dupersunc

Air boxes are pretty simple devices, the biggest problem car guys have is how they interact with the rest of the aero package. The primary issue as has already been said is the resonant length of the inlet tract. Bell mouths do 2 things, 1 they provide a clean efficient transition from atmosphere to inlet, and 2, provide a very clear transition in cross section and pressure which gives a very strong signal for the inlet tract. A pressure wave travels back and forth between the back of the inlet valve and the edge of the bell mouth at the speed of sound. The shorter the bellmouth, the more pulses per minute you get, time this with inlet valve opening and you increase cylinder filling at that rpm. Very power full tool. Sometimes pulse plates are fitted in the air box, to give a secondary effect, or even the lid of the airbox is used, but this isn't that efficient. The main purpose of an airbox is to provide still non turbulent air for the inlets, turbulent air buggers up your pulse signal. No airbox on a moving bike leaves you with all sorts weird interactions with the fairing and rider in the area of the carbs, which can cause all sorts of problems. If you can draw the air from area of stagnant flow such as the front of the fairing, that's even better, and it will be cooler. What you do with the air between nose of fairing and airbox is where the bike world is fucking cluess. Only in recent years have Gurls blouse, and Ducati started to deal with it properly, it wouldn't surprise me if the NHRA bike guys got there first though. You also have take into account that manufacturers need to suppress inlet noise, so that becomes an important design consideration of airboxes on most road bikes. If anyone is wondering about ramair. Don't. It's marketing bollocks, unless you can make the air entering the airbox flow supersonically.

Ceramic bearings are a waste in motorcycle and car applications, no benefit what so ever, other, than a few grams in weight and pub bragging rights. Flick the seals out and a squirt of WD40 is the way to go.

This the one I built for @Markz9and have the same on my slabbie. it mounts and raises the seat unit, there is a -6 from the cam cover that feeds in to bottom but an internal tube means it goes to the top of the tank, a -10 goes from a modified clutch cover directly to the bottom of the tank so any oil can drain back to the sump, as well as allowing it to breath, a 3/4" peace of flexi hose runs from the top rear of the tank to atmosphere.

I'll post the 26t gear to you this week Garry. Looking at the engine mounts I'm fairly sure it was built for a gpz600 originally. 750 mounts seem quite different

Decided the wr swingarm would suit another project better and was a bit heavy, so got a 750m arm and cobbled a R1 brace, and some sheet together. It's a 10yard job really, but not much extra weight, and should stiffen it up a bit.

Blasted. Given a quick once over. Bit of work to do, Remove some ugly added on brackets, and repair the subframe and lower rear engine mount which has been poorly modified when the water cooled motor was fitted. I want to add a few brakets for an oil cooler, and lower middle engine mounts too. On the whole though, it's in really good nick.

Thanks @nlovienfor the kind offer, but I think I'm sorted for a front end.

I would call my riding decent. The bike was designed around crossply tyres and I guess and 18" rear, 16" front. It will be set-up around modern supersport radials so the optimum rake, trail, swing arm pivot, weight distribution etc. will all be different. Once I have a set off forks to hand I can see where we are. Just found out how much it's gonna cost to have a decent set of forks built. Gulp. Needs to be right though

Swing arm pivot position is a huge can of worms The angle of the pic makes it look a little strange. I'm pretty happy that it's in a good working position Once the frame is back from the blasters I'll build up the rolling chassis and empty cases with a base line ride height and head rake and take some measurement, and then analyse the geometry to se if I need to move the swing arm pivot. I don't want to move the, swing arm pivot, but it's something I'm comfortable doing if I need to.

Not me. I'll move it to the centre in the final build.

I think you could be correct on the Gpz 750. The log book states it had gpz600 motor in 97 when it was road registered. The rear mounts aren't the same as the gsxr frames though. This is a friends F1, this has a good provenance, note the magnesium flat slides and big fin barrels, the head casting is different to. Top rear engine mount is quite different.

Still chipping away at this.

This my little workshop space I rent. I like to keep it tidyish as I do customer work here. My garage at home is a over run tip at the moment.

It fits!

I don't know what you mean...

After I done the deal, I made a nice little score on eblag.

So, most of you will be familiar with this bike, but there's been a bit of a change around, and I'm the new custodian. Being a big fan of the current Oil cooled XR69s and team Force Harris F1 bikes, I'd long fancied building something myself. The final straw was following @Mole28down the pit lane at Donnington a couple of months back on his freshly built Magnum 2. A wanted add on here produced a couple of tempting offers of Harris Magnums, and a near miss on a facebook ad too. I even looked at the Saxon engineering replicas, but didn't like the quality of some of those bits. Then Gary @fatblokeonbanditdropped me a PM. A quick viewing, and a price was agreed, lot's off projects and surplus parts were sold off, and yesterday I took a trip to the cosmic centre of the universe to collect this. So for those that don't know, it's a genuine Circa 1985 Harris Performance F1 frame and rear suspension, the tank is also a Harris F1 endurance spec Item but made later. I'm told the bike originally was built for a GPz600 engine, is that right Garry? Later in the Mid Nineties it was rebuilt as a road legal Streetfighter, though we believe never used, with a Gsxr750wp engine, and won a few shows. Garry has configured it for an oil cooled engine, but stuggled to get clearance on the carbs for an 1100. I intend to build it into a race bike, with a nod to a day light mot, and using it for the seting new course records on the West Bay TT. Motor will be a 1052 board to 80mm with a worked head and cams, and rs40 flatslides. I have all the bits to build this motor, but need to mock it up and see what mods are needed to get it in the frame. Running gear will be astralites, and probably 43mm GSXR 750j/k forks, with Maxton internals. If anyone has a good set of these forks let me know. Body work will be a cut down XR69 tail, and either an RGB500 or Harris half fairing. The tank is beautifully made and very light, and never had fuel in it, but I'm not sure I like the shape, so may make a tank similar to the square low line tanks on the current iterations from Harris. First job is to get the thing fully stripped, and get the paint chemically removed from the frame, and see what modifications and repairs are needed.

I'v ealways run 750cdi on my 1100s with out a problem. The race bike regurly sees 12,000rpm, it's got no cam lobes left now...

Decent radial m/c first You can still use it if you do decide to up grade the rest.

That thing is all sorts of wrong. urrrghhh. I have seen a gsx in slabbie frame, it was only lightly modified, and I think the back of the cases were ground down a bit, to get it in. It may have been a 750 frame, as they're a bit longer in the engine bay believe it or not. Either way the W frames are shorter still, so you won't fit the gsx motor with out doing something ugly.

Not something silly like throttle cable adjustment not giving you full throttle? The torque figure is low also. It's like it's just not getting enough air.

That looks well.

you need a longer shock or a different rocker link. An 1100 link jacks up a 750. 1100 need a custom rocker link. Pre 2006 r6 shocks work well on the 750. in all cases you need to clearance the swing arm to get the correct sag.

New fairing collected.

Yes mate, your old frame. going to have 88-89 Sert endurance replica fairings.