Specialized 8 Speed Rocket

View attachment 79978 specialized 8-speed rocket

 

[gary55]

No need to get nasty. Anyone with extraordinary claims should expect some scrutiny. Lets face it 73 on the flat is really really fast. So what have you done to the engine. We can see the pipe, and it looks like maybe a dio reed setup with a big assed carb. Tell us about the build.

 

[mattrgray]

Get real

was real

 

[Street Ryderz]

Ratios dont mean sh*t in my world

The ratios make fact or fiction of your claims and right now they dont add up.

 

[Street Ryderz]

Because you got no experience

If I have no experience after 40 years and the last 10 plus working on these with well over 100 builds what would you consider experience?Your own statments are what make you look like your full of s**t.If your pipe falls off at 9,500 rpm and the rpm with your ratio requires 10,300 to hit 73 mph how is that possible then you say you went 83 down hill witch is 11,700 rpm a full 2000 plus over your peak off the pipe that doesn't happen!then you said you dont go over 10,000 rpm LOL so whats up with that?

 

[6blueoval9]

Hell yeah...love these type threads.

 

[gary55]

wha,,,,wha,,,,Whaaaaat. Were gettin turkey the night before.

 

[Mrmotion]

If I have no experience after 40 years and the last 10 plus working on these with well over 100 builds what would you consider experience?Your own statments are what make you look like your full of sh*t.If your pipe falls off at 9,500 rpm and the rpm with your ratio requires 10,300 to hit 73 mph how is that possible then you say you went 83 down hill witch is 11,700 rpm a full 2000 plus over your peak off the pipe that doesn't happen!then you said you dont go over 10,000 rpm LOL so whats up with that?

it's called beating your engine, the motor will free rev to 12000 , if I did that every time I wrote it it wouldn't last 6 months , gravity and wind play a big role , and your actual speed . I don't claim to be doing 73 miles an hour with a the head wind , if you know where I'm coming from . I've got a Long Hill with a decent slope . have you had any experience with Motocross and dirt bike engines , I was racing mini cycle Motocross when I was 9 years old , I started modifying my 77 RM80 when I was 12 years old , port and polishing on the cylinder expansion chamber's and carburetor jetting ,

 

[Street Ryderz]

it's called beating your engine, the motor will free rev to 12000 , if I did that every time I wrote it it wouldn't last 6 months , gravity and wind play a big role , and your actual speed . I don't claim to be doing 73 miles an hour with a the head wind , if you know where I'm coming from . I've got a Long Hill with a decent slope . have you had any experience with Motocross and dirt bike engines , I was racing mini cycle Motocross when I was 9 years old , I started modifying my 77 RM80 when I was 12 years old , port and polishing on the cylinder expansion chamber's and carburetor jetting ,

LOL simular experiences I built from rolling chassis and two boxes of parts containing the engine and trans for a kv 75 in 1975 at the age of 9 with no help just nay sayers yet I still rode that bike for a year and then it was stolen from my school.I had mean time aquired more and raced 80cc mx and 125cc after two years I started riding on the street and of course wanted to get on the road courses and did!I have always liked the small displacement 2t engine so simple yet so percise.These china girls have plenty of room to improve performance no question as I too have hit 70 at 12,000 with a completly redone engine and a two stage pipe but that set up doesn't last is hard on everything and just cost me too much to keep up with.The engines I currently run only turn between 9,000-10,000 rpm max with a very numericaly low ratio for these engines at 9.7 :1 on the street and 11.2 at the track, My pipe falls off at 9,000 and at those speeds with that much load from gearing and drag even though the engine maintains the rpm at that point thats it if load is decreased on a hill the engine doesn't spinn up more since the pipes return wave is now not timmed properly the a/f mix is not sufficaint to support making more rpm.If the hill is steep enough to actualy over rev the engine with the a/f mix now lean detonation ocures and makes short your journey LOL as my son found out this past summer.So beat on your engines all you want and have fun doing so!What I'm saying is that I know at 60 going down a hill if I lift the bike decelerates just from the drag alone,Then your ratio requires higher rpm than your pipe makes so still doesn't make sence,So tell us more about the engine build what your port map look like,what port volumes,timmings and or durations are you using,how did you over come the crank issues,the clutch also has to be done when making real hp and torque what did you do to address that?

 

[Mrmotion]

LOL simular experiences I built from rolling chassis and two boxes of parts containing the engine and trans for a kv 75 in 1975 at the age of 9 with no help just nay sayers yet I still rode that bike for a year and then it was stolen from my school.I had mean time aquired more and raced 80cc mx and 125cc after two years I started riding on the street and of course wanted to get on the road courses and did!I have always liked the small displacement 2t engine so simple yet so percise.These china girls have plenty of room to improve performance no question as I too have hit 70 at 12,000 with a completly redone engine and a two stage pipe but that set up doesn't last is hard on everything and just cost me too much to keep up with.The engines I currently run only turn between 9,000-10,000 rpm max with a very numericaly low ratio for these engines at 9.7 :1 on the street and 11.2 at the track, My pipe falls off at 9,000 and at those speeds with that much load from gearing and drag even though the engine maintains the rpm at that point thats it if load is decreased on a hill the engine doesn't spinn up more since the pipes return wave is now not timmed properly the a/f mix is not sufficaint to support making more rpm.If the hill is steep enough to actualy over rev the engine with the a/f mix now lean detonation ocures and makes short your journey LOL as my son found out this past summer.So beat on your engines all you want and have fun doing so!What I'm saying is that I know at 60 going down a hill if I lift the bike decelerates just from the drag alone,Then your ratio requires higher rpm than your pipe makes so still doesn't make sence,So tell us more about the engine build what your port map look like,what port volumes,timmings and or durations are you using,how did you over come the crank issues,the clutch also has to be done when making real hp and torque what did you do to address that?

It's funny you mention that clutch issue , I did some radical cylinder work on this engine, I removed the cylinder wall from the transfer Port area , made a very big third transfer port the exhaust Port timing isn't that radical at all , I'm guessing around 165 ? didn't measure anything just took out a big old air powered die grinder and some carbides and went to town all by eye and experience and it works finally I found the right combination , it felt like I doubled torque and horsepower and that's when I started melting clutches , dropped and broke a fin on this cylinder and didn't really care how it was going to perform , I put in a used piston with a big window cut in it , and whatever the port timing is I will clone it as soon as the motor starts to rattle , hopefully not explode . I can get back to you with some port timing numbers but so far I've got 6 months on this engine and it is got some serious nut I'm sure it's days are limited but I don't feel like going another engine just yet not around the holidays plus camera Rhode Island we're getting high temperatures of 45 degrees BURR !, I did some speed runs while it was fresh, now I just enjoy the torque wheelies in first second and third gears , cruise at 45 to 50 all day but she drinks a lot of fuel at that speed , I'm not trying to get another speeding ticket !!! , my first and hopefully last speeding ticket was 10 over 55 in a 45, the cop fortunately did not know the law of motorized bikes that are not supposed to exceed 20 miles per hour but he did write me a $95 ticket. I thought they was going to impound the bike ,I've got $350 into the wheels and tires alone , I run a Kenda high pressure tire @ 125psi when I was making the speed runs , I now run the recommended 100 PSI with teny mags hope rotors and hydraulic brakes , I added it all up at around $900 that includes the fox terralogic front fork , the frame I picked out of my friends scrap pile chromoly specialized Hardrock from 92 .the complete bike weighs in around 40 lb I weigh around 180 lbs. I was expecting this motor to grenade a long time ago , but if it's not broke then I don't want to fix it just yet I've ported cylinders in the past with up to 192 exhaust duration that had very short power bands and not much torque , they would love to rev but wrist pin and piston ring flutter was an issue and ring lands were getting hammered was running into detonation issues and piston overheating . as far as the clutch goes I was melting clutches with the red high temp pads , switched to some Zeda pads that helped ,when I build the Clone to this engine I will be installing a spring stronger than the factory maybe a car valve spring ?. The clutch slipping actually keeps the engine on the power curve longer but in higher gears sometimes won't totally locked up . I intend to machine some semi-metallic sintered pads from Automotive brake pad material ,I would like to try the sintered pads on this motor before she lets go that way I don't need to split the cases to install the heavier spring ,these things take a lot of time I don't have to tell you that , my friend likes to bust my balls and say it's a 10 to 1 scale model work on it for 10 hours write it for 1 hour and blow it up , and I'll admit I was doing that for a while till I figured out the combo , you got to run a shift kit I'll never go back to a single speed .I've bent a few axles by popping the clutch and riding wheelies , but that's when I beat on it . I've been running the JL engine with the big crankshaft main bearings zl con rod with full complement needle bearings (no) (cage)Integral ignition ,

 

[gary55]

It's funny you mention that clutch issue , I did some radical cylinder work on this engine, I removed the cylinder wall from the transfer Port area , made a very big third transfer port the exhaust Port timing isn't that radical at all , I'm guessing around 165 ? didn't measure anything just took out a big old air powered die grinder and some carbides and went to town all by eye and experience and it works finally I found the right combination , it felt like I doubled torque and horsepower and that's when I started melting clutches , dropped and broke a fin on this cylinder and didn't really care how it was going to perform , I put in a used piston with a big window cut in it , and whatever the port timing is I will clone it as soon as the motor starts to rattle , hopefully not explode . I can get back to you with some port timing numbers but so far I've got 6 months on this engine and it is got some serious nut I'm sure it's days are limited but I don't feel like going another engine just yet not around the holidays plus camera Rhode Island we're getting high temperatures of 45 degrees BURR !, I did some speed runs while it was fresh, now I just enjoy the torque wheelies in first second and third gears , cruise at 45 to 50 all day but she drinks a lot of fuel at that speed , I'm not trying to get another speeding ticket !!! , my first and hopefully last speeding ticket was 10 over 55 in a 45, the cop fortunately did not know the law of motorized bikes that are not supposed to exceed 20 miles per hour but he did write me a $95 ticket. I thought they was going to impound the bike ,I've got $350 into the wheels and tires alone , I run a Kenda high pressure tire @ 125psi when I was making the speed runs , I now run the recommended 100 PSI with teny mags hope rotors and hydraulic brakes , I added it all up at around $900 that includes the fox terralogic front fork , the frame I picked out of my friends scrap pile chromoly specialized Hardrock from 92 .the complete bike weighs in around 40 lb I weigh around 180 lbs. I was expecting this motor to grenade a long time ago , but if it's not broke then I don't want to fix it just yet I've ported cylinders in the past with up to 192 exhaust duration that had very short power bands and not much torque , they would love to rev but wrist pin and piston ring flutter was an issue and ring lands were getting hammered was running into detonation issues and piston overheating . as far as the clutch goes I was melting clutches with the red high temp pads , switched to some Zeda pads that helped ,when I build the Clone to this engine I will be installing a spring stronger than the factory maybe a car valve spring ?. The clutch slipping actually keeps the engine on the power curve longer but in higher gears sometimes won't totally locked up . I intend to machine some semi-metallic sintered pads from Automotive brake pad material ,I would like to try the sintered pads on this motor before she lets go that way I don't need to split the cases to install the heavier spring ,these things take a lot of time I don't have to tell you that , my friend likes to bust my balls and say it's a 10 to 1 scale model work on it for 10 hours write it for 1 hour and blow it up , and I'll admit I was doing that for a while till I figured out the combo , you got to run a shift kit I'll never go back to a single speed .I've bent a few axles by popping the clutch and riding wheelies , but that's when I beat on it . I've been running the JL engine with the big crankshaft main bearings zl con rod with full complement needle bearings (no) (cage)Integral ignition ,

Don't know if this will interest you, but it might fit your needs for clutch improvements.https://www.mcmaster.com/#clutch-lining/=17j2m58