dadof2

Birks had a shedful so rumour has it.

Unless it has been modified it almost certainly uses regular unleaded and handbook (if you can find someone with one) should give actual minimum octane number. All my Hondas of that era used regular unleaded and I think 95 octane minimum. There is a chance with TLR 200 that compression has been raised in which case higher octane will be needed. Of all the small cc Honda trials bikes I knew non were unmodified as they were a bit short of power as standard. If it is un modified octane boosters will reduce performance.

When I wrote "The specialised trials bike era probably started with the late 1960s Bultaco developed by Sammy Miller." I chose my words carefully inserting probably and era. Sure there were marques like Greeves and other specialised one off or small batch trials models prior to the late 60s but many people would regard that a significant change in the sport took place with the introduction of the Miller Bultaco. It heralded a new type of mass produced specialised trials bike that effectively ended the big road bike type 4T bikes and limited production specials that had gone before. With this bike Miller pretty well established the modern trials bike format regarding general layout, wheelbase, wheel sizes and weight distribution that remain to this day. On the subject of rim / tyre sizes when were 19 inch rims discontinued? I know in about 1974 I could not get a 19 inch rear trials tyre despite quite a search at local tyre dealers (pre internet era for our younger readers)

Full or semi synthetic best for trials. The castor based "synthetics" like A545 and A747 only have an advantage at the extreme limits of lubrication. At the limit non castor oils thing out and evaporate of meaning no lubrication. At this limit castor oils thicken and char preventing metal to meta contact, or at least trying to

Whether it can be decently welded depends on the exact alloy composition. I would keep it in near boiling water + janitol heavy duty degreaser at 10 or 20:1 for several hours at least. Then try welding one of the small cracks. Cut out using a carbide burr then weld using 4043 filler. Big problem with high % magnesium castings is cracking on solidification and cooling due to very high coefficient of thermal expansion. Yam TY 250 ignition cases are effectively un weldable whereas TYZ clutch cases weld quite readily, you just can't tell till you try. I find JB weld to be the best of the epoxies but some get very good results with Devcon.

Apart from stipulated tyre sizes and tread patterns (I don't know exact date these were introduced) pretty well any thing could be modified. Reducing weight / removing un needed parts like sidecar mounting frame lugs. Swing arms were changed to fit different shocks and accommodate 4 inch tyres. Probably commonest mod was to move footrests up and back and change them from rubber to serrated steel. A few would change headstock angle or change yokes.

Apart from stipulated tyre sizes and tread patterns (I don't know exact date these were introduced) pretty well any thing could be modified. Reducing weight / removing un needed parts like sidecar mounting frame lugs. Swing arms were changed to fit different shocks and accommodate 4 inch tyres. Probably commonest mod was to move footrests up and back and change them from rubber to serrated steel. A few would change headstock angle or change yokes.

Yes posts have gone a bit off topic - blame Dabster for bringing EFI into it. To get back to original topic my impression of the relative results of JD and JF was based on the years 2012 to present. Up to and including his last year on Beta JD seemed to be closing on JF and top 3 just needing a bit more consistency to maybe be in top 5 overall. This year JD seems to be slipping back to 7th or even 8th whilst it seems likely JF will be 3rd or 4th.

Quite a rapid and substantial response to my initial post. Some seem to have mixed up the cables vs hydraulics debate with discs vs drums. I certainly favour discs over drums. My view is that for the very few top riders hydraulics probably give a degree of control not available with cables but this extra control is not so applicable to non stop sections. My overall preference is for cables, lower initial cost, lighter, more robust and easier to fix in the field. We still use cables for the throttle control, pretty important in trials. No sign of a potentiometer on the twistgrip even on Vertigo, Ossa or Mont / Honda.

Putting it very simply and briefly its as following summary. Initially trials started as a test of reliability and capability (mainly hill climbing) for road bikes so manufacturers could show whose was "best" Somebody will probably correct me but approximately the last time minimally modified road bikes were the norm would be the late 1940s or very early 1950s. The specialised trials bike era probably started with the late 1960s Bultaco developed by Sammy Miller. The mods between say 1950 and 1968 generally consisted of lowering the gearing, lightening the bike, raising ground clearance and fitting rims suitable for 18 inch rear and 21 inch front off road tyres. On 2T engines the porting would be changed to make the power characteristics suitable for trials (compared to road or MX porting)

Just having a bit of the joke about the train, its generally fairly reliable and punctual. Its one of those 2 carriage Northern rail thingies with diesel engines underneath. Don't know if it EFI or mechanical injection. The "cow" scoop on the front is a flimsy plastic thing, could do with one of those iron girder jobbies like the old cowboy & indian engines. Give me sir Nigel Gresley anytime.

Dear English Electric, could you do me a favour. Just pop out and fix the 08:53 Carlisle to Leeds train. Seems this supposedly reliable FI device has broken down. I am now sat twiddling my fingers at Carlisle. Should have taken my reliable carburettored road bike. PS last week I had to call the wife out to collect me with the car because the train ran into a cow, probably be leaves on the line followed by the wrong sort of snow next.

Since its been implied I am a luddite (regarding EFI) and the number who have problems with hydraulics I thought I would start tis thread. Do we need hydraulic brakes and clutches on trials bikes? I have never had to retire from an event either trials or MX because of a cable failure. I have had retirements because of damage to hydraulic parts as do several others I know. Quite a few seem to struggle with brake hydraulics in particular, but I would think most could fix mechanical systems much easier.

I may put more on the EFI vs carb or other threads but briefly: The problem of fuel leakage from or water ingress into a carb can be sorted easily and cheaply. EFI precise fuel metering? In theory yes with an oxygen sensor in the exhaust and steady running. In practice on a 2T probably no because the residual fuel / oil mix in the crankcase will override the fuelling settings on initial pick up and during varying throttle conditions typical of section riding.

"Road Racing is huge with massive sponsors and an even bigger following and audience with every boy racer with his Rice Rocket on our roads wanting to be the next Rossi, hence the TV Company's wanting to broadcast it, even Mr Honda can see the value in that?" I have been to 4 popular road bike meeting venues recently and there are very very few boy racers, middle age to geriatric being the vast majority MAMIL mania seems to be taking over. I am pretty certain the newish learner laws are hitting trials and road bike uptake quite severely. My guess is WTC will struggle on in some form.

Getting a bit off thread but need to state that I have no anti Vertigo agenda, I wish JD, DL and the Vertigo every success. I just believe that EFI is an unnecessary complication whatever 2T off road bike it may be fitted to.

For peace of mind I would get a second opinion from an experienced mechanic or measure con rod movement by a specified method. Depends how much use your bike has had and what sort of use / care but 2004 big end could be getting a bit tired. Any doubt and it may be better to replace it and the mains. Even if big end does not fail suddenly bits of bearing cage can break off and wreck piston, barrel and head.

Another masterclass from the Dr today, big congrats to Danny Kent as well.

Just thought I would mention a couple of recent incidents (tools & equipment, about £20,000 per theft, not bikes) I am aware of regarding theft where CCTV was fitted. In one case the police were called whilst the theft was in progress but they parked on the wrong roads and the thieves escaped. In the other the thieves wore balaclavas and disabled the CCTV. However in both cases the CCTV contains plenty of evidence, vehicle types, size and build of thieves etc and the Police are in a far better position than they would have been without CCTV info.

Is your bearing gone or has the outer race come loose in the alloy?

FYI. Two of my bikes have fat bars, one braced Renthals and the other braced steel. I sold two of my bikes recently and they had braced Renthals. Baldilocks - The bar with the end blanked off does protect the throttle tube more than an unmodified bar end. Sometimes I wonder what motivates posters on TC. I merely suggest I have a preference for a certain type of bar and get all sorts of insults, What next, capital punishment for suggesting a different grade of oil?. My preference for steel is based on near 40 years experience. I have never had a steel bar break unexpectedly yet this has happened to quite a few alloy bars, sometimes with painful results. I still have scars under my chin from alloy bars breaking in late 1970s. The way to fit 7/8th bars to fatbar clamps is with curved aluminium shims. I think Renthal used to supply these shims.

Regarding recent BTC, Would Roberts have beaten Dabill if they had both been on Beta? Disregarding Fajaro for a moment, I still have a suspicion that Dabill would have been more likely to have gained a top 6 WTC place on a Beta than on the Vertigo although he has had a very good single lap on the Vertigo. Be interesting if he were ever to compare the bikes from a completely neutral position.

Honda FIM conspiracy? They don't seem to be having the same luck with the FIA. I have to laugh at the latest Honda advert "Honda, the power of dreams". Honda dreams of power more like.

My impression was not based so much on the end of year WTC standings nor had I studied results in detail. I just felt on average Jeroni had moved nearer the front at most events this year whilst JD seemed to have moved back a place or two. It is not a criticism of the riders, just a casual observation. SSDT is too different to be considered alongside present WTC.

For those of little understanding. When you drop a bike on the clutch lever side the ends of the bar tend to punch through the rubber grip. If you braze a disc of metal on the end of the bar the grips stand up to crashes far better. Also if the end of the bar is open crap can get in and work its way over to the throttle side spoiling the throttle action. Brazing a disc onto throttle side is for same reason. You braze the discs on and polish it smooth before fitting the grip or throttle assembly. The OD of the disc is slightly less than OD of handlebar. I have found alloy bars braced and unbraced more likely to break off unexpectedly than steel. Also alloy bars are not knurled and are more likely to rotate in the clamps. Large diameter bars such as akront or tapered are better but still not as robust as welded brace steel and they are far more expensive. Another advantage of steel is that if you do bend them slightly they can easily be straightened by heating with a gas welding torch. Once heat treated alloy bars are bent they are not safely straightenable and are very likely to crack unexpectedly. http://motocrossactionmag.com/home-page/10-things-you-need-to-know-about-handlebars