Hey @rhodes5150, Nice early example which should hopefully be full power. Best thing you can do with these is to start by getting them full stock. That's a derestricted CDI (yours sounds like it should be), then making sure you've got a working YPVS system which is setup correctly. If the engine is sweet, then leave it alone for the time being. If it's aged and worse for wear, then getting it rebuilt is the way to go. These engines are incredibly simple and easy to rebuild with no specialist tools required. Can drop the bearings in by using a conventional oven heating the cases up. Checkout Yamaha DT 125 r derestriction to see what's needed for your bike. Once you've got the stock motor running sweet, and you still want more power then here are a list of mods I'd do (haven done most of what can be done, experience tells me this is the best order and bang for buck). Exhaust System Full DEP system Really perks up the mid-range punch Cuts out significant weight over the stock system Zeeltronic Ignition System Over my DTRE/X (pretty restricted CDI) really punches up the midrange Carbon Reeds I run VForce4 Reed block on my DTR But generic carbon reeds can help Mileage may vary I'd struggle to tell the difference Porting work Making sure the head/squish is correct is where you'll get the most gains Cheap to get someone to do and can make or break a two stroke Having the cylinder done can be more expensive and mileage may vary on this Athena 170 I've grown to appreciate the 170 kit It doesn't compare to RS 125 big bore kits or other extreme setups Massively increases the mid-range (reducing overrev) Makes the ride much easier to live with Of course this can also be ported to make additional gains here. You can do other mods, such as skimming the flywheel. This doesn't give you any more power per se, but allows the power to be obtained faster. This can drastically affect the overall performance though, so sometimes it's best to leave it alone.

@Calum thank you buddy appreciate

@Michaelashbrook Doesn’t matter which side they go, as long as they run through. Is that what you were asking?…

Here are the differences in the 3BN Cylinder head [image: 1483566896896-dt125rheads-diffrences.jpg] It'll be marked on the cylinder head. [image: 1663628447669-874e98a1-e604-4e06-9310-d20f77cae655-image.png] The 3BN head is interoparable with the 3MB head, but has a combustion ring which is said to adversely affect performance. Here is a video of the difference between a 4FU cylinder and a Belgarda 3MB00P cylinder. https://www.youtube.com/watch?v=P8okvTxe-Bs Here is a 3MB cylinder. [image: cylinder-1_medium3MB1131100-02_4baa.jpg] [image: 1663628477295-8e899a28-4514-4881-89ec-bfcc824ade10-image.png] You'll see the crankcases are stamped 3BN [image: 1663628512647-b054f520-0af7-4920-948f-cc532b8bbd25-image.png] For the most part you don't need to worry about it, it'll be rare that you'll find a DTR with a 3BN crank/cylinder and most of them will be 3MB cylinders. But it's just worth bearing in mind. There are variations in CDIs and Exhausts which affect the performance, but these are less important as there are aftermarket support that recitfies any loss in performance

@facundo-duarte There are loads of unused block connectors all over my 1988. Just cause it’s there doesn’t mean it HAS to be used… Your jetting is perfect for a late model Mikuni 28mm flatslide… I’d try removing the side of the air box yourself (don’t take somebody else’s word on it) and remove the the foam element. They fall apart over time, especially the aftermarket ones…. They need cleaning with solvent, or petrol but make sure it’s proper dry. Then you have to wet it with oil and squeeze out all the excess…

@gazza76 the neutral switch is part of the side stand curcuit. its when you take it out of neutral and put it into gear that it cuts out the engine, i think. someone who has one fitted would be more 100% more definite than me who doesnt have one fitted... its probly best to follow the wires from the side stand switch and see what they leed to...

@BalnAndCantGetUp Yeah, the problem is, is the way they are and what are you have are two different things. The way Yamaha intended the machine, and the way it ended up varied from its release in 88 to its discontinuation in 2007. I am merely recommending putting it back to how Yamaha originally envisaged the machine makes a lovely bump in performance with minimal degredation in reliability. So in the DTRE/X they put a huge honeycombe restriction in the exhaust expansion chamber. They gimped the YPVS to retard post 10K RPM, and the reeds are just a nice to have as they're cheap and easy to fit. That's all I was getting at. I had/loved mine in stock trim for a good while before I started fettling with it.

Hi Andy! Fab! My Dad has a DT400B that he's been in the midst of restoring for about 8 years now. I think he has all the parts, but he's since moved on to a Vespa and Lambretta obsession! But I'm hoping he'll throw the DT400B back together and talks of passing it on to me [image: aeJ7dpP.jpg] [image: WYp7ieO.jpg] This is predominantly a DT125R website, so knowledge about early models is very limited. But of course we're all motorcyclist enthusiasts so we welcome any bike really. Although, admitably, traffic has plummet in the last 12 months.

6Nm rings a bell Haynes is invaluable.

Also got me thinking about that high mileage bike you had maybe it had a slightly diff sprocket setup or something or just a blessed engine my current one pulls so nice with a larger front sprocket I took the Keeway out for a test drive today and man its slow af compared to my DT rid it like a 2t lol trying to get it warmed up but rekon it only hit 40 max on my street my DT would happily hit 60 here hehe can't wait to get her mot'd but really itching to get the TZR running right and having a proper go of her before I decide to keep or part with her do really want the hat trick with a 90s TDR as well though a French import like you had would be the icing tbh

In my opinion is very stupid to stop termic vehicles and force people to reply them with electric vehicles because they are not the main cause of pollution. The governments worry about stopping an 70's year vespa, which can go for 30 kilometers with a litre. But nobody talks about the trucks that travel all day and consume more than every other vehicles. Or the ships and plane, which have no anti pollution law to comply with. And even if we stopped all this vehicles, the pollution will not disappear, because just one country like China or India pollutes as much as Europe and North America together. We should stop to trade with the countries who are destroying the world. The thing I hate the most is that the people who protest against termic vehicles are the ones who daily buy stuff on shein, temu, aliexpress, thinking that there will be no consequence on the environment. Unluckily, who make the laws don't want to understand this. I hope people will become more aware of the real problem, and I hope the eco-madness stops soon.

thank you all for the warm welcome, and tips. be sure to keep you informed. I see that you can find a lot of information here!!

Gorgeous color scheme!

@Calum Don't be sorry, I think it looks great too, it's just they aren't my colours and they're way louder than I am. However I've ridden the bike and now, and immediately realised I actually couldn't care less what it looks like. Cheers!

Looks pretty tidy

I would have a guess and say, we aren't sure. This isn't an LC Forum it's the R and therefore there isn't a wealth of information on the LCs unfortunately.

@DTTOLATE You’ll need a very accurate measurement of the bore top middle and bottom, you’ll need for this is a dial bore gauge, it’ll tell you the OD of the bore and tell you how round it is etc etc, I send all my barrels and crank to Jim bailey (roadrunners) and he does it for me, I’ve been using him since 2017 for all my dts and mx bikes rm yz etc anything that has a steel liner which all mine was as they was sleeved, he’s very good and last time he did my dtr barrel I did 11k miles before stripping the bike for a restoration it still ran lovely.

I use Apico pegs on my 2005 DTRE. I don't have any specific photo [image: 7Nvfxxs.jpg] https://www.ebay.co.uk/itm/363326677211?hash=item5497f520db:g:XJkAAOSwoN9hQ58x&amdata=enc%3AAQAIAAAA4MQHTQDqQZgaSUbR41SECdVQC9SKHoZ9z0Rtfooo7bD18BAdcDgXW%2BrELfnZegRT49Egrp0E86gII4ALplrEMYUv7njMv8ZC8ThCO3WC%2B4KXoOgfjNAXX2OJr9HIYoqXBl6PYKMQYsNvGRwpBkBsstCO2ukRTZA1ifjTww0UoYGpwziz6BF%2FrNYI6GJ2TVPuPk73Uy78wq8jIXErR5%2FOGIQRlImPHyYaMjenabKbSXlPQUtUcWEzmxOpGgyEm%2BXgupwaskcDFwQ7fSJ8kG8X6R5qJerUCDoUpphyubbHgI%2B6|tkp%3ABFBMjNWp_KVi [image: s-l1600.jpg]