DT125R FORUM

@NINJA it's raining where I am or would do a video, I do have a spare relay and batteries etc so will wire together when I've had my tea and turn my kitchen light out and switch on, so bright can't look directly at the bulb or just see a black spot for ages everywhere you look.

No thats how every 2 srtoke silencer has always been made apart from most are welded up.

@declan using glue is the last thing you want on an O-ring just a bit of silicone grease, but having a poorly machined groove the O-ring sits in probably doesn't help.
Yamaha use an O-ring on there best 125 cylinders the SP although don't actualy make that cylinder themselves.

2 stroke silencers are the simplest design of any silencer known to man, there is just a tube running straight through with lots of holes. If you could be bothered just drill every hole 1mm larger than they are and the best sound absorbing material is fibreglass loft insulation cut to the length of the perforated tube then roll tightly around to thickness of silencer. As you can see I went the complete opposite.lol

Bought these 100/90w Super White Xenon https://www.ebay.co.uk/itm/2x-HB12-410-P45T-100-90w-Super-White-Xenon-Headlight-Bulbs-12v/191434589033
Didn,t really make much difference so changed my battery to a 50amp 4S Lipo pack
from a radio controlled car and half the size of DT battery. Although rated as 14.8volt fully charged they are 16.8 volts so added a resistor and a diode to make 12.8volt.
Then got a 12volt relay used for car spotlamps etc and ran live from battery to relay
with a 25amp inline fuse, now my original live for the high and low beam are just trigger wires for the relay.
So when switched on now the bulb gets it's power direct from my 50amp Lipo pack and now my headlight is insane and stood in front of bike now can't look direct at the light as way too bright. Also now no longer have to start the bike to run headlight and can sit forever with headlight on now just turning on my ignition due to the 50amp hard case Lipo pack and lights unlit roads so bright and the beam can go miles now and shines brighter and further than my car spotlamps.

@declan what silencer is it, just shortened my Gianelli silencer and then blocked half of the inside to make mine louder as too quiet.

Cost £30 to cut the groove from a machine shop in Southbank

Hi @Bluestoesonnose £85 posted ?

The O-ring conversion on a DT 125 using a 90,s YZ 125 O-ring , the tighter squish and less combustion volume really helped. On average I would say this mod gives around 1,0 a 1,5 HP. This will lower the squish from +/-1.35 to a +/-0.95mm

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.

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

Took my DT out the other night and on unlit roads couldn't see at all and would of been brighter with a candle. When braking headlight goes nearly out even with clutch in and revving it high, battery is new and all outputs from engine exact voltage meant to be. Taped a voltmeter to handlebar so could see whats happening with lights on and revving past 10,000 it reads 14.8v. Just cruising at low revs with lights on reads around 12.4v so don't know why headlight is so bad.
https://www.youtube.com/watch?v=aCKiCBGyKy4

https://www.youtube.com/watch?v=AyYkYlVaTmM

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.

Don't like look of sm wheels and do a lot of green lanes as all country side where i live and prefer to keep my knobblys although had a few scares on high speed corners. With a ported athena 170 on my dtr flat out weaves about a bit, don't know how fast though as speedo only goes to 80mph and goes faster than that. Accelerates lots faster so do a lot of heavy braking and at 20 stone the front dives crazy.

Cheers lads will see if can get some progressive springs and heavier oil, changing to
usd forks seems too much work.

Hi, will putting thicker oil in my forks make much difference or will I need different forks. Now I have made my DT far quicker and need to brake far harder the front end dives down quite scarily under hard braking although being 20 stone probably doesn't help.

@Bluestoesonnose I have a fully ported Mick Abbey 3MB00 barrel with Mick Abbey skimmed 3MB head if your interested will send you some photos. Don't need it as I now have a fully ported Athena 170 kit on my DT now.

Fitting electric start on DT 125 R engine. Has anyone tried doing this and if so what parts will I need to get. cheers

Yes mine goes off the clock as well as only 80mph on the clock and thats with a 16t,
pulls well really considering I'm 6ft and 21 stone.lol

@Glynn123 Yes also have a new 17t as well but my car is off the road at the moment so will be doing a lot of dual carrigeway riding so want decent cruising speed with less revs and acceleration not important.