Engine Problem Help!!!

[newnitrofan]

Alright guys today I started to tear down my savage so I can do some mods to it. Well I bought a new cooling head for the 21BB and I took off the old cooling head and well I am frankly quite concerned after what I found Look at the head shim and the top of the piston this is concern #1

Ok and concern #2 is when I saw all of that burnt mess I decided to pull off the pullstart and found a bunch of oil back there and just mess so I think to myself I just need to seal it up so I pulled off the backplate and opened up the crank and I found a small pin about 3MM long floating in there. Ok before I took off the head and everything the motor had good compression. What are your thoughts and comments about how the engine had been running. That pin that was floating around concerns me greatly. HELP Please.

 

[Error401]

1st: Is that pitting on the top of the piston? If it's just discolored, it's probably carbon buildup from the fuel. The top of my piston and the inside of the head on my mills are blue (from burning blue thunder). If those are pits, you have some problems. I have not personally encountered this prolem, so my knowledge is kind of thin on what causes it. I have seen a TRX 2.5 with a hole burned in the piston, but some of the guys here say that the 2.5's piston is thin and gets really hot and causes it to develope holes. Just what I've heard.

2nd: Oil will seep into the PS through the backplate via the starter shaft. This is normal, a pain, but normal. If it's filling the PS with oil, that's not normal. It might have something to do with the pin you found in the case. If the starter shaft isn't aligned properly, it will wallow the shaft hole in the back plate and probably would cause the engine to loose power and make the PS fill with oil and fuel.

3rd: Find out if that pin is part of the engine. The bearings in the case are ball based, so that's probably not it. The engine wouldn't run if it was the wrist pin (in the piston). And the 1 way is on the other side of the back plate (1 ways have needle bearings that look like pins). My best guess would be that it's a pin that fits in the crank and interfaces with the starter shaft. It's been a long time since I've torn a 21BB down and the mind is the first thing to go. If that pin does go in the crank, and it isn't, that might cause the starter shaft to be mis aligned and cause the 2nd problem.

 

[rptorman]

That pin you are talking about may be the pin that goes in the end of your conecting rod with the spring. I,ve been lucky enough to lose a couple of them. If that is what it is, your motor won't start without it.

 

[Bodie Jr]

That pin is what engages the crank from the starter shaft.

The pin fits into the crank where the connecting rod journal is on the crank. (Last pic you have in your post).

BUT!!!..............The spring goes in first and then the starting pin. That's so the starting pin will engage the starter shaft.

Mine fell out also when I sealed my S-25. No biggy really, you just have to make sure when you put it back together that the pin doesn't slide out of the socket before you put the back plate on.



Have you found the spring?

 

[newnitrofan]

LOL this is an old thread. Yeah I figured out that is what it was. Yesterday I started looking at the BB and noticed that the backplate was wide open. I couldn't get it started and also the one way bearing wasn't working. Well that is just because the backplate was loose. I lost that pin that when in the con rod so I had to make a new one. Just took a drive axle from my Nitro MT and ground it down and it worked like a charm.

 

[Bodie Jr]

Cool deal.:thumbup:

Wished it wasn't so freaking messy outside. I wanna run my truck!!!

Guess I can paint my new body...Can ya tell I'm bored?......LOL