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Finally got a few short rides on my rebuilt RX1 while there was snow. Issues?

NLP_SLED_GUY

Extreme
Joined
Sep 14, 2021
Messages
105
Location
Northern Lower Michigan
Country
USA
Snowmobile
2019 SkiDoo GT-L 600R
2005 RS Rage
2003 RX1
1980 Arctic Cat Panther
First off, I was very surprised just how quick it was. My yard is covered in trenches. Never got to go very fast due to space. I didn't find the ride all that bad... so far. Steering is pretty heavy at slow speeds.

But what I found most annoying was the low speed stumble/miss at 4.5k to 5k RPM. After fooling with it and waiting for a new sensor for my Wideband I finally determined that the ECP was causing the carbs to be poorly tuned, 165 mains and silver springs. Turns out that the entire fuel curve except Wide Open Throttle was very very rich. At time exceeding 10.0:1. The limitation of my wideband. Any attempts to address this one way only caused different issues. I finally found the true problem. The silver springs. They were so light that they were opening considerably at idle. This explains why the plugs were so rich and the choke was pointlessly rich and any use at all fouled the plugs. It explained almost everything about the way the sled ran. Even the small amount of gas in the oil.

So I rounded up the stock airbox, ordered new genuine Mikuni stock sized jets. I had a hard time sourcing stock springs. It appears color is the thing with the aftermarket but not with Yamaha. Did the stock springs have a color? But I found that Holtzman sold a set of Green springs that were setup to work with the stock sled and airbox and were well reviewed. So I ordered those. All of this stuff showed up the same day. Swapped out all of the jets and the CV springs, then double checked all needle jet clips and pilot screw turns, 2. Reinstalled the stock airbox "and fired that mother up!" CDB... Choke actually worked perfectly! Once the sled warmed to 150-160F the idle mixture was about 13.8:1. Which is a perfect target. It was 37 deg, 900 feet above sea level and will allow use of E10 or Rec fuel in normal temperature ranges. Almost any other condition will lean that up. Almost as if that's what Yamaha intended. The sled is quieter and smoother and on a short ride in the wet grass the burble/miss appeared to be completely gone. It also has SBR primary and secondary clutch kits. It will be fine with no ECP. I prefer the the sled run perfectly.

I did spend many hours reading up on the history of the ECP. I saw a lot of discussion about these types of problems but I never heard that anyone actually figured it out. Did somebody and I missed it? I also understand the the maker of the kits had some big problems and eventually passed. I kind a felt reading this that it might of had something to do with support falling off. Sad to learn this. I actually think that it is possible but to retune the carbs for less trouble with the ECP but it's been so long it's not worth the time. And I'm not going to bother for myself alone. I do have two brand stinking new K&N filters that were the most expensive K&N filters I ever bought. And that's a good number of them.

I still have to check the sync. I'll do that tomorrow.

On the trail without much snow the sled was a darting monster. Simmons Original Flexi Skis, aligned with no toe as per their recommendations and rear most mounting holes. I'm gonna add a tiny bit of toe out. But with no snow now or seemingly in the future it might have to wait till next year.... Just kidding... i hope for a test ride. I do have a UP trip planned for late January. But I really hate to take a sled that's been completely rebuilt, that I haven't owned before on a road trip. It really needs a few shake down runs. For no other reason to get the suspension adjusted at least a little bit.

Thanks,
 

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sounds like you are getting it sorted out. i can help point you in the right direction if it still has a proaction in the rear as i have set quite a few.
 


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