dadof2

Find someone / machine shop with a lathe. First turn the part with the O rings on but leave a large end where the elbow is. Drill and tap (1/8 BSP) and you can then screw a standard pipe nipple in. If BSP tap not available then turn both parts out of brass and solder them together. You might find someone at your local technical college can do it for a few £ If you go to a hydraulic or pneumatic fittings supplier the may be able to tap a hole in you existing fitting and screw a new elbow in. A few years ago I made a similar fuel filter connector for my car as list price for part (a bit of pipe with banjo fitting) was £139 + VAT.

I think there can be a grip problem when riders move from 2 stroke to 4 stroke. Although I have had a lot of time on 4 strokes near all my competition experience is on 2 strokes. I have got used to the firing intervals you need to keep above to prevent stalling. When I ride a single cylinder stroke I half expect it to stop at any moment because of the lower firing frequency at the the same RPM. This is possibly why some ex 2T riders are inclined to rev them more and loose grip, they tend to subconsciously expect to ride 4T at similar firing interval to 2T. My instinct is that 4T is inherently a better gripper. It would be interesting if a physicist / engineer could devise an objective test to determine whether 2T or 4T had the best inherent gripping capability. I remember the 2T Moto GP era when the firing strokes on 4 cylinder engines were timed to give similar power characteristics to a single large cylinder, resulting in improved traction and tyre wear.

I am near certain the manufacturers recommendation is 20w-40. 75 wt gear oil should also be OK as should 10w-40. ATF is in my opinion too thin. ATF is designed for hydraulics, epicyclic gears and self or power activated clutches, not manual transmissions.

Mix ration is probably more important than make, pick one with the FC or preferably FD classification

mikuni should be ok try dellorto uk

I would try to find photos of what it should look like. The middle section is steel and the rear section is aluminium so they can't really be welded together. I would guess the cost of new ones would be well in excess of £100 each. Once you have the photos take them to a sheet metal worker who can MIG or TIG weld thin steel and TIG weld thin aluminium. You will need to dismantle (by removing the rivets) and thoroughly clean the tail pipe first. I would probably have charged 3 to 4 hours for such a repair and nothing or very little for materials.

The FIM minimum weight limit got me wondering, what is it makes a trials bike manufacturer a success AND commercially viable. Greeves, Bultaco, Montesa (original) Ossa (original) Merlin, Mecatecno, SWM, Aprillia, Yamaha, SWM, Suzuki and probably a few more that don't immediately spring to mind all went bust or pulled out of trials despite producing decent and in some cases WTC winning bikes. What went wrong? why did they fail? What lessons can the newer manufacturers in the sport learn from others past failings?

Wow, that's really amazing, I never knew they had blue estate cars in Brazil. Thanks for interesting video, looks a bit like a DIY version of a Rokon.

http://www.offroadmart.com/category/305/PETROL-TRIALS-BIKES-FOR-SALE/listings/1608/2014-Montesa-Factory-Repsol-4RT.html

Wow, light the blue touchpaper and stand back as they say Steveo, not jumping to any conclusions at all, I just rather like the Einstein quote as it highlights that different people can have different ideas of common sense. You Antipodeans certainly seem to like your light bikes. If there was widespread desire for light technically advanced bikes why are'nt Ossas and Jotagas selling in larger numbers? I don't have any sales figures to confirm my thoughts but in my area there seems to be a drift towards Montesa Hondas as people perceive them to be solid and reliable. 4RT ownership is definitely on the increase despite a scarcity of dealers. Something I need to reply to is that that some of the replies to my post contain quite blatant inaccuracies. I am not going to go through them all but it would take too long so I will stick to a few examples. 1) Seals cost far less than bearings and if properly specified and greased last for many years. I recently bought about 800 seals of various sizes for about £25. One set of linkage bearings can be £60 to £100. 2) My proposals will kill the sport? What will kill the sport is unfettered technical development, bikes you can't fix at home and high costs. 3) Jotagas have demonstrated that it is possible and cost effective to make ongoing component changes in small batch sizes (50?) Plenty of manufacturers have killed themselves off without any restriction on development - I will start a new post in general trials talk on this Incidentally I have been involved in the manufacture of lightweight components to improve performance in speed events. These included a lightweight aluminium framed seat (to replace perforated steel), titanium wheel spindles and fasteners (to replace steel) , lightened hubs and low friction bearings and lubricant. This helped set a British mile record near York in the 1980s.

"Common sense is the collection of prejudices acquired by age eighteen." (Albert Einstein) Let me make it clear that I do not favour increasing weight just for the sake of. The reason I am in favour of a weight limit of around 74 Kg is to increase reliability by making some components less fragile. Just have a look round some of the bike specific forums and it is easy to find plenty of examples of where a bit more metal would have made breakage less likely. Also it removes the need for expensive lightweight materials. Even the F16 fighter was designed to minimise the use of titanium and carbon fibre to keep costs down Nor do I look back on heavy bikes of yesteryear with rose tinted glasses. Many of the pre 1995 bikes had faults, Mont frames used to break at the headstock and their gearboxes gave trouble, Bultos chassis welds cracked, the chrome came off the brake drums and bearings came loose in the hubs. Ossas brakes used to give up at the sight of water and their sump bungs could punch up into the gearbox. The peak of reliability was probably the late 1990s to early 2000 with bikes such as JTR gassers, TYZ yams and Mont / Honda 2T Cotas. But all these weigh around 85 to 87 Kg. Take a look at the Beta and Gasgas SSDT preparation guides, and JS Jnr.s comments. It is pretty well acknowledged that modern bikes have become fragile. A weight increase of a few Kgs particularly when most of it would be concentrated low down would not be that noticeable, probably not at all to most riders. Until the present limit designers have had to concentrate on reducing weight as their primary goal. Increasing the limit will allow them to make improvements where presently they may have to compromise to keep weight down. Instead of a race to the bottom weight wise, development will be able to concentrate on reliability, suspension improvements, torque characteristics and any other area they think will give competitive advantage. It will also enable manufacturers to re design and strengthen parts that have proved to be too weak without having to worry about the extra weight. As in previous post not all done at once but introduced gradually over several years. I would not apply the limits to arena / X type trials leaving manufacturers free to modify bikes for these very specialised show parts of the sport. The following is what I would like to see done and why. 1) Sprockets to be free from holes, increase safety, increase strength, reduce manufacturing costs 2) Discs to have minimum thickness specifications, continuous inner and outer radii, No drilling in rear disk pad area and limited drilling in front disc pad area. Reduces manufacturing costs, reduces wear rate, reduces chance of breakage 3) Front and rear brakes to be restricted to 2 pistons per caliper on same axis. Reduces manufacturing costs 4) Set minimum weight limit for rear shock linkage and maximum bearing stress rating. All linkage bearings to have secondary oil seals and be fitted with grease nipples. Would be slight initial cost increase but more than offset by increased reliability, less breakage and easier servicing. 5) Ban the use of titanium, magnesium and carbon fibre. All materials including plastics to be readily weldable grade. Reduces cost makes parts repairable. 6) Specify minimum thickness and weight for sump guard. Sump guard to protect rear suspension linkage, underside of frame in footrest mount area and extend a specified distance up sides and front of engine. Would be an increase in manufacturing costs but long term saving on damage to other parts and increased reliability. 7) Specify a minimum coolant capacity and require a see through header / catch tank and “boil vent tube” be in easy view of the rider. Specify a minimum kW rating for the radiator. Slight increase in cost but increase in reliability. 8) Specify minimum thickness for engine casings. Slight increase in cost but less chance of breakage and quieter. 9) Specify minimum widths for gasket faces, slight increase in cost but greater reliability due to reduced chance of leakage 10) Wheel and swinging arm spindles to be steel with standard locking nuts as appropriate. Reduces cost and increased reliability. 11) Specify minimum fastener diameters particularly on sump guards, sub frames, engine case, exhaust mounts and frequently removed items. Increase strength, increase reliability, reduced thread stripping 12) Specify a minimum seat height about 60 mm higher than present. Aim is to allow more room for better air filtration and silencing. 13) Specify minimum material thickness for exhaust parts to increase resistance to crash damage and reduce noise. 14) Fork sliders to have minimum thickness. Increases resistance to damage or breakage. 15) Fork stanchions to be steel, readily re platable and the sliding area fitted with protectors 16) Adjustable forks not permitted. Damping can be varied by oil viscosity changes and various springs offered to suit riders weight. Reduction in costs Another area that needs regulating is EFI / ECUs. OBD II was introduced for road cars ad even F1 uses standard ECUs. Should the weight limit be applied to Clubmen? My feeling is it won’t be necessary. The older lighter bikes will wear out and become obsolete. Just apply it to WTC, new bikes and championships I know I will get a fair bit of criticism from some regarding this post but I know many riders in the north of England would welcome such changes. The topic of discussion at events and practice sessions is not about bike weight, it is about poor reliability, easily broken parts and high parts costs. Obviously the situation and opinions may be different in other areas of UK or other countries.

F1 and sense is not a combination that springs to mind All the drivers are having to become skinny midgets to be competitive, no more Mansells or Fangios. On the subject of minimum bike weight I would be in favour of FIM gradually increasing weight say by 0.6 to 1.0 Kg per year until it reaches 74 or 75 Kg.

I don't think you would go far wrong with a Beta 2T, 250, 290 or 300. plenty of good bikes around £3k and over

Try Beta USA website, it has a lot of manuals / downloads / technical info

Just a suggestion - I think Sammy Miller will know someone

On greasy grass / mud between limestone rocks I found the 4Rt gripped better than my gasser. Just copy Bou's technique he usually outgrips the strokers.

It is meant to build up pressure when its hot, just top the coolant up again

Hi again Splitting one wire into two will not work. Can you post a photo of the stator. Once someone has changed something from original tends to be best to go back to the start. DC made from single phase AC (which is what you have with one wire) would certainly not be ideal to power a DC fan motor.

GGs seem to be stressed in this area, I have seen a couple where to steel frame that connects under the back of the engine has broken rather than the crankcases

My Suzuki 1100 has valves to pressurise the front forks and I understand the new Honda MX bikes have air (spring less forks) Removing the sprigs, fitting Schrader valves in the caps, and using air springing was an effective modification on Honda TL 125s as the standard front end was pretty crap

One of the big differences between budget and premium grades of branded petrol is the amount of costly cleaning detergents they contain See http://en.wikipedia.org/wiki/Top_Tier_Detergent_Gasoline In UK shell V power and BP Ultimate contain larger % of cleaners and if you use these better fuels no additional cleaner is necessary. I ask that other forum users write to their MPs asking that fuels (and pumps) be labelled with exactly what the fuel contains. Food has to be labelled with contents, why not fuel. There are a number of parties asking the government to label fuel properly, including ethanol content.

Polish as much of the roughness off as you can with wire wool. Look onto simply bearings website, then adhesives, then truloc superfit 211 bearing fit. Also fits seals to housings I find blue Hylomar works OK as well

Bike trader and other comparison websites, cheapest we got recently was about £235 on a 50 cc

Pro crankcases used to be weldable metal, its about 3 or 4 years since I did some. TIG with 4043 filler. As well as thoroughly V ing out the crack and filling it with weld add some reinforcing plates if possible.

As I said I am not familiar with 311 electrical system but from what you have said I guess it will have 3 to 5 AC generating coils to power the fan and lights. These will produce AC from about +/-10V at tickover up to over +/- 60 volts at high revs. THis power goes through the rectifier where the negative parts of the AC are flipped over to give a ripple DC voltage. The separate regulator then "clips" the tops off the voltage ripples at about 15 V leaving a near steady 12 to 15 V DC to power the fan. If the regulator has failed or is not earthed properly it will not clip off the high voltage that will then burn out your fan. The earthing arrangement varies depending on type of regulator, sometimes its via regulator body / base, sometimes by a separate wire. On a multimeter the output from the regulator should show about 12 to 14 V DC with maybe a bit of flicker, to see what is really going on you have to use an oscilloscope.