dadof2

Yep, ideally you need to take the seal out and then used a proper bearing puller. If you have access to a MIG welder then weld something onto the bearing to block the hole in the middle, you can then punch it out with a rod from the other side.

Faulty HT coil can cause these symptoms, See if you can borrow a known good coil. Alternatively find an autoelectrician with a PICOscope or similar who can check the coils output and waveform.

I agree with previous posters advice except strongly advise against the use of flame heat. Use a hot air gun or rag soaked in boiling water. Ideally make a large washer from a piece of 10mm plywood or similar which is a tightish fit on the fork tube. put it at the top of the fork tube. You can then warm the fork tube without the heat getting directly at the cap. At the same time as you heat the tube cool the cap with a plumbers freeze spray. Then whilst applying torque with a T bar and socket sharply strike the part top of the socket with a copper mallet.

I get fed up with trials being referred to as "a race" or "grand prix" Sooner people get back to calling them observed or reliability trials the better. Words like race and grand prix conjure up images of speed and hoards of noisy bikes tearing up the countryside. This impression will only result in land being lost, higher insurance and is an open goal for the numerous organisations that hate off road motorcycling.

In general ATF and gear oil contain much less detergent than muligrade engine oils. Use of detergent oil in engine not designed for it can increase wear significantly. Some semi and fully synthetic oils dissolve clutch lining bonding materials, I would think ATF is much less likely to do this. Why do some people think a gear box designed for 20w-40 should have ATF put in it? Would you put 20w-40 in your cars auto box? Cheers

You will need a dial indicator to find TDC and measure the number of mm BTDC. You will then need a strobe to check and adjust the timing. Find TDC then rotate the engine the required number of mm BTDC (probably 2.5 to 3.0mm on these engines) Then put a small mark on the engine case and a mark on the flywheel that exactly aligns with it. Set the points gap exactly then start the engine. Using the strobe check the alignment of these marks and adjust the backplate as necessary. If the backplate can't be rotated then you have to adjust the timing by varying the point gap, increase to advance, decrease to retard. The points ignition on these is generally very reliable. Cheers

If you can find someone with a lathe and tig welder they can turn up a new pivot from a large bolt and weld it on. I have done this repair for people several times, mostly it works and lasts but occasionally does not.

Might be best to do a basic carburation check first. Check float level is correct and that air filter is clean and properly oiled. As a guide:- 0 to 1/8 throttle mixture is controlled by air screw 5 mins running 1/8 to 1/4 throttle mixture controlled by slide cutaway 5 mins running 1/4 to 3/4 throttle mixture controled by needle / needle jet 2 mins running 3/4 to full throttle mixture controlled by main jet. 30 seconds running - assuming plug not too far off from 1/2 throttle run You need to mark these throttle openings on your twist grip and ride with the throttle in the centre of each range for at least the running times above, with the engine fully warmed up. Use as high a hear as possible to keep the engine working steadily. You have to get the carburation correct at each stage before moving on. At the end of each run do not move the throttle, pull the clutch in and press the kill switch at the same time. Check your plug colour (centre electrode insulator) after each run. It should be pale chocholate brown, lighter means too weak, darker means too rich.

Water in fuel could cause it - it tends to block the slow running jet

There would be quite a good manual with exploded parts diagrams supplied with the bike. Try Jim Sandiford - type sandifords montesa into a search. There were a couple of things that could cause gearbox problems Chain too tight - some people misjudged tension because chain hidden in tubes Gearbox sprocket is on taper and with wear or overtightening can move too far onto the shaft putting side pressure on the bearing.

Make up a blanking plate to block the exhaust where it bolts onto the cylinder. Drill a hole to suit a tubeless valve in the blanking plate. You can then lightly, say up to 25 psi, pressurise the cylinder and crankcase and listen for any leaks or see where the air comes out.

Assume you have a digital camera or camera on your phone - use that and photo each stage, then you have a record of how to put it back together. You would be amazed at the wrongly assembled items i come across. Recently on a gasgas pro I found a washer/shim off the kickstart shaft on the clutch release bearing and on another, one of the rear brake pads put in wrong way round so its steel backing plate was pressing on the disc. It was only by chance I found this as the brake was working acceptably well. Cheers

Copemech # 18 - your underlined comment, please do share any more info you have. I am aware that a hall effect sensor is not a trigger coil and works differently, it does have square wave output at lower voltage than a magnetic induction "self generating" type trigger but I still would not regard it as digital. The digital term usually refers to the processing method used in the CDI for the advance curve. PS sometimes what i post is true as far i feel the reader needs to know, not the full whole story, in your case different interpretation is probably compounded by me being English and you American. I am guessing you may know quite a bit about these things and therfore when i say I use a 4 channel scope you will know what I have, but although an excellent piece of equipment there is little point in suggesting it as a diagnostic method to most trial bike owners. Cheers

I would flush out the engine with fresh two stroke mix. I think Yamaha recommend 20w-50 for the gearbox on these. 20w-50 is about 5 times as thick as ATF at 100 degrees Celsius.

Try a Bieffe - they have a screwed on mouth guard and they are available in quite small sizes.

Bike model and date would help. This is the poor pick up you get if the pilot is clogged, pilot way too rich, too little cutaway on the throttle slide or throttle slide in wrong way round.

Hi there, firstly don't use oil of any kind on brake seals. Moisten the seal with brake fluid before fitting it into the groove. If it is fitted dry it sometimes does not bed in properly. Lubricate the piston with brake fluid, red rubber grease or silicone grease and work it in very very carefully. It is easy to damage the seal lip if it has to be forced in. You need to strip it all out again and inspect everything under a magnifying glass.

Motors TV Sky 447 Thursday 20:00

I don't own an OSSA and have not ridden one of the FI models. Watching them they seem to go as well as the opposition. However a friend did have one and does not have a good word for it and neither do several other owners or ex owners he has talked to. Depreciation certainly is an issue I would not buy one because of the depreciation and the stage its development is at. Far better wait a year or two until the problems are sorted. FI and 110:1 oil mix ratio might seem like a good idea, but so did invading Iraq and the Ford Edsal initially. Cheers

Why not to kick the bike over without the plug properly connected and earthed? Even at starting rpm the coil will supply in excess of 7000 volts. If these 7000 volts can't get to the bike earth they can go back through the coil and CDI wrecking the CDIs transistors which work at around 5 volts. Disco - sorry for hijacking your post a little with the following - I was aware you were not happy with a voltmeter when I made my earlier post but usually you can find someone who is. When diagnosing potential ignition failure many years of experience has taught me to start with the basics first. First change the plug for a known good one. If that does not work I go straight to the stator. Being subject to heat and vibration this is where component failure is most likely and resistance out of range is one of the easiest checks to carry out and only needs a multimeter which can cost less than £15. my next check is to spin the engine with a power drill and check the outputs from the source and trigger coils. The trigger coil is hall effect with an analogue output (the digital processing takes place in part of the CDI unit) If these outputs are OK then the next check is the CDI to coil output, coil and HT lead resistance etc. It is well worth the taking the time to learn about ignition systems and what you can do with a multimeter - it will save you time and money. Although I am a qualified motorcycle mechanic I have done quite bit of work on cars where swapping components is not an economic proposition cost or timewise, You have to be able to diagnose based on OBD info or outputs. Cheers

If you really need extra cooling an extra radiator where your front number plate goes. Alternatively have a larger (thicker) radiator made to fit in the standard position. Just an extra loop of copper pipe where it catches the airflow can make a difference. Another way to cool the engine is to jet as rich as you can and run a rich oil to fuel ratio. Cheers

Perhaps someone drilled and tapped a decompressor hole?

10w-40 semi synthetic, mobil 1 5w-40 or 75w gear oil are better than atf. some atf not up to the job at all.

Zippy #9 - don't do this - it can wreck your CDI, I will post why when I have more time. Disco - I guess you will try a new plug cap - they usually contain a resistor that can fail.

Brownrigg fell near Nord View used to host motocross with well over 100 bikes and trials with similar number. Now no MX and restricted to occasional trial limited to 40 bikes due to SSSI status. I urge ALL forum members to write to their MP and the minister for the environment urging them to stop the extension of the national parks. it is Natural England who are behind this proposed expansion and it is they who designate areas SSSI natural England are a quango, as are the national park authorities and in these austere times they should have funding withdrawn and be reprimanded for embarking on costly anti democratic ventures.