DTRUS Posted February 19, 2011 Posted February 19, 2011 im new here so firstly hello to all. im wondering if somone can help me i have a 1999 yamaha dt125r (i beleave it was from holland originally) it might make a diffrence i dont know. :S the problem i have is a lack of power ive cleaned all the carb there was a little amount of what looked like rust so cleaned it out but the bike is the same still. i had a very similar problem to this a few months ago put a new battry on and it was perfect. but ive changed the battry again and its still the same. the bike builds up speed slowly if i open the throttle to far its like it floods it and the bike wants to slow. the bike can be very gitery. im wondering if it is a power valve proble. ? any advice would be greatly appreciated thanks rus.
Moderator Airhead Posted February 19, 2011 Moderator Posted February 19, 2011 Hi Rus we have a noobs forum .......for noobs
DTRUS Posted February 19, 2011 Author Posted February 19, 2011 Hi Rus we have a noobs forum .......for noobs your dead right ill have a look and introduce myself. cheers.
2 Wheels Posted February 19, 2011 Posted February 19, 2011 Does she start easy and then idle. Can it take a quick blast of throttle from idle How many miles are we talking about on the bike.
DTRUS Posted February 19, 2011 Author Posted February 19, 2011 Does she start easy and then idle. Can it take a quick blast of throttle from idle How many miles are we talking about on the bike. yes starts easy then idles fine aswell it can take a blast of throttle fine from idle aswell and it has around about 30.000 km just under i think i cant be sure but i think the revs are only going up to around 5500 ill have to check tomorrow. thanks for your reply. sorry i forgot to mention a few things that might be of importance here. the righthand crankcase cover gasket was blown for about three months and i was using the bike. and also there is two holes in the back of the exaust.
Moderator Airhead Posted February 19, 2011 Moderator Posted February 19, 2011 30000km's thats 18600 miles, ever had new rings? I would say it's time for a compression check
DTRUS Posted February 19, 2011 Author Posted February 19, 2011 30000km's thats 18600 miles, ever had new rings? I would say it's time for a compression check no never had new rings. how do i test the compression. ? thanks for your reply. when i kick it over it feels like there is good compression there.
Moderator Airhead Posted February 19, 2011 Moderator Posted February 19, 2011 no never had new rings. how do i test the compression. ? thanks for your reply. when i kick it over it feels like there is good compression there. well it's a bit tricky on these bikes but... with a hot engine remove the fuel tank remove the spark plug and screw in the compression tester open the throttle wide kick over the engine until the tester registers its max reading (about 4 good kicks) read the indicated compression, should be around 90 - 110 psi as far as the pv goes have you checked it? does it make the characteristic buzz buzz of the cleaning cycle when you turn on the ignition? have you looked at the pulley when it does this and seen it move back and forth?
2 Wheels Posted February 19, 2011 Posted February 19, 2011 30000km's thats 18600 miles, ever had new rings? I would say it's time for a compression check Yep, thats what i was thinkin too no never had new rings. how do i test the compression. ? thanks for your reply. when i kick it over it feels like there is good compression there. I have a compression tester with a flexy on the end of it so i dont need to take tank off,,,,,,,,but the rest is as OG says. Have you given the carb a really really good clean,,,,,including all the jets and like Member Vez would say, check the power pipe/jet,its the one that conects the float bowl to the carb body. Is this loss of power a gradual thing or did it just happen all of a sudden ???
DTRUS Posted February 20, 2011 Author Posted February 20, 2011 afternoon gents. sorry for this quick reply ill answer all your questions when im not in such a hurry. and thank you for all you advice so far. just a quick update. lastnight i took the power valve off and gave it a good clean and made sure it was moving freely put it back and the bike was perfect went on it today same problem again i did take off a bit quick from cold.! so today i made sure the valve waqs still moving freely and it was. i then found that one of the cables from the power valve motor has nearly rusted through all the way just leaving a strand of cable working. there was loads of strand of wire cable haning off so i wondered if these could be jaming up and stoping the valve doing its thing. i cut away the loose cable bitas and the bike is running fine again. do you think this cable will be anything to do with the power problem ive been having. ? :S thanks rus.
Moderator Airhead Posted February 20, 2011 Moderator Posted February 20, 2011 afternoon gents. sorry for this quick reply ill answer all your questions when im not in such a hurry. and thank you for all you advice so far. just a quick update. lastnight i took the power valve off and gave it a good clean and made sure it was moving freely put it back and the bike was perfect went on it today same problem again i did take off a bit quick from cold.! so today i made sure the valve waqs still moving freely and it was. i then found that one of the cables from the power valve motor has nearly rusted through all the way just leaving a strand of cable working. there was loads of strand of wire cable haning off so i wondered if these could be jaming up and stoping the valve doing its thing. i cut away the loose cable bitas and the bike is running fine again. do you think this cable will be anything to do with the power problem ive been having. ? :S thanks rus. yes thats the problem Rus.
DTRUS Posted February 20, 2011 Author Posted February 20, 2011 yes thats the problem Rus. thank you.! i also spoke to a motorbike repair guy near me today and he seemed quite sure that the cable was my problem ive got the parts on order so fingers crossed this is the fault. thanks for your help rus.
DTRUS Posted March 3, 2011 Author Posted March 3, 2011 yes thats the problem Rus. your dead right too. it was the power cables at fault. i could have had the bike right running sooner but i adjusted the old nacked cable incorrectly. and then set the new ones up wrong aswell. reallised what i was doing wrong. and then ajusted them and the bike is perfect thanks all for your help. top chaps.
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