08 D8 68 vs 62 g weights re mid range stumble on flatland

[Dave4441]

Need some help here. I have a mid range stumble that just about makes the sled unrideable. It was into the dealer and they looked at a # of things, and all testing, including latest flash is a wash. You name it and it has been looked at. The sled was hitting 8200 on first past and then forward would hardly hold 7000 rpm. Worst, most tiring day of riding i have ever had with the constant threat of the motor falling off at the worst possible time. This is flatland riding at about 2000'

Today i stuck the factory mountain weights (62 g) in and the bulk of the stumble has been reduced. Everything is factory and they did try a different primary clutch when it was into the shop, that had flatland 68 g weights in and it did not change anything, rulling out a faulty clutch. Today, I could ride at 8200 rpm and the lighter weights, at this low elevation seemed to not overrev. SHould i try 60 or 58s to reduce the stumble further for flatland use. Does this lead any of you to any reasons why this is happening? Is the guide on weights that comes with the machine to be taken with a grain of salt? Do you see a overweighted machine bog terribly at the high rpm and not be able to hold max rpm properly. Help!!!!!!!!!!!

 

[Trenchmaster]

Not to sure about your clutch weights, but these sleds come from the factory super lean in the midrange, to pass emissions. Some sleds are worse than others, the fix for most has been to add a Power Commander fuel control box. If you do a search on here for PC111 or PCV you will get all the info you need. Good luck

 

[Dave4441]

Not to sure about your clutch weights, but these sleds come from the factory super lean in the midrange, to pass emissions. Some sleds are worse than others, the fix for most has been to add a Power Commander fuel control box. If you do a search on here for PC111 or PCV you will get all the info you need. Good luck

The issue is that the stumble/bog is so bad i am kinda convinced it is something else and trying to eliminate everything before i go with a PCV.

 

[allblowdup]

Usually what happens is that you start elimanating pistons while you are trying to find out what is going on. Every 800 is lean in the mid. They will all lay down without a fuel controller and some actually takeout the pistons. Most of them will sooner or later.

 

[chumbilly1]

I think the heavy weights could be loading the engine sooner and increasing its fuel demands in the midrange. The 62s are letting it rev through the lean spot in the mapping and yes the lighter weights will definately help it rev more freely, but maybe not pull as hard through the rpm range. I have 69.5 grams of mtx in mine and it doesn't rev as freely as some but it is faster on the upshift. These sleds are better suited to true mtn. riding but you should be able to set it up for your 2000 ft. flatland riding. 1/2 bottle of lucas octane boost per tank is what slp recommends to make the mid range safer. If I was riding mine at low elevation I would call poweraddiction and purchase a low compression head. Best of luck

 

[RamrodAK1]

I've posted a few times on here bud but Im tellin you that the PCV will solve your prob.

 

[151Viper]

I am running 10-68's in mine at 1500' elevation. I am seeing 8150 very concictantly now with the PCV. Before the PCV I was seeing 7900 most of the time sometimes less sometimes more. You should not have to go down to 10-62 weights to get your rpm's back. There is almost certainly something else wrong. It seems like these sleds should come standard with AFR quages.

 

[Dave4441]

Thanks guys, dealer asked to have it back, took it in today and they are going to go thru it some more tomorrow AM. If they can not get it straightened out it is time for the PCV. The real piss off is that i was riding with a guy who has a 08 D8 and it was running like a top, nothing different then mine. That is what is driving me nuts.