DT125R ARCHIVE

madrevs · DTR Senior Member

RE: now a non runner

dread123 · Moderator

it's supposed to spin that way... when revs pickup you will notice it starts going anti clockwise

dread123 · Moderator

think there posts regarding your problems... have search

Victor · Guru

Victor · Guru

dread123 wrote:
it's supposed to spin that way... when revs pickup you will notice it starts going anti clockwise

pretty sure it didn't do this before

dread123 · Moderator

-- Edited by dread123 on Friday 7th of March 2014 07:29:53 AM

dread123 · Moderator

that's correct.look at all the YouTube videos.. mine does same... starts off clockwise and then spins back when higher up rev band

madrevs · DTR Senior Member

Oh really dont dare rev it that high also its idling at 1.5k but as soon as I touch throttle it sticks at those revs only way I can get it back down is to pit in gear and pull clutch out a bit throttle cables not stuck anywhere.throttle snaps back nicely also idle screw doesnt appear to do anything even if I adjust it in all the way

Victor · Guru

dread123 wrote:
that's correct.look at all the YouTube videos.. mine does same... starts off clockwise and then spins back when higher up rev band

Ok will give it some more revs in the morning it's had 2 heat cycles now

dread123 · Moderator

perhaps needs airscrew adjustment to help revs settle?

madrevs · DTR Senior Member

Thanks dread after stripping carb and remove throttle slide many many times worked out it was the throttle free play was adjusted way too tight now sorted and seems to be running spot on am going to take it into work tomoro hopefully all will be well.shouldnt of stayed up this late got to be up at 6 at least its sorted now though

dread123 · Moderator

Victor wrote:

no thats right :p watch the video i posted and you will see as revs climb the valve starts spinning the other way :p

Victor · Guru

dread123 wrote:
Victor wrote:
no thats right :p watch the video i posted and you will see as revs climb the valve starts spinning the other way :p

I Have given it more rev's it didn't spin the other way, just stayed at around 3 o clock on a clock dial. Maybe your's is broken as well if it does this

madrevs · DTR Senior Member

Didnt check mine again as it was getting late will have another look tonight it might just turn clockwise on lower revs to fully close and then open when the revs get high like say 6k but dont dare rev mine that high to find out yet

madrevs · DTR Senior Member

Have been searching on here on the running in procedure and alot people are saying use mineral oil rather than synthetic but my tank is still half full with fully synthetic stuff will it do it it any harm using this or am I better draining it I used mineral when assembling

AndyYam · Guru

Lol, just spent ages youtubing and scratching my head on Victors thread. I'd never noticed it before but as Dread says its normal. It seems that at idle, the valve is about 3/4 closed. As the revs start to rise it closes fully and then begins to open again at whatever engine speed it its set to by the cdi ( i think its about 6krpm). I'm trying to work out why it does this and wont if someone with a zeel could post a video to see if theirs does the same. Will have a word with Cal.

It could well be a part of the restrictions on the bike. Heres a video of a 350 ypvs poweervalve from dead engine to riding including full open valve ( sounds like its about 9krpm when its fully open). It does its set up, then remains fully closed and doesnt move until about 6krpm. I may be getting my 350 out later today to check it over before its mot so will have a look.

My money is on it being a restriction as part of the cdi. As Cal has found out for us having bought the Zeel, the stock ignition is heavily restricted on the RE model and id expect its similar with the R too.

AndyYam · Guru

madrevs wrote:
Have been searching on here on the running in procedure and alot people are saying use mineral oil rather than synthetic but my tank is still half full with fully synthetic stuff will it do it it any harm using this or am I better draining it I used mineral when assembling

Theres a fair bit of debate between a few of us guys on here about this. The logic behind using mineral oil is that it will allow the piston rings/bore to wear down quicker to run in. I think what is being said is that the synthetic oil is so good at its job that it prevents the rings bedding in as quickly.

Personally, I use the same oil as I would normally. I've always done this and never had a problem at all. I dont think running mineral oil would be a bad thing but I also can say from experience that fully synthetic during running in has always served me well. My personal opinion on running in is that the way the bike its treated will make far far far more difference to the engine condition than the type of 2 stroke oil you use. As my dad keeps telling me when I buy epxensive 2 stroke oil "back in the 70's we bought whatever 2 stroke oil was in the shop next to the chippy and chucked it in without a problem, the quality of oils these days is so good that anything on the shelf will be superior to the stuff back then".

I'm not saying use 'CarLube' 2 stroke oil and i personally would always use a good quality oil for peace of mind but providing the oil meets the required standards and enough is being supplied to the engine then it wil do its job.

madrevs · DTR Senior Member

Does seem a bit silly seems yamaha went a bit overboard with the restrictions.only explanation for it but if it is a restriction maybe locking the valve 3/4 the way open would give better performance than a restricted powervalve servo.

Victor · Guru

AndyYam wrote:
madrevs wrote:
Have been searching on here on the running in procedure and alot people are saying use mineral oil rather than synthetic but my tank is still half full with fully synthetic stuff will it do it it any harm using this or am I better draining it I used mineral when assembling
Theres a fair bit of debate between a few of us guys on here about this. The logic behind using mineral oil is that it will allow the piston rings/bore to wear down quicker to run in. I think what is being said is that the synthetic oil is so good at its job that it prevents the rings bedding in as quickly.

Personally, I use the same oil as I would normally. I've always done this and never had a problem at all. I dont think running mineral oil would be a bad thing but I also can say from experience that fully synthetic during running in has always served me well. My personal opinion on running in is that the way the bike its treated will make far far far more difference to the engine condition than the type of 2 stroke oil you use. As my dad keeps telling me when I buy epxensive 2 stroke oil "back in the 70's we bought whatever 2 stroke oil was in the shop next to the chippy and chucked it in without a problem, the quality of oils these days is so good that anything on the shelf will be superior to the stuff back then".

I'm not saying use 'CarLube' 2 stroke oil and i personally would always use a good quality oil for peace of mind but providing the oil meets the required standards and enough is being supplied to the engine then it wil do its job.

I agree I got told by the engineer i bought my piston from, the engineer who did my rebore and the mechanic at the garage i stopped at on the way to grab some oil, to not bother with semi or mineral oil

dread123 · Moderator

not a restriction pal... they all do it i believe even the 3 wire powervalve system on the older models... no idea why they do this either? but it is normal? mine runs fine and it's not broken at all as possibly suggested in the posts above. watch the videos from the early DT125R s.

i used mineral oil to run mine in... Still using it till its all gone amd then will move onto semi synthetic.others have used the same and others used synthetic which works for them.

Victor · Guru

dread123 wrote:
not a restriction pal... they all do it i believe even the 3 wire powervalve system on the older models... no idea why they do this either? but it is normal? mine runs fine and it's not broken at all as possibly suggested in the posts above. watch the videos from the early DT125R s.

i used mineral oil to run mine in... Still using it till its all gone amd then will move onto semi synthetic.others have used the same and others used synthetic which works for them.

Be nice if you could post one of these video's cause mine DOES NOT SPIN ANTI CLOCKWISE at any rpm

dread123 · Moderator

how about looking on youtube? there are plenty of videis there which i have mentioned... even Andy has seen them as he wasn't sure i was correct too lol. if its nit moving anti clockwise then perhaps your adjusters are set too tihht and you haven't the correct slack. i had that problem before and had to get tension right by messing about each side

dread123 · Moderator

i believe it opening clockwise to close port is to benefit torque at lower engine revs. thats what i read somewhere when i was trying to solve same issue last year? definitely think your adjusters are too tight!

madrevs · DTR Senior Member

Will stick with the castrol ive got in the tank then I think

dread123 · Moderator

i would... just take it easy as Andy stated and you should be good.

madrevs · DTR Senior Member

Will have to check mine tonight when I get home see whats going on as long as it doesnt hit the piston again I did find I had to unscrew the no.1 adjuster nearly all the way out to get the notch to align though

Victor · Guru

dread123 wrote:
how about looking on youtube? there are plenty of videis there which i have mentioned... even Andy has seen them as he wasn't sure i was correct too lol. if its nit moving anti clockwise then perhaps your adjusters are set too tihht and you haven't the correct slack. i had that problem before and had to get tension right by messing about each side

Ok my bad

dread123 · Moderator

found a video of dt125lc ypvs and that does the same as them too.

AndyYam · Guru

dread123 wrote:
i believe it opening clockwise to close port is to benefit torque at lower engine revs. thats what i read somewhere when i was trying to solve same issue last year? definitely think your adjusters are too tight!

Yeah it closes to lower the exhaust port at lower rpm to widen the powerand whilst still giving good power higher in the rev range. But theres no reason for it not to be closed at idle. If it its not closed at idle, and by the sounds of it is closing between idle and 2-3krpm, then anything below 2-3krpm you're wasting fuel and power. It's not going to be a bhp restriction and granted, how often will up to 3krpm be used but it doesnt make sense as to why it would not just close and stay closed until it begind to open higher in the rev range. I've not seen or heard of any other powervalve system that works like that.

dread123 · Moderator

to be honest... the problem is that the system is fully open when ignition off. when idling it is closed.. hence moving clockwise. so not really that different... just odd that the system sets itself fully open to start with?