DT125R ARCHIVE

zo0op · DTR Senior Member

bike keeps flooding

fray · Guru

id try just a new spark plug first if it were mine.

zo0op · DTR Senior Member

fray wrote:

id try just a new spark plug first if it were mine.

il give that ago :)

Spartan · DTR Senior Member

Let us know how you get on with that mate, if that fails you could try checking your carb needle setting if you think it's flooding. What position is the little circlip in at the top of the needle...just a thought.

Edit: Plus you could try checking you air mixture screw is set correctly.

biggrin

-- Edited by Spartan on Monday 20th of September 2010 04:28:58 PM

zo0op · DTR Senior Member

Spartan wrote:

Let us know how you get on with that mate, if that fails you could try checking your carb needle setting if you think it's flooding. What position is the little circlip in at the top of the needle...just a thought.

Edit: Plus you could try checking you air mixture screw is set correctly.

-- Edited by Spartan on Monday 20th of September 2010 04:28:58 PM

im notmuch of awizzwith 2strokes as im used toworking on 4strokes so nota clue whatthe mixture screwis sposed to be but il have a look atthe throttle needleand seewhat thats setto iv bought a new iridium plug today so going to try that see if thats got anythingto do with it ..cheers

zo0op · DTR Senior Member

zo0op wrote:

Spartan wrote:

Let us know how you get on with that mate, if that fails you could try checking your carb needle setting if you think it's flooding. What position is the little circlip in at the top of the needle...just a thought.

Edit: Plus you could try checking you air mixture screw is set correctly.

-- Edited by Spartan on Monday 20th of September 2010 04:28:58 PM

im notmuch of a wizz with 2strokes as im used toworking on 4strokes so not a clue what the mixture screw is sposed to be set to. but il have a look at the throttle needle and see what thats set to iv bought a new iridium plug today so going to try that see if thats got anything to do with it ..cheers

podlee · DTR Respected Member

last time i had this problem was with 1 of my tzr`s
everything looked ok , i couldnt get my head round it , in the end i just brought a secondhand carb fron ebay for sumthing daft like a 10er ,, chucked it on and it went like a rocket . ( my float in my original carb had a small hole in )

-- Edited by podlee on Wednesday 22nd of September 2010 05:57:17 PM

Malc · DTR Senior Member

More likely a sticking-open or non-sealing float valve. Take the float chamber off the bottom, and the small valve which is operated by the float, check/clean and make sure it seals okay in its seat. Check the float height while you're there.

zo0op · DTR Senior Member

Malc wrote:

More likely a sticking-open or non-sealing float valve. Take the float chamber off the bottom, and the small valve which is operated by the float, check/clean and make sure it seals okay in its seat. Check the float height while you're there.

sorted that problem now :) but not need new piston and rings because the previous owner just put 1 of them cheapey pistons in an the compression is pants have to bump it

fuggie · DTR Senior Member

is it definatly the piston, even the cheepy ones i've measured come to pretty much the same height off the gudgeon pin with a vernier gauge, the heads with the recessed squish band will kill compression if you have one of them

zo0op · DTR Senior Member

fuggie wrote:

is it definatly the piston, even the cheepy ones i've measured come to pretty much the same height off the gudgeon pin with a vernier gauge, the heads with the recessed squish band will kill compression if you have one of them

i dont get what you mean lol ?

Malc · DTR Senior Member

What compression ratio, or at least how much pressure, are you getting? Did you measure it with a tool, or just going off the difficulty starting?

zo0op · DTR Senior Member

Malc wrote:

What compression ratio, or at least how much pressure, are you getting? Did you measure it with a tool, or just going off the difficulty starting?

just going of how hard it is to start it wont start with the kick start it needs a good bump to get going an it duznt go like it used to its lost everythin :(

DTR-Mat · DTR Respected Member

its your bike trying to tell you it needs rings!

-- Edited by DTR-Mat on Thursday 30th of September 2010 02:04:53 AM

zo0op · DTR Senior Member

DTR-Mat wrote:

its your bike trying to tell you it needs rings!

-- Edited by DTR-Mat on Thursday 30th of September 2010 02:04:53 AM

got new piston an rings on order hopefully be sorted after

fuggie · DTR Senior Member

get a compression tester on it if you can get hold of one, managed to get mine going roadside with a bump but wouldn't run under 3000rpm so suspected the worst and was right had a slightly melted piston with just 60 psi when i tested it after trailering it home. couldn't believe it even ran! with the heads the two look like this piggybacking a picture off another thread

the difference in compression is amazing, the one with the cutout around the edge (y1 in the picture) is a awefull thing for yamaha to have done to a cylinder head!

-- Edited by fuggie on Thursday 30th of September 2010 06:18:26 PM

-- Edited by fuggie on Thursday 30th of September 2010 06:20:26 PM

-- Edited by fuggie on Thursday 30th of September 2010 06:42:38 PM

fuggie · DTR Senior Member

not trying to insult by teaching a granny to suck eggs but dunno how much you know about engines, have you actually had the top end off to have a look because
1. have you ordered the right size piston cus its probably not a standard size and may need a rebore
2. the one you have might be fine if you check the bore against the rings because it could be a separate problem
3. have you got a top end gasket set, probably wants new o-rings on the powervalve and thermostat housing as you've never worked on it before & exhaust gasket
4. before you get the top end off check the carb rubbers and reed manifold for possible leakage and the airfilter was fitted correctly as these would be problems which could finish off a piston in the first place if its not that old as it would cause the engine to run lean, also check the two stroke pipe is in place on the carb, also check the jet sizes against a manual if its a standard bike

and on the rebuild because theres unknown quantities being a new bike do you know what kind of oil was in the twostroke tank? i'd drain that and bleed the pump if you don't just as a matter of course and put plently of twostroke on the bore and small end bearing when you get the top end together so its not running dry when you first start it ( if you have budget for it i'd replace the small end bearing while your in there too bout 8 quid or less) also check the conrod for up and down play, sideways is fine

when you've had it running have you had the radiator cap off while the engines COLD do not do hot as you will burn yourself, to see if the pumps doing anything on the coolant side or did it even have anything in it as this would be bad

again not trying to insult your inteligence as you probably know most of this just giving a few pointers on where to start if you don't

zo0op · DTR Senior Member

fuggie wrote:

not trying to insult by teaching a granny to suck eggs but dunno how much you know about engines, have you actually had the top end off to have a look because
1. have you ordered the right size piston cus its probably not a standard size and may need a rebore
2. the one you have might be fine if you check the bore against the rings because it could be a separate problem
3. have you got a top end gasket set, probably wants new o-rings on the powervalve and thermostat housing as you've never worked on it before & exhaust gasket
4. before you get the top end off check the carb rubbers and reed manifold for possible leakage and the airfilter was fitted correctly as these would be problems which could finish off a piston in the first place if its not that old as it would cause the engine to run lean, also check the two stroke pipe is in place on the carb, also check the jet sizes against a manual if its a standard bike

and on the rebuild because theres unknown quantities being a new bike do you know what kind of oil was in the twostroke tank? i'd drain that and bleed the pump if you don't just as a matter of course and put plently of twostroke on the bore and small end bearing when you get the top end together so its not running dry when you first start it ( if you have budget for it i'd replace the small end bearing while your in there too bout 8 quid or less) also check the conrod for up and down play, sideways is fine

when you've had it running have you had the radiator cap off while the engines COLD do not do hot as you will burn yourself, to see if the pumps doing anything on the coolant side or did it even have anything in it as this would be bad

again not trying to insult your inteligence as you probably know most of this just giving a few pointers on where to start if you don't

cheers for that mate iv had it apart today my new piston kit come my old piston was batterd at the top .. checked conrod etc everything looks in order from what i can see .. but since iv had the bike its been makeing a rattleing noise and i havent got a clue what it is i thought mayb it could be somthing to do with the powervalve or clutch?.... the 2stroke is premix in the tank with it being an 88 modle but i will have a look around everything on the coolant side :)

fuggie · DTR Senior Member

i have a 88 model and its got a twostoke pump! checked your jets bigger than standard to compensate for the twostroke going through it? Whats the rattle sound like? did you put the expander ring behind the bottom ring if your piston came with one as some of the manuals don't explain about that in it i had to find out from a manual from a different yamaha twostroke and i imagine that would make a bit of a rattle, got a picture of the old piston? powervalve could move side to side rapidly if the end covers arn't securing it properly, or even something silly like the heat shield isn't tight enough on the pipe will rattle away

ton of questions there lol

zo0op · DTR Senior Member

fuggie wrote:

i have a 88 model and its got a twostoke pump! checked your jets bigger than standard to compensate for the twostroke going through it? Whats the rattle sound like? did you put the expander ring behind the bottom ring if your piston came with one as some of the manuals don't explain about that in it i had to find out from a manual from a different yamaha twostroke and i imagine that would make a bit of a rattle, got a picture of the old piston? powervalve could move side to side rapidly if the end covers arn't securing it properly, or even something silly like the heat shield isn't tight enough on the pipe will rattle away

ton of questions there lol

iv checked the jets etc its all standard + its not a flat side carb cant see any numbers on the jets to work out the size :( . im new 2 all this 2stroke stuff cause iv always worked on 4 strokes ... cant get a picture onto the comp but it looks like a dogs been chewin it lol.. it sounds like its in the barrel the rattlein noise thats why im thinking powervalve as everything else looks ok :/

dt125cc · DTR Respected Member

u sure its not top end bearing thats rattlin jack

zo0op · DTR Senior Member

dt125cc wrote:

u sure its not top end bearing thats rattlin jack

they look sound mate dont think its them its had new 1nz in

fuggie · DTR Senior Member

carb wise its pretty much the same as a fourstroke except the venturi are a little different but you don't need to worry about them, think as standard its suppost to be a size 125 on the main jet ( the small mikuni hexagon type) with the 88 round slide but this would need to be bigger running premix or you'll just knacker the piston again,

plus i think yamaha sized that a bit lean as standard, i'll tell ya when mines run in and can do some jetting runs as i have the horrible little round slide too atm, the tzr with similar engine and carb had a 180 main as standard and the pilots only slightly bigger with a power jet thats also alot bigger!

did you have one of the little wavy backing rings for the scraper ring in the end?

if the powervalves floating about if you look at the end of it at tick over on the left hand side of your engine from sitting on it you'll see it moving about side to side

if you can get a vid on youtube of the sounds its making would be easier to help

zo0op · DTR Senior Member

fuggie wrote:

carb wise its pretty much the same as a fourstroke except the venturi are a little different but you don't need to worry about them, think as standard its suppost to be a size 125 on the main jet ( the small mikuni hexagon type) with the 88 round slide but this would need to be bigger running premix or you'll just knacker the piston again,

plus i think yamaha sized that a bit lean as standard, i'll tell ya when mines run in and can do some jetting runs as i have the horrible little round slide too atm, the tzr with similar engine and carb had a 180 main as standard and the pilots only slightly bigger with a power jet thats also alot bigger!
did you have one of the little wavy backing rings for the scraper ring in the end?

if the powervalves floating about if you look at the end of it at tick over on the left hand side of your engine from sitting on it you'll see it moving about side to side

if you can get a vid on youtube of the sounds its making would be easier to help

il take the jet into the bike shop an ask them to size it me up and get it up jetted.. just pisses me of buy a bike for it to f*ck up on me :( + no mate not got 1 ov them wavey rings they just standard rings by the look of them when i put them in ... on the powervalve on the left hand side where u set it etc abithas been snapped in side ... on the manual powervalves they have the 10mm bolt that goes into it dont they..well the thing that is screws into has snapped inside so u hav to piss about to get it to screw in :/ i can try and get a sound video if that will help

fuggie · DTR Senior Member

tell me about it being annoying lol, only got mine a month ago and in the same boat having just rebuilt my motor lol though knew mine was a heap when i brought it!

the bit inside isn't the peg for holding it in place is it cus it could allow the valve to revolve if you havn't got any servo bits holding it in place which could in turn hit the piston

zo0op · DTR Senior Member

fuggie wrote:

tell me about it being annoying lol, only got mine a month ago and in the same boat having just rebuilt my motor lol though knew mine was a heap when i brought it!

the bit inside isn't the peg for holding it in place is it cus it could allow the valve to revolve if you havn't got any servo bits holding it in place which could in turn hit the piston

lol i did a 60mile trip back from nottingham on it an then it stopped workkin fixed it then this happend lol only payed 570 of ebay with tax and test wich isnt to bad :) ... could that be causeing the rattleing problem?

fuggie · DTR Senior Member

would cause a rattle and potentially worse if its not secured and if you had it apart and cleaned it it will move easier as you probably had loads of carbon to hold it in place

zo0op · DTR Senior Member

fuggie wrote:

would cause a rattle and potentially worse if its not secured and if you had it apart and cleaned it it will move easier as you probably had loads of carbon to hold it in place

il just have to buy a new power valve and if that doesnt sort it out il sell the thing an get a car lol

fuggie · DTR Senior Member

i wouldn't go that far mate, just see if its vibing about at tick over, its probably not going to be a massive problem you have to fix, at the worst get it running right then at least you'll get what its worth for it to get a car, get that vid on the go if you can its not easy guessing in the dark trying to help you, seriously if you've done fourstrokes before there is soo much less that can be a problem!

zo0op · DTR Senior Member

fuggie wrote:

i wouldn't go that far mate, just see if its vibing about at tick over, its probably not going to be a massive problem you have to fix, at the worst get it running right then at least you'll get what its worth for it to get a car, get that vid on the go if you can its not easy guessing in the dark trying to help you, seriously if you've done fourstrokes before there is soo much less that can be a problem!

easyest thing to do it to get a cideo so il try and get 1 up b4 monday :) il private messege it to u cheers for ur help mate