Cases
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Can't see this reply properly as it comes up blurry.
@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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I'm confused by all the codes, remember I'm only learning about these engines atm
@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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No idea what Rotax motor your on about though
@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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Hi @Bluestoesonnose £85 posted ?
@2stroketerry 85s a good price
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Hi,
Looks good to me, no idea what the going rate is for one, ummm £75 posted?Hi, sorry to say I got offered one for £50 all in so I've bought that.
Thanks anyways
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To get DT to pull a lot harder should of fitted Athena 170 kit rather than a ported 125 barrel, have got a ported head and barrel off Mick and the 170 is miles better with the extra torque and being 20 stone the torque makes so much difference. My 170 is fully ported and revs to over 11,000 on a 2003 DT R using standard TM 28 carb with the powerjet blocked and standard air filter with snorkel on.
People who say ports are 3mm to low don't know anything about tuning as when mapped the ports and they are 125 ports and same hieght as 125 ports. The reason they don't rev past around 8,000 or so is because of the exhaust port width as on 2 strokes exhaust port width has to be a certain percent of the bore diameter, so going from 56mm bore to 65mm bore totaly screws up the engine. Exhaust port width limit is 73% of the bore diameter (measured straight across). So 56mm bore is 41mm and the 65mm bore can be opened up to 47mm.
Double check the pv cable setting on Athena kit as with holes lined up standard the powervalve is only 3/4 open, on mine set powervalve in cylinder flush then drilled a new 4mm hole in center of powervalve pully.
Engine tuning is all about everything working together and a combination of ports, compression, carb, ignition all perfectly matched. With the Athena kit most people run wrong plugs to suit it best like br9es or a br9eix irridium plug. The plugs to use on any ported DT are NGK B10EG non resister plugs along with 7mm HT lead copper core and a non resister plug cap.
The bottom end makes cruising more relaxed, and the extra top end means it'll now do a wheelie in 4th gear easy.@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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@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 ??
@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 -
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@theportingmaster is that your dt in the YouTube clip ??
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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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