1974 dt175

[bambamwpebbles]

Hey there,

I jst picked up an old DT175 in pretty good condition. It was running until i cleaned up the carb, although barely. Anyway, I pulled offthe flywheel cover to clean the points and there was fuel inside - What does that mean? It was not fireing the spark plug, but it had enough juice to power the light meter when kicked prior to pulling the cover.

Anyhelp would be a great. I don't have a lot of tech knowledge but thought this might be an easy project as it was running. Maybe some bad seals.

Thanks.

[Airhead]

Hi, it sounds like it needs new crank seals, magnetop side is dead easy to do, you will need a flywheel puller though.

The other (clutch side) is harder, you may need to buy or make a clutch tool, and also may need to remove the barrel for that one, which then leads to...why not fit new rings while the barrel is off, Oh and of course new gaskets for cylinder base, head and clutch cover.

You would be well advised to read this thread

And an introduction would be good

...Paul

[bambamwpebbles]

Thank you for the reply, any help is useful. I checked out the link and read it through, very interresting and full of good advice. I certainly hope I don't need to go that far as that level of tear down is way over my head. Every step involves another tool - I have three: Phillips, Staight head, and a hammer (a big one too). so, certainly hope I don't have to go that far.

Anyway, it sounds like he was racing towards home and I just need to get to first base - I don't have a spark through the spark plug. There is enough juice to get the light meter to light however at the spark plug cap - To Technical? See, I am not a mechanic,just a guy trying to get a bike running for my son and probably bit off more than I can chew. Allready having buyers remorse although the bike looks great for being 36 years old. Maybe the shop just put a little lipstick on the pig to get her sold. Who knows.

Like I said earlier, it was running just not great - top speed of about 45 and it would bog down trying to climg a hill. So, I figured cleaning the carburator couldn't hurt - boy was I wrong. Now it doestn't even start. There is no spark and I have know idea how I did that. Oh yea, my son did take a small spill with it and busted a tail light off. I replaced that and that is when I decided to clean the carb - so maybe a short. The lights work though, so I don't really understand.

You all should be happy to know the repair manual is on the way! When it arrives I will really be able to get in there and screw things up.

Thank you again for the reply and when i recieve the manual I will keep you posted on the results.

[Airhead]

OK good luck with it. Just check one thing

on bikes that were made much later than 1874 there is sometimes an engine kill switch somewhere on the handlebar controls

Just check yours isnt in the wrong position as this will kill the spark.

[DeTour]

You tried a few different spark plugs right? Somethings funky. I'd check all connections a few times. Unplug and replug them in, twist them around a little bit if you can. cleaning a carb shouldn't affect spark.

[bambamwpebbles]

Tried a few plugs and the kill switch checks out good. Tested via the light meter - kick over with the kill switch off no light, kick over with kill switch on and VIOLA there is light. So it seems to work. Correct thinking or wishful?

New points are on the way, but I need a flywheel puller to get to them and the condensor. Not sure if these are the issue, but picked up the parts on ebay and will change and see. On kick start the plug will not fire, but if you use a light meter it will glow when you kick it over. Maybe not enough charge to spark, but enough for the light? A spark plug tester also has no spark. So I believe there is current reaching the plug but not enough to spark? Does that make any sense?

Have the manual now and it isn't really shedding any light on the situation, it does explain how to tear down and rebuild but not really a whole lot on trouble shooting.

Battery is also near dead, but this is a magneto so not necessary? Correct? Or could it be draining juice from the plug trying to charge, don't think so - but i fugure if I think out loud maybe some of you guys with real knowhow can trouble shoot this for me. At least a few readers can get a good chuckle.

Any advice is helpful and I do appreciate it.

[bambamwpebbles]

An introduction is in order I believe.

Sorry about my rude frist post, i followed someones link about "Hi I need help" not being an introduction - you are correct and I appologize for the rude introduction.

My name is Brett and I live in Cheyenne, WY. Married, two kids, dog, and one rabbit. Balding and not in as good of shape as I used to be. Just like my new bikes tires.

In an earlier life I owned an old Yamaha 100 enduro and thought this would help me relive some old memories - maybe take me back to a happier time(teenager and first bike). However, the first bike was new then and had no issues. The current bike is a 1974 Yamaha Enduro 175DT, it is not new and neither am I. So, after a brief couple of rides it decided to take a little nap - something I am trying to bring it back from.

I am not a mechanic nor do I have any background in the mechanical field except for following chilton books to fix problems not requiring too much tear down.

I joined the forum hoping to learn form people smarter than myself that might be open to helping someone get an old bike up and running. I certainly hope this puts me back in the good graces of those I have offended.

Thanks for listening and I will try not to wine.

[Airhead]

An introduction is in order I believe.

.............My name is Brett and I live in Cheyenne, WY. Married, two kids, dog, and one rabbit. Balding and not in as good of shape as I used to be. Just like my new bikes tires.

...............

Welcome Brett

Might be wise to check the ignition timing, 1.8mm BTDC fully advanced, you'll need a dial gauge but may get away with it if your flywheel has timing marks scribed on it

If you go to the workshop forum, you will see a topic 'Parts manuals for yamaha bikes'

Download the one for yours...(DT175A ?)

There is useful info in the back 'Service Data'

This will tell you things like points gap, timing, coils resistances, oil capacities...all sorts of stuff.

...Paul

[blackhat250]

OK good luck with it. Just check one thing

on bikes that were made much later than "1874 "

I think they would be riding horses and being chased by the Chyanne at that time Auld Een

[Airhead]

He changed it without acknowleging my little witticism, humour? ... which is surprising as his into is quite funny

[bambamwpebbles]

Not sure what all that was about. I did notice I had 1874 vice 1974 in my bio or whatever, so did change it.

Guess that one was over my head. Back to the bike: still trying to find a fly wheel puller for the bike so i can check the points and coils. So, no update as of yet.

Looking on EBAY and bike bandit, but non yet unless you get a complete kit.

[DaVinci856]

Hi There, BamBamwPebbles:

Just a thought...

Still no spark?

I'm not sure about this one because you said a test light would glow on kicking, which has me puzzled, but you might want to check another simple thing that goes unnoticed sometimes.

On my CT3 (and probably on your DT, but I can't be sure) the spark plug rubber cap is a right angle connection with a short wire that just pushes onto a connector on the ignition coil wire. There is no secure connection connection, it just a pushes together.

It is entirely possible that when you were removing the carb that you inadvertently put a little stress on that cable - just enough to separate the connection, but not enough to make the wire look any different from the outside than it was.

Once you've tried pushing that together, if you connect the plug and lay it next to the head and kick in the shade and still don't see a plug spart, it can be traced back. As has been said elsewhere however, don't try removing the magneto flywheel without a real flywheel puller. Including shipping it will probably cost you $16 or less off of Ebay. If you try to remove it without one, you'll likely regret it for a very long time.

Good luck. Just give a shout if you need some advice.

[bambamwpebbles]

Hi There, BamBamwPebbles:

Just a thought...

Still no spark?

I'm not sure about this one because you said a test light would glow on kicking, which has me puzzled, but you might want to check another simple thing that goes unnoticed sometimes.

On my CT3 (and probably on your DT, but I can't be sure) the spark plug rubber cap is a right angle connection with a short wire that just pushes onto a connector on the ignition coil wire. There is no secure connection connection, it just a pushes together.

It is entirely possible that when you were removing the carb that you inadvertently put a little stress on that cable - just enough to separate the connection, but not enough to make the wire look any different from the outside than it was.

Once you've tried pushing that together, if you connect the plug and lay it next to the head and kick in the shade and still don't see a plug spart, it can be traced back. As has been said elsewhere however, don't try removing the magneto flywheel without a real flywheel puller. Including shipping it will probably cost you $16 or less off of Ebay. If you try to remove it without one, you'll likely regret it for a very long time.

Good luck. Just give a shout if you need some advice.

I have the fly wheel puller coming from local dealer at about 14$, so have that covered. I also have a new battery arriving today, just in case that somehow makes a difference - I doubt it though.

As to the spark plug cap, I have trimmed the wire and reseated the plug to the wire. I think it was a screw on and off, at least that is how I did that. So, that should all be good. The light meter testing but no spark is what has me confused, maybe enough juice delivered to run the light but not to bridge the gap in the spark plug. Thank you for the hints and maybe I will check the spark plug cap again to make sure I didn't make things worse - although in my defense, it isn't any worse than it was. Not running is not running - getting a little old and frustrating.

I guess it is still a project bike, just more of one than I was hoping for. Ha

[bambamwpebbles]

Hello again,

Seems like I talk to myself alot here on the forum, But wanted to let everyone know the status on the bike for those with similar issues.

A new battery arrived the same day as the flywheel puller, so the path of least resistance was putting it in just to make sure before I dug any deeper. And there was fire - felt like Tom Hanks from that movie.

Anyway, I guess there is a short in the system that can be overcome by a properly charged battery - I do not know. I stopped the tear down and put it all back together with fingers crossed. It runs like before - only it starts on the first kick now, still only top speed of about 35 or 40. Not bad considering it was a paper weight for about three weeks. It needs new rings from what the dealer who sold it said. The compression is low at about 65.

So, I will work on the short for now and then the top end this winter when the snow flies.

For now we ride - not fast, but faster than before.

Thanks to all for the help.

[blackhat250]

You say top speed 35-40, should be 70, is it reving out [ redline]? . is it got correct sprockets on, ? 15 front . standard,

[red1devil]

Hello my name is warren I live in Utah this is my first project bike a 1974 dt 175 Yamaha and runs great having problems with wiring I am changing out the headlight to a 20 w one will that affect the wiring at all or do I have to run it off the battery and send all the charging wires back to battery or will it run like the other one off the yellow and white wire the kid I bought it off had all the wires jumbled up and its a mess trying to fig it out