Project X

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madforitkev
Posts: 292
Joined: Tue Dec 13, 2016 7:21 pm
Location: Poole

Re: Project X

Post by madforitkev »

Guys

You are right. Not a great camera angle.

Important thing is wheel centre is on frame centre and engine head fits between frame although it is a bit offset to left and my drive is only out 5mm.

I started looking at the steering head today to get the forks in and work out any exhaust clashes.

The VRF yokes and GSXR yokes are similar but the GSX uses a larger top bearing (bottom ones are the same.

VFR yokes are pretty crappy so i will re-machine the GSXR stem to take the smaller VFR top bearing. Looks easy enough :D
IMG_1314.JPG
Then the chassis is 'a rollin' and I can get back porting and exhausts......(just gotta explain to the wife where the shiny new wheels and forks appeared from). :?
Honest baby....this is probably the cheapest bike I have ever bought!!
madforitkev
Posts: 292
Joined: Tue Dec 13, 2016 7:21 pm
Location: Poole

Re: Project X

Post by madforitkev »

Yoke stem cloned to look like a VFR one.

GSXR forks fitted (couldn't hide them any longer!)
IMG_1318.JPG
Streering stops are a tad out but i can fettle that later....
IMG_1319.JPG
Now I just have to make the CBR axle work with the GSXR front wheel!
IMG_1320.JPG
Honest baby....this is probably the cheapest bike I have ever bought!!
madforitkev
Posts: 292
Joined: Tue Dec 13, 2016 7:21 pm
Location: Poole

Re: Project X

Post by madforitkev »

GSXR front end with CBR1000R wheels all grafted in. Had to machine out the bearing seats to take larger bearings to take the GSXR axle but it all lines up nicely.
IMG_1362.JPG
Looks pretty sexy so far!

Just sorted the expansion chamber design, so its fun with Origami next.

I want all three pipes to end up under the seat subframe but we will have to see how that goes. Might have to compromise a bit but at the moment it looks dooable.

I've pretty much got the porting and pipe design sorted so will start with a cardboard model and see how it goes.

All good fun.
Honest baby....this is probably the cheapest bike I have ever bought!!
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yeadon_m
Posts: 7401
Joined: Sat Jan 02, 2010 7:10 am
Location: Canterbury Kent

Re: Project X

Post by yeadon_m »

Kev,
Looks terrific. Where do you expect / hope the power to weight ratio will come out, as compared with the heavy lump original (which isn't too slow anyway, IMO)?
Good luck with folding!
Mike
teazer
Posts: 1035
Joined: Mon Mar 07, 2011 8:10 pm
Location: Chicago

Re: Project X

Post by teazer »

Hope your welding is better than mine. I recently fabricated an RD350 set of chambers from a set of rolled cones and I was going well until I had to "bend" the cones. Cutting them into slices left some ragged edges. The key to welding is to get the individual slices right without gaps and that sounds like the way you are approaching it.

BTW, I stripped my motor to see why there's so much bass boat sized metal flake in the oil and it turns out to be the large dogs on 3rd gear driven. Early (SOHC/8v) GS750 trans has the same design on that pair of gears but later GSX (DOHC/16v) has a much better six round dog design. The shafts are long and require machining, but that's the way to go. GSX 750 trans is like an 1100 trans and they are close to bulletproof.
madforitkev
Posts: 292
Joined: Tue Dec 13, 2016 7:21 pm
Location: Poole

Re: Project X

Post by madforitkev »

Mike

Kettle weight/power is about 230kg/70bhp.
Just working on the major components for now (and ignoring engine weight savings which should be good as well), I am hoping for about 190kg/100bhp.
So far i've also taken 100mm off the wheel base which should be fun!

Kev
Honest baby....this is probably the cheapest bike I have ever bought!!
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yeadon_m
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Joined: Sat Jan 02, 2010 7:10 am
Location: Canterbury Kent

Re: Project X

Post by yeadon_m »

Kev,
That sounds like fun, but not nuts. Good targets.
Cheers,
Mike
teazer
Posts: 1035
Joined: Mon Mar 07, 2011 8:10 pm
Location: Chicago

Re: Project X

Post by teazer »

Kev, stock kettles seem to make around 50hp at the rear wheel. Mine was ported with stock OEM clean exhausts made around 56 or so. It's not really kosher to compare one dyno with another but all the dyno runs I have seen for more or less stock bikes are in the 47 to 52 ish range. Your planned HP improvement should be achievable.
madforitkev
Posts: 292
Joined: Tue Dec 13, 2016 7:21 pm
Location: Poole

Re: Project X

Post by madforitkev »

Barrels are off for porting now and I will post the port map later.

So I've just started to look at a squish head design. The plan is to make a Skull Cap where the whole head section on each cylinder can be removed and refitted with one with different squish dimensions to gauge performance change.

I had a chat with Ian last weekend and now plan to do an O ringed replaceable skull cap if I can get O rings (probably Viton) to work at that temp.

So to kick it off (and being a complete tuning novice) I started to look at the standard head and the bikes current compression ratio. Primarily because as my target is 100bhp @8000rpm most people seem to be saying dont up the compression ratio and use the squish design to improve ignition and keep relative head/piston temperatures down.

I started with doing a rough measurement of head volumes and have ordered a burtette and will use a acrylic sheet clamped in position (pics later) to do an accurate measurement but for now I just did a rough fill test.

So spark plug in to simulate the true trapped compression volume and fill the head with a syringe graduated in CC's.

Middle pot is about 30cc but left and right are about 38?!

To calculate the current trapped compression ratio I'm using the Torqsoft software. Things you need to know are;

1. Head volume in CC
2. Exhaust port height from TDC (not top of cylinder) which on mine (and assuming piston top at TDC is on average 0.5 mm down from cylinder top) is 39.07mm
3. Bore = 70mm
4. Stroke = 64

The program lets me calculate either compression ratio which for the numbers above on the centre cylinder comes out at 6.01:1 and 4.96:1 for the 38cc volume.

As far as I know standard kettles should 6.7:1 :o

If i use the program the other way round and put in the 6.7 compression ratio and the exhaust port dimension from TDC, I get a head volume of 26.38CC, much less than I measured.

Are kettles really 6.7:1 is the first question?
Am I missing something with regard to gasket volumes? I don't think so.

As the whole point of this is to decide the squish head volume to make 6.7:1 CR then I need to get the volume right first and then when the porting and zero deck height is done adjust the squish to keep the same ratio.
Honest baby....this is probably the cheapest bike I have ever bought!!
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Alan H
Posts: 12104
Joined: Fri Aug 05, 2011 6:38 am
Location: Wombwell, Republic of South Yorkshire

Re: Project X

Post by Alan H »

If you want some extra compression, speak to Baz. He has a good set of 'L' barrels (torque porting) that we found have 1mm off the bottom deck which drops the ports and lifts compression. Those have done about 2000 miles and still not been above 6500rpm as I never needed to.
The barrels are 1mm over - so that makes about a 760cc engine. The compression was 150psi per pot and caused two cylinder head gaskets to let go when the barrels were on my B Kettle earlier this year after a full engine rebuild. I now have a set of 1mm over 'A' barrels on, and the engine is 'happier'. Easier starting (for the starter motor) and less vibration. I'd had the crank balanced when it was rebuilt, but not teally convinced it was worth the money.
Anyway, those barrels may be worth thinking about.
Baz did a good job on the engine - and bike - and I did provide the barrels that I bought when I got the hippo last year so the issues certainly weren't his fault!
Proof that four strokes are over complicated
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