Carburetor

[Robert Horvath]

FYI Shifter Go Kart Guys,

I'm getting this experimental test carb fitted up to the CR125 Honda.

Mikuni Super Butterfly Type SBN38mm Diaphragm Pump Carburetor
No jets to change ever (well almost never) as it has easy to get to externally adjustable low & high speed mixture screws just like the Vortex RoK-tt carb only a much bigger bore (38mm) to fit the CR125 Honda engine and the fuel pump is built right in too.


I'm getting tired of always taking off the carb to change the high & low speed pilot jets and I don't care for float types of carbs either.

These are one of the best performing and easy tuning carburators that money can buy





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I still have to add a air box adapter and a choke primer bulb for cold starts

The fuel pump shown in the photo is going to come off of course




Ocono Bob

Robert Horvath
W352N6446 Road J
Oconomowoc Wi 53066 U.S.A.

rhorvath4@wi.rr.com

[Bobby McCourt]

Why would you run that when you could just run a GFS ? Also that didn't come on a cr125 oh wait neither did the carbs they make you run. Lol. I actually have one of these on the shelf that used to be on a cr500 outlaw kart. It works well.

[Michael Taksa]

[Robert Horvath]

Bobby McCourt & Michael Taksa

Most all of us guys here do run the GFS system although it's not needed with a pumper > see the photo below:

The GFS does not help at all with the proper jetting for the race day weather !

You still have to physically change the jets all - all the time .

Most all of us guys have also added back in the OEM kickstart (I don't why karters took them off in the first place ?) and electric Paddle shifting for the ease of driving a shifter...So can see in the photo below too how nicely the kickstart tucks in by the CDI ign. box.

If you stall out on the back forty you don't even have to get out of the kart to start yourself back up.....Just a snap with your right hand being careful with the hot pipe right there and your back on your way.



Ocono Bob

Robert Horvath
W352N6446 Road J
Oconomowoc Wi 53066 U.S.A.


rhorvath4@wi.rr.com

[Howie Idelson]

We went down this road around 2001.
_________________
Howie Idelson
howieidelson@mac.com
www.coroflot.com/howieidelson

[Sam Zavaglia]

[Robert Horvath]

Sam Zavaglia

I do hope someone out there does reply with a explanation and/or some photos because I hear this all the time but I have never had it happen to me or any of my teammates in the last five years that I've been with shifters ?

I know from my testing the kickstarter mechanism does not engage on a backwards spin with reverse engine rotation.

I been around all kinds of dirt bikes in my career (over 60 riding years) and I have never seen it give trouble on a bike with some pretty nasty jumps and very hard spills!

True Sam I do not see many installed on the Honda CR125 shifters...But I do see pretty many installed on the Honda CR250 super karts.

Ocono Bob

rhorvath4@wi.rr.com

[Bobby McCourt]

Apparently karts are in some sort of 5th dimension where none of the stuff that happens in the normal world applies. I was joking about the gfs. I ran a kicker for 3 years on my rm80 shifter kart back in 1997 with no problems as well .

[Brian Wilhelm]

[Robert Horvath]

Jim McMahon & Robert Lawson

I do use both types of boots CR125 & RS125 on the Honda and no boot at all with the TillyCarb :

But you guys seem to think that "RS125" is a better intake so I will use that one with the Mikuni SN38mm...correct ?

Honda RS125 Intake Manifold w/ 5° Boot...
This pre-1995 Honda RS125 intake manifold (P/N 16220-NF4-900) has a 5° boot and can be mounted to 1999 Honda CR125 Moto engines, without having to remove the kick starter boss.

and the

The 5-degree angle design makes it much easier to mount the seat strut, on the engine-side of a 125cc shifter kart, versus using the 1999 CR125 OEM 30-degree intake





Jim McMahon,
I plan to be at Blackhawk Sat. June 1st with this Birel Shifter # 92 in the photos of Craig Hemmen as Tuner/Mechanic and here is a photo of our old Tony Kart KF-1 with my driver/grandson.....I put front hand operated brakes on this Tony Kart and they work out to be very useful.

I'm old guy in back of him kneeling down so you'll know what I look like when we get to Blackhawk.

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And as far as the performance of the Tilly KF1 34mm carb on the shifter it seemed great in the corners & at the way top end too...With plenty of ZIP !

Did you notice the exhaust note change with a pump carb??? Robert asked > yes we did > a sharper higher tone coming out of the corners.



But my testing was cut short and inconclusive because my buddies thought the carb might be too small a bore for a shifter and wanted me to get going on the larger SN38 pumper to be used on there machines.

I am going to get KF Tilly back on the Honda as soon as I finish developing the SN38mm for them as I thought it ( the Tilly) was a perfect combo > CR125 and the Tilly HW12 34mm carb !




I posted my homemade axle driven H.D. 24 volt starter pack before..but here is it again because it works so well .




And also a few more pics. of the SN38mm....A work in progress :







Ocono Bob

Robert Horvath
W352N6446 Road J
Oconomowoc Wi 53066 U.S.A.

rhorvath4@wi.rr.com

[Robert Horvath]

Jim McMahon & Robert Lawson

I do use both types of boots CR125 & RS125 on the Honda and no boot at all with the TillyCarb :

But you guys seem to think that "RS125" is a better intake so I will use that one with the Mikuni SN38mm...correct ?

Honda RS125 Intake Manifold w/ 5° Boot...
This pre-1995 Honda RS125 intake manifold (P/N 16220-NF4-900) has a 5° boot and can be mounted to 1999 Honda CR125 Moto engines, without having to remove the kick starter boss.

and the

The 5-degree angle design makes it much easier to mount the seat strut, on the engine-side of a 125cc shifter kart, versus using the 1999 CR125 OEM 30-degree intake





Jim McMahon,
I plan to be at Blackhawk Sat. June 1st with this Birel Shifter # 92 in the photos of Craig Hemmen as Tuner/Mechanic and here is a photo of our old Tony Kart KF-1 with my driver/grandson.....I put front hand operated brakes on this Tony Kart and they work out to be very useful.

I'm old guy in back of him kneeling down so you'll know what I look like when we get to Blackhawk.

[/URL










And as far as the performance of the Tilly KF1 34mm carb on the shifter it seemed great in the corners & at the way top end too...With plenty of ZIP !

Did you notice the exhaust note change with a pump carb??? Robert asked > yes we did > a sharper higher tone coming out of the corners.



But my testing was cut short and inconclusive because my buddies thought the carb might be too small a bore for a shifter and wanted me to get going on the larger SN38 pumper to be used on there machines.

I am going to get KF Tilly back on the Honda as soon as I finish developing the SN38mm for them as I thought it ( the Tilly) was a perfect combo > CR125 and the Tilly HW12 34mm carb !




I posted my homemade axle driven H.D. 24 volt starter pack before..but here is it again because it works so well .




And also a few more pics. of the SN38mm....A work in progress :







Ocono Bob

Robert Horvath
W352N6446 Road J
Oconomowoc Wi 53066 U.S.A.

rhorvath4@wi.rr.com

[Brian Degulis]

I posted my homemade axle driven H.D. 24 volt starter pack before..but here is it again because it works so well .


Looks good!!! How about sharing what it's made up of and how it's built?


Brian

[Robert Horvath]

OK Brian Degulis,

I'll put something together & post it....It's not real easy to do..as It takes sometime to procure all needed parts.....it utilizes a high torque 24 volt motorize wheelchair motor as the cranking motor and some standard on the shelf Coleman parts.





Ocono Bob,

Robert Horvath
W352N6446 Road J
Oconomowoc Wi 53066 U.S.A.


rhorvath4@wi.rr.com

[Brian Degulis]

Great I ask because I'm using a standard Coleman now and even in high gear it's marginal.


Brian

[Robert Horvath]

Brian and other Shifter Go Kart Friends,

This setup below will start any Honda Shifter either a CR250 or CR125 at the axle with plenty of torque to spare. No need to drop it in gear > just start out in 5th or 6th gear first thing from a dead stop and no need to get the tire spun up to speed first.

I'm working on a electric 24 volt external starter over this winter using a motor that's originally made for motorized wheel chairs to start our shifter karts for the first start of the day when on the stand or any time
or when the Kart is on 2X4 blocks while on the ground.

I found a very used motorized wheel chair at our local resale shop for $100.00 which inc. two good worm drive motors so I can actually fab up two of the units.

Here are 2 photos below of the proto type axle driven external starter for the Honda Shifters
[img]
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This all might sound like a lot of work...BUT ..I hurt my shoulder pretty good while trying to start the kart with a rope / strap here at home because the engine was so flooded.

So the unit will consist of one HD 25:1 gear reduction worm drive DC electric motor and two 12 volt/18
amp hr.TaG batteries connected in series in the Coleman bag.

Use a 60 amp starter button from any auto parts store on the unit. I also put external 12 volt charging leads on each battery so I never have to open up the starter pack to recharge it.

I found out that I will need some type of over running free clutch once
the engine fires..
so it doesn't rip the starter pack out my hands.

So I'm using this OEM Coleman starter bendix part # COL-SB-27-R-S-10-49 (about $50.00) with a 5/8inch impact socket on the end of it This has a sprage brg. contained in it.

( a sprag bearing locks up in one direction and is free floating in that other direction for when the engine fires up > we don't want go spinning around with tire!)

It will be all self contained & portable just like the Coleman units with plenty of Zip ( the Coleman starter packs will not crank over a shifter at the axle as they are only geared down 2 :1 )


To drive the very hard to turn drive axle...there will be a tailpipe expander (Harbor freight part # P37352 about $10.00) protruding out of the right rear axle hub that's located deep inside the rear axle of either a 40 or 50 mm tube.

The tailpipe expander will be trapped between the hub & and the axle to prevent it from falling out on the track. to cause trouble.

See the 2 photos below for more clarification.

[img]
[/img]

Or you could used a very HD 1/2 inch low speed high torque electric drill (Harbor Fright # 97622 on sale for about $92.00) on 120 volts AC with track side power,1000watt AC generator or a
1000watt DC power converter and good 12 volt car battery.

A 11mm or 7/16" hex drive Allen wench (with the bent end cut off) is just the correct size to fit. the Coleman starter bendix and the 1/2 inch drill.

Again see the photo below for more clarification.

[img]

It's not real easy to do..as It takes sometime to procure all needed parts.....it utilizes a high torque 24 volt motorize wheelchair motor as the cranking motor and some standard on the shelf Coleman parts.

The cost of the thing really got out
of control fast.


Here is a honest breakdown on the money I have in it .

And I don't know about the reliability of the thing...It does seems to work well ?

From the Good Will thrift store I got two wheel chair type motors for $80.00 a pair used.

They are 24 volt motors > That's why it takes two TaG type batteries.

My unit cost a little more then a Coleman unit because of the two batteries required.

Coleman Self Contained Gear Reduction Starter with Battery from cometkart is $265.00 ( But you know this won't start a shifter )


$30.00 for the axle driver. 40 mm and I hve a more H.D. setup for the 50mm axle tube & sill light wieght

The parts breakdown for the starter pack is below :


So we have one motor $40.00

One HD NAPA starter button & bracket $12.00

Two TaG type batteries at $25.00 each $50.00

One used cooler bag for the two batteries $5.00

One T carrying handle & grips $10.00

Stainless steel handle brackets from Ace Hardware @ $4.00 each $8.00

10gauge wire, wire connectors , tie wraps $8.00

Two special RC car battery charging leads & connectors @ $5.00 each $10.00

One fully automatic RC car battery charger $25.00

One Coleman starter bendix & extension shaft from Franklin Motorsports Phone 262-814-5400 # COL-SB-27-R-S-10-49 $45.00



One SK impact socket from Grainger $8.00

One bendix reducer sleeve from Ace $4.00

If after reading all this and you still want to go ahead with the project or you get stuck you email me
rhorvath4@wi.rr.com

.


Oconomowoc Bob Horvath

Robert Horvath
W352N6446 Road J
Oconomowoc Wi 53066 U.S.A.

rhorvath4@wi.rr.com