416 Motor Help

[a1965gt]

I really need your help guys.
I recently built my 416 as listed below. It ran fine when I first put it together but has since started making noise and it gets worse every time I ride it. Its sort of a clacking noise, sounds like somthing internal is whacking the case, definaltly coming from the left side. Still runs great just making a lot of noise.

I pulled the flywheel cover and everything looks good, changed the oil, no metal found. I thought maybe the flywheel had come loose since I removed the sparks advance key when I built the 416 but everything looks OK.

Any ideas???????

Thanks,
James Wilson

[UglyMotha™]

check your timing chain and make sure it's tight my tension busted and let the chain slap around and it made a god awful noise and it sounded the same no matter which side you were on also make sure you have no leaks around where the header meats the head cause can also make a wierd clanking sound

[hook]

check starter gears an flywheel gear an bearings:devil:

[2001400ex]

Maybe your piston pin slid over somehow if maybe you didn't put it on the right way and it's scraping the left side of your cylinder wall? Or maybe your rings slipped over some and are flapping around? Hope I helped some:confused:

[4TraxRider]

What about your valves. Right after you build an engine I've found the valves go out of adjustment faster than usual the first time after a rebuild.

[Kilabanshee]

are u running the right octane. Ide run in race when breaking in ur piston or 93 what might be why its making all those odd sounds.

[2001400ex]

Just wondering...why should you run race octane when breaking in a new piston/bore kit?

[a1965gt]

I checked the timing chain tensioner and it is good.
I pulled the flywheel it looks good no cracks on the hub or chater marks on the shaft.
The starter gears and bearings look good.
Changed the oil and there is no sign of metal or engine damage.
I run AV gas so I dont think its detonation but it does kind of sound like it.
I will also check the valves but it doesnt sound like valve noise. I had just adjusted the vavles right before it started makeing the noise.

[UglyMotha™]

Originally posted by 2001400ex
Just wondering...why should you run race octane when breaking in a new piston/bore kit?



theres no reason you would need to run race gas during breakin unless you running a higher compression then you might want to just so you don't risk pre-detonation but if its under 11:1 you would be fine with 92 from the pump

[wgbanks]

Detonation/Knock can be had to identify. At the end of my first break in ride, after doing my 416, I noticed a clattering noise. It was only when you had a pretty good load on the engine and after it got warmed up. I envisioned everything from piston slap to the wrist pin coming loose. I finally decided it was knock and have been using a mixture of 93 and VP C12 race gas and it has been fine ever since. Do not rule out detonation, and boost that octane so don't burn a hole in the top of that new piston. All this IMHO.

[hook]

i broke mine in on 93 oct an it made alittle noise but after 30 min run time it quite .i did go to c12.also put airbox lid on see if u still hear it

[YZROOSTINYA]

I have to run a mix of race/pump in my 10.8:1 motor.

1 gallon of 108 VP c12 to 4 gallons 93 pump

[a1965gt]

AV gas is 100 Octane so I would think it would be more than enough to prevent detonation. The clattering noise does not change with engine temp only with engine load. Only does it when I really get on it.

PS The method used to measure octane for AV gas is stricter than the method used for automotive fuels... on the automotive scale AV gas would rate higher than 100 but im not sure how much higher.

[wgbanks]

Search other posts for discussion on the use of AV gas. Some say it's ok but it seems that the majority wouldn't run it. It is a different formulation. As with most ideas on the site there are those that are hard line on their side. I personally would not use AV gas but that position is more a matter of preference than specific reasoning that AV gas is bad. Again, all this IMHO.

[a1965gt]

Yeah seems like most people dont like to use AV gas but when asked why not it always seems to come down to rumors and speculation about being damaging to the motor or not burning as fast, hot etc. as automotive fuels.
I have done a little research and found a couple published articals online about AV gas and while there are certianly differences I could find no real drawbacks, AV gas is actually refined to higher specifications, and greater care is taken during transportation to prevent any kind of contamination. They wont even ship AV gas in the same tankers as automotive fues because of contamination issues.
The only problem that stands out in my mind has to do with getting water mixed in with AV gas... It can be corrosive to internal parts. AV gas has Bromide mixed in with it... somthing to do with also having lead in the gas. After the gas is burnt I think the lead, bromide and water can combine to form a very caustic solution. This is ONLY a problem if you get water in your gas AND the motor is not run on a regular basis... if it sits for months at a time this bromide solution can start to eat into your engine parts. As a preventative measure I plan on running a tank of automotive fuel through it before I put it away at the end of the season. Regularly changing the oil and using a synthetic oil also helps.

[mikeboone]

Mine never did run good on av gas. I had to run 102 octane with 10.8:1 piston at 416cc's. Some airports still carry the old av gas--80 octane as well as current 100LL. Check and be sure you dont have the 80. I would switch to a good 100 leaded gas if this continues.

[hook]

check timing maybe a tooth off