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Hallo, new member about to put a DT125RE back together here.


Bish
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Good afternoon ladies and gents, 

My name is Charlie, I was researching some information for a build I'm hoping to get started in the next couples of weeks and figured I would join up as a full member so I don't have limited access to threads and can engage properly with the Yammie community. 

I'm going to be picking up my mates old 2007 DT125RE in pieces this week and start putting it back together accompanied by a full engine rebuild. This is how she'll be run until the winter when I have time to deconstruct it again and do a full restomod jobbie on it. 

Hopefully I'll get a chance to meet some of you and have a natter about this and that. 

All the best!

Bish

PS: I will upload photos etc as I go along don't worry :D

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Slight update to this: 

Off to go see the frame hopefully tonight or tomorrow but it seems the engine might be a touch more difficult to get back as its with a bloke who is nigh uncontactable. I may look at sourcing an engine from elsewhere instead.

My understanding is that these bikes had 2 main engines that came with them, a 3B and I think I saw mention of a 5B somewhere. Does anyone know which is best to go for and/or where is best to source one from?

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Not sure on a source other than the usual ebay, Facebook groups etc. There is a DT125 forum too.

 

I think you're referring to the 3MB00 barrel? That's the one to have unless you can get a 4FU from a TDR or TZ125 belgarda 

 

But the stock engine in your bike is pretty good, the only restriction being the exhaust (and cat) and the rev limiter. Both easy to get rid of

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TWO posts and the conversation is already over my head!!!

 

Welcome in! :D

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13 hours ago, finnerz89 said:

Not sure on a source other than the usual ebay, Facebook groups etc. There is a DT125 forum too.

 

I think you're referring to the 3MB00 barrel? That's the one to have unless you can get a 4FU from a TDR or TZ125 belgarda 

 

But the stock engine in your bike is pretty good, the only restriction being the exhaust (and cat) and the rev limiter. Both easy to get rid of

Ah okay, the ones I'm finding on eBay all want 500+ and don't include power valves, coolant pipes, and some even cylinder heads! I'm going to extend the effort into tracking down the one that was supposed to be with this bike... :D

I was indeed, the other one I was thinking of was the 3BN which apparently has an extra amount of material protruding from the cylinder head which disrupts the combustion flow or something (they called it a combustion ring when I first read it which made me think it was one of the piston rings they were talking about). Very much new to 2 stroke mechanically, I wasn't quite as interested in engineering when I had my 50cc at 16... 

Interesting, why is the 4FU considered better? Is this just down to the Nikasil plating in the barrel or are there other advantages?

I wonder whether the cranks are interchangeable between these, i.e. whether just changing the barrel and cylinder head would work...

 

If I can get the stock engine back I'll be more than happy running it with a fresh rebuild for quite a while, I'll need some time to get used to the 2 stroke powerband anyways :D 

I imagine I'll end up getting a spare engine to start porting/tuning down the line anyhow.

11 hours ago, Snakebite68 said:

TWO posts and the conversation is already over my head!!!

 

Welcome in! :D

haha thanks mate I appreciate the welcome!

Love your prev bike section on your profile btw... 

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I'm not expert on the engines to be honest so I couldn't tell you for sure.

But I think the 4FU was tuned a bit more, in what way I don't know for certain. You'll noy go far wrong with a 3MB though. Mine is good for 75 (GPS speed so accurate) and that's geared down for acceleration

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10 hours ago, Bish said:

Love your prev bike section on your profile btw... 

Yes... Means exactly what it sounds like...
A miss-spent youth, but no stealing! I bought all of them fair & square lol.

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23 hours ago, finnerz89 said:

I'm not expert on the engines to be honest so I couldn't tell you for sure.

But I think the 4FU was tuned a bit more, in what way I don't know for certain. You'll noy go far wrong with a 3MB though. Mine is good for 75 (GPS speed so accurate) and that's geared down for acceleration

No worries, can never hurt to ask. 

 

From what I have gathered in my ever continuing research:

4FU: Higher compression head, Nikasil plated liner, flat piston

3MB: steel liner, more aggressive porting, hole in inlet side of piston for lubing the small end 

Basically people tend to favour the 4FU but at the end of the day they are about the same. 

 

In a turn of events, we MAY have tracked down the original engine and are hoping to get it back next week. 

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