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Mat, Sorry seem to have hijacked your post a little, sorry about that, but it's all relevant to 248's. Have you check out a site called Teflon Mike. If you put Teflon Mike 248 Montesa in google it should take you to his site and it has a full downloaded comprehensive 248 manual which should show you what you need. If not I'll take mine off and send you some images. Where are you in the UK? Dave.

Hi Larry, Have checked my pm's and tried the GasGas carb, but it won't fit without buying new inlets etc. So not wasting money. Spark plug tester arrives today, see if we're getting a spark under compression. If not it's definitely a carb problem so I've priced up an Oko flat side save messing around anymore. Dave.

Sorry about the orientation, always does it when posted from an iPad . The bolt that secures it is about 5" long and locates through the frame and into the engine casing. Dave.

Not sure how this will help, but here are a few images of the chain tensioner on my 1980 248.

They're pretty much tucked away on these and sit very close to the front sprocket. I'll try and get a photo of it tmrw and post it. Try Inmotion trials shop.

Wil do Larry. The only thing I'm presuming is that the engine dying is electrical not fuel and is still drawing fuel but not firing,hence wet plug?????

Thank you for the replies, just checked the plug and it's wet, which is back to electrics . Just ordered an inline spark plug checker that'll be here on Tuesday. But saying that all the electrics are new from rewound stator, to the condenser, points , plug cap, plug, ignition is 2.5mm from TDC. I'm missing something really basic here........................ Will repost with results of spark plug analysis , see if it's sparking in the barrel, it's sparks really well externally, strong blue spark. Thanks guys. Dave.

Here's the 248 that's so close to running beautifully .

Hi Mat, Have a look at my post,' 248 coil relocation 'had a few problems with mine, lots of info on there from some guys who know some helpful stuff. Good luck. Dave.

Hi guys, been a month or so since I was able to do battle with my love/ hate 248 Montesa. Still having issues. As previously stated in this forum,she has been virtually rebuilt apart from splitting the mains crankcases, as there was no need, the mains and crank are in good order. She still refuses to run on the Amal concentric carb. I've sent off for a full rebuild kit which has been fitted, float level set etc. She fires up fine and will run on choke but slightly hesitant, then drop the choke and it runs for 30 seconds or so and then if you open the throttle it just dies. I've split the pet cock and cleaned the filters, fuel gets through fine , the tank vent is fine, just seems like it's fuel starvation. All the electrics are fine, rewound stator, new coil, new condenser ( now at the top of the frame ), new points, new plug and cap, good blue spark. HELP ........................

Thanks Wobbler, That may be the way ahead, just going to go over the electrics again first. Dave.

Thanks Kingscorpian, I have replaced the points and condenser, moving it to the frame near the coil. The coil is brand new, the stator has been rewound, new plug cap and plug, Timing set to 2.5 mm BTC, points at .04mm. It starts but won't run at low revs, I feel it's going to be something simple when I find the problem. The original Montesa 248 manual I have with the bike says it's a Bing carb and gives all the settings. When I moved the condenser I have ground it to a bare part of the frame ( painted rubbed off ), and spliced the condenser wire into the black and white wire from the stator which then goes to the spade connector on the coil. Very annoying .

Ok Larry and all other helpful people, another one for you........... She's up and running but pretty poorly in that she takes a lot of kicking and the plug gets wet. When she fires she will run at higher revs but not low down, like bogging. Got to be a carb issue as the ignition system has been rebuilt ,but I bought her as a non runner so no benchmark to go from. The owners manual for this 248 gives details of a Bing carb, but the one that's on her is a Mk 11 concentric Amal carb. I've had it apart and cleaned it to an inch of its life, thought it was the slow running/ pilot jet but that's fine. Thought it may be the float height letting to much fuel in but I can't see any tangs to alter, not like on other carbs, is there a way to set these or is it just , buy a new one. Any help is appreciated, even the Amal site doesn't recognise the 248 as having an Amal carb fitted just the 247, but 348s did I believe. Have I got the wrong carb????????? Thanking you all in anticipation of speedy cure. Dave.

Well............................ , puller, lots of heat and a dead blow hammer a really Big Bang and it travelled 8 feet across the garage when it gave up. Had to replace the stock Sealey bolts in the puller with high tensile ones as the originals gave way at half pressure, it was like being under fire. Really would advocate safety glasses and fast footwork to anyone contemplating this task. New seal installed, just letting the gaskets set before filling it with oil and seeing if all this work has cured the problem. Thanks for all the help guys, really appreciated. Dave.

Hi anyone following this, the primary drive thread is a conventional clockwise to tighten, anti clockwise to loosen. Tried a normal Sealey gear puller to remove the primary drive, Not A Chance, snapped very early, .....................seen the pictures on here of an 18 ton puller latched on and nothing's happening. Going to MachineMart tmrw to get a hydraulic puller and see who gives in first. By the way, the ignition tips helped, the stator was cream crackered so sent it to West CountryWindings and it came back in fine form , the spark is a belting blue colour, but on starting her she coughed and spluttered and blew out blue smoke and was unresponsive off the throttle. The ignition timing is bob on and the carb seems ok, so I'm assuming it's the primary drive crank seal that's perished and it's drawing in oil and air and that's the problem, anyone had a similar problem ???????

Hi lbhbul, Sorry no nearer only due to lack of time, it's a project that's get attention when I'm free. Hopefully going to get at it over the next week. One further question though, the counter shaft on the opposite side of the crankshaft to the flywheel, is the thread on the nut normal anti clockwise to release, or clockwise, just need to replace the crank seal. Thanks, will let you know how the electrics go. Dave.

Thanks lads, just for clarity I already have a wire from the stator connected to the spade connector on the coil, do I double these two up? Thanks..........great help.

Hi everyone, Looking for some simple electrical knowledge please. I want to put the condenser under the tank out of the way of the heat as the many threads suggest. What do you connect the red wire from the condenser to, does it get earthed to the coil/frame mount, or to the spade connector off the coil? Thanks.

Thanks guys, always helpful. Half link ordered, put it on and its fine. May invest in some new cams the original ones are hard to line up .

Is it just me, but I have just ordered a 10 tooth front sprocket, ( had an 11 on it ), for my 2013 250 Gas Gas Pro, i'm still running the original Gas Gas 41 tooth rear as in very good order. I ordered a new Regina 520 chain and when it came to fitting it was too long, even on max adjustment on the snail cam, so I took one link out and now with some pressure I can put the split link in, but its way to tight and I fear if I rode it like that it would put undue pressure on the gearbox bearing that carries the drive shaft. Has anyone else had this problem ?????? Would a set of Jitsie or similar snail cams give more adjustment???????? I've changed lots of chains in the past with no issues. The previous chain was an O ring which was too heavy duty, but fitted perfectly adjustment wise with the 11/41 setting. I fear I'm missing something obvious here. Thanks. Dave.

Hi Mudyman, I'm currently renovating a 248 and my tank is away for spraying. Mine has the external fuel gauge, which is an external clear tube and raised numbers in litres 1 to 5 which gave a view of the fuel level. I have seen others without that which I think are the later models. Dave.

Hi John, Nothing on the horizon, I do them as a hobby, between work riding the Gas Gas and everything else. Probably get something later in the year to see me through the winter months. Dave.

Sorry everyone the IPad has cropped the images for some reason, it was the full bike.......sorry not that computer friendly

This the one I've been asking the questions about. Montesa 248. Anyway nearly done, petrol tank has been lined to protect from ethanol and is being professionally sprayed and new decals. Hope the images attach. Then it'll be on Trials Central for sale. Dave.

Thanks guys, what I didn't mention was that the felt pad has worn through and then the cam has worn through the metal strip that supports the felt pad so theres nothing to support a new piece of felt. I understand guys that these things are going to be likes hens teeth and i'm probably going to have to manufacture something, thanks for your help. Regards Dave.