difference between four stroking and lean bogging?

Well, I finally got my Newport put back together after finding the crunchy metal bits inside my engine. I was really excited to ride it...it's been since the Cranks rally. That's just too long.

I was excited to find out that the bike fired up and idled great after just 3 kicks. I quickly called another local mopeder and we went for a ride around town. The bike seemed great at first, but I quickly realized that the problem I had before this all started was still there. It pulls nicely up to nearly half throttle and then it falls on its face. If I left off a bit...it'll start to accelerate again. It definitely bogs out, but I have no idea if it is four stroking or lean bogging. What the heck is the difference? I mean, I know conceptually what the difference is, but I have no idea how to tell the difference while riding the bike. I feel like this is something I should know by now. Don't you?

After I got home, I realized that in my haste to ride this bike again, I completely forgot to:
A. Put any ATF in it. Nice job!
B. Tighten my spark plug more than just by hand. Again, nice job!

I fixed those items and took it out again, but it didn't seem to make a difference.

So, last night I checked the bike for air leaks. It may be leaking slightly between the cylinder and the head. I could hear a faint drop in RPM as I sprayed carb cleaner around that area. I was comparing that to spray carb cleaner right on the metal mesh air filter. I could definitely hear a drop in RPM there.

I then tightened up the head a little more and up-jetted from 82 to 86 on the main jet. I also down-jetted from 50 to 40 on the idle jet. I've been wanting to do that for a while.

I wonder if my crank ended up failing because I was actually running lean (air leak?), when I initially thought I was running rich. See...knowing the difference between four stroking and lean bogging really could have helped me out.

BTW, my Pinto is currently doing something similar. It doesn't run above half throttle. I've even heard it backfire a few times. Do you know how lame it is to ride kitted bikes at 20-25 mph?

Old LA Times article about the Pinto

Thanks to doubleaey:

crunchy metal bits in my e50

Well, it looks like I found the source of my problem. The connecting rod bearing failed on the crank side. There are crunchy metal bits all over the inside of my e50. The rod has about 2mm of play in it now. I bet that is why the piston hit the head and put those dents in it.

I'm planning to look over my crank options and determine which one to get. Funds are a little low right now after finishing up my Pinto build, so I may have to go with a stock one. Anyone have a spare they want to sell me? I think I just sold one to someone else about 2 months ago. I knew I should have kept that thing.

dents in my metrakit piston

A couple of weeks prior to the Cranks rally in Milwaukee, my newport started running poorly. It basically wouldn't do anything above half throttle. I figured it was jet related because that is usually where the main jet kicks in. However, that seemed odd because I've never changed the jetting on this bike before, regardless of the weather. So, during the weeks leading up to the rally, I worked on the bike quite a bit, but never solved the problem. I ended up taking it anyway, because it was the only bike I had and it would at least go 30.

Well, fast forward to the rally and the newport was just getting slower by the minute...until...I heard some loud, metal crunching noised and it died.

Last weekend I took the engine out and started to investigate. So far I have the head and the cylinder off and the only thing I found was some build up of carbon and possibly a little bit of metal in the dished area of the head. I also found these two dents in the top of my piston, in the same area where the build up was. Any thoughts? The cylinder and the piston both look good otherwise. There is no sign that they seized. The rings looks good, too.

My next step is to split the case halves and see if there are any problems in there. If not, I think I am going to clean up the top of the piston with dremel/file and put it all back together. Is the piston salvageable?

pinto gila project done

I think the few people that left comments on my last post about my gila kit being loud convinced me that it is just the ringing of the cylinder. I plan to add the dampeners to it this evening and take it for a spin to start the break in process.

Last night I was able to get a few pictures of the finished product:













And a couple of pictures with the sunset in the background:



I accidentally shot this one with the flash on, but I think it made for an interesting effect:

Gila kit first start = loud?

I finished up the wiring on the pinto last night and decided to try to fire the bike. It only took about 2-3 kicks and it fired right up, but it was loud...like a ringing loud...or something is hitting something it shouldn't loud. Any thoughts on this?

Two of my thoughts:
1. I didn't do anything with those rubber blocks that come with the kit. I read on 1977 Mopeds that they are for sound dampening. Where do these blocks go? Will they really help with what I am hearing?
2. I remember reading something about "make sure you grind this down" or "make sure you take this off or this will happen", but I can't remember what it was. I'll have to go back and see what I can find. It was definitely in regards to the Gila kit, but I don't remember what it was.

I used all of the gaskets that came with the kit, except for the extra intake gasket. Why did it come with 2 intake gaskets?

Is it possible that I don't have enough clearance between the piston and the head? It turns over smoothly by hand.

Any comments would be appreciated. I'm not very interested in blowing up this $200 kit before I even get to ride it.