Midas

[Kartorbust]

So is it a lawn tractor battery or a motorcycle battery?

 

[KartFab]

Wait, is this thread renewed??? SAWEEEEEET! It's so creepy to stare at a locked ghost thread... I am MIDAS biggest fan by de way! exhaust is an amazing idea, just apologize to your neighbors afterwards...

All of my neighbors are pretty cool, so far. The gearing is off, with ony 8t on the jackshaft and 54t on the axle sprocket, we are looking at approximately 43 mph at 5500 rpms, which is okay. Id like the max to be 50-55ish as the kart does accelerate too fast as is. I know for sure i will max at 49ish mph with a 9t sprocket (which I had on it originally), and 55 mph with the 10t sprocket. Im comfortable with tthe 9t, but I want to see if i can finagle that 10t in there (it will be a tight fit with a half link if anything).

Its either that or slap the 22" tires on there.... which are beign saved for a different projet.

So is it a lawn tractor battery or a motorcycle battery?

I dunno, some junk battery you get on ebay for $10-$15 shipped. I went ahead and got a duracell AGM platinum 180 cranking amps battery over the weekend and will be putting it in.

Also, on top of all of this, i was thinking i was getting some "torque steer" - how may you ask on a live axle is this possible? Well, one rim is welded to the axle to save both the axle and rim from being tossed, and the other rim is a tiny bit wobbly. Ill be doing the next video on that fix, which involves welding and locking collars (semi permanent fix).

Also the axle sprocket hub and brake disc hub are a tiny bit loose I noticed as well.... might need to freshen that up eventually, but seems good enough right now.

and heres the video
https://www.youtube.com/watch?v=egnfCeWmCuk&feature=youtu.be

 

[KartFab]

muffler added

The kart still wont wheelie with me on it (just a baby wheelie maybe 1" off the ground) as I kept the stock compression ratio. I got some lighter rollers for the 40 series torque converter and stiffer springs. The engagement rpm stock is aroudn 2000 rpm, and this will make it go up to 2600 rpm- conveniently right where I would like it to be as it has max torque at that rpm. Haven't installed it yet though.


Well, the exhaust was too stinkin loud. Deafening.

I put on a 28mm pit bike muffler, and it was literally the same intensity as the open pipe with no attenuation of sound pressure.

I was saving the Yamaha R1 exhaust for another project, but decided to use it here.

Next was adding the R1 muffler from ebay (i got a pair of them for like $15- people like getting aftermarket exhaust for their bullet bikes so there is a bit of a glut of stock mufflers now and then). I used some 1" ID flex exhaust tubing, then shortened the muffler so the tubing could be removed. I was thinking about welding it all together, but I'm glad I didnt. Turns out that the muffler is made of titanium, so when I shortened the exhaust on the muffler, i had to cut a section of the muffler pipe off to use as filler metal to weld the clamp adapter onto the muffler. Worked out nicely!

I also added header wrap and secured it with some stainless steel filler wire. Sounds much better now has a nice deep idle sound, but much quieter.

Breather tube for valve cover is vented to atmosphere, but its chucking a bit of oil on the muffler now. Any ideas/links/advice on what to do?

 

[KartFab]

Never Weld an Axle

Whadaya do when you dont want a buy a new set of rims and a new axle?

BUST OUT THE WELDER haha.

https://www.youtube.com/watch?v=sP6KyzUvwkQ

 

[KartFab]

yamaha R1 muffler on the go kart

Put one of the two R1 mufflers i got on ebay for $15 on the kart. Sounds a lot better now in my opinion. Really quieted it down, but still sounds nice.

https://www.youtube.com/watch?v=1MiHc2Hs20k&feature=youtu.be

 

[Kartorbust]

Wonder if an analog tach would work faster than that digital tach?

 

[KartFab]

Digital tach isn't grounded so it's not getting a good signal. I got a glowtach already, just got to install it. I'm thinking I'm maxing out at 5-5.5k rpm.

 

[KartFab]

40 series torque converter engagement rpm modification

Was dinking around with the engagement rpm of the drive unit and finally got the go kart to do a baby wheelie with me on it (im still too fat). Engagement RPM does matter for launch, but I wouldnt run this set up just putting around as it engages too high (2600 rpm engagement).
https://www.youtube.com/watch?v=-8ymMBnfR84&feature=youtu.be

Also, thanks dennis for milling the head last night. Ill be doing a video on that soon! Also am working on porting and polishing. Intake port is 95% there, exhaust was not completed yet. Will debur head, and sand extra flat on my countertop.

 

[WeddingRing]

Hmmm. Usually it's a sheet of wet or dry sandpaper layed on a pane of glass that's been misted with water.

 

[ezcome-ezgo]

Sounds like a heck of a good time.

 

[bob58o]

Sounds like a heck of a good time.

I tried to take 0.025" off of a head sanding on a pane of glass. It was not fun. I can assure you.

 

[Kartorbust]

The only fun thing sanding by hand is wood. Just more satisfying. So what did you use instead is sanding it by hand?

 

[bob58o]

Breather tube for valve cover is vented to atmosphere, but its chucking a bit of oil on the muffler now. Any ideas/links/advice on what to do?

I use a breather filter, but they get oily.
I also added another vent to the top of the crankcase this time (with another breather filter).
Some use a oil catch can system, some of which are simple and some are more complex.
http://www.ebay.com/itm/BILLET-ALUM...R-TANK-CAN-HOSE-INDICATOR-BLACK-/201249093731
http://www.ebay.com/itm/K-MOTOR-BLA...NK-WITH-BREATHER-FILTER-BAFFLED-/172467848160
Some run a tube into a gatorade bottle with a vented cap.

 

[ezcome-ezgo]

I tried to take 0.025" off of a head sanding on a pane of glass. It was not fun. I can assure you.

I once helped my Dad flatten out the head of a 4 cylinder Datsun (Nissan) engine using this method, so I know what a good time is.

 

[bob58o]

The only fun thing sanding by hand is wood. Just more satisfying. So what did you use instead is sanding it by hand?

Shipped it to Dynocams. He told me I took like 0.005" off of one side and 0.008" off the other.

They mill for $15 plus shipping.

 

[Kartorbust]

Dang that's cheap and nice. Totally doable.

 

[KartFab]

.073 shaved from the head, cut to length pushrods cut to be .073" shorter, ported head, polished exhaust runner. Stole the starter, 10A flywheel/coils from my honda gx340 and set timing to 26 DBTDC, indexed the spark plug. Had an extra honda gx620 regulator and keystart from the worst craigslist purchase of my life laying around. Got rid of that ugly red box, rigged up the key and wired it under steering wheel, installed pull choke next to key start. Ground the exhaust flange to match perfectly to exhaust port. Sanded intake insulator to intake port

Brake light works independently of all electronics, lights on their own switch. Regulator/Rectifier is putting out 13.6v when running at the battery terminals.

Cant wait to get a few runs on it. Maybe i added enough compression for it to be wheelie time, but I also added a lot of weight with the battery and starter in front of the axle. Also gained 10 lbs since the last time I ran the kart. RIP diet.

Still need to fab up a bracket for the choke cable, which I have laid out in my mind as being able to bolt to the stock throttle plate, and aftermarket choke holder, that will use the honda cable holder from another engine I dismantled.

After I get all this finished, i will move over to the mini bikes to finish before october.

 

[KartFab]

Here are a few pictures from top to bottom

dennis milling the head .073"
intake and exhaust prior to porting
intake and exhaust after porting
intake port runner after porting
exhaust port runner after porting
head surface with valves installed after sanding down head to as flat as i was comfortable with
stolen gx340 parts on my gx390, coil, starter etc,
setting timing (looks like its at 27, but i fine tuned it to 26 DBTDC
honda electric start key put below steering hoop and pull to choke installed (not finished with it yet)
head after having installed chrome moly cut to length pushrods and a thicker guideplate that is mandatory when installing push rods with the stock rockers.

 

[KartFab]

Okay, so im getting the finishing touches done now. Letting paint dry at the moment. Ive gotta pick up some ~1/4-5/16" Tee nuts and bolts at the hardware store tomorrow so my regulator/rectifier will hold the head rest on. Original tee nuts are a little small for the regulator rectifier bolts.

Battery wouldnt fit, so i had to put it on a 10-15 degree angle with a plate, then weld up some new 1/4" threaded rod and braces to hold it in place, then painted it.

Choke was kind of hard to figure out, but i got it done. I took the existing throttle plate where the air filter housing was, and bolted a piece of 1/8" steel bar to it, did a little pounding on the vise, and fabbed up this removeable bracket that i tack welded to the choke lever holder for the high flow intake. I ground out the bottom of the bracket so the choke would still freely move without contacting the metal at its highest point.

Then, i chopped off a cable holder from my honda gx390 stroker throttle plate because i have a mikuni flat slide for that and wont need the plate. Then i welded the cable holder to the right spot. Messed around with the positioning of the cable, bent it up a bit so there is plenty of wiggle room to keep the choke open /closed with the pull choke.

Engine starts and runs, everything seems good, but its a little late to take it for a spin.

Tomorrow ill be reattaching headrest, backrest, and having a little fun!!!

If i cant get it to do wheelies, i'm going to be a little disappointed (but not surprised). If it wont do wheelies, I will go ahead and re-gear this thing to have either a 9t jackshaft or 10t jackshaft sprocket so it will have a higher top speed. 10t would be ideal, but I may have to put a half link for the chain on it.

Its been a long time coming, but i am finally feeling like the go kart is 'complete' so i can start working on the mini bikes.

 

[bob58o]

Let's see these wheelies!
https://www.youtube.com/watch?v=-W6as8oVcuM