any manufacturer and have no reason to make spurious posts. I am pretty certain if anyone looks at my post history they will realise I criticise any marque where I feel criticism is due. People will always have different opinions, as the recent posts on Penrith WTC ticket prices show but what does degrade the forum is when people make untrue assertions, misquote other posters or resort to personal attacks.

#283 I will repeat my comments as often as I feel appropriate. It was you who used the example of a Normandale round as an example of reliability. I know several riders who ride a few of the Northern Normandale rounds and they all have one thing in common, they have had at least one Gasgas gearbox failure, 2 of them have had 3 Gasgas gearbox failures the most recent being on a late 2013. These riders have other things in common, they are all mature, reasonable or professional mechanics, are light on the bike and have never had gearbox trouble on other marques. Gasgas know they have a gearbox problem but their idea of a "fix" was to make it easier to change some of the components, not the substantial redesign it really needs.

Hillary #8 Let me start by saying how much I enjoy the chips & burger freebie we observers get at your trials, pity the midges occasionally find us so appetising as well. Could you give us a breakdown of where the £17 typically goes? Some are probably aware of the bad feelings created at a Northern centre club last year when a portion of the entry fee was going to what many thought was an inappropriate place. I agree that trials still is a cheap form of motorsport but it is a fair question to ask why £17 for a ride when an autograss entry is £9. One bloke I know who also has 2 kids and moans about entry fees spent close on £60k on a tractor. If a portion of my fees is used to fund the purchase of land (as is case with WMC) I have no problem and would be willing to pay a bit more, but if it just disappears into an ACU black hole then I do not like it one bit. I think it would be in the late 70s when TT was still, or had just ceased to be a word championship round that there were pretty well substantiated rumours circulating that the ACU was using receipts from off road biking to subsidise road racing to the tune of about £100k per year.

http://www.autograss.net/AutograssReviewOld/how_to_start.htm Take a look at the above, Initial license and club membership a bit more but entry fees under a tenner. I can go to a practice night at the local Kart track and for £110 hire 3 karts with all the gear for the whole evening. Although its called practice its pretty well racing without a mass start. The time in the kart will be a fair bit more than the total in section time at a trial. Yes trials is still a fairly cheap motor sport but it is no longer as cheap compared to other activities as it used to be. As a rough estimate I would say that entry fees for karting, mx and trials have increased nearly 10 fold, but over the same period that wages have increased only about 5 times. If bike dealers and anyone else whose living depends on sales to competitors want to make a decent living, then they need more potential customers, the lower the entry fees the more likely it is people will be attracted to and stay in the sport. This is not whinging, its just as it is.

http://www.ydgla.co.uk/Latest_News.htm I suggest reading the above link as an example of what we (off road motorcyclists) are up against. Totally agree with Johnnyboxers post. I cannot remember the name of the consultants whom the labour government engaged prior to the Crow and Nerc acts. The conclusion of these consultants was that recreational motor vehicle use had very little or negligible negative impact on green roads. Agriculture and Forestry vehicles did far more damage. Yet the government and in particular Alun Michael (now fortunately dead) ignored the research. Properly regulated vehicle use is actually beneficial on green lanes, it keeps the open and free from excess vegetation and other obstructions.

http://listings.findthecompany.co.uk/l/167143144/Northern-Centre-A-C-U-Limited-in-Kendal-United-Kingdom See the above £81,000 net assets. I do not know what these assets are or if they are available to spend on land for MX or trials. What I have been told by what I believe to be reliable sources are that quite a few clubs are sat on quite a lot of money. Those who have told me this are of the opinion the money should have been spent on land and tracks. Over the years I have given quite a bit of time (and am happy to do so) to observing, setting out, collecting in and flag making and a bit of secretarial work. It would perhaps be a good idea if results sheets had a breakdown of where the money went, EG Payment to landowner(s) ACU fee Insurance Flag / consumable costs Club funds Observer food / gifts. I ask that organisers keep entry fees to the absolute minimum. As my forum name suggests it is not only my entry fee I have to find. Despite being relatively comfortable financially I have not entered as many events as I might had the fees been lower, multiply everything by 3 and the sport becomes quite expensive. I know of other families in the same situation and frequently the preference is a days practising with friends rather than entering an event. I also know of some dissatisfaction at fee levels for nationals where the clubman fee is the same as the national championship fee. The response of some clubmen (who could easily afford the championship fee) is to ride elsewhere or practice instead as they resent this, particularly as they fee they are used as "slime scrubbers" as well. "Fook that for a bunch of coconuts" was the actual phrase used.

For measuring my 2t oil I use 100 ml syringe (about £5 to £6 for 2 on Ebay). Take plunger out then put my finger over nozzle, Pour in 2t oil to right level then put nozzle over fuel can as I pull my finger away. Leave to drain and flush through with petrol to get all oil out. I would never go as lean as 100:1 let alone 140:1. The Ossa has a metal fuel tank and as such will suffer from water condensing inside it on cold nights unless it is brim full. Synthetic oil can be badly affected by quite small amounts of water, much more so than mineral oil. The photograph of the crankcase mouth is revealing. Note the machining mark on the right hand side transfer port that is not visible on the other side. Looking at one or two other areas its looks as if these parts of the transfer ports are mismatched, a sign of poor quality control which does not bode well for the barrel port quality. It might be worth getting a two stroke tuner to check and blueprint the ports.

Could it be clutch rattle or waterpump bearing?

I am not speaking from personal experience here but I have heard that sheep can escape from wellies a bit easy but once a boot is clamped up there is no escape. As for not clobbering things at 40mph on trials bikes that's not quite the case round here. Quite frequently we do over 25 in bracken, heather or rushes that hide rocks and all sorts of obstacles. I have had to have toenails removed and have torn ankle and foot ligaments as a result of hitting hidden items.

The Beta manual says 25:1 for mineral oil and 65:1 for Bardahl VBA (a high quality viscous synthetic) Oil mix ratios are often cause of disagreement. I run at 32:1 on good quality synthetic oil which is too rich for many peoples liking. If you look at the labels on most oil manufacturers bottles they do not advise leaner than 50:1. To a large extent it depends on how you are going to ride the bike. Autolube systems give about 100 or 110:1 at idle then richen up to 25 or 20:1 at full revs and full throttle. Tyre pressures depend on your weight and how much you want to risk punctures and sidewall cuts. I suggest 5 to 6 in front and 4 to 5 in rear as a starting point although quite a few riders will go a good bit lower than this.

I have never owned a 4RT but those I have had a go on have started dead easy, just a steady push that spins the engine. For lights use the standard lights and rig up an additional separate rechargeable battery and high power led cycle front light.

The Beta is 2 years newer and at this time 125cc development was quite rapid. The Beta has quite a bit more power right at the bottom end, not that it has a lot but the Sherco has virtually none. Nothing much wrong with Sherco, what have you heard? Beta may have case corrosion issue and Gasgas prone to gearbox problems.

200 hours is very little for a piston / bore. What oil and mix ratio are you using? Also previous questions regarding filters and airbox?

A few thoughts on Braketec performance issues. There could be variations in manufacturing quality, perhaps a batch where the tooling was at the end of its life or unexpectedly damaged. Certainly a few years ago some Braketec parts were full of machining swarf and had sharp edges on ports. Even if the callipers and hydraulics are spot on and identical their performance can vary from bike to bike. Factors like mounting angle, fork flex, brake disc type and mounting all play a part. I have 2 DOT 4 fluids with identical spec. One is Castrol motorcycle racing brake fluid and the other is Halfords own brand. The Halfords fluid is slightly less viscous (i think to give fast response in ABS). The difference in the feel at the brake lever is very noticeable depending on which fluid I put in.