The 2012 racing season is fast approaching. I know that many of you race or have been thinking about racing next year. My brother who raced clones on and off last year will be racing the 2012 season at our nearest track. Since my father, my brother and I all started messing with these clone engines my Dad and my brother have really began to figure out how to get peak performance out of a stock class clone. Despite race day issues we all face, last year he was able to always qualify in the top 3 and finish in the top 3 of his class. Clone classes over here have at least 15 racers.

As my brother ramps up for next season we hope to post more videos and perhaps some tips on tuning your engine for race day. Here is a short video of my brother doing an engine swap and some on track footage from one of my Gopro cameras. Below are some photos I took through out the day. Enjoy!

A friend of mine, Casey Nydahl, who I used to race with back in the 90′s came across a bunch of old track footage. He has been cutting it together and putting it online. Its pretty cool to see all of the old faces, many in which I have not seen since the days at the track. The track we are at in this video is Hillsferry Speedway in Newman, CA, a high speed banked 1/4 mile oval. The track still exists but I don’t believe anything has raced on it in years. I am sure if I dug deep enough into some old boxes I could find some old track footage myself. We used to record everything. This video does not contain any racing but you can see a lot of old karts and motors from the mid 90′s. I believe I was about 15 years old at this time, so about 15 years ago. I’m the idiot who flips off Casey as he is filming. Everybody likes to act tough for the camera.

Growing up kart racing was probably one of the best experiences of my childhood.

This last weekend I loaded up my kart along with the karts of my brother and father. In the midst of all of that, I twisted my ankle pretty good. I was not going to let that get in the way of testing out my freshly rebuilt Honda GX200 Modified. Yes that is correct, no longer do I have a clone modified. After tearing the motor down to fix the issue with the head we decided to take everything out. It had been a few trips to the track since I had completely taken the motor apart and I wanted to see how everything was wearing. My father, who has had a bit more spare time then I, spend the time taking it apart and reporting his findings to me.

The wear on the remaining clone parts that were in the motor was minimal. I have been really impressed with how some of the clone components hold up. The block looked great, with minimal cylinder wear considering the many times I have taken that motor over 9,000 RPM. At this point the only clone components that were left was the block, bearings, crank and side cover but they all still looked in great shape.

Being that I had a new stock Honda GX200 motor sitting on my bench I decided to put my modified parts on the Honda and use my clone as a semi-stock backup motor. The original plan for the Honda was to build an open motor but I have since decided against spending more money on motors and decided to move the parts over to the Honda. The stronger block and crankshaft will help me sleep better at night. My old clone block is going to receive a flat top Honda piston, Honda rod, Dyno CS Cam, 1.3:1 stamped rockers and a blueprinted carb. This motor will be placed on my Margay which I hope to make my backup kart soon. It will also serve as a good kart to have friends drive when I go to the track.

This weekend we decided to go to Prairie City since the Stockton track has been closed down. Prairie City is a fun and brutal track with a lot of tight corners. I was excited to be there as I had not driven that track in over 15 years. Saturday was a practice day before a club race the next day so there was a few karts out there. I was surprised to find there was a few drivers sporting modified YF200 motors. Anything other then stock clones was a sight for sore eyes. There was one other modified clone out there but I did not get to see it run on the track.

The YF200′s were pretty quick. I had never seen one in person so I was very interested to see one run. I know about them but I had never seen one on the track. I went out for my first trip around the track to break in my motor and my clutch. My motor had not yet been ran, except for 10 minutes at idle on the stand, and my clutch was completely new. I was very excited about my SMC Vortex Clutch. I felt that this clutch was going to change my life forever.

After the break-in session I went back out for a few more laps at a medium pace before putting a few hard laps on it toward the end. I felt good about my motor. It ran strong. I was peaking at about 8,900 RPM and needed a geer change. The track is so tight that I was losing a lot of momentum in the corners and could not come out of it like I should with the chosen gearing of a 4.75 ratio. I added 3 teeth to the rear sprocket and gave it another go.

I had the power I was missing in the corners, for the first two laps that is. After that, my motor seemed to bog way down in the corners, so I started adjusting my carb. When that didn’t help, I tried driving harder through the corners to keep my RPM up. That didn’t seem to help much either. After about 5-6 laps of trying, I gave up and came in. When I was almost off the track I noticed that my clutch was not disengaging. My new Vortex clutch was stuck, so I rolled to a stop.

After getting out I looked down and saw a disc hanging out of the clutch. The clutch drum had locked up on to it’s shaft causing it to be locked up. The outer disc that was hanging out was a bit chewed up from grinding on the outside of the drum and there was some wear on the outer plate that the disc normally sat inside of. The clutch looked to be in pretty bad shape. It probably got quite hot. I was really frustrated. The paperwork that came with this clutch promised it to be for large engines and for the most part worry free. At the price tag it carries I was not happy. I ordered the clutch from APS, whom I called today. I hope to get at the very least a replacement clutch. My motor seems to just destroy clutches even though the Vortex clutch is suppose to handle motors much more powerful than mine. One of the YF200′s had the same clutch and he said he does not have any issues with his. My last trip out on the track when the clutch problem occurred was with the YF200. He was able to stay on my tail through the corners when I couldn’t keep my RPM up due to the locked up clutch. Regardless, I was still pretty impressed with the power those YF200′s put out. I am not sure how much was done to his motor in comparison to my motor. On the straight away I was just as fast as a TAG however out of the corners they pulled on me quite a bit. Even before the clutch issues
came about I needed more RPM through the corners. We had the Vortex clutch set to the second to last setting.

So where does this leave me? I am not really sure. I am really considering giving up this modified stuff for a while. It is just to much work for someone who does not have the time to keep up with it. I have been a bit to busy this year which has kept me from spending much time on the kart. What I really need is a kart that is fast and worry free, however that doesn’t make much sense now does it.

I have some pictures of the damaged Vortex clutch I will post later along with the results of my conversation with APS. As for my Modified Honda GX200… I am not sure if I am going to keep it or not. Time will tell…

There are a lot of people concerned about stock clone flywheels. At first I thought it was a lot about nothing. I only lost one flywheel years ago, and that was my own fault. It was on a modified Briggs. I have witnessed a Briggs 3 hp aluminun flywheed explode in the pits. But since have only heard rumors about clone flywheels coming apart, I believe the magnet coming loose causes most of the problems with the clones, maybe not. BUT, take a look at these flywheels. Except for the Honda flywheel the rest are from HF Clones.

The last HF clone had the 5.18 lb flywheel with the row of holes. A lighter flywheel is good, but would you trust that one? REALLY it came that way stock.

I like to balance my motors, other than stock class, and I do it with removing material from the flywheel. I know that’s not the right way, but it works for me. I prefer not to add weight to the crank. I checked the static balance on a crank with four different flywheels. A stock Honda, an ARC billet, and two clones. They all checked about the same even considering the rpm range between 5 & 7 thousand. The higher the rpm range and the lighter stock rod and piston, the more out of balance they were. I was using an ARC rod and Honda flattop piston, which are considerably heavier than stock.

I now have 5 HF motors and one Dupar. No comparison. The first two HF I found loose bolts, each one seemed to have more metal pieces and shavings inside the crankcase, and they all had scratched pistons and cylinders. To make them competative, you have to shave the top of the bock and maybe the head, minimum. The Dupar needed no machining to end with 28cc. Our local rules call for 27.5cc. I helped with another Dupar and with no machining it was 27cc. I am not sure I am sorry that the Blue HF Clones are gone. I don’t think I will ever lighten and balance any Clone flywheel.

What are your experiences with clone flywheels?

Post written by Ken Hill

I have not been able to put as much seat time in with my kart and modified clone as I would like, however my clutch looks like I have raced two seasons on it with out bothering to maintain it. My current clutch, the Horstman Reaper, just can’t handle the power. I will post some of the damaged Reaper photos to the blog later.

After a few conversations with the Thomas, the owner of SMC, I decided to purchase their Vortex 3 Disc Clutch.

When I received the box, it was pretty heavy. I was surprised and thought that there must be more then just the clutch inside. When I removed the clutch from the box I was surprised at how large of a clutch it is. The photos I have seen of the clutch online did not do it justice, this clutch is massive.

Just holding and examining the clutch with my own hands I could tell that this clutch is going to perform much better than the Reaper ever could. My modified clone just produces to much power for the Reaper Clutch. I am pretty excited to get my motor back together after the issue with my head from Minidragbike and get back on the track to test this clutch.

The clutch is independent from the drum. Most clutches hold the drum onto it’s own shaft and become one unit held together by a snap ring. This clutch remains as two pieces that are held together on the crankshaft once bolted down. The drum itself has 4 points of contact from the discs where as the Reaper just had three. When I get some photos of the Reaper up you will see the damage on the drum from having a lot of power and only three points of contact. The Vortex drum is very light. I was surprised at how light it was considering the clutch itself is pretty heavy.

Here are some photos of the unboxing of the clutch. Once I get it on the motor I will take a few more photos which will give you a better idea of just how huge this clutch is. I am going to have to move my motor over even more now as this clutch is much thicker than the Horstman Reaper.

SMC Vortex 3 Disc Clutch: http://www.kartclutches.com/Products/v3.html

I purchased my clutch from APS. You can purchase direct from SMC but I found it easier just to order from APS. APS had the same price as SMC for retail purchases. I would link to the clutch on APS but their website is horrible and I don’t trust their link to stay valid. Just go to http://www.apskarting.com/.

I had a great time at the Stockton Motorplex club race this last weekend. I had not been to a race in years. Even though there was not much of a kart turnout it was still fun. My Dad and I finally made it out with our karts in hopes to drum up some interest in a Clone Modified class. We were able to get a few practice runs in. I ended up having some trouble with my Clone. You can read about that in another post. However I did bring my camera and captured a few shots from the track. I also shot some video but probably won’t have time to mess with that for a few weeks. These are just a few of the shots that I edited really quick so I could get them up. I may post more later. I also ran next door to Delta Speedway which was hosting a Sprint Car race at the same time as our Kart race.

Enjoy.

I have been fortunate enough to get some track time in two weeks in a row. On the 7th I just wanted to test my kart running the new jackshaft I had installed to allow for more seat room. I also tried running my clone on gas for the first time since I put the modified head on. The last trip out to the track which was a few months ago was not that good. My motor ran horribly. I attributed it to the weather. The last time my clone ran well was in 60 degree weather and it was now in the 90′s. This practice session was a battle to get my motor to peak 8,500 RPM. The battle I was used to having was to try and keep my motor below 10,000 RPM.

Yesterday, the 20th, my Dad and I went out to a race in Stockton. Some of the guys there had been bugging us to come to a race because there was talk of a “Clones gone wild” class for modifieds. Although we ended up being the only two, they let us get in a bit of track time.

The two times I went out on the track was with the Yamaha KT100′s. Normally my clone would make KT100′s look like amusement park rides, however with my motor issues I was a bit slower then they were. After that embarrassment I decided to start taking my motor apart. I knew something was not right. Going down the straight away I felt like I was towing another kart behind me. My motor was working hard to do something but it was not performing like it should.

When I removed the head and looked into the intake port I noticed a good size chunk of metal missing. When Minidragbike ported the head for me, he went way to far and there was not enough metal left between the wall of the intake port and the channel that allows oil and pressure up from the crankcase. I have ported 100′s of small 2cycle engines and this is a careless mistake. I have accidentally ported to far on heads before and when I do, I throw them away. If you look close at the photo you can see how paper thin the wall was. For my application, there was no reason to port that far, especially with out strengthening the areas that were ported so thin. One other problem I have been having since receiving the head is with intake gasket leaks. The port job left such a small amount of port face left that the cylinder head actually just cuts the gaskets and allows leaks.

I have written before about how good the head performs. I am not complaining in that department, however had I spent the time to measure and look more at the work I would not have trusted this head in a race.

My Dad is going to MarineTex the intake port and try to salvage the head. During this process we are also going to fill in the port a bit to add back a bit of the port face that is missing so we can port match a manifold to it.

I am not to thrilled with this. I could say a lot more but I would rather just report my findings and leave out how I really feel. Regardless, I hope that we drummed up a bit of interest for modified clones. I really wish my clone had been running at it’s peak for everybody to see. However there is always next time.

You never have enough tools. Some you can buy and some you have to make. There are certainly more tools available for the clones now than there was last year. Even so, there is always a new mousetrap.

Until recently I used an aluminum Z block, home made, to hold my dial indicator to check the cam. Then I went to HF and bought a magnetic base to hold the dial indicator. I removed the magnetic base from the vertical post. The post threads are 8 mm and I changed them to 6 mm. The longer of the two horizontal posts I cut off and use. I can reach any position from one spot.

Installing stiff or dual valve springs with aftermarket keepers can be a challenge. How do you hold everything in place and install the keepers too? Use a vice grip from Harbor Freight. I shortened both arms of the vice grip, for a better positioning of the handles when they latched. The attachment on the top was a piece of 1 in. aluminum machined to go over the spring and retainer with a shoulder inside to push with. The stock pad, relocated, is placed on the valve head. With the adjustment on the handle you can position and hold the spring/retainer with no hands needed. Then you can deal with the keepers at your leisure. This tool works better for me than what is currently available.

I’m beginning to think I spend to much time at Harbor Freight.

What are some of your favorite clone tools?

Post written by Ken Hill.

A future kart racer in training. This is what Liam, my 14 month old son and I do on a regular evening. Circle tracking the house is our favorite past time.

View this video full screen with the volume up!

Shot with 1 GoPro camera mounted in various places. The lighting in the house was less than desirable being that it was 8pm when we started recording. I just turned on the lights that were available to us. This was kind of a last minute idea.

Edited in Final Cut Pro X.

Racing sounds borrowed from Ken Block’s Gymkhana video on Youtube.

Background music by Killswitch Engage.

When I first started working on the clone motors, especially the carbs, there seemed to be a limit on what you can change for tuning. Primary air jet setting is absolutely necessary for idle and low speed. Even a drop of oil in the primary air jet will ruin your day, and it happens. I use a .0225 primary jet for my modifies.

With the stock clone carb we are only given jets and emulsion tubes correct? Different jet sizes .038 thru .043 are used for both the smaller gx200 and the gx270 carb. All the tubes and jets are interchangeable. The real tuning is in the emulsion tubes. Most commonly, the 140 emulsion tube is offered by most companies selling parts. What’s the big difference between the 140 and stock? So far I have found 6 different tubes. Different size holes and at different locations on the tube. The measured volumes of all these holes varies very little. The big differences is in the inside diameter (id) of the tubes. They range from .063 thru .087. The 140 tube is .068, only the second largest. So if you solder holes and make the tubes close to the same except for the id, you can tune your head temp by ten degrees. Add spark plugs and a little air density information and your good to go.

Spark plugs can allow your engine to run at different temperatures and are also good for tuning. We all live in different climates so your tuning may differ from my tuning out here in the middle of California.

So far I haven’t seen a carb, Tillotson or stock, that couldn’t be helped with enlarging the mid-range fuel delivery. Good for 3 tenths or a second off your laptime with a stock carb.

I enjoy getting the most of what is available before I buy what everyone else has and I like using my mind and experiences rather than sticking on a Mikuni or Tillotson.

What are your experiences with stock carb tuning? Share your thoughts in the comments box below.

This post was written by Ken Hill, a karting engine builder with over 25 years in the industry.