So, as most of you know my story I won't bother with that but in all my fettling to try and get it working I reset the points gap to open at 2.5mm before TDC. It was timed differently the the last owner previous to this reset. I use a cigarette paper in the points to feel the moment that it releases.

I now experience a situation where she wont rev all the way out. It also feels nasty at high revs and looses power.

I am wondering if the previous owner had the timing slightly advanced maybe?

I know there is no advance mechanism so it's all about setting it where I'm happy with and getting it to run nicest in the rev range that I intend to use most, but at the moment despite being great in the low end I don't really have that top end. It's all about compromise.

So I think I'll advance the timing, half a millimetre, a whole millimetre?

I just want to see what opinions are out there?

Cheers again.

UPDATE.

Having advanced the timing a little bit with no improvement I have tried both a fully advanced and fully retarded timing setting with no improvement I have reset it to 2.5mm before TDC now and am open to suggestions.

Basically starting the bike is great, low down lots of power and running REALLY nicely. However high revs (and I do mean quiet high) aren't there. Power drops out, it splutters (a little bit) and just won't rev beyond a certain limit... Like it's starved of fuel or air. (I guess fuel?)

I'm quiet astonished after all I've been through, I thought it was plain sailing from here. Ha.

WORTH NOTING.

I didn't make any adjustments to the carb but I did take it apart a couple of times to clean it and investigate any problems.

After all the messing about with the plug (heating it and flooding it with fuel) have you replaced it as it could be breaking down. It could be that simple and after all the problems you have had you are looking to deep.

I'll try a different one tomorrow. I say different because I haven't got a new one.. I have the one that came in the bike and a brand new one that I have already used in trial and error. I forget which one is which. I will buy a brand new one at the next opportunity.

Ha, I couldn't wait. My poor neighbours. I put in the "other" plug, which seems to be the older of the two upon inspection. Again, she starts BEAUTIFULLY. I ran her gently in the garage to warm her up a bit and then pinned it in neutral. It revs high... Still kind of falters but maybe that is the "red line?" It's hard to tell without a ride tomorrow - I'll update you.

I guess there is no "limiter" so to say they just rev until the engineering says stop?

The bike is really keen to go and feels very powerful, maybe I'm just expecting a higher rev range than is available... It's amazing how sporty these two stroke competition bikes feel compared to my Royal Enfield's that I'm used to. (A 500cc road bike and a 350cc trials trim Enfield.)

An amazing machine.

My memory of Montesas is timing at 1.8mm BTDC (but the passage of time may have affected my memory). And checking every couple of trials as I liked it to run just so.

Well of course you never did tell us what the jet sizes were in the carbs ?

Tony

My memory of Montesas is timing at 1.8mm BTDC (but the passage of time may have affected my memory).

I've seen it referred to as being 2.5mm BTDC a few times across forums and on the net. Can anyone confirm for us?

Well of course you never did tell us what the jet sizes were in the carbs ?

It ran fine when I first used the bike before my hot start problem made the bike unusable... Maybe I just wasn't brave enough to rev it this high though? Ha. I can check the jet sizes tomorrow if anyone thinks it will help? Are they stamped into the brass on the jets or will I have to measure them with my callipers?

Thanks again.

My very old scruffy manual describes it word for word as -

Alternator flywheel. MOTOPLAT 9600450

Points contacts gap 0.4 mm

Spark advance at t.d.c 2.5 mm (21 deg over flywheel)

I could possibly scan the manual and send as a PDF in a few days if it would help!

If the bike still has an amal carb I would replace the needle and needle jet as these wear and will cause the bike to run poorly at high revs

Cheers Greg

My Montesa manual provides the timing specs as follows:

Cota 247 - below serial number 21M2999 = 4.0 mm

Cota 247 - after serial number 21M3000 = 2.5 mm

That's interesting, I'll check the serial number tomorrow. A PDF of the manual would be great! No worries though.

It's the Mikuni carb by the way.

You will be able to read the size on the main jet as it is easy enough to read. The Pilot will need to be unscrewed with a small flat blade screwdriver and also where the needle clip is will give us info on the set up, likewise the slide may also be marked numbers from 1.5 to 3

Tony

its not a moto cross bike nor a fast road bike its designed for the torque to be used more than hi revs ,its not very often you would get into a situation where you need to be flat out other than up a steep hill ,unless your trying to keep up with enduro bikes its not ment for that , you really could do with someone that has more experience with this type of bike to have a ride it could just be too rich top end or your expecting too much from the old girl