DT175 Ignition

[Blackhauk90]

Hey i need some help with my Dt175 engine..

My setup basically is a 1974 DT175 engine that i have just rebuilt (new seals bearings piston rings etc..) I had swapped the stock points and condensors igntion out and put a 1981 Dt175 stator and flywheel on it (cdi unit) . Its build up minimal. It has a high RPM pipe on it and stock carb and the compression is raised just a touch.

Now the problem i am having with it is i cannot rev it up.. at all. I can get the bike started the first kick everytime when it's set to the stock ignition settings but i cannot get it to rev above 2k.. Basically all it does is idle. I advanced the engine and the engine got a bit smoother then got really rough and started to kick back when i kick started it. Yet still it did not rev about 2k. I know for a fact it is getting enough gas as it puddles it as the exhaust comes out.

I was curious if anyone had any experience with these engines and if they've done a points/condensor swap to a cdi ignition.. Also are there any signs of what could be wrong from the gas puddling up like is? I really thought 100% it would be the timing but i could be wrong.

[tecateboy]

im gonna take a guess and say its not anything with the timming, how are your reeds, if this bike has reeds, some older ones dont, but also it sounds like your jetted waaaay to fat, lower your main a size or two and try from there. it sounds like your basically flooding your motor out when you try to rev it up, set your timming back to where it runs smooth and then change the jetting and see what happens.

[370banshee]

sounds to me you may have a weak spark.... test your sprak and check it for color.... it should be a very bright lite blue...... if it's orange... your fucked.....

[AZrider2020]

ya I'm going with spark too..... it might be gapped wrong. check the gapping to make sure thats not it. When you let the quad sit do you turn the gas off? This happens on my little kx-60 too. If I leave the gas on it shoots niagara falls out the tail pipe so make sure you turn it off when you park it for a while.

[Kane]

Done this a million times. When converting the DT/MX 250's and 360's you have to elongate the mounting holes almost a half inch as they are retarded too far to just bolt on. They start super easy but won't rev at all. I've acyaully even gotten one to start backwards and rode it for a good 100 feet before it died out.

Fuel puddling can be a plugged overflow/drain hole on the bottom of the carb allowing the fuel to simply run into the cylinder due to a bad needle or misadjusted float.

[Blackhauk90]

Originally Posted by Kane

Done this a million times. When converting the DT/MX 250's and 360's you have to elongate the mounting holes almost a half inch as they are retarded too far to just bolt on. They start super easy but won't rev at all. I've acyaully even gotten one to start backwards and rode it for a good 100 feet before it died out.

Fuel puddling can be a plugged overflow/drain hole on the bottom of the carb allowing the fuel to simply run into the cylinder due to a bad needle or misadjusted float.

Heh its about time i found someone who's done this before. So basically just advance the plate about a half an inch and it should run decent? I've heard that DT's can get weak sparks without running batteries though.. i don't know if that would make a difference?

[zillaguy89]

Originally Posted by Blackhauk90

Heh its about time i found someone who's done this before. So basically just advance the plate about a half an inch and it should run decent? I've heard that DT's can get weak sparks without running batteries though.. i don't know if that would make a difference?

I'm pretty sure the battery is just for the lighting system, mine runs just fine with no battery. Mine still has the factory points and stuff too

[Kane]

Yeah, there's ZERO power supplied to the spark coil from the battery. There is no reduction in spark power when you remove the battery.

You'll have to play with the timing a tad to get it into the correct setting. The best thing to do is to find an old Clymer manual from the early 80's. They tell you in the hop-ups section how to do the switch over and how to make a static timing light to use to get it dead on.

Why Clymer ever removed the mods and hop up section is beyond me.

[sblt500r]

just thoght i would add, my 74 dt125 won't run unless it has a charged battery. the spark would take power from the battery to run. what i found out later on is the generator/starter is fried. it has electric start. the crank seal leaked and burnt up the generator, so there was no way to generate spark and charge the battery. its been sitting ever since i found that out, plus i moved on to bigger and better things since that, plus i couldn't find a good used starter/generator.

[Kane]

You sure thats a DT? With electric start?