Jump to content

Help with DT 400


This post is 5682 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 think the oil pump is not working on my DT 400(1978 I think), I'm thinking I can just mix the gas. What ratio should I use? the electrical doesn't work either, do I need a fully charged battery? I've lost the key, but I can move the switch to start and ride the bike. Maybe I can't move the switch far enough to get the lights to work? The bike has been sitting around for a few years, I'm just trying to get it going to teach my son to ride bikes (he's a teenager). Any information would be greatly appreciated.

Link to comment
Share on other sites

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

I think the oil pump is not working on my DT 400(1978 I think), I'm thinking I can just mix the gas. What ratio should I use? the electrical doesn't work either, do I need a fully charged battery? I've lost the key, but I can move the switch to start and ride the bike. Maybe I can't move the switch far enough to get the lights to work? The bike has been sitting around for a few years, I'm just trying to get it going to teach my son to ride bikes (he's a teenager). Any information would be greatly appreciated.

I've seen some quote 20:1 and use that myself although she's a bit smokey. At the top end revs it will need that but it overdoes it at low/med revs. Autolube's supposed to solve that but if it's not working and you don't know = buggered piston/barrel. Pre-mixing can be a pain but I'm not 100% confident about an old pump so I go with it.

Some electrics like indicators/stop run of the battery so if they don't work that's the first place I'd be looking with checking the bulbs as well.

Link to comment
Share on other sites

I think the oil pump is not working on my DT 400(1978 I think), I'm thinking I can just mix the gas. What ratio should I use? the electrical doesn't work either, do I need a fully charged battery? I've lost the key, but I can move the switch to start and ride the bike. Maybe I can't move the switch far enough to get the lights to work? The bike has been sitting around for a few years, I'm just trying to get it going to teach my son to ride bikes (he's a teenager). Any information would be greatly appreciated.

my dt400 runs without a battery,and i put 20-1 in tank till i put pump on.runs better with pump. good luck ;)

Link to comment
Share on other sites

  • Moderator

The pump, tank are there and piping been disconnected, the cable works, I'm unsure how the oil lines go. I think one goes to the pump and a smaller one goes to the carb from the pump.

So if everything is there, would it not be wise to see if it can be got working before going down the 'awkward' pre-mix path?

First check if the pump is stroking, with the engine idling, turn the pulley by hand the same way the cable would turn it on open throttle, watch the pump you should see it stroking.

Link to comment
Share on other sites

So if everything is there, would it not be wise to see if it can be got working before going down the 'awkward' pre-mix path?

First check if the pump is stroking, with the engine idling, turn the pulley by hand the same way the cable would turn it on open throttle, watch the pump you should see it stroking.

I have already checked to see if the pump strokes, it does I've gotta get new oil lines, they are gone(the bike has been through many hands). I'm just unsure how the lines go. Does an oil line go to the carb? I believe one should. But I also thought that an oil line should go the bottom of engine to ensure proper lubrication at higher speeds. Which I thought is an advantage of oil injections proper lubrication at all speeds.

Link to comment
Share on other sites

  • Moderator

I have already checked to see if the pump strokes, it does I've gotta get new oil lines, they are gone(the bike has been through many hands). I'm just unsure how the lines go. Does an oil line go to the carb? I believe one should. But I also thought that an oil line should go the bottom of engine to ensure proper lubrication at higher speeds. Which I thought is an advantage of oil injections proper lubrication at all speeds.

Not familiar with the 400 but if it's the same as the DT175E there will be two pipes, one from the oil tank to the oil pump and one from the oil pump to the carb, let me know if you intend using the pump and i I will look up the part numbers for you. As for "But I also thought that an oil line should go the bottom of engine to ensure proper lubrication at higher speeds."...not sure what you mean here, there is no oil line to the engine.

Link to comment
Share on other sites

Not familiar with the 400 but if it's the same as the DT175E there will be two pipes, one from the oil tank to the oil pump and one from the oil pump to the carb, let me know if you intend using the pump and i I will look up the part numbers for you. As for "But I also thought that an oil line should go the bottom of engine to ensure proper lubrication at higher speeds."...not sure what you mean here, there is no oil line to the engine.

I've connected an oil line to the pump, bleeded it, wasn't pumping oil, adjusted the stroke of the pump and it pumps oil but the output flow is slow and doesn't pick up when reving up engine. The input line I used has bigger diameter then the original one (used what I had in garage), I'm gonna try a proper size one when I get one. I'm thinking the pump is worn out that is why who had the bike before me disconnected and removed the lines. Maybe the flow is right I don't know how much oil it should put out.

Link to comment
Share on other sites

bleeded it, wasn't pumping oil, adjusted the stroke of the pump and it pumps oil but the output flow is slow Maybe the flow is right I don't know how much oil it should put out.

HI / The mix is 32/1 . yeh and the oil delivery is slow [at pipe to go on carb] If its pumping up steady [ slow but pulses] its working [its slow coz if it was pumping fast & lots the tank wud empty in a few miles] . is the cable connected ?

lights are on left handle bar switch [ engine needs to be running 6v magneto system .]

Link to comment
Share on other sites

HI / The mix is 32/1 . yeh and the oil delivery is slow [at pipe to go on carb] If its pumping up steady [ slow but pulses] its working [its slow coz if it was pumping fast & lots the tank wud empty in a few miles] . is the cable connected ?

lights are on left handle bar switch [ engine needs to be running 6v magneto system .]

The lights don't work with engine running, fully charged battery, no electrical works only headlight on low beam, engine stop swtich doesn'twork. I've checked some wiring. Any help with ideas would be awesome.

Link to comment
Share on other sites

I think the oil pump is not working on my DT 400(1978 I think), I'm thinking I can just mix the gas. What ratio should I use? the electrical doesn't work either, do I need a fully charged battery? I've lost the key, but I can move the switch to start and ride the bike. Maybe I can't move the switch far enough to get the lights to work? The bike has been sitting around for a few years, I'm just trying to get it going to teach my son to ride bikes (he's a teenager). Any information would be greatly appreciated.

http://www.ydsparts.com/Tech%20tips.htm

You might want to have a look at this, this site shows the strip and rebuild of autolube pumps helped with my DT 175 twin shock pump rebuild

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...