Greyhound Clone Build for a 2005 Ty-Rail Gokart

#61
I hooked up the fuel and let it idle for a few minutes outside while looking it over. It just wants to pump oil into the intake without the mystery canister. Also the side cover gaskets I tried to use leak oil at the 2 o'clock looking at the side cover. Turns out the clone gaskets I got specifically do not fit '09 harbor freights. I thought mine was an '08 but it looks like I need a non-hemi gasket.

I still don't have the TAV hooked up but it revs extremely fast and idles smoothly. Even at 230 lift it sounds mean.
 
#63
Finally got a sketchy first test ride in today. Didn't hook up the throttle so I had to thread my arm through the frame to hold the butterfly. Things I found:

1: It is tough to keep oil in these engines! The mystery can is a definite improvement over stock but I still smoked out my neighborhood. I might need to ditch the PCV valve because it literally pumps oil into the intake.

2: My plastic intake does not appreciate the hot oil. It split around the oil breather hole. I will use a hillbilly-style catch can until I can figure out my oil problem.

3: This shit gets EXPENSIVE!!! As you know, this build started off very budget-oriented but as soon as I layed my eyes on a cam, my money drank Red Bull and got it's wings. And there's still more to be done...
 
#64
I welded some baffles back into the valve cover to help with the oil problem. Probably a dumb move just cutting the stock baffle. First I took a section of u-channel and welded it over the breather hole:

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As you can tell I absolutely suck at welding. That's why I didn't take a picture of the second baffle. It is a plate similar to the stock baffle except it has 4, 1/4" holes in the top and 7, 3/32" holes in the bottom.
 
#65
Been awhile since I've posted. I've been working full time at my summer job and my daily driver required some attention in between. Now my summer job is over and I have next week to myself until school starts. I did pick away at some things in the past couple weeks so this will catch you up:

I've scrapped the baffle I poorly welded into the valve cover and made a new one that bolts to the rocker studs:

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I am also upgrading all the lines on the engine. I've been using a rip-off tygon that was actually yellow PVC tubing and it doesn't like the hot engine or the ethenol in pump gas. Now I am making new lines with real tygon and stainless steel braid. Here's how I make it:

First obviously you need to find how long the tube needs to be:

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Then cut the braid about a 1/4" shorter than the tube on each side:

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Side note-they say to cut this braid with sheet metal snips but I could never get them to cut. The way I do it is to mark the braid with a marker, shove a piece of rebar in it, and use a dremel with a cutoff disk and work your way around the cut.

Next, cut two 1-inch pieces of the thick heat shrink with adhesive on the inside, slide them onto the braid, THEN slide the braid over the tube:

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Finally, slide the heat shrink over the slightly frayed ends of the braid while pulling it tight over the tube and put a heat gun to it:

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The braid protects the tubing from abrasions and heat while making it look snazzy. They also make a copper braid if you want that look. All of the material was purchased from McMasterCarr.

ARC finally got their 25mm valves back in stock so I was able to get the missing piece of my valvetrain puzzle. I got the 25/24 valves, split keepers, lash caps, and 26lb springs to go with my Burris rockers. I test-fit the components and it seems I need to mill the bosses for the rocker studs to get correct geometry with the new rockers. That's the plan for today!
 
#66
So today I milled the stud bosses and clearanced around the head studs so I could get a socket around the nut:

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I just made a guestimate and milled 0.250" off the bosses. After the fact I researched it and found I only needed 0.125" but it works. Then I guestimated pushrod length and thought 5.160" looked good. When I went to cut my pushrods, I should have used my chopsaw and finished it with my bench grinder. Instead I chucked it in a lathe and tried using a part-off tool. Just in case you try the same, expect these results:

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But at least I can buy a 5.160" set.

All and all I'm glad I only screwed up a pushrod tonight because I'm sorta pissed. When I went to mill the head, my truck is parked right next to the mill. I stepped through a puddle of green coming from the truck. I wasn't even going to touch it because I knew I'd be walking into a mess that I wasn't anticipating.
 
#67
Today I bored out my carb. It measured 0.611" before and 0.629" after. I couldn't get the choke butterfly apart so I went in through the throttle side. Before:

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I used my drill press to keep everything plumb and spun the chick by hand. First I used a 0.625" reamer than finished with a 0.6285":

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After:

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As I reassembled it I drilled my jet from 0.035" to 0.036". I'm thinking 0.038" will be the size but I want to creep up on it before I drill the jet uselessly big.
 
#68
Yesterday I made a linkage for the throttle. Well, 1/2 of a linkage:

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Now I have to make the bracket that holds the throttle cable. BUT before that I need to pull the head again. When I was mocking up a return spring for the throttle, the magnet on the flywheel kept sucking it underneath the cover. When I went to turn the flywheel away from the throttle, it spun over pretty quickly and I heard air seeping. I almost thought it was the compression release but realized it had no pushrods. So I go pouring snoop all around the head gasket and found nothing. I finally cup my hands over the intake port and there it was.

Now I have to lap the intake in again even though I already did for a good 15 minutes. I even did the sharpie test and got good seating all around. Either way, I'm not going to let it run like this and burn my nice new valve.
 
#69
Success on the valves! When I looked at the intake valve seating surface, there were 4 grooves all the way around the valve. I'm going to assume this was from me lapping with too much force and too coarse of a compound. I originally used a 220-320-ish grit silicon carbide compound. This time around I used a 600 grit diamond compound and lifted the valve frequently to distribute the compound evenly. I ended up lapping both valves like this because the exhaust valve had 6 shallow grooves too. After I assembled the valve springs, I filled both ports with alcohol and they held for 10 minutes. Now I can get back to the throttle.
 
#70
Well I learned today that improper valve lash will damage your throttle mechanism:

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So I got it all buttoned up to do a test ride. Roll it outside, give it a yank, nothing but it pulled over a bit harder than I remembered. Give it a tad of throttle and another yank and it rips the cord out of my hand, punches my other hand, and latches onto the throttle rod breaking the plastic piece on top of the butterfly.

After sitting on my bucket for awhile, I decided to give it another pull, but this time slowly with the plug cap off. It felt like it had diesel compression...like when I had the pushrods out of it...and there was no compression release...but the compression release is there...and the lash is set to 0.004" so the compression release should open the valve...Is the compression release stuck?...no, can't be, it's a brand new cam...hmmm...it's acting like the lash is just loose enough to ignore the compression release...OH :001_9898:! where exactly did I set the exhaust lash?

Yup. And this is the guy who tells everybody to set their lashes on the ignition stroke so they're not on the compression release. Sure enough I brought the engine around to the correct stroke and my exhaust lash was 0.020".

And sorry my posts are so long and boring but I like to get this stuff out of my head and on record. And hey, if you enjoy reading, or you learn from my stupidity, I did something good for society!:laugh:
 
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#71
Whoo Hoo! Test drive! The internals of the engine are in their final form and it feels so good. Now time to work out the bugs...

1) The biggest problem is trying to keep the oil in the engine. It's near impossible to stop the oil from coming out the breather on the valve cover. I probably did more bad than good by gutting my stock valve cover. This issue could be death of the build.

2) I have to finish the throttle. Not a big deal...I hope...

3) I have to wire my kill button and new tachometer.

4) After the tach I have to tune the TAV and try different weight/garter/contra combos until I find the rpm sweet spot.

So far the engine itself sounds extremely happy and feels strong. For as low compression and as small a carb, it does very well IMO.
 
#73
I "think" I fixed my oil problem! I ditched the baffle mystery tube thingy and made a sort-of pump out of a plastic tank and two check valves. I will explain when I have pictures.
 
#74
Been slackin on the updates. Here's what's goin' on:

I've been running the engine on short test runs because I don't think I want to go on long trips and get stranded. The plastic reservoir/check valve combo has been doing its job, but not quite enough of it. I plan on designing and machining my own high flow check valve with a Viton ball instead of a Buna-N disk like the McMasterCarr-bought check valves.

My short tuning trips have been fun as heck blasting down my road at 40mph.:scooter: I did get stranded once when the TAV's jackshaft spun both bearings and pulled the inner races out. Had to push it a mile to safety.:doah:

I've been running a TAV2 with a 7" driven, the tighter -90 size belt, and a 10 tooth driver sprocket. I decided to test out my 6" again:)biggrin:) with my OMBwarehouse 8 tooth driver sprocket. That is where the fun was! It was fast as lightening but it still had the dreaded belt slippage while trying to climb hills but that will be fixed as I just purchased a yellow spring and three Comet belts.

I plan on getting a Chikuni kit and a MOD2 cam in the near future. The NRR 230 0611 is a great cam, but I think I want more hence the MOD2. I chose the MOD2 solely on the stats and not the name (as the big Youtube people do). Being I have 1.3:1 rockers, I will have 290 lift at the valve and 246 duration.

I recently installed the Trail Tech TTO tach and it's pretty good. You get cheapest of the cheap tachs for $20 and this middle-of-the-line tach is $45. You honestly get what you pay for. Yes I would recommend this tach.

Now I've been extremely conservative while tuning this engine so far. I have 28* timing, 9.2:1 compression, and it hasn't seen past 5k rpm yet. Now that may have saved me because I completely overlooked the fact that you need to check the installed height of the valve springs. I did check for coil bind but didn't realize how little closed pressure was on the valves. With incorrectly set up 26lb white stripe springs I had 16lbs closed pressure:doah:. I spent the last few hours measuring and machining custom 0.070" shims. I brought a 0.884" installed height down to 0.814" (note I was shooting for 0.8125" but who's counting?). Now I have 25lbs on the intake and 28lbs on the exhaust.:thumbsup:

While I have the head off I will be milling the head 0.020". This should bring 9.2:1 to about 9.8:1. I'll probably take off more in the future but baby steps are my friend.
 
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#75
UPDATE! Good news:

I just got the ARC bare head with 27/25 valves and a 4-bolt cover. This head is gonna be sweet because it'll give me big valves for about $35! I plan on milling it and cutting the rocker bosses for my Burris rockers tomorrow.

I also plan on adapting an old GY6 carb to this engine. I have it lying around and I can 3D print an intake boot for it (when I buy the material). The carb is a 24mm constant vacuum that had the butterfly bored to 26mm. This should yield the biggest gain by far over my dinky little 0.6285" SA carb.

BAD NEWS:

Well, maybe bad news, maybe nothing...idk... I just pulled my stock Greyhound head for the last time to double-check my deck height. I wasn't sure but I think I remembered 0.015". It just measured 0.023" now. Now that, coupled with the fact that my lash has kept opening up leads me to fear my jug is stretching.:scared::freakout: I have absolutely no block reinforcing but I thought I would be alright considering the low compression, timing, and small cam. Anyway, I'll just act like I didn't see anything for now but if this engine ends up like [MENTION=55159]BWL[/MENTION]'s Predator, I'll know why...
 
#77
Finally got my new Ninjatek Cheetah filament and got it dialed-in last night. I'm currently designing the intake boot to adapt my GY6 carb to the ARC 27/25 head. I ported and milled the head 0.040" last week. PROGRESS!
 
#78
If it isn't to late... read up on the Mod2 cam before you buy it. Many people say it isn't as great as the 12 year old kids say it is.
If you already bought it, let us know how it works for you.
If you didn't buy it, then look at the CL, CM, CS from Dynocams and also the tried and true Black Mamba and Mamba Jr.

Danford1
 
#79
If it isn't to late... read up on the Mod2 cam before you buy it. Many people say it isn't as great as the 12 year old kids say it is.
If you already bought it, let us know how it works for you.
If you didn't buy it, then look at the CL, CM, CS from Dynocams and also the tried and true Black Mamba.

Danford1
I hear exactly what you are saying and I preach it too. I am currently running as NRR 230 0611 and was thinking I need more duration, hence the MOD2. The reason I'm not going to a CM, 275, or 308 :drool: is because I am running 1.3:1 rockers and have coil bind at 340 lift. If it weren't $100, I would get a custom Isky 250 lift, 246 duration custom grind. This all leads me back to the MOD2. If I end up buying one I might consider twisting the crank gear to a 105-ish ICL.

And I'll have to wait to see if I even want the extra duration after trying out the new head and carb setup. With the 25/24 valves and SA carb, my powerband was extremely low and I felt like I needed more rpm. The new 27/25 valves and 24mm CVK carb might raise the powerband to the level I want without the MOD2.

Which speaking of, I got the first prototype of the intake designed. The filament's in the oven and printing's scheduled for 9:30. Here's a peak:

(if the forum would let me post pictures)
 
#80
I just got the engine running again with the 27/25 head and the GY6 carburetor. I left out some little stuff (carb insulator, air filter, throttle, etc.) just so I could test the combo out this morning and WHOA!!! It throws you in the seat! Now I'll get those little things tied up because it seems this carb's here to stay!

Also, now that the website's updated, I'll try posting pictures again.
 

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