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If any of you remember at the end of summer I completed my dragster bobber build and had it mot'd and on the way home the engine broke. This is such an understatement as everything that could of broke with the engine did lol. After a lot of swearing and asking for help and advice Robo (member of this group) came round to mine to lend a hand he got the bike running but it didn't sound good so we took the engine apart and realised that the previous owner must have known nothing about motorbikes and abused this bike no end, the engine was f&£ked and beyond repaire. That hit hard as I had spent a year building her. This is why you get the engine running first, a big learning curve. After a while of looking we found a doner bike and after a lot of conversation with the seller this looked like a goer. So I bought it and got it back to the garage (that's another story all together getting that bike back). Another visit from robo to check the new engine and we found that none of the parts that the seller had said were in there were in fact not. But hopfully a set of rings would fix this. I put some new rings In, re lapped the valves, set timings and now after a new battery finally I have a working bike. I have a few tuning issues but very happy to be out riding again. So a big thank you to this group and Robo for getting me back on the road. Oh and also the left over whole dragster, bar engine now has a virago engine in it and is on the road too. Result.

I can't seem to find any engines just high milage ones. Really thinking about putting a virago 125 or Sachs roadster 125 one in. They seem to be coming up. There also a lot cheaper on parts and I know the mounts are the same. Is it a slower engine?

Quick update! after another visit from robbo and my engine in pieces we have come to the decision that my engine has been abused so badly that it really is not worth saving. The cylinders are scratched. Piston rings shot. Probably cam rods. Front cam chain. Valves lapping. Hairline cracks in the clutch basket. Lots of rust then we managed to get off the sump bolt. Killer blow! There was so much mettal flake in there it wasn't worth going any further. So anyone got an engine!

Thank you robbo. Your visit was really apreciated and very helpful. It's really good to see someone that knows these bikes work on them. I learnt a lot that evening. I have now started stripping the engine down and trying not to get over whelmed by it. But really good to have people on hand thank you again to the forum and robbo.

lol. Yes I have tea.

Your not a murderer are you robo? Lol

Thank you robbo. That would be really good and much apreciated. Thursday afternoon/ evening I will be free. I will email you. I will fair worn the pregnant lady that I'm working on the bike. Lol.

Oh the decision was made when I bought the thing that I was in it for the long run. But at that time the scooter hadn't broke its crank shaft and I didn't have a baby on the way. And my wonderful other half has put up with me being every waking hour Available in that garage to get her done and to be honest I was all ready at the limit she can take me being away by the mot. and now it really has got to that point 3 months till due date. I now have to finish the house and lots to do. I can probably squeeze a few more days in on the bike but my heads on the chopping block. Robbo yes if you could spare a bit of time I would really appreciate that. To chat to some one face to face about this bike who knows them would really be helpful.

Here's a bit of an up date but not much. Cleaned all the conections. Coils etc. Checked pipes again and replaced manifold. put back together. And still nothing. It sounds like it wants to start but just doesn't. Is there anything more I can try before I start delving into the cylinders. As that's going to start getting expensive quickly. Urgh and it's really good weather for a ride too. I still can't find an earth from the battery to the frame. But if it needed one why would it start before without one.

Yes this is that bike. It don't look anything like it did when I bought it now though.

Thank you I will check my valves out when I do my cam chain. do you know if my cylinders should be a combined 12. Or each cylinder should be? It's not clear in the service Manual.

So should compression be 12 for both cylinders or combined and why would cam chain jumping loose compresion? Whe I bought the bike I was told it was running on one cylinder but the guy didn't really have a clue about the bike. So I took the gamble. I did manage to ride my bike up and down the road the day before the mot and it seems to be running fine lots of power. Why would this suddenly go and loose power on the way back from mot if the guy I bought it off was oviously having this trouble before. Which were talking he had it working years ago. I'm a bit confused now. And not sure what to do next. And thank you robo that is much apreciated. I'm still learning and a very sharp learning curve on this bike, also the fact that I really haven't heard or rode this bike when it's running right isn't helping much as its all gues work, reasurch and forums. I do have the service manual but that's a bit vague some times lol. Maybe it would help having some one look at her that knows this bike a lot better than me. And for my moral as all I want to do now is go out and ride her. It's a very expensive paper weight at the moment.

I will try to answer all the questions. Millage - 39905 the front cam chain is loose but not loose enough I think to jump tooth yet. I have had the tentioner out and it's working fine I believe, screws in then springs out nicely. The noise I believe coming from the front cylinder was like a sewing machine that's why I checked the clearances and they were to big so adjusted them. And have checked twice more. But will do again as I want to double check tdc. I also had rattling from the clutch case so had that off as well. There was lots of rust in the oil which was from the back of the fly wheel. That's been all cleaned. I think that was he rattle from there. So how do I do a valve test. I wish I could get her started too. At least I could test her then. When I checked the spark plug the front was bright yellow and the rear was a weak blue. As I have to change the manifold, it split in me keep taking the carb off. Which is hear and a rebuild kit for the carb so will check all the conections on the bike at the same time. Do you know where the framed earths are on this bike?

Running start I feel like I have all ready done a couple of marathons lol. Ok I have done a compression test. The front and back should be 12 kg/cm2. The front is 5 and with oil 6 and the rear is 5.5 and with oil 6. Surly with the oil it should be up to the 12

Yeah I will prob pop in to wemoto and get them to cross reference there part codes as they have done that before when I couldn't find a petcock. They looked to see if the part apeared on another bike. As far as my reasurch is going I believe that the xv 125, 250, sach roadster, xvs 125 and 250 share the same engine just the Pistons are bigger on the 250s.

As parts are very expensive for the xvs 125 and vary limited is this engine used in any other bikes. Maybe I could search for a cam chain. Piston and rings. For another bike. I'm finding lots for the xv 125, 250 and xvs 250. Are these the same

Cheers bud. I'm from Brighton. Ok well I will leave the compresion issue and cam chain for the moment as this I defiantly know is a problem. I have done test with tea spoon of oil and finger over plug and defiantly better on front cylinder. But I can check again properly when the compression kit turns up. Prior to me riding her to the mot it was starting on the button and ticking over lovely. Obviously compression issues and cam chain would not have got this bad on a one mile journey. I also lost power on way home so Since getting her back I have checked valve gaps and adjusted. Now the bike will not start turns over and wants to start but doesn't until I run battery out. I'm getting spark although the front is brighter than the back. I have also had the fuel tube off the carb and turned engine over and it's coming out. Any more checks I can do. Thank you for the help. Ian

I'm not going to touch it now till I can do the compression test. If it is the Pistons it's looking like it's going to get very expensive. Any suggestion how this could be fixed cheaper. I have a baby on the way and this project is getting harder to fund Gutted.

Hi, I bought my dragster 125 about 8 months ago not runing with the intention of bobbing it as my first bike project. I managed to get the engine runing breafly but not test driven as I had not done my cbt and the bike was not road worthy. But the engine was running well so I started restoring the bike, 8 months of a lot of hard work and looking forward to riding it this summer. I finally finished the bike the day before the mot and managed to get a couple of test runs out of her and all seemd good. The mot went excellent not one bad thing said. Glowing in fact. On the way back from the mot was where it all started to go wrong. there was a bit of rattling from the clutch case and taping but I haven't much experience on motorbikes. Then I loose power and the bike struggles to get up to 30mph. I thought I had run out of petrol so I filed up at a station and then I realise I was on reserve. So thought I must have dirtied the carb. Since then I have had side case off only to find rust behind fly wheel which I have cleaned that must have been the rattling. I have checked valve gaps and cleaned carb. Now the bike turnes over but won't fire up. I'm getting a spark. I'm getting fuel through. I also think there could be low compresion from the front cylinder but can't confirm that till the compresion test kit turnes up this week. I'm really fearing the worst and this bike has had a lot of time money and effort in it and only got to ride it once.

hi. I took my side case off on the gear side as my starter motor had disingaged from the starter gear. When I took case off I found that there was oil on my stator and flywheel. Not much but enough to coat like gravy. This could have got in there by me taking casing off. I have never known oil to be here? I thought there might be a seal behind the flywheel that has gone but at present I haven't been able to get the flywheel nut off to have a look. It's on there tight. So my question is, is this normal for this bike to have oil in with the stator/ flywheel. Cheers for any help. Ian

hi I'm new to this forum. I have just purchased a 125 yamaha xvs dragster which I am trying to fix to get it through its mot. After which Im thinking of bobbing it ? Or somthing. I have learnt a bit about bikes but only on automatic chinese scooters so this is another learning curve for me.