Tis The Season... For Bikes.
Took the lil Yammie on her Maiden Voyage today, a short 1 mile trip (kitted out with a backpack and a helmet that matches the paint job on the bike), to set the timing on my friend's Dodge.
She ran awesome...ish. When I pulled out of my driveway I got really happy on the throttle and did a 1-2-3 Burnout with the brand new Kenda K270 Tire (gotta break it in :burnout: )
She pulled hard and fast up thru 3rd. I forgot just how fast this thing will wind out, it buries the tach needle in the blink of an eye and feels like I'm short-shifting the whole time just to keep her from smacking the redline.
Once I hit 4th though, she began to lose oomph (and still had 2 gears to go. Yeah, the little DT is a 6-Speed). It felt like she was starving for air or fuel. When I arrived at my friends, it idled HIGH, like a vacuum leak... HMMM.
A little research and some testing, she's leaning out, due to a vacuum leak. 2 things are known to cause this problem on the little DT's. 1 : The Intake Manifold/Boot is prone to cracking due to old age (they are molded rubber, after all). 2 : The Crank Seal behind the Magneto/Stator Plate sometimes pops out of its bore. Both cause a vacuum leak, so tomorrow I'm gonna pull a few parts off the bike and see what part needs to be replaced.