Upper pic is of a later 200 with engine frame guards , lower pic ( actually a friends bike ) is early 200 these tend to have an alloy tank under the shelter and shock mounts are much wider on the frame
Fan works as it should coolant level OK no loss or pressure build up fresh fuel tank n tap cleaned carbon on piston top is prob only after 3 to 4 gallon use so soon recarboned up fuel is standard not high octane but not from super market did try hi octane but wasn't much better if any
Can't visually see a fault with exhaust definitely not oiled up more on the dry side. Tried the new carb from other bike which runs very good and no difference
As far as I know the head is standard I've had it 6/8 years id say it went like this gradually just wouldn't run right low down at a trial. Had 2 differnt carbs one brand new from 07 250 which I'd say is like a motocross bike in comparison swapping stator n cdi is all the loom involved with spark. I added a separate ground to coil and thought I'd fixed it but nope. On a cool day it could take half hour or more to occur on a hot day as today 10 mins
Got a 2006 250 rev 3 with low use having trouble with an erratic running when warmed up pulls through gears fine but looses response just off tick over goes droggy n plenty pinking Almost like it's too rich but with pinking at same time to date I've changed Crank bearings and seals rings case gasket cylinder gasket new plugs of differnt heat range stator and cdi brand new and good used coil Inc lead n cap kill switch disconnected 2 carbs Reed block assembly flywheel new air filter tank drained tap cleaned out can't pick up on any air leaks spraying carb cleaner around it problem was there before rebuild n suspected Crank seal I am thinking it needs a crankcase pressure drop check. Just pulled head wondering if rod was bent piston comes up square but not level with cyl top ie 2 to 3mm lower is this normal
simular to 307 and 310 never actually seen one but would snap one up if had chance make sure gears select OK most parts can be sourced even pistons engine same as 310 reed valve electronic motoplat ignition conventional forks Nicosil bore
Model and year id
in Montesa
Posted
I'd say cota242 125cc around 85/6