Building a Ht Motorized Bicycle or Three.

[sub66]

well i might to edit lol. what do u think t? have you seen ports at diff heights ???

ex ports yes but i think im perhaps barking up the wrong tree.
i will need to think about it more as im in the middle of cyl reed work w is different »when discusing yours. i will watch anyway as i have got this far in 8 months.

i feel uselessly unable to get help sometimes. i wish to broaden the GP MX minded thinking. its very hard sometimes without purchasing the sweet ass books available.
please pardon my candid 10 minute old ideas if it is not working.

 

[Theon]

The only two barrels I have with the same port timing came from Screaming Roo.
http://screamingroo.com/online-store/47mm-barrel/
Every other barrel came with variable port timing.
Inlet port usually the biggest difference.
Also different deck heights on different barrels, this is were the Deg wheel is good, making it easy to choose correct base gasket for Tr timing.
I may have missed your edited post.
Have the Goat set up with 44t, forget port timings, but they were conservative, Ex around 105 transfers angled and around 120.
Long fat Header, Multi stage pipe, and Hi compression, totally different to the Mongoose, which I'm leaning towards slightly lower compression to start with, as I'm worried about getting the primary comp hi enough, I feel that this is largely over looked here with the amateur builders, and I think the more revs the better the ratio needs to be. Bolting on a hi comp head will give better low down, but from what I understand to get good top end, hi comp head isn't everything.

 

[sub66]

yes to that in concrete. so whats next?? you have more surprises for us?

im sure u will get many off their seat allready t but be patient alot of folks still have rough 1hp mills

 

[sub66]

whats the roo monster mag all about.

also please consider that calculators do everthing and more than u need. crank angle... everything and more. d wheel is just a visionary tool to express the flow of air in 360 degrees. the degree of crank rotation is about leverage of rod vs burn rate. nothing else period. so how are you managing air better by measuring crank angle?
lost in numbers.....

 

[sub66]

online calculator. or math.

 

[sub66]

crank angle will be needed to input measurments specific for real time opening. thats even further down the rabbit hole im affraid. that is way beyond what your doing to manage your air.

 

[sub66]

when inputing measurements to a calculator. a degree wheel is visual to the correct input output calculations. so iinvolving a degree wheel is to express information as a percentage of stroke. lamans terms. simple breakdown of forces in a generic evvironment.

 

[Theon]

I try and avoid the math when possible, Have a good grip on math, but lazy,
Mostly working from experience and reading, Curious to have another look at Mech's maths.
But open to others advice on port size and timing also.
Tony from RSE has offered to put any of my motors on his Dyno, He say's a lot of the standard 66cc China Girl motors he's tested come to little over 1200Watts.

 

[sub66]

well the discusion helped me.....the issue i see w fox hole ports is they are to linear and broad in air supply leaving rpm to sort it out.

i do quad ports netting various hits through till redline. better lows/ more character wo rpm skyrocketing past my safe rpms.

 

[Theon]

The Goat.

Sub, you've inspired me to boost port the Goat.
I did a big week at work last week, the Boss is away this week and so I've got a bit done on my bikes.
The Goat has been stripped and painted with a can of Ford Dark Blue Engine Enamel.
The job was quick and rough, however looks much better than it was.
She's nearly all back together.
Had to do a bit of 'clearancing' hear and there to get the 203mm brakes to spin freely, and spent a while trueing up the rear sprocket, one of the things with tight clearances is it makes getting every thing spinning true more important, but also easier to 'judge'.
I've given the barrel a triple boost port which is also aimed a cooling and lubricating the wrist pin. I have a few more holes to drill in the piston to suit.
My new airfilter fits snug and should give good protection from dusty trail conditions.
And all the old 'floating' wheel bearings have been swapped for 6000's.
She's getting close.

 

[Theon]

I've had a bit of a tidy up and got a bit done so I thought I'd show off the collection again.
There's a few other projects still in the container, but I have enough her to keep me from going to work, lol.
Also pulled the leaning Tadpole out to get a little more done, very curious about the $80 CVT for her.
Have been offered a SEIG lathe for $500 that I'm seriously considering, its on the other side of the country, see what it costs to rail.
But a lathe is what I need to finish the Tadpole the way I was hoping.

 

[sub66]

thats great to hear. i wanted to give u some room to breath i had alot on my mind as i have been doing custom stuff for awhile. i will share soon i hope.

t i want a video of the stinger pipes u got dang.

good job on the filter/ good purchase. the goat frame i like cause i have a thing for square tube rear ends. and blue... man up to the front end... mighty nice. can you build rigid fork from the suspension maybe. slip on fork lmao... i guess thats alot of work including a brake.

we need decals detailing mods. gas tank w say.... 3.5cu/ reed valve/ mikuni etc etc

 

[Davezilla]

Very nice collection for sure... For that Seig lathe, $500 is a good price if everything works on it and it comes with all the extra gears for thread cutting etc. I still hadn't attempted cutting threads with mine but I got all the gears that came with it so when I got more time to play I'll try it.
That tadpole project does look interesting... what all do you need to do to get it on the road?

As for decals, I do have a vinyl plotter and can make decals out of just about any image, I use it more for cutting stencils when I do an airbrushing job than for making decals but I do make a few decals from time to time, I made some cool logos for my Buell with it and ended up selling a bunch of them in that forum when others asked where I got them from.
Here's one of the Buell logos I did...

and this is my Intruder's tank right after I clear coated it, I made all the stencils for this job with the same cutter...

I'm also going to see if it can cut the thin gasket material like .040" thick, it should be able to cut it if I can get it to stick to my backing boards... but since I need to make some gaskets for my reed valve project I'll find out soon enough.

 

[mech_engineer]

try to ad a port from crank to intake this increase time port area... for reeded engine only. remember this time area is the problem... thats why the case inducted project.

 

[Theon]

I'm thinking more holes in the piston.

 

[Theon]

May just need one more hole, 'the third eye'.
No, I just gave it three.

 

[sub66]

do u think a long baffle to keep rpm rising or what? should i get a 20 a 15 or less baffle?

 

[Theon]

too early in the morning for math here,
on one exhaust I have 3" pipe to 0 in approx. 5". That pipe was doing over 9000.
the other pipe is 3" to 0 in 4" and stops at 8500.

 

[Davezilla]

The longer the baffle cone or the more gradual the taper, the wider the powerband will be and the more rpm it can produce, but at the cost of a slightly lower peak horsepower. A more steep taper will produce stronger power at it's peak but the powerband will be narrower and the power above peak rpm will fall off sooner.

 

[Theon]

At 3" to 0 over 5", I think my baffle must be around 30 Deg total angle, and produces a peaky top end with good revs.
Lengthening this would probably be better, I havn't tried it jet in it's new longer header config.
I've given it long multiple bellies to try and give it multiple bands.