New engine (upgrade in progress)

[redsox985]

someone has got to buy a bunch of flywheels and hook them up to an engine! i'm going to take a wild guess saying the mythbusters thing hasn't done anything? maybe an e-mail should be headed there way.....

Oh, jeez. Not this again...

 

[Screendoor]

Well it only took 4 hours but I removed the governor. It is a long story but I got the arm stuck on the crank. Yeah I know stupid! But It was my first time. I got it all back together. Now I have to put in the valve springs! My hands are all cut up and I literally put my sweat and blood into this thing. Blood mixes well with oil right?

Anyways I pulled the Cam during the process but the arms didnt fall out. As long as I line up the dimples I should be ok right? I turned the crank and It sounded fine.

 

[Screendoor]

For the Hole in the top of the engine! I know to get a 1/4 inch #20 self tapping bolt, but what grade?

 

[anderkart]

Yep, line up those dimples.

That bolt wont be under much stress but grade 5 or above would be a safe bet:
http://www.americanfastener.com/technical/grade_markings_steel.asp

I thought Toystorys flywheel reply had a lot of very good info and I totally agree.

I'd feel fairly safe with your stock flywheel using stock valve springs that limit your rpm to around 5500 where the valves would float. But with your 18lb valve springs I'd be more concerned with the engines potential to spin up higher into the danger zone.

I dont run a clone but I've raced against dozens of them for a couple years now. As far as I know we've never had any flywheels fail at my track but I do believe its possible.

If you wanna do some serious research from guys that race these engines, start with this thread: http://karting.4cycle.com/showthread.php?t=359833 (posts #4 and #9 are from race kart engine builders I've dealt with and trust)

And then enter the term flywheel explosion into that forums search window for hours of reading on the subject. (i think you have to sign up/register before you can use their search function)

 

[Screendoor]

New question. Now that I have my engine back together where do I find how many ft lbs to torque the bolts back down?

 

[Doc Sprocket]

9 Lbs-Ft according to my Honda Manuals.
EDIT- My bad- that's for the GX120. it's 17. The numbers were too close together.

 

[anderkart]

Voila: http://www.affordablegokarts.com/torquevalues.php

 

[CriticalMass]

I am making a mental note to come back to this thread when i decide to build a racing clone. This is good stuff.

 

[Doc Sprocket]

FWIW- instead of a 1/4" bolt in the governor hole, I drilled and tapped it to 5/16-18 and installed a bolt wrapped in teflon tape.

 

[r97]

Oh, jeez. Not this again...

Bahahahahahah!........ lol.

 

[Screendoor]

Im taking my engine to ezbore 2morrow to get the valve springs and fly wheel installed. I dont feel comfortable putting in the valve springs. I bought a torque wrench at HF and I love it.

Got the crank torqued to 17 ft lbs with the help of my wife holding the engine while I was torquing.

Once again thanks for always giving great advice everybody. However I have another question. Where is the main jet located. I ordered a 90 but I think I want to try to drill it out.

 

[Torquerolljoe]

When you take off the carb bowl you will see it!! Can miss it.

 

[Screendoor]

Here I go again showing how novice I am! What is the carb bowl?

 

[Torquerolljoe]

My personal recommendation would be to add an oil catch can on that breather. Otherwise, there will be oil everywhere!! I know from personal experience with mine. Comet Karts has them and you can find them on ebay.

Just wanted to share some photos with you guys. Got the chain on and boy was that an animal. But it is on and I am happy.

 

[Torquerolljoe]

The carb bowl is the copper colored "bowl" underneath the carburetor. It has a bottom retaining bolt that you remove to take the bowl off and a bolt at an angle to drain the fuel from the bowl.

Joseph

 

[Torquerolljoe]

Looks super nice!!!

 

[Screendoor]

thanks. What if I angled the Breather up? Would I still have oil spilling at the top? I was going to get a bracket and angle it up anyways!

 

[Torquerolljoe]

I tried that as well...just took a little longer for oil to get everywhere!! It you don't mind clean up, you don't need the catch can, otherwise, I would spend the 25 to 50 dollars for one!!

 

[Screendoor]

Do you have a picture of the catch can on your kart?

 

[Screendoor]

I looked at comet karts web site! Can you send me a link to the one you are talking about!