lemur

Point of engagement to full engagement is called the 'friction zone' and the position it starts should be adjusted at the brake lever adjusters. The thing that makes cork or paper clutch plates swell, stick and make noises is water in the transmission oil from leaking seals or condensation (transmissions are vented to the atmosphere), cork swells more in the presence of water. Water in the transmission oil can be seen as opaque or milky colour to the oil instead of clear oil. Yes lots of people use ATF for the transmission but I swear by hydraulic oil same as used in tractors and excavators because it has greater lubricity compared to ATF. Transmission oil in a 2-stroke engine never ends up being burnt in the engine, smoke from the exhaust has no relationship to the transmission oil. (or you have a big end seal or gasket leaking) If the clutch action is mushy that is generally caused by air in the hydraulics of the clutch actuator and your hydraulics need fluid changing and bleeding. Clutch hydraulics use either DOT brake fluid which is hygroscopic and requires changing more than once in 7 years, or they use thin mineral oil. It will be marked on the clutch. master cylinder cover which fluid you should use. When DOT fluid contains too much water there is a risk of boiling the water in the hydraulics and that will cause the brakes to drag when hot and it can introduce air into the hydraulics because when water boils it makes steam which is O2 being released from the H2O. aka worlds smallest steam engine. Too much oil (oil level too high) or dirty oil is more likely to make a clutch slip because oil gets trapped between the clutch plates and causes a hydraulic pressure that works against the clutch springs which are trying to push the friction plates together.

Grips for anything that uses a thumb throttle are the same size on both sides (7/8" dia.) don't purchase bar grips intended for snowmobiles, sea-doo or quads in error.

🤔 The grips should have the same outside diameter if they are bought in sets, it's only the throttle grip inside that is larger bore to accept the twist grip tube. If you need to build up inside the grip, 2-sided tape works but that is to make the grip not slide on the bar. Trials grips are typically smaller diameter outside compared to street grips and trials grips are available in soft or hard rubber compounds. Do you not wear riding gloves? Gloves usually work good with trials grips, required equipment for most.

Oset technical service videos can be found here if you can obtain permission to view them all: https://osetbikes.com/au/support-en-AU/electric-tech-videos/ edit: for free versions of the videos search the file names, service videos show throttle to use a hall effect sensor, failure rate for the component used in that assembly is high and the video shows how to test and repair the old unit. ... not something I would recommend unless you have a complete replacement assembly and service the old one later.

From what I've seen of electric bike fails so far they are often related to the the twist grip assembly electronics on the handlebars. Which I would guess to be a rheostat control (variable resistor). I think that is a part I would keep in inventory for replacement after a crash or for trouble-shooting.

Commutator is the rotating copper colour metal surfaces that directly contact the carbon brushes. There must be videos and/or documentation online by now detailing the steps required to test and make adjustments where you can. Meter testing for battery power (voltage) and meter testing the resistance (ohms) through wire circuits and ground wire connections back to the battery will confirm it's not just a damaged wire connection, anything that is sealed in a black box (epoxy) is generally not a user serviceable component unless there are obvious adjustment knobs or screw settings incorporated. Black box assemblies are where you need a second bike or a dealer with access to special test equipment, or known good (new) parts to swap out and ride test. Any exposed electronics can be visually inspected for burns. People with electronic repair experience are more likely to know were to look and what components are most likely to fail with age or heat from over-voltage. Wiring diagrams are always the best place to start, but they will rarely show detailed contents of anything black boxed, for sealed assemblies a second bike to swap out parts to test is unbeatable. That's how a dealer would easy find all the problems, they would use a bike to swap parts until the problem went to the other bike.

more performance oriented cdi implies more ignition timing advance. You can adjust timing at the stator to some extent or even the plug gap to a lesser extent.

Have you done an actual compression test or only based on the kickstart? Ki Is the throttle tube white or black? White is the fast tube, the black throttle tube retards the response slightly. Good chance your bike came with black tube originally like a friends evo factory bikes did.

It's the people who build the sections and tabulate results now that likely know what your regional definition of difficult is. In general terms entry level classes don't need to assault anything taller then the front wheel no need to hop, intermediate classes don't need to hop to negotiate the sections but that ability can be an advantage in sections, intermediate classes should be able to assault a handlebar high obstacle or bigger with control, advanced classes are your top riders consisting of former experts (older) and current experts (younger). Hopefully nobody sets out sections at any level that have not been tested unless you are the guy setting up world round class events, but I think we are all talking about amateur trials club events here.

You need a VOM meter and know how to use it if you own an electric bike. Meter test the voltage going to the motor at full twist and if it does not represent the same voltage as the batteries then it must be curbed by the motor controller, if it reads as full volts to the motor and the motor works but performs poorly, that pretty much has to be the motor brushes doing a poor job of powering the magnets. Adjusting the motor controller to perform at a higher level will make it far more responsive to the point of wheel spin, make adjustments incremental and ride test.

The Oset motors are brush type, the carbon brushes and the commutator that they contact will be the first motor assembly to fail and need service and replacement.

Are you aware they generally put an adjustable potentiometer on the control board so you can curb the performance ?

Link for the event entry is posted here : https://www.ataont.ca/category/events/upcoming-events/

From here it sounds like a very poor fitting piston and rings and I would be concerned with the bottom end seals because of the bikes age and that sound. Compression testing would be a good start followed by inspection of the top end and if you don't find stuck piston rings or serious damage there you might be looking at a major overhaul that requires splitting the cases.

If it is a non-original carb, how did you set the float level? If the valve clearances are set perfect, I’d be visiting the float level to possibly address the off idle stumble. Carburetors need to be isolated from heat that can boil the fuel and from vibrations that can turn the fuel in the float bowl into froth. Plug read should tell if carb settings are rich or lean, post up a photo of your carb setup and sparkplug after running for a while might help us to assist.

Does the bike currently have a lighting coil installed?

No tail light leaves you required to hand signal stops. 1975 Bultaco Sherpa 250 pretty sure did come with lights unless they were removed at the dealership to race prep. Brochures from the period show them with scooter sized lights and a rubber plate mount on the rear fender, speedo and a horn.

Here's the catch as quoted from the SY250F owner manual: "As the time goes along, the play of the valves changes and it may alter the ratio of air to fuel of the inlet air-fuel mixture. The solution is so to make it adjust by your dealer, as often as written in ‘List of the regular maintenance and lubrications’. It is a really complicated operation, which requires a professional expertise." Twin cam with 5 valves all adjusted by bucket and shims on cams that do not ride on roller bearings is a bad design for trials bikes that might regularly encounter low oil pressure because of slow engine speed operation, low oil pressure is the reason the 4RT engine cam rides on roller bearings and uses roller rockers.

One of my friends that has always ridden Scorpa had one of those for a very short time, after a spill I seen him trying to start it and that was the last time I seen him riding that bike. Twin cam engine maintenance reads as an issue even in the manual and carburetor is likely the root of the starting and performance issues which could be solved if it had Honda fuel injection technology.

😎 Almost completed setup and loop marking for the July 20th & 21st. 8 sections per day and three or four loops to be determined by the weather, pre-registration is greatly appreciated. I'll post the official flyer here soon I hope.

My venue has the reputation of being very hard but that is because we have the roughest natural terrain around and I think hard is what the more serious riders want. Very difficult to set out novice sections here because the loop I ride all year round including winter is apparently too much for anything short of a competent and slightly brave rider. Pro rider class only exists when you have enough extremely talented riders to support it and that is another area I am lucky with, it's difficult terrain that attracts the top riders on a regular basis. We were recently been compelled to somewhat standardize gate colours but the recommendations are not very conducive to the materials and terrain available here, plus they don't even match the number plate colours which is only sensible. We set out 5 lines of difficulty per section here so there is always a significant number of options and I build sections to have optional lines at some of the really hard stuff. After it's all setup and ready the whole thing is at the mercy of the weather gods to make the event easy or crazy hard. Success is when everybody has fun and nobody gets seriously damaged. One serious problem we are seeing here is too many classes, eventually you can't attract the required 3 riders per class to call it an official class competition and the results are discarded, which is significant when you travel great distance at considerable cost only to discover too few riders entered to make it count.

You can also determine max torque values by knowing only the material used in the nut & bolt and the size of the threads, there are charts based only on that information. Maximum torque will typically be something prior to elongating the bolt or spoke unless the bolt is designed for single use like in some cylinder head bolts, this is not the case for spokes and barring physical impact damage we hope they last the life of the machine. There is a lot more flex and movement in a spoked rim then most might think, watching a pro riders rear rim impact a rock face during a big splat will reveal just how much deformation can occur and how far a rim can spring back to being round again is fairly amazing to watch.

Wet or dry? ... hit one of the old spokes with penetrating oil first, might make a huge difference in the readings.

Ouch looks like she swallowed some sand pit, new parts are in order. Service manuals will show you how to test measure the crank short of taking it apart.

If motorcycle salvage yards where you live are anything like here you get 2 completely different results if you phone contact a wrecker, or go there in person and have trusted access. Telephone contacts for a specific part to a wreckers will often be ignored, it's the difference between you locating and identifying the part or the guys wife on the phone giving you the stock answer to locating some weird part request. You also get 2 different prices and the deals are on the in-person purchases. You only have to put yourself in the wreckers position for an instant to realize why it is this way.