Cases
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@Bluestoesonnose Two strokes also don't like over square engines. More power can be gained from the original 125 barrel I'm certain. I've had 170 kit in the past and it is a blast for sure. It was also a damn sight reliable, I just feel it takes a certain part of fun out of the 125, with the loss of overrev. But to be quite honest, that's not a bad thing.
There are many variations you can play with on these engines, I've yet to see a properly tuned up 4FU barrel on the DTR engine. I fettled with the concept on paper, but bottled it and sold my 4FU spares.
The stock porting on the 4FU looks better than the 3MB.
Also also, if you really want a decent 125 setup, then you will want the SP barrel. It will be comparable to the Rotax Gilardoni barrels, and they are superb!
Oh that makes sense, it's designed by Gilardoni. Yeah, that does make sense now.
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@Bluestoesonnose The images? Yeah it's hosted through Flicker, or from Google.
But if you google.
Yamaha TZR 125 RR Belgarda SP Barrel
You should see exactly what I'm talking about. I've spoken to people who've ridden the SP engine and they say it's sublime.
Personally, it's no better than a Rotax 122 engine && Costs substantially more.
So just transplant a Rotax engine, or get a better bike.
The 4FU, again costly, is a more viable options.
in the end, I just spent a little money on the 3MBP barrel, but wasn't impressed with the results against a STOCK RS.
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So these things are a direct swap on the DT cases
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@Bluestoesonnose That's why I've linked you a video. The 4FU can be found on the European 4GW Belgarda TDR models.
Google and Search should help you find what you're after.
Yes they're direct swap.
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No idea what Rotax motor your on about though
2002 DT125R
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@Bluestoesonnose Rotax 122 barrel. £20
https://www.ebay.co.uk/itm/Aprilia-RS125-Mitaka-Barrel-1991-2011-Rotax-122-And-123-RS-125-Spares-Or-Repair/192690108309?hash=item2cdd39b795:g:0UMAAOSwaIJbdEd3:rk:7:pf:0And the difference between that, and an SP barrel is negligible, yet you'll pay £500 with an SP barrel.
Yes that one is the 4FU, but you will need the 4FU powervalve to suit.
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Hi @Bluestoesonnose I have a spare 4FU00 barrel with the powervalve if you want will post some photos, just make an offer as no use to me as Athena 170 kit on my DT
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I could be interested as I've just discovered that my spare barrel is FUBAR as it's got a crack in it
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Hi, photos of the 4FU barrel with powervalve fitted, you can see the bore is scored
so will need replating or reboring. Just make me an offer if any good to you.
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@2stroketerry 85s a good price
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Hi, sorry to say I got offered one for £50 all in so I've bought that.
Thanks anyways
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@2stroketerry what’s top speed you had out of your dt with the 170 kit on ?? Coz A few people saying there no good get a 4fu00 barrel and head ??
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@sprintall84 It's not necessary speed you benefit from, but more torque. So gear it appropriately you should be fine.
As a general whole, the Athena kit isn't brilliant. A 3MB00SP Barrel is what you want. But the price for those is astronomical.
4FU is a decent barrel which is plated rather than steel liner. This benefits from better heat transfer. But draws back from expensive repairs. Ultimately the DT is limited.
A decent spec'd Athena 170 should top out at 100mph. Plenty for a 125.
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Here is my ported 170 athena when first fitted it using standard gearing and went off the clock. Fitted an Athena exhaust and a 34mm polini carb with top of air box cut out to it after this video, did 110mph with an 18t front sprocket but really scary on nobbly tyres,lol
https://www.youtube.com/watch?v=8a_sBkpuQ14
