Jump to content

78 dt 400 fuel mixing


popalong
This post is 5530 days old and we'd rather you create a new post instead of adding to this one. You can't reply in this post.

Recommended Posts

I just bought a dt 400 77/78 unsure if the oil pump worked so i took some of my kx"s premix and gaver a drink,well it run but no power and smoked like a frate train.so wile it was running, i pulled the right hand cover of from where the pump is and it was pulsing in and out, so i pushed in on it gently.and there was a definite pressure and a resistance (pulsing) and there was oil in the tank but probly 3 oz, how can i tell if the oil is actually getting ware it needs to be?

oh and it sounds like there is a marble in the top end is that normal for it to be so noisey?

Link to comment
Share on other sites

Do you want an ad-free experience? Join today and help support the Yamaha Owners Club.
  • Moderator

, how can i tell if the oil is actually getting ware it needs to be?

Pull the oil pipe from the carb, hold the pulley on the pump at max when the engine is idling, this allows the pump to stroke at maximum and you will see if its pumping ok.

...Paul

Link to comment
Share on other sites

Pull the oil pipe from the carb, hold the pulley on the pump at max when the engine is idling, this allows the pump to stroke at maximum and you will see if its pumping ok.

...Paul

just went and done just that paul,and got crazy oil out. so i took a tip cleaner and made sure the port on the carb was open, and it was. so on thease modles it is best to use the oil pump?

and will the to much oil cause the problems i mentioned? thanks

ronald

Link to comment
Share on other sites

  • Moderator

just went and done just that paul,and got crazy oil out. so i took a tip cleaner and made sure the port on the carb was open, and it was. so on thease modles it is best to use the oil pump?

and will the to much oil cause the problems i mentioned? thanks

ronald

Hi Ronald

Just make sure that the pulley is working fine as you twist the throttle, Now you have proved your pump is working if i were you i would drain the fuel premix and give it back to the kx, personally i prefer the pumps they really are quite reliable and a look now and again if the cable and pulley are working ok is all you need to do. As for the noise its always difficult to comment without witnessing it, maybe it needs a rebore, a compression test would be a good idea, it might just need new rings though, there are gap tests for these in the workshop manuals.

Link to comment
Share on other sites

Hi Ronald

Just make sure that the pulley is working fine as you twist the throttle, Now you have proved your pump is working if i were you i would drain the fuel premix and give it back to the kx, personally i prefer the pumps they really are quite reliable and a look now and again if the cable and pulley are working ok is all you need to do. As for the noise its always difficult to comment without witnessing it, maybe it needs a rebore, a compression test would be a good idea, it might just need new rings though, there are gap tests for these in the workshop manuals.

Link to comment
Share on other sites

Thanks paul,

out of curiousity i pulled the jug.(still inspecting) there was no score marks or scratches on piston.or cylender walls.two of the top reeds was stuck, freed them up and reasembeled. added 93 oct fuel,and used amzoil dominator pemix,to tank, Kicks off first stroke,huge diffrence in power.

are parts hard to find where your from? I would like to find oem fenders and side covers.and guage and headlamp assembly.i have all the oem part #s,but there like gold here.all wireing and accessories work, at the batt i have 6.5 to 7.1 .im amazed at what all works it was in a barn for god knows how long.

guess ill strip it to the frame and get started,

Thanks agian Ronald,

Link to comment
Share on other sites

  • Who's Online (See full list)

    • There are no registered users currently online
  • Recently Browsing

    • No registered users viewing this page.
×
×
  • Create New...