Slight bog to 2k from start

[ragedigital]

how long does the temp take to cool down after adjustment?

I keep the motor running and blip the throttle after each IMS (Idle Mixture Screw) adjustment.

You will see adjustments very quickly.

[megaloxana]

You do know that you should tune from high rpm to low rpm. Make sure your top and mid range feel strong before moving on to low rpm. Cuz if you have to change your mains, it will affect your low end richness.

The Mains shouldn't affect the low end (throttle less than 1/4 turn) at all.

Here is a good chart for reference on what affects what throttle range:

Correct, but he mains will affect your float levels which in turn affect low end.

[fadlan12]

how close do they need to be? is 20 degress close enough shold it be ten?
readings are now .
#1 288
#2 270
#3 300
#4 300
noticeable smoother, I had to lower idle screw, it was at 2k after turning #3 to 4 turns out.

[ragedigital]

Correct, but he mains will affect your float levels which in turn affect low end.

I think that's backwards. The float level will affect almost the entire range. The main is really restricted until the jet needle is pulled out of it's way at full throttle. The Pilot Jet is the on supplying most of the fuel at low throttle.

I have changed Main Jets and not seen a bit of difference in temp measurements at Idle or up to ~1/8 throttle.

I know Factory Pro has a tuning guide out there ([urlhttp://www.factorypro.com/tech_tuning_procedur ... gines.html]LINK[/url]), but he confuses his own thinking. Just because a Main Jet works well at WOT, doesn't mean that you can correct the entire throttle range around it. The Main Jet has to be properly selected.

Here is another good reference ([urlhttp://www.iwt.com.au/mikunicarb.htm]LINK[/url])

[ragedigital]

how close do they need to be? is 20 degress close enough shold it be ten?
readings are now .
#1 288
#2 270
#3 300
#4 300
noticeable smoother, I had to lower idle screw, it was at 2k after turning #3 to 4 turns out.

That's fine. What RPM was that set at?

[fadlan12]

1.2k

[fadlan12]

Hesitation/lurch still present, I took it out last night for some backroad action and it was fine at speed but starting from a stop it felt like it was hesitating until 2.5k + rpms. Friction zone is ok as it will start pulling me with no gas but as soon as I start gassing it to accelerate is when the hesitation starts. Of course if I get to rolling well like 5-10 mph without gas it lurches bad.


Thanks for all the responses so far.

[Dborne1]

I found Header temp not accurate at all for me. All my headers were within 25 degrees of each other. I have a 5 gas analyzer at my shop and uncapped the plugs in each header and checked CO (carbon monoxide) and HC (hydrocarbons). I found 1 cyl. way too rich and another cyl. too lean. I was able to dial each cyl. in perfect with analyzer. It sounds like your idle may be too low. I set mine to spec.s (Cali model) 1600 rpm I think yours may be around 1500? not sure? Try raising idle a little.It may just be loading up do to low idle. If your headers have individual plugs call a local autoshop and see if they have a 4 or 5 gas analizer and see if they can dial in your idle mixture. It probably took me 30 minutes to do with plastics off. Aim for approx. 1.5% CO or what ever give it the lowest HC reading at idle. My bike idles perfect now with no bogging. Good luck.

[fadlan12]

So its still lurching a little when cold from a stop, When its more warmed up its minor or if I ease very slowly of the clutch its less pronounced. I will turn out the a/f screws out to 4 and see if that helps. is there a standard temp for headers to adjust to?

[Luke-a-Tron]

I think you're going to have a very hard time eliminating the lurch below 3k completely. It's a function of the amount of torque the engine is putting out. If the rear wheel is able exert a significant fraction of that torque back through the drive train, it will slow the engine significantly. I don't even start letting the clutch out till at least 3k. A multi plate wet clutch can take quite a bit of heat so don't be afraid to feather it liberally.

[fadlan12]

Ok, well that makes me feel better. I'll just work on easing it out real smooth.

[Luke-a-Tron]

Oh and also, don't even bother trying to correct problems that are only present when the bike is cold. Carburated engines run like crap when they're cold. Just let it idle a few minutes before you take off. My rule of thumb is to wait until the coolant tube going into the top of the radiator is good and hot. It generally takes between 5 and 10 minutes, depending on the ambient temperature. It won't be quite fully warmed up yet but will get there quickly once you get moving.

[fadlan12]

Thanks, I can tell a difference when its warm, I had only been giving it a few mins.

[yamaboy]

I have the same issues . I adjusted the chain , changed fuel filter and cleaned petcock because it was full of crap.Try taking the air filter out and see how it runs. If it runs good most likely you are running rich. If it runs bad your are running lean. Now i'm running without the air filter untill wednesday when I get the K&N filter. With the stock air filter it bogs and jerks from idle to 2K rpms. I installed a Yoshi exhaust so in my case i'm sure that i'm running rich. Even though we have different configurations , we have the same symptoms..crazy..

P.S also feathering the clutch helps a lot. When you start rolling try holding it a little or let go of it slow , don't just let go of it .Don't know if it makes sense
Hope this helps