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Discussion Starter · #1 ·
I just got back from a week in Yellowstone on my Z and I think I have found a quirk in the EFI program I have not seen discussed here. At home (2200' ASL) my sled runs pretty well. I have been using solid pins instead of the stock hollow ones (still waiting for a clutch kit) and running the TRA in 3. This usually gives me about 7700 rpm and pretty good performance. My best is 116 on the speedo in far from ideal conditions. In Yellowstone (6600' ASL) I put the stock hollow pins back in and ran the TRA in 4. This seemed OK till I went up in altitude just a bit, like maybe 1000'. Then everything went to s**t. The sled developed a dead spot at 6500 rpm and would sit there for maybe 3-4 seconds before jumping up to 7500-7600 and taking off like it had a turbo on it. The higher I went the longer it would lay at 6500 before reaching full revs. Eventually, if you got to say 8000' it would never break thru the dead spot and would just sit at 6500 rpm. I tried the TRA in 5 but it made almost no difference. A trip to the local DOO dealer got me some Summit clutching (ramps and spring for 6000') and I thought it was cured as the sled was more responsive, but as soon as I started to climb the bog would return.
BTW we have been riding at altitude for years and are very familiar with what it takes to clutch a sled for mountain riding, but this sled runs different. I am convinced there is a fault in the program causing this mid range flat spot. My local dealer at home tells me that the Summit opens the power valves sooner and this will likely fix the problem. I guess that means that every time you want to head for the hills you will need a trip to the dealer to have the computer flashed *%@!!!!!!!! The purpose of EFI is to meet emissions and NOT have to be making adjustments every time you ride a different altitude.
Next I will have to find out I am going to be paying to keep having these programs swapped back and forth.
 

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Sounds like the same problems the summit machines were having too,they are getting a second year warrenty free,guess they are having more problems than Mach Z, but mine is in the shop,1 1/2 weeks now and no fix yet,they don't seem to know,but hey no 2cnd year for me
 

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Yes, there is an occasional dead spot as you described, but it is pegged to temperature. If you are substantially below freezing (around 25 or so), a bog will start to appear at altitude. However, I have never seen it get worse as you go higher. We go up to 10000+ without any change despite the colder temperatures up top.

This is why we are waiting for the re-flash.
 

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Discussion Starter · #4 ·
There did seem to be a relationship between temperature a the flat spot. Our temps ranged from 30 to 35F during the days and 10 to 20F at night. The sled would run well around West Yellowstone (6600'), but as soon as we headed up South Plateau is would start to bog down. On top of the plateau at around 7500 feet the bog was 3-4 seconds. At Two Top (8000') the bog was even longer. On Lions Head (10000') the bog was permanent-the sled would not pull over 6500 rpms, PERIOD! This was using 6000' Summit clutching.
 

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xcpilot said:
There did seem to be a relationship between temperature a the flat spot. Our temps ranged from 30 to 35F during the days and 10 to 20F at night. The sled would run well around West Yellowstone (6600'), but as soon as we headed up South Plateau is would start to bog down. On top of the plateau at around 7500 feet the bog was 3-4 seconds. At Two Top (8000') the bog was even longer. On Lions Head (10000') the bog was permanent-the sled would not pull over 6500 rpms, PERIOD! This was using 6000' Summit clutching.
[snapback]299444[/snapback]​
Any input on how this sled runs in the Black Hills? Does anything have to be done to the sled to ride there?
 

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Discussion Starter · #6 ·
Kordon said:
xcpilot said:
There did seem to be a relationship between temperature a the flat spot. Our temps ranged from 30 to 35F during the days and 10 to 20F at night. The sled would run well around West Yellowstone (6600'), but as soon as we headed up South Plateau is would start to bog down. On top of the plateau at around 7500 feet the bog was 3-4 seconds. At Two Top (8000') the bog was even longer. On Lions Head (10000') the bog was permanent-the sled would not pull over 6500 rpms, PERIOD! This was using 6000' Summit clutching.
[snapback]299444[/snapback]​
Any input on how this sled runs in the Black Hills? Does anything have to be done to the sled to ride there?
[snapback]299912[/snapback]​
Not quite sure how to answer you Kord. I have been to the Black Hills, but only in the summer and I can't remember the elevations that you might be riding in. If you know the altitude I might be of help. We ride at home at 2500', in Yellowstone at 6000 to 10000 feet and in the BC mountains mostly in the 6000 to 8000' range. I can tell you this much right now, your sled will not work if you go over 6000' even with Summit clutching. They say the fix is a Summit computer flash, but then you will need to change back when you go home!!?? I have not gone to the dealer for a face to face on this yet-maybe tomorrow.
 
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