philhill

Oh right better get that spark plug changed for the right one or your cooler one before any damage done. Good job I checked with you! Will study that web site later. Thanks!

By the way it's a later model from 1982.

I have read in one of the manuals for this model that an earlier model than mine was supplied by the factory with too hotter plug causing overheating problems and it was replaced with the B8ES ( I think, from memory ). With this in mind is it possible that using a cooler plug will reduce the running temp and help avoid a piston holing? Also does modern petrol burn hotter than the old leaded stuff?

Hi Airhead, sorry the plug is a B6ES not what I wrote. If I remember right the timing is not adjustable and as i said it starts very easily now with first or second kick and full choke from cold so think the timing must be ok? I started with mains around 160 but have kept going up with each holed piston!! Thinking about it I was on the 195 when it last holed but went up to 220 then back down after replacing the piston. It's running really well on the 195 now, it's over bored to +1.50 and has a K&N type filter, exhaust is repaired standard if that helps to explain??

Hi, have not been on here for a while but still have my DT, nearly sold it recently though as was getting fed up with holing pistons!! Have gone up to 220 on the main jet but still holed a piston after overtaking a car at full revs. Now rebuilt but have gone back down to a 195 main as it was running rough and was better with this jet though still not right. Was passing a motor factors the other day and thought I would drop in and get a new spark plug as guessed that might be the problem. They didn't have a E8ES only a E6ES which the bloke said was cooler but should work only it might not last. After putting it in it now starts with just a half hearted push on the kick start and goes like stink!!! I still haven't done a prolonged thrash to see if it will hole the piston again for obvious reasons but as its running so well am tempted to give it a go down the bypass. Before I do I thought I would just check with you lot to see if this is wise as another piston hole will force me to sell and I don't really want to as its great for blasting around town and getting to work and back. It's also been a great winter bike and can get me to work when the car can't. But I do want it to be reliable for longer journeys and the odd blast. Any comments?

Yep, is now running well, smoking was down to all the kicking over and the oil pump still pumping oil into the barrel and not getting burned. Still have problems when the CDI is fully connected to the loom and cuts out/won't start. Key Switch is not original but cheap looking ebay item, could this be an issue here? Also do you know which is the correct light bracket if any? Phil

YIPEEEEEEEEEEEE, not sure what i did but after connecting and disconnecting the wire connections near the mag and pulling and untwisting the wires going into the mag I decided to try for a spark and there was a faint blue one each time so put the plug back in and it started about tenth kick, now firing up first kick each time. Must have been that dodgy connection!!! Smoking loads for some reason but I'm happy, just going to put the seat back on and give it a short test ride, hopefully all will be well. Thanks for help. Phil

Hi, whats the recommended method for stopping the engine from rotating whilst undoing/doing up the rotor nut, without special tools? I have considered putting a screw driver through the drive chain but dont want to damage the chain! or a spanner on the lock nut on the small sprocket with the engine in gear or a G clamp on the rotor body? any suggestions? Phil

Hi, haven't made any progress with the sparking but the inner metal rear mudguard has just come and i have offered both light fittings up to it and they both fit !! I was hoping this would identify the correct one but obviously this doesn't help now. I think it must be the larger one with the larger fixing holes but can anyone confirm and tell me what the other one is and i will put it up on ebay. Phil

Hope you two had a good time at the Squires Cafe, I have been enjoying the roads around Wales this week and had a great time except for the Guzzi handling like a pig on rollerskates, now sorted and down to worn tyres and fork pinch bolts! Anyway back to the DT. Have checked the readings and don't get many as they should be! Don't know if this is a good or a bad thing regarding expense in rectifying? Figures are as follows; Readings between:- Orange wire and earth = 1.5 [200 Ohms scale] Brown wire and earth = varying and rising between 6 and 10 ![20k Ohms scale] White/red wire and earth = 10.3 [200 Ohms scale] Both black leads the same between earth point on ignition coil at 0.4 [200 Ohms scale] Black/white and earth ignition off = 0.5 [200 Ohms scale ] key on = 0.08 [20k Ohms scale] I also got 0.31 on 2k and 0.9 on 200ohms which I double checked and don't understand?! With the kill switch down/on/in kill mode I got 1. I have put figures in bold where the scale is different to your stated ones. All connections appear good but I haven't pulled of the flywheel to check inside. I can't make any sense of the above but if it is the charge coil wouldn't that just affect battery charging and not ignition? Also am I better getting original or going to Electrex World [?correct name] ? Hope you can make sense of this? Phil

Hi, still waiting for the rear mudguard to arrive so don't know which fits. I think the smaller is off a DT100. Hopefully you will see an image below, not done this before Will have another look at the earthing of the ignition coil but just got back from work and going to have my dinner first. The CDI is 6 lead, 3 in and 3 out. Phil Off on the Guzzi now for few days holiday, going to leave working on the DT till the weekend, hopefully you can help me solve the problem then. Thanks Phil

DT is still stripped down and looking sad waiting to be kicked into life. I am guessing that as we haven't solved the problem yet it is going to get expensive from now on. Is there any way I can test the CDI or is there someone I can take it to to get it tested? Also is it possible to test the output direct from the mag? Phil ps I am wanting to restore the rear end of my DT to original. Have just won a metal inner m/guard from US ebay for $9 + $32 postage which is about £28 which seems a good price! I now need the plastic rear mudguard in either white or red, does anyone still sell these at reasonable prices? I also have two rear light brackets but they arn't the same, one is longer than the other so not sure which is correct, or if either are? Does anyone have a pic of the correct one for a DT125MX 1982 and rough measurements for the fitting holes? Thanks Phil

Have tried breaking and remaking the B/W wire but no more luck with any sparking. Checked /cleaned the connections to the CDI tried again no luck. Don't know where these wires earth to but getting good continuity with earth. Phil

Hi Cynic, I got one spark first kick(push)over then nothing despite trying for ages, then reconnected b/w wire and got another single spark then nothing !? Sorry don't know what PM is. I am charging the battery just in case but i don't think its important here is it? Phil PM=Personal mail, got it thanks

Hi Cynic, thanks for the reply. Have got 3 wires in and 3 out. Checked the cap, yes have got 5.05 on 20k setting. Plug cap is now a black NGK off the Guzzi as original is rusty inside. Presume this wont make a difference? . Have done the jumper lead thing on a weak battery (now charging) and got a weak spark. Coil and plug are new. What do we do next? Phil