Re: Cobrafreak's board track racer project, never ends!
the gx engine is used in cart racing right? that's going to be great.
the gx engine is used in cart racing right? that's going to be great.
Cobrafreak's board track racer project, has ended
- Thread starter cobrafreak
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Re: Cobrafreak's board track racer project, never ends!
Yeah, It's big in cart racing. That is what's cool about it. Lots and lots of parts and options. Different cams, springs, exhausts, speed tricks. I'm not really trying to be fast, I just wanted something rugged and reliable with that good old four stroke chug. The CTV transmission is made for the GX160/GX200 engine, so that steered me in this direction. The CVT is the clutch and tranny and is fully automatic, so I don't need to pedal to get going, just give it throttle. A buddy on another site said his GX200 with CTV went 65mph before he decided to slow down. This is with the rev limiter still in tact. The trick is, and it's going to be a big trick to pull off, is making it look at home within the bike. It's big, almost too big physically, but I've seen people pull it off nicely. Making it look retro as much as possible is another trick. I have some ideas. The frame is going to need reinforcement to keep from twisting from torque. I can't wait to tear into it !
Yeah, It's big in cart racing. That is what's cool about it. Lots and lots of parts and options. Different cams, springs, exhausts, speed tricks. I'm not really trying to be fast, I just wanted something rugged and reliable with that good old four stroke chug. The CTV transmission is made for the GX160/GX200 engine, so that steered me in this direction. The CVT is the clutch and tranny and is fully automatic, so I don't need to pedal to get going, just give it throttle. A buddy on another site said his GX200 with CTV went 65mph before he decided to slow down. This is with the rev limiter still in tact. The trick is, and it's going to be a big trick to pull off, is making it look at home within the bike. It's big, almost too big physically, but I've seen people pull it off nicely. Making it look retro as much as possible is another trick. I have some ideas. The frame is going to need reinforcement to keep from twisting from torque. I can't wait to tear into it !
Cobrafreaks's new engine project
Ok, started phase two of the Indians engine upgrade. Here I have a Harbor Freight 6.5 hp 200 cc air cooled engine other wise known as the "Greyhound" or "Honda GX 200 clone". BTW they are one sale now so get one now if you are interested. They are internally governed to not rotate past 3500 rpm. They can spin to 6500 rpm but you must do a couple of things first to keep it from blowing up, which is what I am doing now. After disassembly and removal of the mechanical RPM governor the connecting rod and the valve springs must be replaced. The connecting rod is merely adequate for 3500 rpm operation. The bearing surfaces on the crankshaft are steel, but on the connecting rod they are just machined into the aluminum. The rod is also thin and will most likely snap and go through the case. For higher rpm duty you need to upgrade to a billet aluminum connecting rod that has steel bearing surfaces for longevity. The valve springs are far too light. They need to be upgraded to 18lb springs to prevent valve float. I am not making this engine for all out power, just the ability to rev higher so the CVT transmission can spool up fully. If I were to truly go all out for all the power I could get I would also upgrade to roller rockers and a high performance cam shaft. Here is the new engine apart with the china girl cylinder for size comparison.
Here is the upright orientation of the clone engine. Normally the engine has the cylinder pointed to the rear, but I am pointing it strait up for looks. Everything is tipped 90 degrees North.
Here is a groove that I ground out to be able to drain all the engine oil out of the case. The oil drain hole is too high when tipped 90 degrees so this little channel that I made will allow most of the oil to now be drained out during oil changes.
Ok, started phase two of the Indians engine upgrade. Here I have a Harbor Freight 6.5 hp 200 cc air cooled engine other wise known as the "Greyhound" or "Honda GX 200 clone". BTW they are one sale now so get one now if you are interested. They are internally governed to not rotate past 3500 rpm. They can spin to 6500 rpm but you must do a couple of things first to keep it from blowing up, which is what I am doing now. After disassembly and removal of the mechanical RPM governor the connecting rod and the valve springs must be replaced. The connecting rod is merely adequate for 3500 rpm operation. The bearing surfaces on the crankshaft are steel, but on the connecting rod they are just machined into the aluminum. The rod is also thin and will most likely snap and go through the case. For higher rpm duty you need to upgrade to a billet aluminum connecting rod that has steel bearing surfaces for longevity. The valve springs are far too light. They need to be upgraded to 18lb springs to prevent valve float. I am not making this engine for all out power, just the ability to rev higher so the CVT transmission can spool up fully. If I were to truly go all out for all the power I could get I would also upgrade to roller rockers and a high performance cam shaft. Here is the new engine apart with the china girl cylinder for size comparison.
Here is the upright orientation of the clone engine. Normally the engine has the cylinder pointed to the rear, but I am pointing it strait up for looks. Everything is tipped 90 degrees North.
Here is a groove that I ground out to be able to drain all the engine oil out of the case. The oil drain hole is too high when tipped 90 degrees so this little channel that I made will allow most of the oil to now be drained out during oil changes.
Re: Cobrafreak's board track racer project, never ends!
I got the extra wide crank today. It was set up for loose bearings and my bottom bracket was set up for cartridge bearings so I ground down the bearing races on the spindle and pressed on a spacer with the hydraulic press and slid the cartridge bearings on. Works great. Lots of room for wide engines now.
I got the extra wide crank today. It was set up for loose bearings and my bottom bracket was set up for cartridge bearings so I ground down the bearing races on the spindle and pressed on a spacer with the hydraulic press and slid the cartridge bearings on. Works great. Lots of room for wide engines now.
Re: Cobrafreak's board track racer project, never ends!
I will be watching this. I may build much the same in the future, im probably buying a fairly cheap Honda GX160 next week, just gotta go look at it. Are they much the same engines?
I will be watching this. I may build much the same in the future, im probably buying a fairly cheap Honda GX160 next week, just gotta go look at it. Are they much the same engines?
Re: Cobrafreak's board track racer project, never ends!
From what I hear, yes. Pretty much the same, other than displacement. I read a speed trick for the GX160 which is to use GX200 head gaskets as they are thinner and it will raise the compression ratio nicely for more power. How much is cheap? Brand new GX200 clones are at Harbor Freight for around $79 with coupon. For $20 more you can get a two year warranty, no questions asked. Blow it up, get a new engine.harry76 said:
New engine time!
I was going to go for a nice ride around the neighborhood and one of the China Girl's engine studs stripped from the block. So I took this as a sign to move forward with Project big engine NOW! So I removed the old power plant (with extreme prejudice) and cut off the front engine mount and the mount I had for the fake engine plates I made for the China Girl engine. BTW, if anyone wants my fake engine plates I will give them to you, you just have to agree to use them for your own bike, no re-selling, OK. I sat the new engine with the head, crank, and cases attached. I am still waiting for my new rod so the engine is not complete inside. As you can see the GX200 engine fits well. The rear engine mount from the China Girl is at almost the perfect angle the GX needs to be so I can build off of it.
I was going to go for a nice ride around the neighborhood and one of the China Girl's engine studs stripped from the block. So I took this as a sign to move forward with Project big engine NOW! So I removed the old power plant (with extreme prejudice) and cut off the front engine mount and the mount I had for the fake engine plates I made for the China Girl engine. BTW, if anyone wants my fake engine plates I will give them to you, you just have to agree to use them for your own bike, no re-selling, OK. I sat the new engine with the head, crank, and cases attached. I am still waiting for my new rod so the engine is not complete inside. As you can see the GX200 engine fits well. The rear engine mount from the China Girl is at almost the perfect angle the GX needs to be so I can build off of it.
Re: Cobrafreak's board track racer project, never ends!
Thats looking good Cobra, real good. And while i was a fan of what you did with your chinagirl, this motor in your frame is a huge improvement. What flywheel do they have? Do they have cooling fins that you need to remove? Are you going planning not to run a heat shield (or shroud), because i read in Lurkers thread how he had heating problems, are you just going to see what happens? Look forward to seeing your progress....
Thats looking good Cobra, real good. And while i was a fan of what you did with your chinagirl, this motor in your frame is a huge improvement. What flywheel do they have? Do they have cooling fins that you need to remove? Are you going planning not to run a heat shield (or shroud), because i read in Lurkers thread how he had heating problems, are you just going to see what happens? Look forward to seeing your progress....
Re: Cobrafreak's board track racer project, never ends!
Real good lookin engine.
Can we hear it?
Real good lookin engine.
Can we hear it?
Re: Cobrafreak's board track racer project, never ends!
Thanks. The stock flywheel is a heavy cast iron unit. The cooling fan is a plastic fan unit that lays on the outside of the cast iron flywheel and attaches with a bolt. You can run it either/or. I may upgrade the flywheel because the AGK guy mentioned (and it makes sense) that past 3500 rpm's the magnet is in danger of flying off the flywheel as it is only attached by a single screw and epoxy. I am tempted to run two more screws on the magnet but that would probably throw the flywheel out of balance and cause bad vibration and early bearing failure. It would be easier to just replace the flywheel with one that has the magnet attached in a way it can't fly off. I suspect that I will need to run the shroud due to high temperatures. I know what cooling fins look like on an air cooled motorcycle engine and the fins on this are not deep enough to carry away heat on their own it seems like. I know Harley Davidson was having overheating problems in the 1980's on some models due to not making the air cooling fins long enough on the cylinder and heads. The fix was taller fins. Imagine an air cooled Volkswagon Beetle that breaks the generator (fan) belt. What happens? It catches on fire. I'm not suggesting that this engine will catch on fire. There are other bad things that can happen. A warped head, a seized piston. I have a laser thermometer and when I get a baseline temp reading with the fan shroud on I will do it with it off to see what I can get away with.
harry76 said:
Thanks. The stock flywheel is a heavy cast iron unit. The cooling fan is a plastic fan unit that lays on the outside of the cast iron flywheel and attaches with a bolt. You can run it either/or. I may upgrade the flywheel because the AGK guy mentioned (and it makes sense) that past 3500 rpm's the magnet is in danger of flying off the flywheel as it is only attached by a single screw and epoxy. I am tempted to run two more screws on the magnet but that would probably throw the flywheel out of balance and cause bad vibration and early bearing failure. It would be easier to just replace the flywheel with one that has the magnet attached in a way it can't fly off. I suspect that I will need to run the shroud due to high temperatures. I know what cooling fins look like on an air cooled motorcycle engine and the fins on this are not deep enough to carry away heat on their own it seems like. I know Harley Davidson was having overheating problems in the 1980's on some models due to not making the air cooling fins long enough on the cylinder and heads. The fix was taller fins. Imagine an air cooled Volkswagon Beetle that breaks the generator (fan) belt. What happens? It catches on fire. I'm not suggesting that this engine will catch on fire. There are other bad things that can happen. A warped head, a seized piston. I have a laser thermometer and when I get a baseline temp reading with the fan shroud on I will do it with it off to see what I can get away with.
Re: Cobrafreak's board track racer project, never ends!
Not right now. There is no piston inside it at the moment. The carb can't run laying sideways so I need to make an adapter to do so. I need to fabricate an exhaust system and the engine needs engine mounts to bolt to the frame. With the crappy stock exhaust "block" on it sounded like a typical 4 stroke lawn mower but with more thump. It will sound vintage when she's all finished.
stocksucks said:
Not right now. There is no piston inside it at the moment. The carb can't run laying sideways so I need to make an adapter to do so. I need to fabricate an exhaust system and the engine needs engine mounts to bolt to the frame. With the crappy stock exhaust "block" on it sounded like a typical 4 stroke lawn mower but with more thump. It will sound vintage when she's all finished.
Re: Cobrafreak's board track racer project, never ends!
I was curious as to wether or not the stock GX200 clone cast iron flywheel is safe at high rpm's. I found this thread on the internet of a guy that sent it in to a place that does destruction tests. The bottom line is the stock flywheel and magnet seem to be fine and will not blow up at rpm's a street ride will ever see. I'll hold out on the billet flywheel for now. Here is the thread post:
"I sent a stock, cast flywheel from one of the yellow engines to The Balancing Company ( http://www.balco.com ) for a spin to destruct test. This company's credibility to properly perform this sort of testing is well established and beyond reproach.
Balco does not verify the safety, suitability, use, or the fitness for a particular purpose, or unintended purpose of the flywheel.
I asked that they give me the RPM where the first failure occurs. I supplied them with a new flywheel, a starter cup, a standard flywheel nut, and a new crankshaft so they could chop off the mag side of the crank and use it as an arbor for their machine. This means the flywheel was mounted in the same manner as we would be using it on the engine.
They have completed the test and are sending the flywheel and the test results back to me. As I stated before I sent the flywheel, I intend to scan the letter from Balco into the computer and post it here for everyone to see.
If one of these engines is prepared according to AKRA's box stock rules, the max racing RPM will be below 5500 RPM. The front runners on 1/5 mile tracks are turning less than 5200 RPM.
The magnet came off the flywheel tested at 11,250 RPM which is more than double the RPM where most are turning them so...
I stand on my previous statement about this engine, which, contrary to some of the conspiracy theorists out there, has not changed one bit:
I am comfortable with the stock flywheel on the engines I sell when that engine is being raced according to AKRA's box stock rules.
That is a very specific statement that encompasses EXACTLY how I am racing this engine myself. Do not confuse my statement with ANYTHING outside of that statement. If you must switch to parts that have the potential to jack up RPM or horsepower, then you should run a billet flywheel. Racing is dangerous, and ANY racing engine part can fail under racing conditions. Failure of ANY engine part can injure, or even kill an individual within the vacinity. If you aren't willing to accept that risk, then you should not be racing or in the vacinity of racing vehicles. You should not race under uninsured circumstances and you should not be in the pits under uninsured circumstances.
End of "racing is dangerous" (duh huh) disclaimer.
And by the way, to assume that I had not personally tested the flywheel myself prior to this would be wrong.
Let the fur flying begin!"
I was curious as to wether or not the stock GX200 clone cast iron flywheel is safe at high rpm's. I found this thread on the internet of a guy that sent it in to a place that does destruction tests. The bottom line is the stock flywheel and magnet seem to be fine and will not blow up at rpm's a street ride will ever see. I'll hold out on the billet flywheel for now. Here is the thread post:
"I sent a stock, cast flywheel from one of the yellow engines to The Balancing Company ( http://www.balco.com ) for a spin to destruct test. This company's credibility to properly perform this sort of testing is well established and beyond reproach.
Balco does not verify the safety, suitability, use, or the fitness for a particular purpose, or unintended purpose of the flywheel.
I asked that they give me the RPM where the first failure occurs. I supplied them with a new flywheel, a starter cup, a standard flywheel nut, and a new crankshaft so they could chop off the mag side of the crank and use it as an arbor for their machine. This means the flywheel was mounted in the same manner as we would be using it on the engine.
They have completed the test and are sending the flywheel and the test results back to me. As I stated before I sent the flywheel, I intend to scan the letter from Balco into the computer and post it here for everyone to see.
If one of these engines is prepared according to AKRA's box stock rules, the max racing RPM will be below 5500 RPM. The front runners on 1/5 mile tracks are turning less than 5200 RPM.
The magnet came off the flywheel tested at 11,250 RPM which is more than double the RPM where most are turning them so...
I stand on my previous statement about this engine, which, contrary to some of the conspiracy theorists out there, has not changed one bit:
I am comfortable with the stock flywheel on the engines I sell when that engine is being raced according to AKRA's box stock rules.
That is a very specific statement that encompasses EXACTLY how I am racing this engine myself. Do not confuse my statement with ANYTHING outside of that statement. If you must switch to parts that have the potential to jack up RPM or horsepower, then you should run a billet flywheel. Racing is dangerous, and ANY racing engine part can fail under racing conditions. Failure of ANY engine part can injure, or even kill an individual within the vacinity. If you aren't willing to accept that risk, then you should not be racing or in the vacinity of racing vehicles. You should not race under uninsured circumstances and you should not be in the pits under uninsured circumstances.
End of "racing is dangerous" (duh huh) disclaimer.
And by the way, to assume that I had not personally tested the flywheel myself prior to this would be wrong.
Let the fur flying begin!"
Re: Cobrafreak's board track racer project, never ends!
You said you would use a CVT didnt you? If so where do you find these and how much are they worth? Sounds like a good idea....
Any other ideas on how you will make the engine vintage looking or are you going to do it as you go? And keep the pics comin....
You said you would use a CVT didnt you? If so where do you find these and how much are they worth? Sounds like a good idea....
Any other ideas on how you will make the engine vintage looking or are you going to do it as you go? And keep the pics comin....
Re: Cobrafreak's board track racer project, never ends!
Here is a link of the CVT (Constant Velocity Transmission) that I have comming:
http://www.affordablegokarts.com/mm5/merchant.mvc?
Screen=PROD&Store_Code=A&Product_Code=GTC100*&Category_Code=PCJAs for Ideas to make it look old school, I'm going to paint the cylinder head high-heat black like a cast iron one. I will probably be adding the fan but it will be highly condensed and much easier to swallow. Nothing like you have ever seen on an air cooled engine. The farther away from lawn mowers the better
, I may brass plate the valve cover. It will look sic.
harry76 said:
Here is a link of the CVT (Constant Velocity Transmission) that I have comming:
http://www.affordablegokarts.com/mm5/merchant.mvc?
Screen=PROD&Store_Code=A&Product_Code=GTC100*&Category_Code=PCJAs for Ideas to make it look old school, I'm going to paint the cylinder head high-heat black like a cast iron one. I will probably be adding the fan but it will be highly condensed and much easier to swallow. Nothing like you have ever seen on an air cooled engine. The farther away from lawn mowers the better
, I may brass plate the valve cover. It will look sic.Re: Cobrafreak's board track racer project, never ends!
You are not going to believe this people. I have been tracking my CVT via FedEx website and they said they delivered it today and it was not on my door. Lost/stolen/undelivered. I contacted FedEx and told them I don't have it and they are going to have someone call me within 48 hours. I also contacted the seller with the details. I live in a really safe very low crime area and have things delivered to me all the time for last 8 years with no problems. Very disappointed. I was hoping to bolt up the CVT and see how it fit on the engine tonight.
You are not going to believe this people. I have been tracking my CVT via FedEx website and they said they delivered it today and it was not on my door. Lost/stolen/undelivered. I contacted FedEx and told them I don't have it and they are going to have someone call me within 48 hours. I also contacted the seller with the details. I live in a really safe very low crime area and have things delivered to me all the time for last 8 years with no problems. Very disappointed. I was hoping to bolt up the CVT and see how it fit on the engine tonight.
Re: Cobrafreak's board track racer project, never ends!
Me too! I was expecting it!
Man that sucks!
Me too! I was expecting it!
Man that sucks!
Re: Cobrafreak's board track racer project, never ends!
Look at the difference between the stock cast aluminum connecting rod and the billet ARC connecting rod. I don't think this unit is going to break. Almost too beautiful to keep inside an engine. Got it at AGK.
Look at the difference between the stock cast aluminum connecting rod and the billet ARC connecting rod. I don't think this unit is going to break. Almost too beautiful to keep inside an engine. Got it at AGK.
Re: Cobrafreak's board track racer project, never ends!
Why didnt you use the stock one?
Why didnt you use the stock one?
Re: Cobrafreak's board track racer project, never ends!
The engine comes from the factory with a 3500 rpm redline and is governed for this. If you take the governor out the engine can go to 6500 rps. If you go above 3500 rpm the stock connecting rod breaks and will throw the rod through the case. So you have to put this ARC connecting rod on and it's safe. You can't see it from the above photo but the pointy thing on the fat end is the oil dipper. On the stock rod all it can do is scatter oil all over. On the new billet rod it is a scooper like a spoon and has an oil hole that leads to the main crank bearing. The crank bearings are made of hardened steel. On the stock rod it is just aluminum, which will last for a long time under 3500 rpm. You also need to put 18 lbs valve springs in it because the stock springs cant snap back in time. My transmission kicks in at 2200 rpm. if I didn't take the governor out I would only have 1300 rpm left to play with. Now I will have 4300 rpm left after taking off from a stand still.
stocksucks said:
The engine comes from the factory with a 3500 rpm redline and is governed for this. If you take the governor out the engine can go to 6500 rps. If you go above 3500 rpm the stock connecting rod breaks and will throw the rod through the case. So you have to put this ARC connecting rod on and it's safe. You can't see it from the above photo but the pointy thing on the fat end is the oil dipper. On the stock rod all it can do is scatter oil all over. On the new billet rod it is a scooper like a spoon and has an oil hole that leads to the main crank bearing. The crank bearings are made of hardened steel. On the stock rod it is just aluminum, which will last for a long time under 3500 rpm. You also need to put 18 lbs valve springs in it because the stock springs cant snap back in time. My transmission kicks in at 2200 rpm. if I didn't take the governor out I would only have 1300 rpm left to play with. Now I will have 4300 rpm left after taking off from a stand still.
