break-in questions

[leo]

my apologies if this has been asked a dozen times. i tried the search and looked online for an answer, but didn't have much luck.

i'm hearing sort of a rapid clicking/chattering sound. doesn't do it in neutral, just when under load. it seems to smooth out once i build up some speed and just maintain, but starts right back when i try to throttle up.

is that a normal break-in thing???
what are the most common break-in issues with these motors???

 

[crassius]

loose/bad exhaust gasket or head gasket can make a noise like that, but first I'd check if you put enough grease on the bucking bar and its cam arm

 

[2door]

I agree with crassius. The most common cause of those 'clicking' noises is usually head or exhaust gaskets.

The kit supplied gaskets are poor quality, especially the intake and exhaust gaskets. Adding to that is the flanges of both are usually warped from the welding process and need to sanded or ground flat to get a good seal. The mating surfaces on the cylinder are usually pretty good but it's the flanges that give the most problem.

A good way to check for a flat surface is to first clean the flange then 'paint' it with magic marker or machinist dye. Lay a sheet of sandpaper on a known flat surface, glass works best, and run the flange over the paper a few swipes. You'll be able to see immediately where the high and low spots are. Keep sanding until you have a uniform surface. Severely warped flanges might have to be ground flat using something a little more aggressive than hand sanding. A bench belt sander works well for this.

Any auto parts store should have gasket material so you can make your own gaskets from good quality material.

Tom

 

[leo]

ok, dumb question.
the bucking bar is the small black rod that gets pushed in and released by the clutch lever arm. correct???
now that you mention it, the clutch was completely locked up when i installed it. i had to open it up and free the clutch assembly, i just figured it had probably sat on a shelf a little too long...

i will grease it well, and also change the exhaust gasket tomorrow, see if that corrects it.

thank you both very much, btw...

 

[Chaz]

Leo, you got the bucking bar thing right. When you said "chattering" I immediately think of clutch issue. You also mentioned that the clutch was frozen at first so that seems like another clue. Try adjusting the clutch again and grease the clutch gearing lightly also. Maybe you just need new pads for the clutch.

 

[leo]

tinkering on them is almost as much fun as riding them, i think i would have been a little disappointed if it were too easy...

 

[xseler]

tinkering on them is almost as much fun as riding them, i think i would have been a little disappointed if it were too easy...

Winner, winner, chicken dinner!!



or......


Exact-a-mundo!!

 

[leo]

found it, head bolts were loose.

 

[2door]

Beg borrow, buy or steal a torque wrench.
120 to 140 inch pounds. Tighten in an 'X' pattern. Corner to corner.

Tom

 

[leo]

when i looked i found a small dark (oily) area around the bottom of the head in the front. i snugged them up for now, and the clicking sound instantly stopped.

i have a friend who has an automotive shop. mostly tires, brakes, exhaust work, etc. i think i will swing by tomorrow.

if nothing else, i'll get to show it off a little.

 

[Chaz]

Good news. Now, when you go to your friends shop, replace those acorn head nuts or just cut the caps off of them. They are often too shallow and will bind up the bolts and strip them out of the case, then you really got a headache.

 

[leo]

i sent him some pics, he seems eager to play with it too. i think he wants to try it out... lol

 

[Chaz]

You're gonna infect him Leo. Soon he will join out cult. A new member and already you're recruiting. Good job!

 

[Legwon]

this is what Chaz was referring to when he said knock the tops off.
the acorn nuts are known to top out. therefor your head doesnt get tight and engine wont run proper.

good luck bud

 

[2door]

Legwon beat me to it but here's another example of replacing those chrome acorn nuts with something better. These are 'shouldered' or 'flanged' hex nuts.

If the studs aren't threaded into the case far enough or if they're too long, which isn't uncommon, the acorn nuts can bottom out before tightening down against the cylinder head. This is where you'll get a head gasket leak even when the proper torque is applied.

The acorn nuts are pretty but they can cause problems.

Tom