[sbronco68]

Hey guys I know this has been talked about and I have been searching the forum and just can't find the answer, Sorry if this is an old question.

I have a 450R with most all the normal bolt on stuff along with a new 06 head and SS valves, CP 10.5:1 piston. My carb has the Quick shot 2 cover and O-ring mod and a 45 Pilot jet. I had a 168 main with stock needle and everything was great, I got a JD kit and followed the instructions with the red needle stock clip position and 180 main. Now the bike definitely felt "different" hard to tell if it’s faster but now it has a bog if you go full throttle and the rpm's are low. It happens mainly in first or second gear if I get the bike slow and then nail it. Is this something I can get rid of?

[Robbie M]

Before I put the jd kit in, my bike did the same thing. The jd kit fixed that, my bike would actually stall when i hit the throtle. Try to adjust the fuel screw also something I noticed with my bike i had a tie wrap on the carb vent hose and it may have been too tight cause when I took it off the bike didnt stall anymore. Why dont you email jd he is great at helping people. He returned my email same day.

[jjrace]

First off that is a really low compression piston. Dont believe that low is available. 05 is the frist year of the 12.1:1 up from the previous 11.5:1 ratio.

The bog has more to do with the AP circuit since it is down lown in the throttle opening.

First off go back to the stock main. 180 is way to fat for the bike. Second, remove the AP cover you have (its junk) and go back to the stock cover and stock leak jet.

I assume you have a longer extended aftermarket fuel screw? If not, get one installed.

Be sure to clean out the pilot jet and the 1 way valves in the carb bowl and carb body.



Now if that does not help, make sure you tried different needle clip positions.

If that does not solve your issue, do this mod with a #90 leak jet:

http://www.squadpage.com/pandora/Profes ... %20Mod.pdf

I have the stock needle, 45 pilot, stock main, fuel screw about 2 turns out, #90 leak jet and the modified AP rivet with the wired up linkage and there is NO bog at all on my bike. It runs like EFI. Had a bunch of friends ride mine and ask to make their motor run like mine.

[sbronco68]

Oops thinking of wrong engine its a 12:1 piston. I will give JD a call as the plug looks good and the bike never bogged before the JD kit so I'm sure its a clip position due to my setup. If the bike is above 4000rpm its a wicked beast with fuel injection like throttle response.

[Robbie M]

doesnt the jd kit come with the o-ring to do the ap mod?

[jjrace]

Why would you call them without trying different clip positions first???

Still your AP circuit needs to be modified and that aftermarket AP cover removed. That is the purpose of the AP, to squirt extra fuel in the cylinder at low RPMs to eliminate the bog/hesitation.

[sbronco68]

Why would you call them without trying different clip positions first???

Still your AP circuit needs to be modified and that aftermarket AP cover removed. That is the purpose of the AP, to squirt extra fuel in the cylinder at low RPMs to eliminate the bog/hesitation.

The AP circuit and the main jet are responsible for the air fuel ration right as you nail the throttle right? So if the bike use to be super snappy (good) with the current AP set up and a 168main now the JD kit with a 180 main makes it bog I figure JD would know what direction to go. This thing is wicked 99% of the time its just when I let it bog down in the rocks or over a log and then I nail it wide open it bogs. I can't see clip position making a difference as at WOT is uninvolved.

[Asmith]

Why would you call them without trying different clip positions first???

Still your AP circuit needs to be modified and that aftermarket AP cover removed. That is the purpose of the AP, to squirt extra fuel in the cylinder at low RPMs to eliminate the bog/hesitation.

The AP circuit and the main jet are responsible for the air fuel ration right as you nail the throttle right? So if the bike use to be super snappy (good) with the current AP set up and a 168main now the JD kit with a 180 main makes it bog I figure JD would know what direction to go. This thing is wicked 99% of the time its just when I let it bog down in the rocks or over a log and then I nail it wide open it bogs. I can't see clip position making a difference as at WOT is uninvolved.

The main jet doesn't come into play until about 1/2 throttle.

The AP is designed to aid in the transition zone between the pilot and the needle, roughly 1/4 throttle. The needle initial taper and clip position are all important in this zone. If the needle comes on too quick, it'll fall on it's face from being too fat or it'll stumble if the needle is too slow to flow. The AP can only make up for so much.

Also, you cannot compare main jet sizes used with the JD needle with main jets used with OEM needles. The taper of the JD is leaner as it's opened more which allows the use of larger mains.

[sbronco68]

Why would you call them without trying different clip positions first???

Still your AP circuit needs to be modified and that aftermarket AP cover removed. That is the purpose of the AP, to squirt extra fuel in the cylinder at low RPMs to eliminate the bog/hesitation.

The AP circuit and the main jet are responsible for the air fuel ration right as you nail the throttle right? So if the bike use to be super snappy (good) with the current AP set up and a 168main now the JD kit with a 180 main makes it bog I figure JD would know what direction to go. This thing is wicked 99% of the time its just when I let it bog down in the rocks or over a log and then I nail it wide open it bogs. I can't see clip position making a difference as at WOT is uninvolved.

The main jet doesn't come into play until about 1/2 throttle.

The AP is designed to aid in the transition zone between the pilot and the needle, roughly 1/4 throttle. The needle initial taper and clip position are all important in this zone. If the needle comes on too quick, it'll fall on it's face from being too fat or it'll stumble if the needle is too slow to flow. The AP can only make up for so much.

Also, you cannot compare main jet sizes used with the JD needle with main jets used with OEM needles. The taper of the JD is leaner as it's opened more which allows the use of larger mains.

Thanks Agent,
From what your saying it sounds like its to fat as it falls hard on face(as I fall into the handel bars) if I release the throttle it come nicely back to life. If it was going to a lean condition I don't think it would want to run as well as it does when I release the throttle. So now the question is do I drop the needle down a clip or work on less AP squirt? I also have a big decel pop problem I'm trying to work out, after reading what you wrote maybe both problems are related. I have checked everything no air leaks carb or pipe, tried 40,42,45 pilot and have the JD flex screw with new o-ring just cant get rid of the pop. It also dies if I pull the hot start in Maybe its just time for a 09.

[jjrace]

Pop on decel probably means you have a header or exhaust leak. Could have an issue with the carb like the hotstart cable routing causing a lean condition.

IT should die if you pull the hotstart. You are opening a air passage in the carb so you just leaned out the mixture drastically.

You can throw money at an 09 also. sounds like you may have the same issues you have now. More time and money than experience or willingness to slow down and think a problem through. You are getting good advice, you just need to stop every time you get an answer throw out more questions, more money at the problem and less patience. You are obviously missing something with your tuning. Sorry, cannot help you out over the internet more than give advice. You have to do the work. I would suggest to talk to a buddy that is good with bikes or take it to a dealer for some advice.