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I love the fact that you're DOING this....I love the weirdness of a reversed engine for nothing more than the WTF factor. I do hope you get it running man, if for no reason more than glorious bench garnish!
Why not reverse the head and slot in some kind of gear based rotation reverse for the cam drive?
Thank you Brother Swagger! It makes me happy to hear that you love I am doing this!
To be totally honest I could never thank you all enough for watching and commenting on this project. You all inspire me each day and whether it be inspiration from compliments on my work which always makes me feel good, or from those that think it may not work which drives me to work that much harder, I am proud to be a member here and thank you all for your Brotherhood!
As for reversing the head it probably would have been easier but I have never seen a true reverse port motorcycle engine and I have always wanted to build one!
I know that back in the day a lot of guys used to drill a hole straight through the header pipe and drop a nail through it and weld it in place, I am not sure what that does but it must offer some advantage as it is still illegal to do in our round track racing rule book.
Joey, I think you could get much closer to equal length if you cross the two inner pipes of the header too, and it will give you a cool tWisted (hehe) look!
Cylinders #1 and #4 should have come into the collector at 3 and 9 o'clock for a shorter distance and cylinders 2 and 3 should come into the collector at 6 and 12 o'clock for a slightly longer run to equalize the lengths. Very cool project.
Cheers, 50gary
Unequal headers have been tried as a technique for stretching the power band. One pair resonates at one speed and the other pair resonate higher up the rev band. There are theories on exhaust length and diameter and on collector angles and tail pipe dimensions, but seriously, it doesn't matter.
I'd leave it just like it is. I like that twisted look. I'd be surprised if making the headers all the theoretically perfect dimensions would make much difference in the real world.
I think the exhaust will be fine and it fulfills the design brief - must look cool and different. A bigger issue potentially is the intake system and the small intake (originally exhaust) valves.
Unequal headers have been tried as a technique for stretching the power band. One pair resonates at one speed and the other pair resonate higher up the rev band. There are theories on exhaust length and diameter and on collector angles and tail pipe dimensions, but seriously, it doesn't matter.
I'd leave it just like it is. I like that twisted look. I'd be surprised if making the headers all the theoretically perfect dimensions would make much difference in the real world.
I think the exhaust will be fine and it fulfills the design brief - must look cool and different. A bigger issue potentially is the intake system and the small intake (originally exhaust) valves.
Teazer, you seem to be stuck on this valve port size part. So I am just assuming you missed where Brother Joey said he would be welding up the original intake ports and machining them back to exhaust port size, then machining the original exaust ports to be intake ports. Just wanted you to know he had said that at some point.
Brothers I am going to pull the head in another week or so as soon as I finish getting all of my measurements for the frame.
I know most engines use different valves and guides heat treated wise fot the exhaust side. Does anyone know if the 550 engine does or are the valves of the same make up just different sizes?
The reason I ask is if they are the same I could leave the original intake valves, seats, and guides as the exhaust side and go to larger valves for the new intake side which would give me larger valves over stock for both the intake and exhaust. I will be able to see them once I pull the head I am just curious if anyone knows whether the valves are different (heat treated wise, I know they are different sizes). As most engines valves are different for heat I would think the 550 would be as well.
I think you'll run into a lack of usable landscape in the combustion chamber before you can get a valve larger than the intake into the exhaust location, though it's a decent idea. I also think you'll likely run out of portable aluminium to make ports big enough. If you do work those bits out you still have to come up with a reverse ground cam.....and that's going to be an expensive proposition. It's different than a regrind...
I'm really interested in how you overcome these hurdles..
Also, as much as it pains me....I have to disagree with Teazer regarding headers and the effectiveness of one design over another. I don't believe a "perfect" static header exists eg: a tube header without mechanical devices akin to an EXUP. I do think that there is solid evidence to prove that things like proper runner length with as little variation as possible, the cleanest merge possible, proper tube order for scavenging at the desired rpm bandwidth etc. are very important and should be taken into consideration when building.
For example, my autocross car: a mid 90's dodge neon with a fairly over built engine. I was making something in the neighborhood of 195-200hp depending on ambient temp, fuel used and the brand of dyno. My header had a weld blob merge, though it had very nicely designed and layed out primaries and a nearly optimal 2.25" collector feeding a bullet cat, 2.5" pipe and a very large flowmaster.
I talked one of the engineers at Flowmaster of out on of their add-on merged collectors and gained an average of 8 hp/11ft-lb with peaks closer to 10 and 15.
I'm a firm believer in a well tuned exhaust.....with heat wrap....because I'm a nogoodnik....
All that being said I also understand that Joey's build is an exercise in "just 'cuz I can" and not sheer power building.
Swagger, I hate to disappoint you but we agree violently on the subject of exhausts.
A well set up motor will respond to a well designed exhaust and changing the exhaust can change power output and shape of the power curve etc. We agree on that.
HAHAHAH! for some reason I was under the impression you had dodgy opinions regarding headers. I think it was these two comments that got me:
There are theories on exhaust length and diameter and on collector angles and tail pipe dimensions, but seriously, it doesn't matter.
I'd be surprised if making the headers all the theoretically perfect dimensions would make much difference in the real world.
Consider me happy to be corrected.
Violently happy......heh
I am not trying to speak for Brother Teazer but I really think he was commenting in regards to this particular project and its use on the street and that for what the bike will be used for it will work well enough, that is how I understood it anyway. I am sure that most all of us here understand and agree with you both on the importance of a well tuned exhaust system especially for use on a race engine and I do not think anyone would deny that a well tuned and matched exhaust, or any other well tuned or matched part for that matter, would provide additional well balanced power.
Brother Swagger there are many different things that can be done as far as the valvetrain goes but I will not know exactly what I want to do until I pull the head this week and see what exactly I have to work with. I have the equipment here to cut the valve seats and do the guides so it should not really be a problem at all mostly just a lot of time and as soon as I start doing the valve work I will post the photos.
I have the cam sitting here in the chair with me and have worked out what I will be doing with it. Before I start reworking the cam I want to put it back in the head and set up the degree wheel and gauges so that I can get the factory lift and duration readings off of it.
I could have phrased that a little better I guess. Joey got it that the comments relate to THIS project and were not intended as an overall comment about exhaust design.
I spend way too much time working out exhaust sizes etc, especially on two strokes where the difference can be amazing by getting it right.
Whether this is to work as anticipated or not. This thread in on itself is a great piece of education. Love the talk and all of the info that you wouldn't get in a classroom because there would be that teacher not willing to entertain the idea of a reverse port engine.
Keep it coming Joey, cool images and our free education. much appreciated
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