Triumphrat

ShikePoke · 08-19-2007, 07:47 PM

Recently upgraded exhaust, pods, intakes, jets, pilots, raised needle. Setup at 128mains/38pilots was just a bit lean. Put 135/42 on, no idle/air adjustment...ran good for one run, without the usual popping on decel. Went to start it up today, and it backfired through the carbs as well as the exhaust, and number one cylinder not even firing anymore. Tried to pull a plug(for the first time ever) and I don't seem to have the right socket. Anyone know what the backfire means and the size I will need for the plugs?

Poke

Chadillac · 08-19-2007, 10:09 PM

You need a thin 18mm deep well for the plugs. Heavy duty sockets, typicaly "name brands" won't work. A universal joint just above the socket, attached to a short extension, helps navigate the tight spots. I only use this to gently tighten and loosen the plugs. I do the rest, threading and retrieval, with a stout piece of plastic tubing(about 4 inches long). I keep the tubing with my tool kit-just in case.
When my first cylinder quit firing, the tach also quit. I had to replace the coil directly above the cylinder head. I used a nology. Good so far.

jimmyj900 · 08-19-2007, 10:09 PM

You need an 18mm deep socket for the plugs.

#42 pilots are too big for small throttle operation and #40s will be on the rich side. With #40s you'll want your mixture screws at about 1 to 1.5 turns.

Backfiring through the carbs can be caused by carbon deposits in the cylinder or exhaust port that stay hot and ignite the incoming mixture on the intake stroke. Rich mixtures leave carbon deposits.

To check your pilot jet size, put the #38 pilots back in and slowly run the bike up to about 6500 rpm in first gear with very small throttle. If you feel bucking that increases with rpm then the #38s are too small. Try the same with the #40s and if the bucking is gone, you're good to go.

You do about 80% of your riding on the pilot jets, so the correct pilot size is critical to the rideability (and gas mileage) of the bike.

Jim

ShikePoke · 08-19-2007, 11:32 PM

Thanks both, will give a try on the #38's.

Poke