'78 carbs/engine parts on a 256 motor?

[scott s]

I have a '78 engine that's had a strange noise ever since a top end rebuild. I simply cannot identify it. I'll probably do an "autopsy" someday and fix it.

But....in the meantime....I have a "long rod" 256 engine with the "hotter" factory cam. I've never heard the engine run, but we've done a valve adjustment, cam chain adjustment and changed all filters.
The only drawback that I know of is that the tab on the RH side of the engine that the kick starter spring wraps around is broken. The spring just rests against the case. The kickstarter still works, but I wouldn't want to kick it a thousand times or anything....maybe in an emergency.

My questions:
1) The cases and valve covers on the '78 are polished. Will they all swap right over to the '72 engine?

2) What about the carbs and manifolds? (I think they're the BS38 and matching manifolds.)

3) If I make sure the starter and battery are in top condition, is there anything wrong with having that kick starter spring rest against the case and only be used occasionally, such as emergency situations?

4) Is there any difference in the charging systems? I haven't tested the stator/rotor in the '72 yet, but if there's a problem can I use the stuff from the '78?

5) Anything else I should know about putting the '72 engine in the '78?

BTW, I'll be using a Pamco, Commando pipes/mufflers, and MikesXS's pod filters.

 

[gggGary]

I have a '78 engine that's had a strange noise ever since a top end rebuild. I simply cannot identify it. I'll probably do an "autopsy" someday and fix it.

But....in the meantime....I have a "long rod" 256 engine with the "hotter" factory cam. I've never heard the engine run, but we've done a valve adjustment, cam chain adjustment and changed all filters.
The only drawback that I know of is that the tab on the RH side of the engine that the kick starter spring wraps around is broken. The spring just rests against the case. The kickstarter still works, but I wouldn't want to kick it a thousand times or anything....maybe in an emergency.

My questions:
1) The cases and valve covers on the '78 are polished. Will they all swap right over to the '72 engine?
LH side cover has one bolt in a different location the 78 doesn' have the decompression valve cover otherwise they swap.

2) What about the carbs and manifolds? (I think they're the BS38 and matching manifolds.)
They will bolt on the 72 engine.

3) If I make sure the starter and battery are in top condition, is there anything wrong with having that kick starter spring rest against the case and only be used occasionally, such as emergency situations?
There is a simple fix for the kick start spring, drill a hole use a pin I think, do a search.

4) Is there any difference in the charging systems? I haven't tested the stator/rotor in the '72 yet, but if there's a problem can I use the stuff from the '78?
The charging system parts will swap.

5) Anything else I should know about putting the '72 engine in the '78?
You need the 78 engine mounts, there might be a slight issue with where the hole is drilled on the lower front of the engine.

BTW, I'll be using a Pamco, Commando pipes/mufflers, and MikesXS's pod filters.

 

[scott s]

So, I may have to have the LH (sprocket/alternator cover) cover on the '72 polished to match my other polished covers?

Hole on lower front...you mean the one that holds the engine to the frame using the lower engine mount....between the two downtubes?

I'll have to search about the kick starter fix.

 

[gggGary]

The hole at the front just below the cylinders I think you are OK on the 72 the 70 71 might be the different ones.

Here's the thread with pictures.

Yeah no big deal to polish covers, I swear I have done 20 of em so far. A 3/4 (Chinese HP) pedestal buffer from harbor fright or Menards is a nice tool.