Fast Eddie
Member
Thanks Geez. I appreciate the kind words. Actually, I've got twin LawnBoy 2 strokers goin' on. Your kart's lookin' sweet! I like the retina-burning orange. Nice choice.
(PROJECT) Rupp Dart restomod
- Thread starter Fast Eddie
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Rotore
Teh SPIK
nice kart dude
Orange Krate
Active member
Nice Work!! Great kart!!
Say, what did you do with these wheels? One pic looks like you replaced them. I'm needing some exactly like 'em for my General Lee kart resto. Yours are the only others I've ever seen. I'd be glad to take 'em off yer hands.....
Still willing to take these off yer hands if ye still got 'em!
Clayton
New member
Great build. I love them old Rupp Darts! And Orange Krate, I think that Rebel kart of yours is really cool, I am a huge Dukes of Hazzard fan (the original tv series).
Fast Eddie
Member
Hello all. It's been a while so I thought I'd give you an update on the Dart progress the last few months. Been buying and selling vintage karts and parts to replenish the kart fund. Here's what I scored.
All the rebuild parts needed for both Duraforces
Two Tillotson 334B's and two Noram Stinger clutches (with full range of engagement springs)
and a Hydraulic disc brake setup
These parts will keep me busy for a while. Step one was to get the carbs mounted to the block flanges. This requires some mods to the block and carb itself. I wanted to get this done first so I won't get metal shavings inside the new motors.
Need to get a vacuum pluse for the diaphram pump on the carb. Here's how I did it. Drilled out a spot on the bottom of the block (within the crank enclosure) and tapped the block for a pipe nipple.
Pipe nipple installed (with Loctite gasket maker to seal it up)
Made studs from the original LawnBoy carb screws
Ive added a Phenolic spacer for a couple of reasons. It cuts down on heat transfer from the block to the carb, but it also gave me an easy way to transition from the square bore of the block to the round bore of the carb.
If you look down the gullet here, you can see where I had some transition issues.
After some careful grinding with the trusty Dremel tool on both the spacer and the intake bore wall, I was able to smooth out the bore dramatically.
Could I have really hogged it out? Probably. Just don't want to get into too many mods right off the bat. I'll get 'er running and then work on increasing performance.
Also had to elongate the carb mounting holes. The bolt spacing on the block was just a bit narrower than on the carb. That also moved the nuts closer to the body of the carb. Had to do some clearancing on the sides of the carb body. There's not much meat in this area, so I had to be very careful.
Viola! All mounted up, ready to go. Got the other one done too.
Next up is getting the short blocks back together and building some mockup motor mounts out of wood so I can start on the exhausts. Once exhaust is done and the motors are in the right spots, the mounts will be cut from some 1/2 aluminum plate and TIGed up.
Stay tuned!
PS-yes O-Krate, Nylite wheels still avail. PM me a number.
All the rebuild parts needed for both Duraforces
Two Tillotson 334B's and two Noram Stinger clutches (with full range of engagement springs)
and a Hydraulic disc brake setup
These parts will keep me busy for a while. Step one was to get the carbs mounted to the block flanges. This requires some mods to the block and carb itself. I wanted to get this done first so I won't get metal shavings inside the new motors.
Need to get a vacuum pluse for the diaphram pump on the carb. Here's how I did it. Drilled out a spot on the bottom of the block (within the crank enclosure) and tapped the block for a pipe nipple.
Pipe nipple installed (with Loctite gasket maker to seal it up)
Made studs from the original LawnBoy carb screws
Ive added a Phenolic spacer for a couple of reasons. It cuts down on heat transfer from the block to the carb, but it also gave me an easy way to transition from the square bore of the block to the round bore of the carb.
If you look down the gullet here, you can see where I had some transition issues.
After some careful grinding with the trusty Dremel tool on both the spacer and the intake bore wall, I was able to smooth out the bore dramatically.
Could I have really hogged it out? Probably. Just don't want to get into too many mods right off the bat. I'll get 'er running and then work on increasing performance.
Also had to elongate the carb mounting holes. The bolt spacing on the block was just a bit narrower than on the carb. That also moved the nuts closer to the body of the carb. Had to do some clearancing on the sides of the carb body. There's not much meat in this area, so I had to be very careful.
Viola! All mounted up, ready to go. Got the other one done too.
Next up is getting the short blocks back together and building some mockup motor mounts out of wood so I can start on the exhausts. Once exhaust is done and the motors are in the right spots, the mounts will be cut from some 1/2 aluminum plate and TIGed up.
Stay tuned!
PS-yes O-Krate, Nylite wheels still avail. PM me a number.
TorqueRanger
New member
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Where did you get the brake setup from ???
Fast Eddie
Member
Knockoff of an MCP kit I found on eBay. Uses MCP parts (pads, hub, etc.) USA made and the quality is good. However, seller claimed it was powdercoat but is actually cheap silver spray paint. I think I'll strip it down to bare aluminum and polish it. This two-piston setup was cheaper than the MCP single-piston kit, and came with the flex stainless lines too!!
Nice. You are doing some quality work there. I am glad to see you have gotten going with this again. I was enjoying your build
Fast Eddie
Member
Thanks. I appreciate it. Just not a #1 priority in the household. But were coming into the winter and my new garage is heated. So hopefully many more updates to come!
Justin9
Member
Can you post a link to the ad so I can take a look at them, I would like to have a hydralic setup, but without the MCPO cost if possible... btw... great work so far... might have to get you to give some measures when you can of the chassis, I'd love to try and build a replica...
Fast Eddie
Member
No longer avail. on eBay. They had only a couple of kits. But keep your eyes peeled. May show up again.
Thanks for the kind words. I tried to draw up some measurements for another member, but if you don't have a frame in person to copy off of, building a replica would be too hard. They make repro Rupp Darts. You can prob. buy just the frame. Google "RobRon". You'll see em.
Justin9
Member
Did you know what the sellers name was that had the kits so I can watch for them or what they were called???
I like building the frames... since I had to put up my racing karts for a while, I have too much spare time... I have already built a dead axle kart and halfway through a live axle I'm working on... lol.... just gotta ge a set of wheels to get the dead axle running...
Fast Eddie
Member
I believe it was "snosalvage". My purchase history doesn't go back but a few months. Try searching 'em out on eBay.
Fast Eddie
Member
Need help with compression ratio
Hello all,
I need some help. Was planning to put together the motors stock without any big mods. I planned to bump up the anemic 5.8 to 1 compression ratio at a later date. But after looking at the blocks and heads, the only way I can bump the c/r is to mill it off the block. And I definately want to run a head gasket. So I better take care of it now while the motors are completely apart.
The head only has about .020 of meat I could mill off before getting into the combustion chamber. But the block (top of cylinder bore) has about .090 before it hits the deck. So what would be an acceptable compression ratio for a 2-stroke and how do I calculate how much to take off? Here's the specs I know.
Bore-2.500"
Stroke-1.750"
C/R-5.8 to 1
Piston-Permanent mold (meaning cast??), high-silicon aluminum
Chamber volume-unknown
Compression (as stated in manual)-115 PSI, 80 PSI service limit (whatever that means)
Any help would be appreciated. Thanks!
Hello all,
I need some help. Was planning to put together the motors stock without any big mods. I planned to bump up the anemic 5.8 to 1 compression ratio at a later date. But after looking at the blocks and heads, the only way I can bump the c/r is to mill it off the block. And I definately want to run a head gasket. So I better take care of it now while the motors are completely apart.
The head only has about .020 of meat I could mill off before getting into the combustion chamber. But the block (top of cylinder bore) has about .090 before it hits the deck. So what would be an acceptable compression ratio for a 2-stroke and how do I calculate how much to take off? Here's the specs I know.
Bore-2.500"
Stroke-1.750"
C/R-5.8 to 1
Piston-Permanent mold (meaning cast??), high-silicon aluminum
Chamber volume-unknown
Compression (as stated in manual)-115 PSI, 80 PSI service limit (whatever that means)
Any help would be appreciated. Thanks!
Fast Eddie
Member
Update-I mocked it up (with the old bearings) and checked clearance with some clay on the top of the piston. About .090 at the spark plug. So I'm going to mill .035 off the decks. Uncompressed head gasket is 1mm (about .039") and Russ runs sans gasket without interference, so I figure .035 is a nice, safe number.
Running them to the machine shop @ lunch. Will post pics when done!
Running them to the machine shop @ lunch. Will post pics when done!
Russ2251
AZUSA:Powered by LAWN-BOY
Take into account squish band area, or can be a backwards step.
Why not eliminate gasket? No machining necessary...just elbow grease.
Why not eliminate gasket? No machining necessary...just elbow grease.
Fast Eddie
Member
Talked to a friend of mine about that very subject today. His thought was because I'm not altering the combustion chamber design at all by leaving the head alone, it should not effect the combustion travel across the piston top. By milling the deck (or removing the head gasket), we're just decreasing combustion chamber thickness, not changing piston to head angles.
He also mentioned that these true hemispherical combustion chambers with smooth, matching head/piston surfaces are very tolerant to increasing comp ratio before causing detonation.
I'm just not sold on eliminating the head gasket. They're just milling the thickness of the gasket off the block so it's not really a major mod. Cost was just a few bucks, and I'll have em back by Friday.
Russ2251
AZUSA:Powered by LAWN-BOY
I used the lapping as it is reversible.
Fast Eddie
Member
Just a quick update. Nothin' big. Just got the cylinder blocks back. Thanks to Randy at BMI/Carquest in Marysville for turning them around quick and doin' a great job. I appreciate it!
BEFORE
AFTER (gotta look close)
Is it finally time to get these rotating assemblies together? I think so! Hopefully I can have a little bigger update next time. And of course with more pics.
BEFORE
AFTER (gotta look close)
Is it finally time to get these rotating assemblies together? I think so! Hopefully I can have a little bigger update next time. And of course with more pics.
Fast Eddie
Member
Got the rotating assemblies together this weekend. Everything went together perfect. Rings were all gapped perfect right out of the box. Guess it pays to buy genuine OEM parts.
Next up-the motor mounts!
PS-feel free to comment, make suggestions, etc. Any help is appreciated.
Next up-the motor mounts!
PS-feel free to comment, make suggestions, etc. Any help is appreciated.
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