I bought a 2005 Roadstar Classic new, I installed a set of Cobra two into one pipes and a K & N filter.?

Question

The bike starts,runs and idles good with one exception. On the first start of the day, I choke to start and leave the choke on until I get out to the highway (about 2 to 3 mins. I accellerate up to 65 to 70. After about 30 to 45 sec. the engine starts to miss and basically runs on one cly . This last for 30 to 40 secs and then everything smooth out. It will do this with the choke on or off. After the bike sets 7 - 8 hrs at work, this problem does not happen, only after it seats overnight. I talked to a local shop mech and he said I was running to lean. I showed him a biuld up of black soot in the tail pipe and that it looked like it was burning rich. He insisted that it was burning lean so I bought a Cobra rejet kit and installed it. Just for curiosity I used drill bit shanks to check the size of the stock main jet. It was larger than the largest jet in the cobra kit. My soot problem is gone now, but the first start problem is exactly the same. Any help appreciated.

Answer 1

turn the d**n choke off while you r riding you will ruin the motor just take a few extra minutes and let your bike warm up its just like u getting up in the morning you r not at normal speed but once you wake up and get going you function better . do not rush your bike simple as that . but you may have already done some damage internally get that checked out (valves,pistons,etc.)

Answer 2

Did you remove the stock airbox and use clampons? If so, try reinstalling the airbox. If that doesn't work, reinstall the stock air filter.

Answer 3

#1 did you have the 4000 mile service done yet? Notorious for needing valve adjustments and carbon build-up

#2 It was running lean because you increased air flow and reduced back pressure - if you had "soot" you could very well

have carbon build-up in your valve system or plugs

Changing the jet goes hand in hand with a K&N and Cobra pipe install

It sounds like a valve clean and adjust issue to me, possibly a fouled plug or carbonized plug if you are lucky. Are you having backfiring issues as well? Are you running the proper octane grade? Clean or replace plugs, gap and install - you are forcing it rich by choking it, thus the possibility of a gap issue your turn to lean eventually burns off. I wouldn't ride with the choke and it's telling me it's not a warm up issue - it's an air-fuel mixture change your doing on the fly - do the easy stuff and then get the valves checked... lessoning back pressure affects valve travel

Answer 4

Mayby too much backpressure in the one cylinder from the two into one pipes? Improper gapping of the spark plug could be it to.