Crazy stuff happening here. It's hard to understand two sleds set-up the same with the same measurements being that different on the belt. Performance yes, belts exploding no.
Since the ZR900, through the M7's, to today, the vibration felt in the running boards at speed is always an indication of the clutches slipping (usually the secondary there 'cause of the smaller circumference in high gears but it's probably slipping on the primary in low ratios too). The diamond drive transfers this to the chassis. Jackshaft didn't.
Change one thing at a time. Make your primary clutch control the rpm. Load your motor (through gearing, upshift) with the secondary.
Mrquick, you say you've tried every thing, but you still haven't dropped the weight a lot. This week your changing three big things. Maybe 4 if you have to set your deflection a lot different. How are you going to put all that data together. Sort of like shooting craps to me. Changing from proper alignment to something else to make up for clutching issues is silly IMO.
I like to think the simple answer to anything is usually correct, but .... happens. Maybe there is some major difference in the chassis in the production line. I certainly have experienced lots of assembly line errors on my sleds, casting problems (clutches) so bad it was seen by eye. Godda be minimum wage workers at AC, even my limited production HCR had simple everyday things like body parts installed wrong, rivet left in the airbox, brake disc machined wrong, one tie rod was treaded in all the way and one was out over 1/2", stripped from overtightening suspention nut. Where's the PRIDE I thought to myself. Could go on but what's the point. I am picky and my dealer is great, always right there to help (which is all they can do). But, there was never anything that my measuring stick couldn't find and hands and tools couldn't fix.
My point, there has to be a physical issue (not that many things there though, measure, look for broken stuff)) or your clutching is still out. You say even stock it ate belts. Was it ever stock, or was the pipe the first thing, or gearing, or engine management. You change that stuff and it`s a new world with something with the power of a 1000. MT8 guys change their clutching with the installation, usually with the kit makers recommendations, or they too would explode belts.
By the way, if youre hoping for an AC cure, I just had a 2010 800 out and it had a solid engine mount on the clutch side. When I got it it had 86 miles and one blown belt in the holder. Checked deflection (about 2.5 inches, big black marks on the primary LOL) and adjusted. Checked alignment ( toed in about 1 inch LOL) and adjusted, and went for a ride (did I say i was picky LOL). Pretty impressive with all the heat the clutches were making.
A little story about my experience this year (hopefully it will help you). Had a `08 SP M8 last year. Installed an SLP pipe set. Spent about 12 rides (3 to 4 hrs, 2hr play 1 to 2 hr adjust, one thing at a time, record to review later, getting old LOL) to dial clutching and boony box. Finished product awesome for me. Very happy. TWO BELTS 3500 mi.
`09 M8 next fall. Installed same stuff. Thought it would be good to go. Wrong. New track and engine (who knows what they change or the HP difference between the two) required me to tighten the helix and the primary spring (shims, funny thing is as I tightened the spring the rpm came down) to get the heat out and proper rpm. Different boony box number`s too (less fuel added in `09).
09 HCR. Installed the same stuff (should be good to go). Wrong. The clutches were smoking hot. It felt slower than my SP and was over revving. Track hooked up good though. Picked up some Dalton adjustables to add weight (HAVE to modify to fit M clutches) and get rid of the heat and over rev (right). Wrong. In a matter of one hour I added lots of wieght (so easy to add weight on adjustables it should be posted as a warning on the package LOL) (wont post numbers to protect the innocent LOL). Got to the point of cooking to bring rpm down. Pulled a string in 1000 ft on a new belt ( broken in for a 100 miles already) with the new heavy weight. Sound familiar. Put on a old trusty spare from M7 days (cause I never needed one before). Added a touch more weight LOL, POW one string slipped completely out in 500 ft. WTF. With all this weight added the rpm only changed like 50 or so and the heat just grew.
No more belts and 20 miles from the truck ( by myself like I do). Decided to ride back easy LOL. In about 10 miles of half throttle or less the belt exploded ( first time for me since DOO) just as I let off the throttle. Unstrung the clutches and put on the first belt and REALLY took it easy. Got back to truck (whew LOL), poked my finger in there onto a clutch sheave to check temp, YEOW, permanent scar LOL.
Next day took 3 (LOL) good belts (worn but good) and a infra red temp sensor (cause Im a technical guy LOL. Before I left I figured it had to be slipping on the secondary cause of all the weight in the primary, right, (or , and it went through my head too, somethings got to be screwed on my sled LOL) so I twisted up the tortional spring. Wrong. 3 miles from the truck, while still warming up the engine I pulled another string. Back to the truck, change the belt, take out the extra weight, untwist the tortional spring, and head up to elevation to start again (with only 2 belts left, oh no LOL).
This time I took a stiffer primary spring. Wrong. Put back the softer spring and took out weight untill there was just a empty hole. So now in less than 24hrs I've added and taken out a total of 8 grs. and my rpm has only changed about 60. F-----g adjustables. Just at the last couple of set screws rpm started to drop a bit (yeah thats right less weight started to drop the rpm) and the temp was way less. Mph increased some put seat of the pants feel increased huge.
Turns out I bought too heavy a weight set (Daltons are way more agressive in their weight distribution than stockers) and had to take some off at home to end up in the correct area. I took off another 2 gr. on the bench, added .8 in the field and loosened off the tortional some. Now I have the quickest sled I ever owned by far running 2.5 grs less than the same size engines of the two previous sleds (there is something special in those HCRs boxes) and have about 1000 more miles on that worn out belt from my 06 M7 LOL.
All this was done with no changes to static alignment (but big changes to running alignment obviously), that's what you would see running it up on a stand or trying to float a secondary)) or deflection.
Morals of the story, change one thing at a time (how confused would I be if I had changed helix, primary spring, alignment,... too), sometimes less is more, trust your measuring stick, let the primary control the rpm,sometimes it is something you have changed and not ACs fault, every sled is different, and most important, usually it's something simple.
Geo
