Erratic idle after 351?
#92
Well, after the sleeve cracked, I got a new sleeve and new rings, but that whole setup never felt right from the beginning and there was always a lot of top end noise, unlike the first time. I mentioned this to Bill, along with the really poor compression and leak down test results, and he assured me that nothing was wrong with the piston/bore/top end. He told me it was jetting. So, I tinkered and tinkered with jetting...
But, from the looks of the inspection, the clearance for the piston and sleeve wasn't quite right. The crank is fine, the oil system is fine. In fact, everything else (valves, carb, transmission, you name it) is fine. The piston, however, is badly worn. I'm wondering if the piston wasn't affected by the failure of the first sleeve? Even though I got new rings and a new sleeve, I wonder if it just didn't check out right with the piston somehow? Anyway, that's where we're at. It was never right from day one with the rebuild after the sleeve failure. It *never* had the power that the first 351 kit had. And now it barely has enough compression to run at all. It's slower than when it was a 250. I'm thinking the sleeve cracking hurt more than just the sleeve and we really should have replaced the entire thing, cylinder and all.
So, that's what I'm going to do now. And for a pretty penny. Honestly, I'm very upset about this. This is another $700 I wasn't expected to spend for at least 10,000 miles, you know? *sigh*
The first 351 was freaking awesome. Purred like a kitten, great throttle response, easy wheelies. Then, the sleeve cracked (this was a recall issue, not anything wrong with my machine or with Bill's work).
So, I got a new sleeve, new rings, and the kit was all put back together.
And it just never, ever felt right. I said this, and was told it was a jetting issue. Very erratic idle, no power, etc. I changed the jets. It changed nothing, just fouled my plug. I changed them again. And again. The power just kept getting worse and worse. Finally, I had the entire bike torn down to the chassis and inspected. The only things wrong? The piston is shot, the sleeve is shot, and there's some minor wear on the shift drum. Other than that, the bike is perfect.
I know I'm repeating myself over and over, but it's beginning to feel like I must not be saying it very well. You keep saying it's my machine, but the entire machine checks out great. What doesn't check out is the tolerances and wear on the piston/sleeve. That's it. And I'm thinking something was just overlooked or missed during the rebuild after the cracked sleeve.
As I said, I think I just got a lemon. It happens.
But, from the looks of the inspection, the clearance for the piston and sleeve wasn't quite right. The crank is fine, the oil system is fine. In fact, everything else (valves, carb, transmission, you name it) is fine. The piston, however, is badly worn. I'm wondering if the piston wasn't affected by the failure of the first sleeve? Even though I got new rings and a new sleeve, I wonder if it just didn't check out right with the piston somehow? Anyway, that's where we're at. It was never right from day one with the rebuild after the sleeve failure. It *never* had the power that the first 351 kit had. And now it barely has enough compression to run at all. It's slower than when it was a 250. I'm thinking the sleeve cracking hurt more than just the sleeve and we really should have replaced the entire thing, cylinder and all.
So, that's what I'm going to do now. And for a pretty penny. Honestly, I'm very upset about this. This is another $700 I wasn't expected to spend for at least 10,000 miles, you know? *sigh*
The first 351 was freaking awesome. Purred like a kitten, great throttle response, easy wheelies. Then, the sleeve cracked (this was a recall issue, not anything wrong with my machine or with Bill's work).
So, I got a new sleeve, new rings, and the kit was all put back together.
And it just never, ever felt right. I said this, and was told it was a jetting issue. Very erratic idle, no power, etc. I changed the jets. It changed nothing, just fouled my plug. I changed them again. And again. The power just kept getting worse and worse. Finally, I had the entire bike torn down to the chassis and inspected. The only things wrong? The piston is shot, the sleeve is shot, and there's some minor wear on the shift drum. Other than that, the bike is perfect.
I know I'm repeating myself over and over, but it's beginning to feel like I must not be saying it very well. You keep saying it's my machine, but the entire machine checks out great. What doesn't check out is the tolerances and wear on the piston/sleeve. That's it. And I'm thinking something was just overlooked or missed during the rebuild after the cracked sleeve.
As I said, I think I just got a lemon. It happens.
#93
I don't want to add fuel to the fire! I'm happy with my 351 so far! Only 120 miles.
Again, I hope everything works out and you will be riding again very soon.
Last edited by 2007 Green Machine; 06-14-2012 at 06:04 AM.
#94
Thanks, buddy! Enjoy yours! Spoke at length with KK on the phone today. Looking promising! Ordering my cylinder tomorrow.
#96
The entire bike has been torn completely apart and everything thoroughly inspected. We're talking complete overhaul. Case split and everything. The bike is a chassis with wheels at the moment.
From anyone who has looked at it, it's only an issue of tolerances in the piston/cylinder itself. Crank, oil system, valves, etc... everything else is flawless.
Like I said, it's a "lemon" issue. So the tolerances weren't spot on and it wore down faster? The rings never sat right? Whatever the case, the piston lasted 3,000 miles. I was hoping for at least double that. After 25,000, the stock piston (and even rings) was perfect.
I'm banging my head against a wall here. What else could it be, other than a lemon issue? I'm thinking the parts we didn't replace (piston, cylinder) were compromised by the sleeve cracking with the first kit and it was just overlooked. EVERY OTHER PART OF THE ENGINE HAS BEEN GONE OVER (I hate using caps, but it's like you're not hearing me). Nothing else is out of whack. Period.
#97
Laurie, I'd say continue on as you are, get the KK kit, have it installed properly, either by yourself or by a trusted mechanic with all appropriate attention to detail and all that. Crank it up, and break it in by the book. I'd recommend at least 3 heat cycles of 20 minutes each. 1st = up and down through the gears, 1, 2, 3, 4, then back down letting engine compression do the braking, 4, 3, 2, 1, and don't exceed 50% throttle, do that for 20 minutes, and let the bike cool for at least 20 minutes before doing the next one. Do again, gradually increasing throttle and decel braking until by the 3rd heat cycle, you are really hard on the gas up through the gears, and hard on engine braking decel on the way down. After 1 hour of run time, 3 cycles, dump the oil and put in fresh and I would call it good to go from there. Do whatever you need to do to make sure the jetting is right, and then put it through it's paces on your favorite road. For the next few hundred miles I would avoid prolonged constant throttle, i.e., no long trips on the highway at a constant 55.
After that, if you still have issues, then go back and delete all your posts here and sell that thing. :-)
But I think you should be good, it shouldn't come to that. You've done your due diligence and then some. Just be sure and cover all your bases - new spark plug, maybe new spark plug cap, new coil, etc, etc. Those are pretty easy things to do that can eliminate suspect components that might affect combustion. New cylinder, piston, and rings, and gaskets will take care of compression. Ensure your mixture is right. That's all there is. You have it covered.
After that, if you still have issues, then go back and delete all your posts here and sell that thing. :-)
But I think you should be good, it shouldn't come to that. You've done your due diligence and then some. Just be sure and cover all your bases - new spark plug, maybe new spark plug cap, new coil, etc, etc. Those are pretty easy things to do that can eliminate suspect components that might affect combustion. New cylinder, piston, and rings, and gaskets will take care of compression. Ensure your mixture is right. That's all there is. You have it covered.
#99
Hope you get it sorted out.
Dan