I already put in the stock carb and it is still there just not as bad. It wont do it as bad when it is cold but 10-15min of hard riding it does it really bad. I cant wheelie or do anything from a dead stop. The stock carb has a 170main and 40 pilot. Once it gets going it is great but from start it takes 3-4 seconds to rev. I know I already said that. It is just getting to me.

 

Sounds like a Carb problem to me, my xplorer 300 had the same problem i took the carb all aprt cleanded it up reall nice and its good to go...

 

have you tried lowering your needle?

 

2manytoys,

Thier are three basic things causing I believe that are causing this.
1. Carb jetting and settings
2. "Piston port" motor design
3. Clutch set-up and heat

I believe the biggest culprit in this is the piston-port design of the motor. Because of this, I don't believe you could ever get rid of it completely. The other two you can influence and change. You could possibly set up the other things perfectly and still notice a bog.

In a"nut shell", the easiest way to get rid of it, is to de-tune your machine. Meaning - put it back to stock. Unfortunatly their is a hard way.

I am at work now so I just don't have the time to go into detail. I'll post more when I get home tonight around 8PM if you would like? The reason I asked about it being the same when hot and cold, had to do with the clutches.

Bubba,
If thier was two people that thought like me, I'd be scared. HA HA.....

 

I know that I will never get rid of all the bog but 4 seconds is a little much. I will be on around 8. Thanks

 

I think its gotta be more of a jetting problem. I have basically the same set up just a different carb and I have no bog from a dead start other than the amount of time it takes for the rpm's to engage the clutch.

 

This is going to be a little hard for me to explain. The more I think about it, the more little variables I find.

It all basically has to do with engine design. I'm sure you can understand the benefits of having a reed cage. The biggest of all, is the fact that it stops the fuel(air&gas mixed) from being forced back up threw the intake. This fuel charge should be making its way down the transfer ports not the intake. The piston - port motor does this crudely. For an example of this, hold your hand in from of the carb while the machine is idling. Give the throttle a good stab and notice the pressure coming back out of the carb? Not to mention the fuel that is all over your hand. That is basically wasted power. Also makes it a little harder to tune because now you have air going in, back out and then back in again picking up a little more fuel on the way.

Of course, the carb not being tuned in right can do this. Then again a carb that is tuned right will still probably have the same bog. So when dialing in your carb, expect that bog and trust your plug readings and what you hear besides that bog.

The last would be the clutching. I'm probably going to start a flaming post over this. I'm sure someone is going to argue with me on some of this and I don't care. If you can prove me wrong, then come fix mine. Any how, the biggest enemy here is HEAT. We have tuned our clutches to get the most out of them. While doing so we are making it create more heat. The heat in turn tends to soften the spring up.(see a problem yet?) Look at it this way;(these are not actual numbers just for comparison sakes)
stock spring: engages around 20# It loses 10% of its stiffness at 150 degrees. Now we are at 18#. Not enough change to really notice. The wieghts would hardly notice the difference.
mod spring: engages around 120# loses the same 10%, now it is only a 108# spring. Now that would be like dropping down a step or two in springs without lightning your weights. This is why I asked you about the difference between being hot and cold.

Mine is a wheelie machine when I first fire it up. After I get the clutches warmed up, she just isn't so wheelie happy. The best thing I've found to do is tune the clutches when they are warm. The only draw back is that it is alot different when its cold. So you usually end up finding a good middle road. Unless your willing to dive into the clutches a little more than most.

Thier some other things to think about that might help. Lightning the flywheel could have some influence on it too. Not to mention the exhaust and over all weight of the machine. The amount of strain it takes to down shift. I think you might get the idea. Besides my fingers are getting tired. Its a little after 9PM. Sorry to keep you waiting.

 

2manytoys
I'm really a novice when it comes to working on Polaris machines
and most of my knowlege comes from my shop manual. So I'm not
here to step on anybodies toes. This is just my experience with my
99TB. I've gone through a wide range of mods with my TB before I
settled with what I have now. Mine always had a hesitation,
except for when it was stock, but never had a bog like what yours
has.
I think you either have a low speed jetting problem or a clutch
problem. Have you checked your belt deflection and clutch alignment?
Do your moveable sheaves show any signs of wear, like grooves
or worn areas? What color spring are you running in the secondary?
Mine too would wheelie easy when the clutch was cold or cool but after
it got warm that was a different story so to me it sounds more like
a clutch problem.

 

talonhawk,

So, you are saying that you no longer have that hesitation? I've asked HPD if they would just weld the reed cage onto my cylinder. The answer was a NO. They wouldn't even set up a whole kit for it just because it was the 300 not the 250. These two motors are really not that different. Atleast as for welding on a reed cage. Was thinking of welding it on with some help of a friend but started thinking I should start fresh with something bigger. Now, not sure what I'm going to do.

 

I have no hesitation in mine at all. I had a small amount of hesitation
after I had the reed cage installed but it was not at all like what I had
before the conversion. Then just this past winter I had the flywheel
race lightened. NO hesitation and a huge difference in throttle responce.
There is another place that makes a reed conversion for the 250's.
I believe its called badboyz and there is somebody in these forums that
had their 250 converted by them but I can't remember who I was.
They might be able to hook you up with something for your 300.
I will do some checking and see if I can find that site again!