Frequently Asked Questions

I keep shearing magneto keys.
Montesa uses a very small key, good thing! When it shears it usually leaves half in the shaft and half in the flywheel, usually not messing up the shaft. The fix is to lap the flywheel to the shaft with valve lapping compound. Compound usually comes in two containers, one medium and one fine. Just paste the compound on the shaft and rotate the flywheel on the shaft (without the key installed, of course) working up to the fine paste. Be sure to clean everything off between lappings. This will remove any high spots on the shaft and flywheel and help to keep it from turning. If it's a real problem, lap in the shaft, heat the flywheel in the oven, and use red locktite, torque flywheel nut to 72 ft lbs. That should keep it in place.

How do I remove the primary gear?
Most pullers are not heavy duty enough to handle this job. The best puller to use, is a automotive pittman arm puller, these can even be rented, you must make sure that the arms get as much contact on the gear as possible. An impact wrench, and the application of heat on the gear, may be needed.

I removed the head nuts, and the barrel will not come off!
Later model barrels are held down by four 7mm allen nuts. This is an uncommon size, but SnapOn tools make a long allen wrench with a 3/8 socket on the end that works perfect. A good metric supply store should have this size. In many cases, use an impact hammer to loosen, to keep from ruining the allen nut. If you strip the allen nut, you will have to drill it out and the cylinder stud will be ruined.

The magneto nut won't come loose.
The magneto nut goes clockwise to loosen, same as the countershaft sprocket nut.

I checked the ring gap on my V.R. engine, and it's over 80 thousandth's. What gives?
The rings in the V.R. are designed to butt up against the locater pin, when measuring, you must take into account the thickness of this pin.

The collar that holds the pipe on keeps coming loose.
Coat the threads with anti-seize compound, tighten with the correct spanner and safety wire the collar to the hole that is in the lowest fin on the barrel. Some people fit a spring from the collar to the barrel for extra protection.

Do I have to split the cases to change the crankseals?
No. The crankseals are accessable from the outside, removel of the magneto and the primary gear is all that's required.

My bike sometimes pops out of gear. Is there anything that can be done?
Remove the 17mm bolt in the rear of the case, on the sprocket side. There will be a detent plunger and a spring. Install a small ball bearing behind the spring and reinstall. Shifting will be slightly harder, but will be more positive.

Oil blows out the breather hole in the rear of the case. It's making a mess!
Block the hole with a dab of epoxy, and vent the filler cap for the gearbox with fuel line, running the line up under the fuel tank.

My ignition points are always pitted, and the condensor keeps failing.
You could not mount a condensor in a worst spot! Extreme heat and vibration will make them fail in no time. Disable the stock unit on the backing plate. Purchase any good automotive condensor with a ground wire. Mount the new unit under the tank or in the open (I use a small hose clamp on the frame backbone) run the ground wire to the coil mounting bolt. Splice the condensor's main wire into the hot wire coming out of the coil. Thats it, no more burned points!

When should I change the primary chain?
Trick question. Montesa does not use primary chains.

My manual for the Cappra 250 GP says to set the timing at 6mm. BTDC, it kicks back hard, and is hard to start.
This is wrong. Timing should be set at no more than 4mm. BTDC

The clutch on my Cota drags, what can I do?
This has always been a problem up until 1984. Check for warped clutch plates, spring height, use a modern transmission oil.

Tip
If you repaint or powdercoat your frame, of course you always remove the coating from the coil bracket for a good ground. But, remember to remove the coating from at least one of the motor mounts to ensure a good ground for the engine to the frame. If you don't do this, you will lose your mind trying to figure out what is wrong with your ignition or carb.