konrad

Does anyone have a solution to this problem? I could not find anything via searching here. No defeat strategy appears obvious to me. I'm unwilling to pay Mitani's price, or to remove it completely. Has this been a "feature" since the bike's introduction? TIA.

Interesting. Is the transmission not vented at all? Maybe that's part of the problem? When the air/oil in the transmission expands, that can't make life easy for the crank seal.

I have no idea what a Dalesman is, but 25:1 seems like a lot of oil for any trials bike. It might take a while for the motor to clean itself out even with no gearbox oil being sucked in. You can test for a gearbox-side crank seal failure by replacing the transmission breather hose with several feet of clear plastic tubing and then submerging the free end in a jar of water. When you blip the throttle, a bad seal is indicated by bubbles in the jar, or water being sucked towards the transmission. It also might just be very, very rich.

I stumbled across this because of another thread. I'm guessing it's been too long for the OP to still care, but perhaps my response will help someone else. CDI = Capacitor Discharge Ignition. The factory wiring diagram is truly horrible, and you were smart to attempt to draw your own. In regard to your .PDF drawing: 1. That "run switch" configuration would be very unconventional (and I suspect it is incorrect -- especially because it would be required to "open" to kill). Typically, one side of the ignition coil would be permanently connected to earth. 2. Kill switches typically "close" to produce the kill function, and "open" for the run function. 3. The wire you have marked "Lights?" is unlikely to power the lights. There's no need to involve the CDI in that task. It's possible this is were a conventional kill switch would be connected (but more investigation would be prudent). 4. Lights typically are powered via the low-voltage winding on the stator that powers the fan.

I'm not a Beta guy. Did you try searching the internet? It brought me back here.

I sent you a PM, give me a call.

I may have misunderstood. You're saying it still runs well once started? Just very difficult to start?

Let's hope this isn't your problem!

So it's not a spark problem. That leaves fuel. Everybody that owns an EFI OSSA really needs to have K-Scan! If you wire the connector described in this document: you can supply +12V via an external battery. You should hear the fuel pump run for a few seconds each time you connect the battery. Start there -- no computer or software needed.

You know, car racers laugh at motorcycle racers saying we can't even change the overall gear ratio without changing the wheelbase too. Unfortunately, I have to agree with them. If the wheelbase changes as a result of the gearing change, this can have a cascading effect on other tuning variables. Moving the rear wheel rearward lengthens the lever arm acting on the shock. This in turn makes the shock spring feel softer to the rider. Without a change in preload, a softer rear spring increases rear sag which changes the bike's fore/aft weight distribution (and therefore traction). These are subtle, but noticeable, changes and often a rider will subconsciously compensate with a change in body position. Speaking from personal experience, my OSSA TR250i "works better" in 3rd gear with a 9T front sprocket than in 2nd with the standard 11T. The overall gearing difference is an almost insignificant 1 percent. And, yes, a 9T front sprocket is horrible from a chain-life standpoint -- but only slightly more horrible than a 10T or 11T. Industrial designers generally consider 17T as the smallest sprocket that should ever be used.

Oaktrials, thanks for sharing your success story. Your description reinforces how I think the AAA cell in the Easy Start gets recharged. Originally, I thought it stole power from the stator's fuel pump winding (which provides the Flywheel Armed Condition). Later, I came to believe the AAA cell is recharged via the red and black wires because this is the only way an Easy Start could work when retrofitted to an older-model bike. I would bet your old AAA cell would still work now that you've fixed the wiring.

Are we all talking the same currency? Scotland is GBP. Indiana is USD.

Have you ever parted-out a complete motorcycle? I have not, but have sold various parts of motorcycles. The lower the price, the quicker they sell (if there's a market for them). You will probably have to ship internationally. My guess is that it could take years to sell 50% of an EFI OSSA. There are some parts that may never sell.

Breagh makes a perfectly reasonable argument. Selling the bike as a project would be infinitely easier than parting it out. But even selling it as a project may not be easy. The US market is small and it's unlikely you'll find a local buyer. Alternatively... graphics is a "don't care" issue for me. Make the bike functional and forego the appearance. I have a huge amount of time and effort in my EFI OSSAs. They return that investment by working exactly to my liking. (I just bought a 4RT for practice and will save the OSSAs for competition.) In the end, I love tinkering with bikes and if I have to make/repair or modify parts to keep the OSSAs running, I'll do exactly that. If the OSSA performs to your liking, fix it. If not, move on to something else.

Recently learned that although the home-made diagnostic cable works with K-Scan, you cannot load a map with it. Loading a map requires the official Kokusan Communication Unit shown below.

Can't hurt, but may not help. Does it run well other than difficult starting? If so, it's probably not the injector.

I just tested the compression on my 2016 4RT 260 (which runs flawlessly). I saw just over 200 psi on a cold engine after 16 kicks with a high-quality Snap-On gauge. I observed no increase in pressure after 20 kicks. These were not "fast" kicks, just normal kick-starting speed. Local atmospheric pressure will have a small effect on the reading, but I would say the decompressor (if it even exists) does not work as Montesa describes! P.S. I'll also add that although I appreciate the quality of the Montesa service manual, it appears Honda just "cut and pasted" some of the information directly from their motocross manuals. Rings every 6 months? Piston every year?

I make difficult-to-obtain O-rings from cord stock and join the ends with cyanoacrylate (Super Glue). To give you an idea, here's a source for such in the US: https://www.marcorubber.com/o-ring-cord.htm Try searching "o-ring cord stock" to find a local supplier.

True, but that will increase the pressure by a relatively small amount -- not from 65 to 200 psi. Did you try jimmyl's suggestion about setting tickover/idle speed? You need an accurate tachometer to accomplish this. I tried to set it with my digital timing light, but the reading was erratic. Ironically, this simple device measures rpm quite consistently: https://www.trailtech.net/tto P.S. I'm curious, what do other 4RT owners use to set their idle speed?

While testing compression are you kicking so rapidly that the decompressor behaves as though the engine is running? That would explain the the high pressure reading. I'm just guessing here, but typical kick-starting speed may be 250 rpm. The decompressor probably deactivates at around 1000 rpm.

The photos in the 4RT manual are not clear. Here is a photo of some of the decompressor parts on a CRF150RB. It may be similar to the 4RT. Does your compression gauge read directly in PSI? Maybe a units conversion error?

There is more to the decompressor than just a spring. There is a centrifugal mechanism to inhibit it from releasing compression when the engine is actually running. Americans call "tickover" the idle speed. There is an adjustment on the throttle body. It should be 1700 to 1900 rpm when the engine is up to temperature. Hard starting can result if set incorrectly. Also check that the valve clearances are set correctly. I see that you've done this already.

Sounds like your automatic decompressor (compression release) is not working. At kicking speeds, the exhaust valves are held open slightly. This system is very common on modern 4Ts. It allows a higher rotational speed for starting and easier kicking. Once the engine fires, the decompressor ceases to operate and the cylinder pressure returns to that of normal operation. The decompressor is built into the camshaft. See the service manual for more information.

Heffergm, did you solve your clutch problem? Your post prompted me to work on my Clake. I installed a new piston assembly and this was a magical fix. Nothing appears to be wrong with the old seals, however they may have grown excessively in diameter. It's a 9.5mm bore. The seal diameter measured about 10mm. Two other used piston seals I have measure 9.7 (from mineral oil) and 9.8mm (from DOT4). So maybe just a lot of seal drag in my case?

Well said! I like riding a variety of bikes and strive to improve all to match the strengths of the best. As Paul Thede says about suspension, "The best you've ridden is the best you know."