Airhead

It can be tested, the best way is to use two multimeters, connect one on series and set this to read DC current, connect the other in parallel, ie between the wire to the reg and to chassis and set to read DC voltage. Start the engine and increase the revs, as the revs increase the voltage rises above the nominal battery voltage you will see that the meter reading the current will start to read the current that is shunted back to chassis ( or battery negative) if your reg is working correctly. You could of course use one meter, first do the voltage versus revs and take note of the results, then connect for current in series, you will know what voltage is at any given revs and can see the current on the meter.

How many wires to the regulator?

I agree at this stage it might be an idea to buy a main jet one size up from the one you have at the moment, are you on 130? Also what about the barrel fins...hope they arent powder coated I believe this can cause heat retention problems and so should be avoided.

Seems not...

Leave em there Phil, if you try moving them you'll only have some kind of a misfortune...

were both clutching at the same straw you mean...

Hi, make sure that the tap isnt left in 'Prime' position, also you carb fload needle on one of the carbs must be passing which allows this over filling to occur. if the tap is not in Prime position it is leaking, you can confirm this by removing the fuel feed pipe to the carbs.

Oh thats a real bummer mate But how come you were "(flat out down the duel carriageway)" you have just done a rebuild and didnt you put new rings in or have I got that wrong? Have you ever checked your oil pump and after the re build did you bleed it and force it to full stroke to expel any air in the system? I have never heard of the weak spark theory you mention, so cant really comment right or wrong! As for checking the coil, use an ohm meter, the primary winding is checked from the small wire to the metal mounting of the coil, result should be 1.0 ohm +- 15%, the secondary winding is measured from HT lead (without cap) to the metal mounting and result should be 5.9 ohm +-20% ...Paul

A field bike...just do it, I would also cut right through the bushes (lengthways) just once (I dont mean cut them in half) with a hacksaw, you will find them much easier to re fit.

I know you checked the switches but try again with the kill switch disconnected followed by the ignition switch, see if you get a spark then!

Hi could be pulling a vacuum in the fuel tank, it me take aroun 10 miles to pull enough vacuum to cause problems, check any vent lines on tank or any vent holes in filler cap. Next time it happens stop the bike and open the filler cap see if you hear any inrush of air and also see if having done this the problem has briefly gone away.

yep will do no harm so long as youre not going for a long ride with flush in, go ahead.

disconnect your fuel pipe from the carb, open the tap and check for a good flow out of the pipe, there is a screen filter in the tap (petcock) bowl and it can get clogged up with debris, this is an easy check and well worth doing on an old bike with unknown history. ...

Change the oil after you fix the running problems because you will be better off draining it when it is warm / hot The manual states 10W30 oil...650cc quantity Personally I would use any motor oil even 10W40 that you may have to hand, these engines arent fussy and its only transmission oil so will be ok

Hi Tom, you would need to buy or borrow a compression tester, basically its a pressure gauge that you screw into the spark plug hole, then you use the kickstart several times while holding the throttle open, the gauge will show how much compression your engine has and is a valuable source of information with regard to piston ring / bore wear etc.

Darren, FYI there is already a facebook group set up, you will see the link in Alexigno's signature area. I take your point though that it would be a good way for Alex to keep us informed, thats a good idea.

All the above are possibilities, but dont forget that 'cynic' mantioned the choke, its going to be a b4strd to start if youre not using it or for some reason its not working, I dont 'know' your bike so try to fatom if the choke is good. also the usual way is to give little or no throttle when trying to start, is this what youre doing?

Drain the fuel and put fresh in, including the fuel in the carb, you dont know if its good or bad fuel and its an easy thing to do, you havent seen any reason why it blew up, no apparent damage to big end, no seizure, no bent valve...who knows what he thinks 'blew up is' !. you said something about if you pressurise the tank its better...is that still so?

Youre lucky, my DT will only run on one

Yes I did ask James to check out the fuel tap in one of the other threads, James I asked for a description of the tap ON OFF PRIME? have you tested the fuel flow to the carb is good?

Exhaust gaskets are the crushable ally type Fork dust seals should also be renewed, to remove the metal caps, I use an electricians type terminal screwdriver with a good sharp edge, tap the cover up at the join line, work your way round evenly, you will soon have a good enough gap to be able to strike it from underneath. It might be an idea to replace the piston rings in the forks too...part mumber 2A6-23157-00 Two off. Dust seal part number is 2A6-23144-00 Two off. One point for concern is the knocking on full rebound, there should be a small spring in each leg to stop this Part number 2A6-23151-00. Gianelli pipes are hard come by now, but you can buy 'Big one' expansion pipes approx £110 new

It would benefit all if you didnt keep opening up new threads, you must have about five on the go now, people who respond may now know what has already been said

Hi phil welcome to the forum, your bike is a DT125MX, the headlight will only work with the engine running, turn the key to position two and then turn the ligh switch on.. I will check on your carb later but it doesnt sound right to me, I think you jet is too big

Welcome to the forum Douth