Issues with brand new Downtown running rough and cutting out / stalling

[sklnzl]

Hi there , question to those who have swapped stock to iridium spark plug ? what is the difference in overall performance ?

[zombie]

None. The plugs just last longer in all engines, and resist fouling in 2 strokes

[de-dee]

it may be wishfull thinking , but to me it runs smoother , I switched at 3000 km. and now at 45,000 km.  it still runs great,. seems to run better as I put more miles on it,. every once in a while I get on the super slab 417  and run for a while at 80 mph. do a few passes at 90 mph. then get the hell off,. and head for the back roads,.I LIKE RIDING  at 50 to 60 mph.
     300i downtown   Don.

[mnpugdog]

I'll second the suggestion of switching to an NGK iridium plug. Cheapest "upgrade" you can do. Also, at a stop, your rear (left) brake will cause the bike to shake more than the front (right) brake. I generally use both brakes to come to a stop and then switch to just the front brake while sitting at a light.

+1 on using the front brake at stops.

[sklnzl]

For safe breaking ,I would suggest using 70 % force on front brakes and 30% on rear brakes .

[mnpugdog]

For safe breaking ,I would suggest using 70 % force on front brakes and 30% on rear brakes .

We're not talking about breaking but when you are sitting still after you have stopped.

[zombie]

we're not talking about breaking at all. We're talking about spark plugs

If you want to keep your mirrors from fogging up... Use spit.

[msolok]

Hey Guys,

Had a bit more of a ride on the bike over the last few days an I am still unsure. Being so new to riding with little experience of other bikes I am unsure how much vibration to expect at idle. When the bike is first turned on (so only front brake applied) how much vibration do you expect.

With my bike I still get a fair amount of vibration when the bike is turned on (or at idle after a decent ride). The mirrors vibrate around a fair amount. How much do you guys think is normal?

[de-dee]

when my scooter was new I worried about the shaking ,. now I dont eaven notice it,. maybe its not shaking as much,  I dont know ? 

[sklnzl]

I have been riding bikes for quiet a long time , and I have not have any vibration issues  at stops and whatever brakes i use to maintain the bike in place ,I didn't quiet bother about that ,provided the bike has a well tuned engine which acts as it should at idle.

[zombie]

Maybe the idle speed is just to low. Try adjusting the idle set screw.

[DMblues01]

Raising the idle speed does help. BUT, any single cylinder engine is going to have vibration when it's running. Even if it has a counter-balancer, you can never get rid of all the vibration. If it's not bogging down and stalling, you should be OK.
BUT, I don't know as much as some of the others here!

[zombie]

You are still 100% correct. They all vibrate to some extent.

[msolok]

Thanks guys. At this stage I haven't had much of a chance to play on the bike more, due to the constant rain. I am hoping to give it a really good run in the next few days and see how it is after that.
After speaking to the dealer he seemed to think it might have been an issue with stale fuel. He suggested I see how it runs over the next few tanks and then get the workshop to take a good look at it.

[zombie]

A double dose of Sea Foam in the fuel helps clean the fuel system, and adds a few octane points to control pre-ignition from "stale fuel".

It's my go to tune up in a can.