Unsaid info about high compression heads

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Bufu, the fact that you are doing something is not a good argument for doing it.
The scientific community can tell runners that its hard on their joints and that when they are old they will regret it. But the runners often continue with the idea that it cant be that bad because they dont feel its negative effects now.
High compression:
1) shortens the life of bearings
2) shortens the life of your cylinder plating
3) causes excessive engine heat
4) will cause detonation if the mixture isnt rich and the octane isnt high enough
5) increases engine vibration
 
Thats why you rebuild yers every 5 months Britt.
86010



Nope! No rebuilt here, 4 years! no rebuilt same piston same rings same everything!

When you know what your doing it's easy. My suggestion is to stop reading all the bogus information your see on forums and get a libery carb.
 
Just out of curiosity how much time and money do you have into that 4 year engine that runs 270 psi? At the vary least It's got some real good bearings, probably a bushing and a wrist pin that is not from any china girl. With that 6cc head the squish has to be nearly non existent. Must be sleeved or nikasiled.
Whatever fuel, parts, and mods made to maintain usable tolerances for 4 years with that comp. is probably not accessible with a library card, let alone a libery carb. Sorry couldn't resist. We know you build some bad assed engines. If it's been on that frame for 4 years that's gota be close to a record without that mount breaking.
Anyways, fan of your work. That's a crazy fast bike. This is the most comp.I have done on one. Belongs to a friend of mine who don't care about getting a new engine yearly. He just want's it to run strong and rides it balls out every where he goes till it eats s**t.
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Bufu, the fact that you are doing something is not a good argument for doing it.
The scientific community can tell runners that its hard on their joints and that when they are old they will regret it. But the runners often continue with the idea that it cant be that bad because they dont feel its negative effects now.
High compression:
  1. shortens the life of bearings
  2. shortens the life of your cylinder plating
  3. causes excessive engine heat
  4. will cause detonation if the mixture isnt rich and the octane isnt high enough
  5. increases engine vibration

The fact that I'm doing something that works! is a very good argument for doing it.

Those are simple tasks to adress. For 1 the 6202 bearing is used on alout of different modified chain saws /scooters/ dirtbikes pushing well over 25+ hp at over 15k rpm daily for years! These 6202 Chinese! Bearing properly installed will laugh at any kind of power level you can make with These motors. Forget that your using high compression but know that your no were even near 25hp!!
 
Just out of curiosity how much time and money do you have into that 4 year engine that runs 270 psi? At the vary least It's got some real good bearings, probably a bushing and a wrist pin that is not from any china girl. With that 6cc head the squish has to be nearly non existent. Must be sleeved or nikasiled.
Whatever fuel, parts, and mods made to maintain usable tolerances for 4 years with that comp. is probably not accessible with a library card, let alone a libery carb. Sorry couldn't resist. We know you build some bad assed engines. If it's been on that frame for 4 years that's gota be close to a record without that mount breaking.
Anyways, fan of your work. That's a crazy fast bike. This is the most comp.I have done on one. Belongs to a friend of mine who don't care about getting a new engine yearly. He just want's it to run strong and rides it balls out every where he goes till it eats sh*t.
View media item 61471
View media item 61472


More time then money. In fact
Just out of curiosity how much time and money do you have into that 4 year engine that runs 270 psi? At the vary least It's got some real good bearings, probably a bushing and a wrist pin that is not from any china girl. With that 6cc head the squish has to be nearly non existent. Must be sleeved or nikasiled.
Whatever fuel, parts, and mods made to maintain usable tolerances for 4 years with that comp. is probably not accessible with a library card, let alone a libery carb. Sorry couldn't resist. We know you build some bad assed engines. If it's been on that frame for 4 years that's gota be close to a record without that mount breaking.
Anyways, fan of your work. That's a crazy fast bike. This is the most comp.I have done on one. Belongs to a friend of mine who don't care about getting a new engine yearly. He just want's it to run strong and rides it balls out every where he goes till it eats sh*t.
View media item 61471
View media item 61472


The frame was reinforced and the engine is mounted using shims. The crank shaft is a $25 mz zl crank that I reworked and Was put together in 2015 using shims and dial indicators. It's all in the install.

The most powerful tool you allready have . But one can get misguided from alout of the false information they get from the internet.

Witch is why I say to get a libery card..lol

To think that a Nasa engineer set off to make a 50cc streamliner that was over 600+ pounds to go over 150mph. I'm sure he didnt get his info from dragon fly 75 lol
 
More time then money. In fact



The frame was reinforced and the engine is mounted using shims. The crank shaft is a $25 mz zl crank that I reworked and Was put together in 2015 using shims and dial indicators. It's all in the install.

The most powerful tool you allready have . But one can get misguided from alout of the false information they get from the internet.

Witch is why I say to get a libery card..lol

To think that a Nasa engineer set off to make a 50cc streamliner that was over 600+ pounds to go over 150mph. I'm sure he didnt get his info from dragon fly 75 lol
2 years ago your specs were completly different,being Zae50 47mm jog piston custom sleeved cylinder (gasoline) mikuni vm 18mm, stuffed crank.. BUFU Racing #1 ,Now it's a zl crank and sleeved,and weren't you just using a big dio not long ago? keep it real brother,you've earned the respect don't f*** it up!
 
It is not impossible to change squish area while keeping CR the same.
Far from it. Just make the chamber deeper.
How many people do you know doing serious investigation into squish?
It's been one of my 2 stroke and 4 stroke power secrets since reading Jennings book in the 70s.

Comparisons. Change one thing while keeping others constant to see the effect.
This is how we learn. I'm no scientist, but I do get paid to do this sort of stuff in industry.
Results. Find what works and go with it. Chase the real results that you find and demonstrate.
Listen and read the other's work but question it. Test it. Peer review.

Note the 3 KTM heads below, all are the same cc displacement but slightly different chambers to test effect.
full

These two heads are the same cc displacement, just looking at chamber shape:
full


These below are both the same displacement (within 0.5cc), although smaller displacement than the ones above to investigate the effect of increased compression ratio.
full

I did earlier experiments with squish area that push me to 50% area being an important dimension.
Compression the same, more squish has a huge effect on power, not always good, but a huge effect.
It also affects timing.

Hey Jaguar, conflicting ideas and theories are a very good thing. They push the envelope of learning.
Just don't shake a 44 year old graph at me and wish me to accept it as holy gospel. Test it yourself.
These engines are so easy to work on, they are the perfect experiment media for these ideas.
That is what I am doing here, and I enjoy reading your work, your sources and your ideas.
If I disagree, I'll tell you why, where it comes from.

And best of all, we can test these things on these engines quickly and cheaply.

Steve
I'm thinking we might want to listen to this guy 😉 he might know a little more than the know all's on here love the attitude and offer of advice.

brapp
 
I'm thinking we might want to listen to this guy 😉 he might know a little more than the know all's on here love the attitude and offer of advice.

brapp
Yeah old thread and Steve knows his stuff. Good read. I have seen that streamliner and met the builder.
 
Yeah old thread and Steve knows his stuff. Good read. I have seen that streamliner and met the builder.
I'm thinking he might know a friend or two of mine that messed with my bikes as a kid no diss but real 2strokes my gasket kit cost more than hole motor kit of these toys and real 2stroke legends you see on TV still taking all comers, if you watch Moto. just the swag he puts out. like it. Brappppppp
 
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