Planet Minis

50rider340

post some pics of the head work???

schofell84

and thennnnn ?

Motarded

No and then!

twosmoke30

an dennn lol

schofell84

is this going to use the stock head and large valves? if so, do you plan on raising the port floor? i've always wondered how they do it.

NO AND DEN

cyclerider57

I have a stock head I'm doing on a 50cc build with 23/19 valves but this will be a superhead. I'll have to give updates at another time. I've been all over the country again lately. I just got back from the US Open in Vegas and I leave tonight for Hawaii.

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The wise understand by themselves; fools follow the reports of others. Goodness speaks in a whisper, evil shouts. -Tibetan Proverb

twosmoke30

An dennn!!!!

50-50

Mmm billet aluminum!

z50 chopper

See if you can rent or borrow a street legal mini and go for a short cruise and take some pics or video of the cruise, in hawaii ofcourse

cyclerider57

This weekend I plan to test the rev limiter setup that will end up on this build.

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The wise understand by themselves; fools follow the reports of others. Goodness speaks in a whisper, evil shouts. -Tibetan Proverb

cyclerider57

Very old picture of the head work in progress. As you can tell it was blown up when I got it. Had to weld up a few spots before installing the new seats for the rather large valves. Finished, the combustion chamber doesn't have any of the boogers on it which are shown in the picture. It had to be reshaped anyway for this setup. 32/26 titanium valves. Ampco45 seats.

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The wise understand by themselves; fools follow the reports of others. Goodness speaks in a whisper, evil shouts. -Tibetan Proverb

LongMooie

huge valves!!!
is there an optimum valve size that relates to the cc?
what would be optimum for 50cc?

50rider340

Where would you suggest to get valves for a takegawa super head? The valves that they come with just dont last. I have a old honda style head the ones with the 25mm intake and 22mm exhaust and it has over 12,000 scoot miles on it. There is still barely any wear on the valves. One season on a takegawa head the intake vavle gest thinner and thinner.
If my memory serves me correct they are 5mm stems old style F5 head with a 27.5mm intake vavle.

BTW that is awesome squishing a 32mm intake valve in there great work.

Kurlon

Looks like you might need to shim the plug to keep the valves from fouling on it?

RobbMeex

I read all of this, but now I need MORE TECH! I like the look of the minis, but I want ridiculous tech, and this seems to be it. Awesome stuff.

50rider340

any news on this?

cyclerider57

Optimum is a relative word. There are a lot of things that come into effect when choosing the major areas of an engine. You have to start with what you want it to do performance wise and the major characteristics you are looking for from it. Everything from that point is about making a happy engine. You can have huge valves, a really aggressive cam, huge carburetor, etc but it could easily run like crap. You have to match all the components of an engine build. Within valve size alone, there are many design theories. For example, a lot of formula one engines minimize exhaust valve size in order to increase intake valve size and breathing ability. This requires a cam/ exhaust system that is designed very well to insure exhaust gases are fully expelled so it doesn't replace incoming charge. Moto GP engines on the other hand, tend to have a little larger exhaust valves in comparison. This doesn't mean the ports are big though... the exhaust ports have quite a bit of funnel to them so even though the exhaust valves are larger in comparison the port size doesn't reflect it. Even within Moto GP there are many different design theories to what breathing capability you need and how to get there. I wouldn't be surprised if they are now favoring a little larger intakes with all the electronic control improvements in the last two years.

As for 50cc, I have a stock crf head that I converted to 23/19 valves but for most other applications I would stick with sizes more closely related to stock.

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The wise understand by themselves; fools follow the reports of others. Goodness speaks in a whisper, evil shouts. -Tibetan Proverb

cyclerider57

I use kibblewhite for a lot of my valve needs but they aren't cheap if you have them make valves. I just purchase valve blanks and make my own but they do make them as needed. Ferrea will make them for you as well. No matter what route you go, they will be custom valves made to order in either ti or st.

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The wise understand by themselves; fools follow the reports of others. Goodness speaks in a whisper, evil shouts. -Tibetan Proverb

cyclerider57

I shouldn't have issues once I index the plug where I want it. Keep in mind those valves aren't set in that picture. They sit a little lower in the head and with the rough combustion chamber in that picture, it makes things hard to compare.

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The wise understand by themselves; fools follow the reports of others. Goodness speaks in a whisper, evil shouts. -Tibetan Proverb

cyclerider57

I've been doing a lot of ecu and clutch "thought and design" stuff lately rather than cutting and grinding so there isn't much "show" stuff. I am considering machining a "simple" ramp slipper clutch to match the high rpm pavement style of the engine.

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The wise understand by themselves; fools follow the reports of others. Goodness speaks in a whisper, evil shouts. -Tibetan Proverb