Hi, I think this has happened to me I have a 56.94 piston and I'm getting mid range noise and vibration. I'm going to look tomorrow. Also if I earth the PV wire will the valve just stay open? Thanks keep em coming 👍
Hi m8 at 57mm the piston normally should miss the powervalve it's normally over 57.4 they rub, as for the valve just turn your key it will do the self cleaning whizzing noise, once it's done the turn ignition off and the valve is fully open, you dissconect the plug and the red and white wire on servo motor and tape them up them take the side round casing on the cylinder off its the one the cables go into, on the black pulley behind the casing there is a black part sticking up with like a u shape notch in and directly behind it there should be a hole, if u can't see the hole adjust the cables till u can get a small bolt, drill bit through the black pulley and into the hole behind once the black pulley is getting kept still by the bolt/drill bit your valve is fully open m8. Best way to see if its set and that you won't have to adjust cables is take they casing off first and turn your key u will see the hole and the top of the black pulley line up just so uve a rough idea were the hole and black part is m8👍
Yes they do hit if you dont grind them back iam gunner get a three wire servo this week for my mates bike their rare tho on ebay but if you find one their the full power one's
Yeah I've seen a few ther for the 88 to 97 bike an harness m8 has ya m8s got the valve that comes pegged in one place aswell, I'm thinking of putting one of them barrels on the project from the early dt cos there 56.40 as std an can be bored up
@@2strokemxclassics it uster have the 3 wire servo but he wants it back has it gives it topend & bottom end power with the full power 3 wire servo has that's the one to get & always the best one for the dt125r just hope i can find one on ebay has i haven't looked yet or even a five wire would do for mine dt125r then you'll get full power bottom end & top end
Yeah there dear and rare bro av seen a couple keep popping up for a 100 a think the tzr might be the same, A didn't know ya could fit the 5 wire one to the 3 plug harness m8 a bet its a mission doing it thers a pre 97 harness on ebay with the small cdi and the 3 wire servo a was thinking of getting it and trying it on mine to see if thers any speed difference with the old cdi on
@@2strokemxclassics you can't fit the 3wire one i was just onbout for mine m8 & tzr is the same yes why not buy them while their on their specially three wire servo hens teeth them m8 ive just got one myself
At 5:18 , aren‘t there supposed to be 2 o-rings on the right and left side mate? The yamaha original service manual and spare parts drawings says it, but yours and including mine only has 1 on both sides. Do you know something about that?? Thanks for your videos mate!!
Yeah m8 there's 2 o ring on the later model( 97 onwards), one is on the powervalve Bush that pulls off and the other orange ring goes on the end cap, the 88 to 97 are different and they only have one o ring and a gasket on the side were the valve end fits with the ten mil nut m8
@@2strokemxclassics Thanks mate! Thats what I was looking for. Thanks to your videos I successfully rebuilt my dt125 engine. Keep it up, greetings from Austria👍👍
Same I had all the 90s ones when they first came out and always opened the valve to full, hunters at Westgate Road use to do a rebore with piston kit for £25 upto 57.4mm cos they was 56.4mm as std back then so always would rebore them ASAP. I do with most of my ellecy motor ones too, the motors good for road driving cos there's no bottem end power when the valves fully open but I always like the valve open on them
Hello! at minute 2.43 you can see two vertical stripes right next to the outlet. It is the same for me with my DT. Is that normal? It now has 1000km on the clock. They are only present optically and nothing can be seen on the piston.
Hi there no there not ment to be on I don't know what there off tbh, it looks like something has came out of each side of powervalve and caused rubbin maybes a bit carbon I'm certain I bought this barrel on a bike and the valve was rigged up wrong and it was hittin piston but those black marks weren't deep or scratches so it was OK m8
@@2strokemxclassics Ok, so is it not that bad? My powervalve should be fine as far as it is in your video. Because the cylinder was newly honed so i'm a little surprised. What could have caused that?
Yeah m8 it'll be OK long as not grooves this had only ran maybes a minute or 2 after the previous owner had it rebuilt and rebored, he told me it wouldn't start after been rebuild. Wen I got It stripped I noticed the valve was in wrong and the piston had marks on the front of the valve hittin it but had non off the black marks. They must have nocked it str8 off cos it would have been bangin but I did wonder what caused the black marks and all I could think was carbon from the valve wen its been in wrong has squeezed out the top of valve and into the bore cos it looked like a stain tbh no groove or scratches and it still worked mint
Do I need to do this on a 56.5mm oversize or is it just when you go to 57 and above as recently rebuilt my dt125re top end and I’ve not trimmed the powervalve but it runs fine starts first kick everytime
True bro it was one of my first vids I made I think. I would have added that part just it happened years ago with one of the pins falling in but tdc would work
Are you on the last rebore their m8 with that cylinder barrel i once lost one of the dowels between the power valve i had to make one from a peace from one of them dremel little tools lol
Hi m8 it was a 57.50 piston the lad I bought the bike off ran it not long after a rebuild and said it wouldn't start back up, and when I got it back the pv cables were crossed and the was a few marks were the pv had been rubbing the piston, yeah I dropped 1 in a bottom end years ago cos I left the barrel on the bike it's all learn by your mistakes m8
@@2strokemxclassics yes we all make mistakes mush we wouldn't be human if we didn't make mistakes buddy iam gunner get mine rebore this time ive been a tight arse been running it on the standard 56mm bore but might as well has ive replaced everything else
If you had barrel on your bike and set the piston to tdc wouldn't you be able to remove powervalve while barrel still attached to bike as piston would block off the exhaust port just in case one of them dowels was to pop off or not? Just wondering
Hi what about head gasket when you have had a few re bores I mean the head gasket is only one size what do you do when had a few Rebore's with the head gasket 🤷♂️
I'm not to sure tbh m8 back in the 90,s we could get a rebore and piston and rings and top end gaskets for 25 and we just used standard head gaskets, I know you used to be able to buy overbore gaskets years ago for them and the Athena one has a larger diameter too
Yeah I know not to sure how you do it cos I've never done it but when the head gaskets on its about a mm bigger than the bore so suppose you could get away with a .50 rebore you'd have to ask someone who's done it before👍
Hi are u putting both on the powervalve?, operating valve has 2 orange rings one goes in the end cap and the other side fits on the ally Bush u can pull off the powervavle
Yeah i grind mine off at home,the valve comes in half,take half out and leave your piston in and you can see how much is to be took off by rotating the valve 360 degrees after youve grinded it whilst the pistons in the area were it passes the valve,hope this helps m8
@@2strokemxclassics great. Thank you. I’ve just sent my barrel off to be rebored. I think it’s only going to be oversized by .50, so the power valve should not need grinding down.
No probs yeah normally its over 57.5mm when they start to catch ,dunno if yours is the std 56mm(1997 onwards) or the old 90,s one were 56.4mm as standard so its worth just rotating your valve fully with piston over the exhaust port to see the gap is ok,good to clean the valve aswell cos over time the black carbon on it gunks it up and stops it rotating back and forwards freely👍
@@2strokemxclassics ok will do thanks. It’s actually a gilera sc 125 which use the dt125r engine as standard. 2008. So same as 2007 I think. Electric start. I used your video to rebuild the bottom end of the gilera sc 👍🏻 just need to get barrel bored that I have just sent off and then fit and test. I brought the bike already in bits with crank bearing gone. So ur video came in very handy. 👍🏻👍🏻
Yeah good luck man lete know how it goes when unget the barrell back,ther the same eng as dtre 125 o4 to o7 ,and the derbi gpr 125 2004 onwards till 2008 and gilera sc 125 2006 till 2012 ive a 2010 sc frame in the loft if u need any parts giz a shout bro👍
