New Slant Heads for 80cc's: Compression Boost!?

I'm back with good news and more good news. The starting problem turned out to be a faulty magneto. It started right up and after some initial tweaking, it runs great, I'm happy say. I then installed my slant head. It gave it significant power. I did have a slight problem with piston slap, that I solved with a combo of using gasket material from the auto parts store sandwiched in between aluminium roofing flashing. I may have used to much gasket material, reducing my compression more than I should have. I may reduce the thickness at a later date, however, over all, it still has more power. Check out the pix. I have an exhaust system I will install when I have a larger block of time, but tonight, good news, bad news, I need to fix a flat on the rear tire, and I will take this time to install the 36 tooth sproket seen in the pic. A report will follow. dance1.fly
 

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Glad things are going well for you. Keep us posted but......would you mind changing the font/color of your text.

Perhaps its just me but the Huge Red Letters are tough on the eyes.
 
What's that all about? We're here to share info not personal attacks or to get side tracked with irrelevant mud slinging. All I was suggesting is that 1) I personally found it difficult to read your text and if I wasn't alone 2) you might get more responses if your posts were in more of a "standard" text.
 
Can't we all just get along and get back on task? I am doing a systematic approach on testing bolt-on conponents and other techniques such as porting and head gasket thickness. I would hope there are those interested in such matters and have the presence of mind to look past the color of fonts!!

.fly The world is more than one shade of grey, It happens to be full of color
 
jflyer said:
Can't we all just get along and get back on task? I am doing a systematic approach on testing bolt-on conponents and other techniques such as porting and head gasket thickness. I would hope there are those interested in such matters and have the presence of mind to look past the color of fonts!!

.fly The world is more than one shade of grey, It happens to be full of color
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Life's not easy (to read) when you're green. :)

Dramamine anybody?

PS I always wonder what's going on in these guys head. The Ones That Capitalize Every Word Too.
 
I was going to go with a slant head for my 66cc but instead went with one of the rocksolid billet heads. Very happy with it so far but I would be very interested in trying a slant head as well just to see if the extra cost of the billet item was worth it
 
EnFlaMEd said:
I was going to go with a slant head for my 66cc but instead went with one of the rocksolid billet heads. Very happy with it so far but I would be very interested in trying a slant head as well just to see if the extra cost of the billet item was worth it
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i see what you meen
 
EnFlaMEd said:
I was going to go with a slant head for my 66cc but instead went with one of the rocksolid billet heads. Very happy with it so far but I would be very interested in trying a slant head as well just to see if the extra cost of the billet item was worth it
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LOL!!!!!!!!
 
Look, if it makes everybody feel better to have a sterile look on the thread, I'm all for it. Now, is everybody happy?
 
Getting back to the topic at hand, can anyone post a pic of one of those billet heads? I might be interested in trying one of those as well. Does it boost compression much, and did you have any piston slap issues?
.fly
 
Ill cut and paste what I put up on the other forum

Well, using the supplied gasket and nuts I fitted the new head in about 5 minutes. I turned the engine over a few times and then pulled the plug to check for fouling. Unfortunately the plug tang had made slight contact with the piston and had bent toward the electrode leaving a miniscule gap but not enough to be safe or provide spark. On Tony from rocksolids advice I shaved the electrode, sidecut the tang and re gapped. I re checked for fouling and no problems.

The first thing I noticed on starting the engine was that it was much harder to pedal start due to the increased compression but when she fired up I nearly popped a mono. The engine sounds much smoother and runs nicer. Its almost like these engines where designed to run at a higher compression. I havent had a chance to take the bike for a decent ride due to the weather but a quick run up the road and back and I have noticed a definate gain in performance. The engine is significantly stronger and I am now able to climb hills in higher gear. The bike accelarates quicker, pulls easier from everywhere in the rpm range and holds higher speeds easier. I can pretty much make it the entire way up my driveway now without pedalling. My driveway is very steep and some cars stuggle to make it up. I'll get some more footage when the weather permits but for now you can compare the engine note with how it used to be and how it is now. So far I am impressed.

Before: YouTube - Motorized bike with SBP shift kit.

After: YouTube - Motorized Bike walk around
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I'll have to do another vid soon as I have done a few more mods since then ie. the new air filter and drilling out the jet.

 
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Please please please, for the sake of mercy... stop installing these slant heads backwards. Just cause the factory does it, doesnt mean you should too.
 
The idea of a slant head is overall negative if its just a slant dome combustion chamber. Nothing really runs good about them. They basically create sonic waves that crash into each other.

However a slant head with a squish band, not only makes great power (though a center fire squish band head will always make more power) it also runs much cooler, allowing you run higher compression, smaller combustion chamber, and tighter squish clearance. But ONLY if the slant is over the intake, not the exhaust. If the slant is over the exhaust it does the opposite. It creates further resonant crashing, and increases the overall engine temperatures.
 
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