Triad

Uh, got another "idea": might the bogging be caused by a bad flywheel side crank seal? I don't think so, as the bike idles regularly 'til it starts bogging and if it was getting air I think idle should go up erratically.

Sorry for the lack of updates... got a bad flu that kept me inside for the whole week. Received the spark plug. Tried to buy an used Polini PWK carb but most sellers are asking €80 when they cost €100 brand new. I was a bit in hurry as I wanted to diagnose this issue (still pretty sure it's due to the stator or the coil, though!) so in the meantime I ordered another PWK (Koso clone), this time it's a 30 (the other one was a 28mm). I'm pretty sure the bike will still have the same issue as it's not carb-related. I was considering the idea of removing the flywheel to replace the crankseal on that side too, and while it's out, to put the other engine's stator/flywheel and see if the bike behaves differently. Not sure they have the same flywheel as one is an Explorer engine and the other is from a Pioneer... in pure theory I'd expect a lighter flywheel on the enduro, but I guess the stator itself will be exactly the same.

Didn't want to hunt the correct spark plug so I ordered one on Amazon, should receive it tomorrow. In the meantime I sent the PWK carb back and plan to buy one made by Polini (don't know if you guys know the brand). It's an italian brand that makes big bore kits for 2 strokes, exhausts, variators, automatic clutches for scooters etc. - I already fitted one of their PWK carbs on a Beta Rev and they're obviously much better than the generic chinese clones.

Yeah, that's what I thought. Weird they used a short spark plug, makes no sense. I think I'll try to make it run with the stock Amal, if possible, with a loooong transparent hose carrying the premix to the bowl and with the end vented to atmosphere... so I can rule the carb out. But as I said, I'm afraid it's an electrical issue.

Thanks! I was a guitar builder and my customers base was always in the US, so I had time to practice 😂 I noticed the spark plugs fitted on the head have a SHORT threaded portion... I'd say 12mm or so, while in pure theory they should be the long version. Could it be the cause of the problem? I doubt it, but you never know.

I checked the impedance of both my Motoplat stators and it's about 32ohm (31.8). I'm having this weird issue... bike hard to start, then starts, works for a short period (1-5 minutes) and then starts bogging. It's not fuel-related as there's still premix in the bowl when it dies.

Found the seals, got both the pullers and managed to take out both the flywheel and the cush drive on my test-engine (Explorer, partially seized). I'll do the same on the good engine as soon as possible.

Thanks for the picture! I understand what the split spanner and the bigger "bushing" are for... but what about the smaller/taller one? What about a bearing puller like this one? https://www.amazon.it/VEVOR-Estrazione-Cuscinetti-Separatore-Autoveicoli/dp/B0FNNLQKQG/ref=sr_1_32?__mk_it_IT=ÅMÅŽÕÑ&crid=1J9OT632AEQI4&dib=eyJ2IjoiMSJ9.F7DabM4KgRoeLNC5m87AKWI_81P6lH4H-JJv9hmS54VsgH7Jl2H_sBto6YefSEh2Mr323F-rM-F6YW7kURCX9k4AS5nS0TQq7oseyI-y_6tyoIFOlLERt7evmcUJ3FppwkGGwQj942Cg5GP412S4qc2SW3V26VtVvBueYD8eTEv9qbVyeMNwz6EW76d88atoDXLtvB6dwI508tvq0yavbEFXIFUbUhArl26l9Kup6xcINWcCpPb23ntBHz3ppRigPMkKMroC5-emTMg1sGRRxL5fJcUrS9xzKy0T9G8Bdr0.Ij-6NlEcHc2accfls-XnAXjYLpCaYct6YzIU-jgxHC0&dib_tag=se&keywords=estrattore+cuscinetti&qid=1766358853&sprefix=estrattore+cuscinett%2Caps%2C315&sr=8-32 I think the flywheel needs a puller M27x1.25, right? I can easily find one locally. Do you remember the measurements of the seals, by chance?

I guess they do, but they probably already have the puller? Is it absolutely impossible to get the cush drive out with a standard 3 arms puller?

Didn't really find it with my google search... I'm in Italy, BTW. I tried to find a mechanic willing to do it... some say they won't open the engine unless it's for a total check of all the parts. Another guy asked for €200, not sure how long it takes but seems a bit on the steep side, maybe? I should also take the engine out and pack it to ship it to his shop (and of course have it picked up after the job).

Uhm... gotta say the videos of guys pulling the cush drive with a handmade puller didn't really make me think it was easy. I tried to get in touch with a few mechanics here, specialized in old enduro bikes, but for now still no luck. Not really too excited at the idea of doing it myself, this bike is definitely way different from what I usually wrench on...

Hello guys, sorry to resurrect an ancient thread... I have an Ossa engine requiring new crank seals as it's drinking gearbox oil. I'm kinda skeptical about doing the job myself as I never worked on such an old bike and I don't have the pullers. Is it hard? What kind of pullers do I need? The engine should be from a late 70s Pioneer, has the coarse teeth levers and runs, so the Motoplat rotor is good and has good compression. I'm in Italy, can't find a shop willing to tackle the job for me.

Sorry to resurrect a 6 years old topic but... was it the model with or without the "powerjet"? I just fitted one of the chinese PWK clones on my 250 Pioneer engine with Explorer exhaust... the stock jetting seems to be too lean (38 idle jet, 120 main). I just replaced the idle with a 45 as the bike tends to die even with the air mixture screw totally closed. Not sure the 120 main is big enough, we'll see.

Don't know how to "repair" the gear lever. I could drill a hole thru and use a passing bolt, maybe, covered with a piece of hose for the time being? Or I could use two metal clamps to keep an L shaped piece attached on it?

Thanks... makes perfectly sense. I don't think I'll be on the hunt for a Pioneer exhaust, it would probably make more power up top but I plan to use it for "semi-trial" stuff at low speed, so it's probably better to keep the Explorer exhaust with the smaller carb. I guess the cylinders are also different on the inside (bigger intake/exhaust ports)? I never worked on Amal carbs, so don't have any jet for it... hopefully the stock setting will work with the actual setup.