Yamahdan

Started it yesterday, getting the polish out on it tonight.. should be easy, I'll wait until I get the barrell back from boring to relieve it to give it room in the bore..

Mine got quiet before it died, check the compression.. if the piston and rings cost £30 I wouldn't be 100% on their quality tbh... may not be a very good fit in the bore? Danny

Any chance the Temperature Sensor could've got damaged by the freezing water?? Could be sending a dodgy signal?? Danny......

Started the work on the DT tonight, (work nights) put the top end through the wash, and baked dry. I began with the head, everything was removed thermostat etc, the dome de-coked and mild-ly polished, then the head sealing face was lapped to remove all of the "dinks" in it from previous work being done. End result: I think in the picture below the glare from the light on the surface messed the camera up a bit! You can see a pretty decent reflection in the pic of the light above the bench! Surface is flat within 0.008mm, and mirror finish (going to try to decrease squish by not using head gasket) Thanks Danny

Hi all new to the forum, thought I'd start a thread on my DT rebuild. I bought the DT about 8 months ago, when I bought it it looked like this. TOP SPEC AS FOLLOWS: Powervavle pegged open, badly! Rusty DEP full system Wobbly back wheel (2 spokes missing) Scuffed plastics Rusted twisted chain Home made number plate bracket that spun sideways Generally s#*t condition Not in the best nick, but I wasn't concerned about that because it cost me £1050 with tax and MOT a full tank of petrol and a few spares! I got it home, fixed number plate, un-pegged the YPVS and got it working properly and used it for work for about 6 months. Then one day on the way to work the bike was getting progressively worse "burring" and "blipping" more and more often until a "ping" come from the exhaust. From then it was first and second gear "burring" itself along, got it to work and in the car park it died completely. No compression what-so-ever spinning over on the button with no resistance at all. Excellent.... Anyway picked the bike up a couple of days later in the van, got it home and whipped head, barrell and piston off... Excellent. Clearly running very lean... I am now in progress of re-building the engine in full... Pics and write up's will follow as and when things happen, but don't get much time so it will be slow! Thanks Danny

Thanks for the replies, You're right, It does have a massive affect on surface finish (rough it up) but it also gives the bore very good geometry, i.e. Roundness and straightness, which when boring will be crap, due to running an interrupted cut over the ports, and as I'm looking to use the bike to basically out-run all of my mates at enduro's I want it to be running spot on without coughing up for a new cylinder!! As far as the bottom end goes I haven't stripped it yet, I've literally whipped the head, barrell and piston off to see what the crack is... There is play on the conrod so its getting stripped down to nothing anyway to rebuild this, when it comes apart I'll see whats happening in the bottom. I believe I know why it was running lean, I intend to replace all bearings and seals anyway so air leaks will be eliminated, I'm going to knock up a "crankcase vacuum tool" before I strip it to see if it was this. However I do know that it is seriously under-jetted, its "rockin" a full DEP system with a 210 jet not a good idea, grey deposits all over the top and underside of the piston (whats left of it) as well as the spark plug! Thanks again Danny

Hi all, DT was running majorly lean from when I bought it so after a month of riding it melted the exhaust side of the piston, grey/white deposits in the engine etc, needless to say the barrell took a beating, I want to keep the rebuild as cheap as poss so want to rebore. I have found a couple of companies but not sure of the quality of their work.. I have all the ability at work to machine the bore oversize but not to hone it ( don't have a hone big enough ), I also have the ability to measure it all to the Nth degree, which I intend to do after the job is done. I don't mean to sound anal about it but I want to get the job done right because I want the most out of the DT. So could anyone recommend a trusted service ( preferably in Kent ) who I could talk to about doing a re-bore on the DT? Thanks Danny

Could it be the CDI? problems revving could be that? Danny