Quick carb tuning question/opinion

[pahako]

There's no set recipe for jetting. What works for you may not work for my bike. All you can do is experiment. I suppose you could still be lean. The only way to find out would be to try a 142.5 main to see if it improves things. If it makes it worse, go down to a 137.5. What is a fact about jetting is that you need to try several sizes in succession to properly dial things in. And sometimes just that one more size makes all the difference.

When I bought the jets I wanted to start with a 142.5 but, Mikes was out of them at the time. I do however have a 145 and a 137.5 to experiment with for now though.

 

[5twins]

Try those 2 and that will tell you what direction (richer or leaner) you need to move in. Popping and misfiring can be caused by both lean and rich conditions. Usually they sound different but it sometimes takes an experienced ear to tell. If main jet changes don't do anything for the popping, I would look at the idle circuit. Maybe another size up on the pilots but that's not very common. You never know though. Like I said, every one of these bikes is a bit different. Your bike is gonna want what it wants.

I also recommend using real Mikuni jets. Mike's are knock-offs and who knows how consistently they're made or if they flow correctly.

 

[pahako]

It seems to do it more when the engine is warmer. I will try the bigger one first and go from there.

 

[5twins]

An engine usually needs more fuel when it's cold. That's why we have the choke (enrichener). If your bike runs worse warm, you may be too rich.

 

[pahako]

An engine usually needs more fuel when it's cold. That's why we have the choke (enrichener). If your bike runs worse warm, you may be too rich.

So maybe I'll go with the smaller one first. I doesn't making any popping noise for at least the first 15 minutes of riding. Thanks for the reply's 5twins. This is the kind of info the carb guide doesn't mention. Perhaps because this is basic knowledge that they figure I should already know.