COTA66

Just pulled the exhaust off my MH 349 and it fits the 248 frame fine, looks like thats what i need. Does anyone have a MH 349 exhaust kicking around that I can buy?

Thanks for the suggestion. Just tried him but no luck. A MH front pipe looks like it has the same barrel fitting but the exhaust routes outside the twin downtubes, not between as per the 248, so I suspect it won't fit. If anyone has tried that please let me know.

Hoping someone can help me find a front exhaust pipe for my Cota 248. it came as a box of bits and I have gradually rebuild it from the ground up. The original 21M engine had a missing RH case so I rebuilt and fitted a 51M 349 engine. Just dropped the rebuilt engine into the frame and discovered the 248 front pipe will not fit the 349 barrel. The port stud spacing and port bore are all the same but on the 349 barrel the exhaust port is more recessed and at a different angle to the 248 barrel. I am told that the correct part number for the exhaust I need is 5160038-02. I have tried my usual suppliers (InMotion, Cycles Avent) but they can't supply either new or used. Anyone got a suitable header I could buy? Are there any workarounds? I could modify a 248 pipe at a push but would prefer a factory part if I can get one. Also need a side stand and engine to swing arm brace bars if anyone has any kicking about. Thanks!

Thanks for the reply. Stripped it all down again tonight and cleaned the engine cases behind the stator plate to get a better earth. Looked at the new points and saw that the nylon rocker bush was too big for the shaft and would affect gap. Changed to a better set of points, gapped them as best I could and hey presto BIG FAT SPARK!! Might have been some of those changes, or perhaps the bottle of Spanish wine I bought to help calm my nerves and the Spanish prayers!

I have also disconnected the kill switch completely and left the green, pink, and yellow wires disconnected. I have read that on Bultaco's which use the same Motoplat system, the green wire needs to be earthed to get a spark. Does anyone know whether this is the same on a Montesa? Also, does anyone know where I could get a manual? I have an engine in bits to rebuild, difficult without a manual!

Hoping someone can help diagnose a no spark Cota 248. I have tried 4 old stators plus one brand new one, 2 flywheels, 3 coils, various new points, new condenser, new woodruff key on flywheel, new plug caps, direct earth of coil to the engine, various contact gap settings Absolutely refuses to spark although I can feel a weak shock from the HT lead if I hold the plug business end. Current setup is brand new stator and wiring, new points, new condenser, new plug, all gapped correctly but absolutely nothing. Only things left to replace are the coil (just ordered a new replacement from InMotion) and the flywheel. Has anyone ever heard of a flywheel losing its magnetic charge? It still holds steel parts to the magnets so I find it hard to believe it could fail, plus I have a second flywheel I have swapped in with no effect. The various HT coil circuits both show resistances so are not open circuit, can anyone advise what the low tension and high tension coil resistances should be? I get about 13.5K ohms on the high tension side, and about 10 ohms on the low tension side. Is there anything I am missing? Checked all the continuity and earths and all look OK. It's driving me absolutely nuts!!!! On the upside I could now probably change out the whole ignition system with my eyes closed! In my experience of other engines I should be able to see a spark of some sort to have a chance of it starting, or does the Montesa have a magic invisible spark?!! Any help appreciated.