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Discussion Starter #1
Hi there!
I'm from Germany, and I bought my first triumph half a year ago. It's a 2001 thunderbird 900.It was stock as I purchased it. I changed some minor stuff, like turn indicators. I definitely wanted to change the mufflers because of the sound. I got some from FEKED, they look similar to the OEMs but sound better and are about half the weight.
As I bought the bike, it was not running, cause of the carbs were dirty. I cleaned everything and it was running fine on idle. When I changed the mufflers it was bad at starting and running not really smooth or dying without choke. I expect it is running to lean at least on idle, I had no chance to drive cause of the winter. Maybe anyone has experience with this combination and had an idea what jets to use to get a good mixture.
My bike has the keihin cvk36 carbs with 0.98 main jet and 0.38 idle jet

Thank you guys!
 

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Discussion Starter #3
Usually there is an effect, cause sport mufflers change exhaust gas pressure in exhaust system.
I didn't change anything, wanted to see how it's work on stock...I have no exhaust gas analyzer, so it's difficult to check the actual condition.🤔
 

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Maybe I should re-phrase my comment. Keihin carbs are relatively insensitive to changes in the exhaust system. The only symptom often reported is increased popping on deceleration.

Changes on the inlet side is a whole different issue.

I suspect your issues are with the carburetors themselves, not the jetting.
 

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When I fitted these silencers to my Thunderbird, I didn't change the jets or pilot screw settings. I have the Mikuni carburetors and not Keihin but they should behave similarly. There were no issues with idle and the bike was running well.

Could it be stale fuel? You mentioned that it has been parked over the winter. If it's not that, then maybe there is an air leak that has developed on the intake side somewhere (cracked rubber perhaps).

Noel
 

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Following up on Noel's comment, has it been sitting for months with 95 octane fuel? In Europe that usually means ethanol content, which in my case led to blocked idle jets when the season started two years ago. I've been filling up with 98 octane non ethanol fuel ever since.

Sent fra min SM-G935F via Tapatalk
 

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Discussion Starter #8
I cleaned the carbs before first run. But I didn't use fresh gas, It was older. I try fresh gas and tell the results. Thanks for the ideas :)
 

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Back again, I found the problem:)...it was a kind of my stupidity. Cause the gas tank is off, as you see in the picture, I've used a gas bottle tool. I connected the fuel hose to the carbs and let it run. The bottle cap has a small hole for air come in, to avoid vacuum. That hole was taped with black tape by my college from the workshop, to avoid gas vapor, when the bottle isn't in use......today I recognized that "modification". The engine cut off all the time, cause it could not suck the gas out of the bottle🤦‍♂️...now it's running fine, at least at idle, later I'll see how's going while in the road.
Thank you for your help!!!
 
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