Taming the DT 250

It's been a few weeks now since Dave and his crew at O'Hanlon's sorted out the mystery problem on the DT. A flattened out lock washer on the timing plate that was allowing it to slip. A couple times the timing was so retarded the engine actually ran backwards.

Yes, you read that right! A two stroke engine can run backwards if the timing is too far off. It was more than odd starting it up at a service station, putting it in first and then rolling backward as I attempted to head out. ...but now I know.

I also know more about the mechanics of fouling plugs and have actually been accorded some finesse with regard to avoiding it. For the most part the plugs on this type of bike foul when you funnel too much fuel through the engine. It can't burn off properly and the rest is predictable. These things tend to bang and pop a little even when they have fresh plugs, and I do mean, a little. If, like now, the bike is tuned well for how you ride it, when the plug is going stale you can develop a sense of when it's going to be shot and how to stretch out your time before you absolutely have to swap it.

Doing things like riding up hill under full throttle, into a headwind or whatever, where you can't get the RPM's up is a sure way to foul that thing out. Riding for too long at higher RPM's will also burn the plug. You just have to get a feel for it and every engine will be different based on the engine itself and how it's tuned.

The DT is currently tuned to start a little harder but have slightly advanced timing to better handle higher speeds. It seems to be working OK and I've gone from replacing one or more plugs a day to maybe one a week depending on how I ride it. They're cheap and easy to swap out so it's not a huge deal to replace them and I've come to think of it as part of the gas budget.

Still hunting a new twin plug head and a bigger fuel tank but that's way down on my priority list at the moment. Just happy to have a reliable bike until something else catastrophic happens to it. I can only hope these repairs will continue to be further and further apart. Finally getting out on it enough to be back in the realm of knowing who's out and about by their bikes and being known the same way. That's certainly a nice thing about riding custom and vintage bikes. You can roll by and know immediately if your friends are about.

DT Misadventures

As seen in the wilds of SOMA

For some reason, in my infinite wisdom, I decided to take off and ride South for a change. Now don't get me wrong, So Cal has it's charms but one of them isn't a slow paced technical ride on highway 1 South. Instead it has some pretty straight fast roads. That's great for getting where you are going but maybe not if like me, you ride a vintage small displacement two-stroke.

Today I learned about spark plug ratings and why some models of DT 250's, not mine, have two spark plugs in the head on the single cylinder. Two-strokes are finicky little monsters at times and they have certain ideal temperature ranges and fuel mixtures. So, they need different plugs for riding on trails and in city traffic than they do going flat out on the highway. Mismatch the riding to the plug and you'll need a new one sooner than you think.

The DT ran like a champ on the run south from San Francisco to Santa Cruz and part of the way back but the extended run into the wind up hill with a hot plug overheated it and fouled the @#$%^! out of it. I, not having experienced this before, did not know what was happening. If only I had and hadn't rushed out of the apartment without my tool kit that just so happens to contain a spark plug wrench and a shiny new plug.

So, I limped the machine into Half Moon Bay, a place where you can buy gas and food and not much else... OK, that's not true but you can't buy cheap socket sets or spark plug wrenches. Nor can you buy anything but an adjustable wrench after 6PM. Thanks Half Moon Bay. Though, I'm told it's the perfect place to go for a weekend with someone you aren't supposed to go away for the weekend with.

So, I pushed the bike for a mile or so and then got frustrated and kicked it a million times until it fired up. No clue why, it just did and it shouldn't have but I wasn't complaining. I kicked out onto the freeway, bad plan, and ran for home. I luckily managed to clear I280 just as the engine went dead again. ...back home-ish but in a terrible neighborhood at 6th and Howard. Try as I might I couldn't get it to light off again and once more pushed it another mile closer to home.

The idea was that I'd find a garage and safely park it over night until I could come back with some tools. At this point I still didn't know if the issue was a clogged jet, fouled plug, something uglier or a combination of all three. What happened was I found out how rude men who who work in parking garages and barely speak English can be. Really flipping rude. You'd think if someone asked a customer service person a business related question they'd at least give decent service even if just to say "No" but alas they need to say "Oh no no no, no motorcycle!" while they waggle a finger at you. If only Bill Cosby had been there, he'd know what to say.

Again, I pushed the little monster up hill another block until I finally found a parking space that looked like the bike would still be there when I came back with my tools, and it was!

After a couple frantic phone calls and talking through the problem with wiser motorcycle guys than me, it was determined twice independently that I'd cruelly ridden the bike too hard and had asked for it. Thanks, I already knew that.

Anyway, failing to find my spare plug I returned with contact cleaner, sandpaper and a pocket knife to clean the plug and hopefully make the .7 mile ride up hill and home.

Fouled plugs kind of don't un-foul too easily but I did manage to scrape and scrub it enough to get the bike started and in a cloud of blue smoke I was off through crowds of drunken Valentines celebrators and unexpected 10PM traffic. None the less, when the DT growls cars usually give me some room. I made it to the top of Nob Hill before the engine died again and I managed to push another couple blocks and then bump start it down a hill just far enough to ride to my parking space like nothing happened.

Some tipsy neighbors walked by and asked if I had been out riding. "Yep, great day for it. Rode down to Half Moon Bay." The response, "Man, I wish I had a bike like that." I just smiled and said thanks not wanting to burst the happy bubble of bike envy.

So, I'll be ordering up a half dozen plugs and making sure to carry spares at all times. Seems DT 250's are notorious for eating plugs.

Another lesson learned. Just happy I made it home.

Flat tire...

Things like flat tires happen to any bike but with old bikes you often discover other things in the course of fixing something like a flat tire. In this case I made it just to the service center by putting some foul smelling messy fix flat into the tire. The tube was predictably, "an odd size" and had to be ordered. OK, good to know. Then it was discovered that the rear brake wasn't out of adjustment as had been suggested by another mechanic but rather in dire need of new break shoes.

So, after only a couple weeks it's back on the road with a new tube and some real stopping power. Wish there was a better way to protect from road hazards than "being careful". I will be adding a tube patch kit to my on board tools but I'm not sure it would have helped in this case as the tube was damaged in a couple places because the screw was so long. Actually, I doubt that even something like self sealing goo would have helped. At least it was the rear...

Happy to have it back on the road again either way.

The bad coil

I've got a few hundred post resurrection miles on the DT now and it's still going strong. I was skeptical about the small displacement at first but it's proving to be less of an issue than I guessed. In less densely populated areas it might still be an issue but in a city where you rarely get over 24 or 30 miles an hour, even in the outlying areas, it fine. In many ways it's somewhat better. Narrow, torquey, quick off the line, all good things. The brakes still need to be adjusted for non-dirt riding but as a whole it's really proving itself.

All this time and aggravation and the offending bit was the unassuming lighting coil seen in the photo. I may have to rewind it just for the sale of having done it.

Still searching out an old toaster tank. Two gallons doesn't get you very far on a gas guzzling two-stroke monster, even if it is only a little monster. I would never have guessed it'd be as bad on gas as it is. Right at 30mpg in the city and that's not even a tuning issue. It's factory spec!

DT Rising

After a protracted struggle of my own that included busted knuckles and a fair bit of frustration I finally sent the bike off to the experts at O'Hanlon's Motorcycles hidden down in SOMA. Then after a grueling wait that stretched on and on as even the experts got frustrated the problem was finally tracked down.

The DT now has new points and condenser, a new lighting coil, primary coil, secondary coil, turn signal relay, a rewired tail light and a rewired turn signal. Though, it was the lighting coil all along and admittedly the weirdest and last thing anyone expected to be wrong preventing it from getting a spark. So, after a cursory carb rebuild, adjusting the cables and putting in some fresh gas it lights off on the second kick even when it's cold. I suppose the upside and those months and dollars spent resurrecting the beast is that it's about as reliable as it's going to be short of rebuilding the top end.

I'm in the snowy Midwest until after Christmas looking forward to getting back to the city and hopefully off down the coast for a day or two. Hoping I can get to my favorite salvage yard and score a bigger tank for the bike before I head back west.

I'd also like to add that Dave at O'Hanlon's really did me right on this and was more than fair on the price. I sincerely hope I don't run into another problem I can't solve on my own but if I do I won't hesitate to have Dave and his crew bail me out.