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Hi Alex, The good news is all our jap bikes are metric! I've used helicoils on both my Honda and Yamaha, in my cases the studs were M6 and an M8 so i just bought the M6 and M8 ones and they fitted fine. There is a useful chart here:- https://www.thorintl.com/Drill-Sizes-HeliCoils-Metric.shtml I had to drill the worn out thread with the correct drill, and rethread the hole (all supplied in the kit) and the tool came with it to insert them, but technically its just a bit of coiled wire that goes in tight within the newly threaded hole and the stud just screws into the thread made by the coil of wire. However a threaded insert sleeve is different to a helicoil and are designed for more load bearing. These are double threaded metal sleeves These require the hole to be drilled to a bigger size and retapped as the threaded insert is made from thicker metal. If it's a cush drive, I'm wondering whether a threaded insert may be more substantial and therefore more suitable.? Either way you will need the thread pitch and diameter of the exitsing stud.

Thinking about it.... You said in your first post ..that she starts and runs fine....if you DID have a snapped off RED wire,: i.e you have the Two Source coils version, and your red wire was missing THEN it probably wouldn't run! The two source coils are responsible for maintaining the performance at low and high speed with the correct corresponding CDI. It was soon replaced with the single source coil and a different CDI more common on the later models. The CDIs are not compatible with each other. I'm not sure why two coils stacked on top of each other was used. On the one hand it seems over engineered to deal with it, and on the other hand with two coils surely there was two chances of failure?. Either way it didn't last long and obviously not a successful method, otherwise they would have kept it and continued to develop it. The simple answer is, probably someone came up with a cheaper simplified solution of the single coil which matched the performance of the two coil version. So in view of the above, I'd venture to say, the fact you have it running succesfully, the reason why the RED wire is missing is you have the later single source coil and you're looking at the wrong circuit diagram. Hope this helps, look forward to seeing the photos you mention in your first post. Well done bud. I must confess i enjoyed answering this one, got me thinking.

Hi welcome back Scott! You say it was a field bike in which case it may not have all its correct OEM parts! which might explain the discrepancy in the number of wires! I have a DT175MX 1978 with the round tube swinging arm and I may be able to help you. You see the RED wire is only found on the earlier model with two source coils. Its actually the WHITE wire which is part of the charging circuit. (NB: The outgoing Green/white wire changes colour to WHITE within the plastic connector) If you have the same two source coils stacked on top of each other as you can see in my photo, then you will have 4 wires going to the CDI as in the haynes manual page 167. If you look in the corner of this photo (yellow circle) you can see all the wires within the generator before they disappear from view within the loom wrapping. Here the wiring is least likely to be under tension and therefore more likely to still be intact even if one wire has snapped off within the loom. You can see and count them and be able to trace them back to the coils where you can see the red wire going to the upper source coil in the photo. There should be 6 wires visible here: x4 (RED, Brown,Black and White/Red) from the two stacked source coils and x2 wires from the dark red lighting/charging coil (Green/white and Yellow). Note the red wire in this layout goes to the CDI. Not directly to the battery. The red wire you see on the battery comes from the rectifier not from the CDI circuit. However, if you have the later generator with only one source coil then it will only have three wires as in the diagram page 172. Note there is no red wire to the different CDI. however there is still a red wire from the rectifier to the battery. Therefore there will be only 5 wires visible: x3 from the single source coil (Brown, Black and White/red) and 2 wires from the dark red lighting/charging coil. (Green/white and Yellow) To explain the charging circuit on the WHITE wire take a look at one of my earlier posts on converting my DT from 6v to 12v. It's a long post but I do explain in detail how the charging circuit works along with detailed pictures. Hope this helps

Excellent news bud, glad to hear you're up and running.

Contrary to popular belief plug gaps don't open up much at all, maybe a few thousandths of a millimetre yes, as the central electrode wears down, but not by a couple of millimetres. The plug gap arm gets extremely hot for sure but it needs a physical force to open the gap up, it doesn't get so white hot in normal running that it melts and moves away from the electrode. Furthermore if the widening gap was detrimental why would it run perfectly normal? I like these sort of puzzles and problems, it makes you think. Keep us informed of your progress bud.

That's interesting!.....and may have some significance. You see modern engines now use very lean fuel mixtures and subsequently have their plug gaps set much wider than they used to be. They apparently are set wider as there needs to be sufficient molecules of fuel in the gap to ignite. Smaller gaps may result in misfiring and incomplete combustion. If you say you're having to run it on choke, you're decreasing the air ratio thereby increasing the molecules of fuel. I appreciate it's a pig to keep removing/replacing the plugs but it's all part of fault tracing and the process of elimination. I'd be inclined to match the plugs to their previous conditions with the same gap and see what happens, there may have been a very valid reason why they were set so wide in the first place.

Does putting the original plugs back in resolve the misfire? if it does then there's something wrong with your new plugs if it's a single faulty plug: it's a case of putting in one new plug (with three old ones) at a time until the misfire occurs, then you've found the faulty plug. Don't stop there, just test all of them to ensure you don't have more than one. Occasionaly you can get cracks in the porceline that can cause misfires,(you'd never know if they've been dropped before you bought them) They may not show up visually on a brand new plug, they do on dirty ones as the dirt gets into the fine crack. If it's the set of plugs: hear me out first! sometimes a full set can collectively cause a misfire if the set is not fully compatible to the correct rating. I have an example where a friend changed a set of plugs on a Ford Mondeo and it transpired there were two different plugs depending on which HT leads were fitted NOT the engine size. So the length of the spark plug head were identical, but the porceline was slightly longer on one set yet they both had the same spark plug number except for a letter on the end. The shorter porceline meant that the HTplug didn't seat properly and caused the misfire on all the plugs. Therefore don't just take the length of the plug head as being correct, check the top for correct dimensions as well.

Then I think you've answered your first post question on what is the problem! You state in your first post that you "Replaced spark plug,stator, flywheel" so based on that sentence, you replaced the stator then it's probable that the stator has not been positioned correctly as it's part of the timing. Set even half a millimetre out will alter the performance. Set many millimetres out and it won't fire up or run. As you're a new member with only two posts and no introduction in the members area, my suggestion would be to have a look at You tube. There are several videos on timing two strokes for your bike which you may find helpful. The timing mark is a scribed line on one of the ribs. That should set you on the path to sorting your problem out. Good luck and keep us informed.

Hi there, The purpose of the regulator is to 'regulate' or reduce the voltage! The generator produces the AC voltage, and if you were to measure directly off the coils, on the charging circuit (with nothing else connected) you will indeed find a rising AC voltage depending on the revs... the faster the revs the higher the output. On a DT 175 MX you will see 26v at 6000revs. The REGULATOR 'clips' this voltage back down to 6 volt (on a 6v bike and down to 12v on a 12v bike) and it is this reduced voltage which charges the battery. Otherwise the battery will get fried on the unregulated output of the generator. So if you're getting 40v it strongly suggests the regulator is not doing its job. You might want to have a read of one of my popular posts on a conversion of my DT175 from 6 v to 12v. It's a long read but I do detail how all the parts work, which might help you understand it. I do note also that some XT owners have indeed used my post to convert theirs. However, i must point out my usual disclaimer: this is what I did with my DT175MX not any other bike. Moreover, I'd also like to add that 10 years later...my 12v conversion is still working perfectly fine. hope this helps.

Hi Ditchkid, Excellent welcome there and first post. Well done. Always liked choppers, so nice to see one. Hope you'll like it here, not as busy as it used to be but still a great website to visit. Great bunch of guys to chat to. Once again, great intro.

HI,Presumably it runs then if you say the speedo doesn't register whilst riding. i did a google search( although I expect you have done too) and came up with this... https://www.motorcycle-manual.com/yamaha-fault-codes/ scroll down past all the green text to see the error codes and explanation although to be fair even this website https://www.vmaxforum.net/threads/er-1-and-er-2-error-codes.17765/ and this.. https://www.r3-forums.com/threads/error-code-er_1-video-of-issue.143570/ they all have one fact in common.....they don't run!!! therefore not sure if this is of any help. having said that some of the suggestions within the posts may be worth checking.

Shame you don't know anyone who's going to America for a Holiday! bring it back in a suitcase.

hi Geiger, DT175MX is 77cm, however, a useful site is Wemoto. just put in "yamaha Tacho cable" in the search field and a lot of the cables have lengths published. i.e: Tacho Cable Yamaha DT 250MX 1977-1982 Outer 800 mm Inner 825 mm Inner thread diameter 11mm Outer thread diameter 16mm if you leave out "Yamaha" then it lists some 120 cables for different makes. Presumably the part number is B38-2240 as I see there is one on ebay in USA at present.

Further to the above thread, I also replied with this which you may find helpful as it relates to the airleak i had..... This idle problem may well be air related, I had a not disimilar problem, albeit it would race away. But mine would not idle properly either until I solved the airleak. One solution to locate a leak (mine was the bottom gasket) was to make a load of soap suds bubbles and brush it all around the engine with an old paint brush whilst its running, any bubbling will locate the leak. (A similar method is used to spray WD40 on the crankshaft seal as mentioned before) Might be worth a go....its only soap suds!!! and you'll clean your bike at the same time!

Hi there, all very familiar!! have a read of one of my previous posts about my DT....

Sorry bud, I was just responding to the opening line... I don't see a lot of Brass studs/bolts being advertised. That's the trouble with text, it's not the same as conversation.

You don't normally see brass studs or bolts as brass doesn't have a high tensile strength and subsequently its threads strip easily. It's quite a soft alloy. Having said that it's easy to clean the threads of a steel stud if a brass nut has been used and it's been overtightened. You just pick out the strands of brass stuck between the theads.

Sure did and within 24 hours of the question....or perhaps you didn't realise you posted twice!

Hi Gordon, Had a look on google for you, came up with an exploded diagram of the ignition switch, and i assume you're referring to the switch cap cover as shown in the diagram labelled no 6. https://goparts.eu/en/genuine-oem/yamaha/scooter/xn-teo-s-125/2000/battery On bigger motorbikes generally these are a push on fit with lugs on the main switch body which holds it in place, it takes a small screwdriver to prise the cover over the lugs to remove it. Not saying yours will be the same but like I said "generally" they are fitted this way so no reason to think it would be alot different. A close up of the part number seems to confirm this https://www.motorcyclespareparts.eu/en/yamaha-parts/5adh25520000 hope thats of some help.

Hi scott, have you thought about replacing the crankcases,? might be a cheaper option. Theres a pair of crankcases on ebay for a DT125MX which are identical. I know they are in Greece but even with customs it would be cheaper. https://www.ebay.co.uk/itm/Yamaha-dt125-dt-125-mx-1978-2A600-engine-casings-cases-motor/124306021524?hash=item1cf1375c94:g:R-AAAOSwH2Be3CHk There was a thread a few years ago about the 125MX crankcase, and Airhead confirmed they are identical. Might be worth thinking about?

Don't waste your money Scott, i did my DT 175 engine without any of those tools. (I did use a flywheel puller though) The crank case comes apart really easy, i think if i did do anything .... i may have used a strategically placed bit of 2x1 timber and a gentle hammer. Just don't use a screwdriver to prise the two halves apart. I certainly didn't use any fancy tools. The clutch centre nut wasn't difficult either, a bit of wood that was all and socket set. I used 2 bits of wood under the piston to do the crank nut and a chain wrench on the generator nut. These photos may help.

Hi Nicomasala, I might not be able to help as regards to the engine casing compatiblity but I can give you some advice as regards to the welding. I answered a similar post the other day and my answer also applies here:- The casing is cast aluminium, if you're not familiar, they make a mould and pour in molten aluminium and it sets into the shape they designed, it's quite strong, but if it gets damaged it's a different story. In my experience aluminium welding is not that successful especially if its going to support something, it's more suitable to say,.. repairing the outer casing... to seal up a crack. (which doesn't always last). Regretfully you're looking at replacing the damaged casing with another or a new one. In my opinion the original casting is always stronger than a weld repair, it simply won't have the same structural strength and will likely break again when put under pressure. Might not be what you want to hear, but that's my advice, hope it's of some help, kind regards

Hi jack, The casing is cast aluminium, if you're not familiar, they make a mold and pour in molten aluminium and it sets into the shape they designed, it's quite strong, but if it gets damaged it's a different story. In my experience aluminium welding is not that successful especially if its going to support something, it's more suitable to say,.. repairing the outer casing... to seal up a crack. (which doesn't always last). Regretfully you're looking at replacing the damaged casing with another or a new one.

Hi Bud, looking at the parts diagram https://www.bike-parts-yam.com/yamaha-motorcycle/900-MOTO/2018/TRACER/MTT850D/FRONT-FORK/2017_76703-76703/26/0/25207 there is no equaliser between the forks and two sets of internal springs are listed ,one for each fork! Mind you proving it that they left out the components is a different matter. Having said that, you're getting new internals fitted, but I certainly wouldn't be taking my bike back to them.

There are some decent good people about Mike and glad it turned out alright. Has anybody had any pillion 'mishaps'? well yes, only the once, fortunately it all turned out 'ok' albiet a very frightening experience. it was also about twenty years ago, when I offered to take a nurse colleague out on my 400/4, as she'd never been on a bike before and admired my bike parked outside. I took the bike out through the countryside of West Sussex and ended up about to join a straight stretch of dual carriageway along towards Chichester. It's a T junction and the road is clear both ways save for a left hand drive gutter sweeper parked in a layby down the road. There was no showing off but i pulled out and opened up the throttles as the road was clear. Then to my horror, that street sweeper pulled out across the road heading for the gap in the central reservation. It was a 90 degree turn and the driver was in the left seat! If i'd braked there was insufficient distance to stop so it was a split second decision to aim the bike at the decreasing gap and to lay the bike down which grounded the off side peg and we shot under the raised cab of the street cleaner. I've no idea how I came out unscathed as I righted the bike on the other side and went over to the side of the road. The guy got out of his cleaner and exclaimed he just didn't see me pull out of the side road. My nurse colleague said it was so exciting and didn't see the danger in the situation. Personally I was white as a sheet and never took another pillion again!