weber installed pics

[treedragon]

Hi all, a couple of quick pics to give you an idea of how it fits.

The installation was fairly straight forward really, the XZ rubber manifolds I turned around 180 degrees to get a better angle of flow into the heads from the closer spaced Weber throats.

This unit was from a Paso and had an alloy manifold set up for your standard Ducati engine. I cut these off the base plate and spent some time reshaping and realigning prior to having them welding back on. A bit of a fiddle but there is a nice flow line and it looks presentable.

The next job will be filter foam......... basically I am going to stretch a thick sheet across the frame rails and down the sides a bit with the carb throats poking through it into the space under the tank. It should be a snug fit all round and allowing for a wide filtration area.

I am also going to stick a layer of sound deadening foam rubber on the inside of the tank as this baby REALLY roars with induction noise when cranked open.

I did another test ride this morning and found little that needed changing, so essentially I'm just keeping the jets from the bigger Paso engine and possibly changing the accelerator pump for a refurbished one. I didn't get to really stretch it's neck in top gear but did note that in 4th it is very happy to rev beyond 11,00rpm without any sign of performance falling off. Decided it would be better to wait for the balanced crank before I explore this zone toooo much  ;D  I would describe the feel of the bike from the 8500 - 9000 and upwards (at least til 11,000rpm so far) as almost turbine like, it gets very smooth and just pulls............ I do believe I am falling in love  ::)  (What!! Again.....)

It's quite the little beasty now and I do like the extra ponies when hoovering out of the corners, might be needing those big front stoppers a bit more now  8) there will be some surprised Ducati riders on the next run methinks  ;D  ;D  ;D

[pinholenz]

Wot!! No YICS!!

Your setup looks amazing and I can't quite believe how you have managed to hide the TCI, battery,water bottle and electrics like that. Great job. I hope that someone has a video with a decent microphone so we can hear it roar.... 

Congratulations.

[Rikugun]

WOW, truly awesome looking! It screams hi performance just sitting there. From your descriptions of it's nature under way it seems the potential of the head design has finally been realized. Very nice work sir.  :)

[Jimustanguitar]

Looks amazing! Reminds me of the Buell Firebolt... Are you doing perimeter brake discs next :)

[VisionMeister]

Very nice looking installation!
Does it still have the Vision stumble? or are you even concerned about lower rpm performance?
Those old Paso's were also known to have a stumble from the Webers which they later swapped out for Mikuni's on the 750ss motors of the early 90's.

[treedragon]

Thank you all for your comments

......hehe the Vision stumble vanished years ago with one or the other previous modifications, I seem to remember it was when I lengthened the inlet trumpets to increase the ingoing velocity, got rid of the flapper box at the same time. Mind you I have experimented that much it's all getting a bit hazy as to what did what and that department is all gone now anyway. I wasn't aware of the Paso stumble not having experienced it on any of the Paso's here.

This unit only gives a slight twitch occasionally if snapping the throttle open, due I think, to the accelerator pump being a little inconsistent in output hence I am going to swap it out for a reconditioned unit.

With this carb it just pulls from the bottom, to an as yet undetermined top with the bottom end performance being the best I have ever experienced on this bike, it is MOST useable.
The bike does need to warm up a little more than before. Keep in mind that currently this combination currently  ::) consists of large bore exhaust hi lift longer opening cams, XZ400 flywheel.

...... already have Yamaha R1 discs, FRZ400 calipers and a Brembo master cylinder maybe we don't want too many different brands in the mix......... possibly  ;D

...... ported heads are next, they've been sitting there for a while now.

........ hmmmmm never thought of trying the YICS....... not,   although the thought had occurred that the inlets would be handy for injecting something at appropriate moments???  ;D   The TCI is in the tool thingie under the seat just behind the tank, water bottle is on the headstock between the clipons and a fair percentage of the wiring is in the rear of the tailpiece, needs tidying you can't see a pic  :)


and let us not forget about the plan for an exhaust/venturi pump to evacuate air from the crankcase to reduce pumping losses, 5-15% is the usual power gain. We have it working well on our race bikes.

I'm thinking Dyno time might be due soon.

 

[VisionMeister]

It may have been the US spec Paso's that had the stumble... worse yet California spec. where all the motorcycle road tests come from. Clean air requirements don't you know.

Interesting idea in crankcase scavaging.

Are those cosworth profile cams in this motor??

[treedragon]

yes they are.

I'm thinking when we get into the hi rev territory with the new crank the bike just might need stronger valve springs to stop valve bounce.......

It seems crankcase scavenging is some of the cheapest extra horsepower available and fairly straight forward to do.

[pullshocks]

As you amp up the performance, how are you feeling about the drum rear brake?

[HarryTakeuchi]

Cool!
And very neat installation!
BTW you wrote of an XZ400 flywheel. I am assuming it is lighter? Does it affect engine response to justify changing?

[fret not]

At first glance it looks to be a track bike, but closer scrutiny reveals the turn signal and tail light, barely.  Looks like a "business machine" to me.

How about another pic from the front?  How about a pic with you on it?  At speed?

I notified Paul Crowe of The Kneeslider website to take a look here, as I think he will be interested.  Don't be surprised if he comes looking for more pics and a story.

[The Prophet of Doom]

You can see the difference between the 400 and 550 flywheel here - with pictures
http://ridersofvision.net/rovforum/index.php?topic=13762.msg124726

[treedragon]

............. Drum rear brake, hardly use it just now mainly because I need to design a better set up for the pedal to suit the rearsets, but it is useful, particularly to nip around some corners.............. or I've over cooked things and have decided butt pucker and prayer are not going to work  :o  :o

When I had the original front brake system I decided I had better learn to ride this bike fast without using the front brakes.......... for good reason I think  ;D
This has stood me in good stead even now with brakes that actually work well under duress (and butt pucker).

........... 400 flywheel is around 750gms lighter as I recall and it does add a bit of extra response, I would go lighter if I could.

fret nut........... many thanks for the Kneeslider thing but really the bike is a bit of a dogs breakfast at this stage and continuously evolving so there are times (like now) when it tends to be more of an upchucked dog's breakfast  ;D  ;D
It's all about the ride experience really, ahem..... but you will notice there no decent shots of the bike, just sorta far away ones it hides a lot that way. No point in adding a front shot, I'm about to change it.............. again..........   ::) and wait until you see the rear view, when it's finished that is.

Today I "created" the air box, ie stretched filter foam over the frame with just the inlet trumpets poking through, added foam and rubber dams at each end, and hey presto the under tank becomes a substantial air box, one of those "proof of concept" things with the thought that i will finish it off sometime. I am sort of hoping that the whole thing doesn't get sucked down the Webers, they sound orders of magnitude worse than a deaf grandmother slurping her soup with gusto :o  :o  ;D

 

[HarryTakeuchi]

roro
Thanks for the link.
The picture was most valuable!

[Rick G]

My '83 discs were warped  when I got them. (the front end came of off the Vision racer)  and the got worse as time went on. They got so bad the I stopped using the front brake on Oatman road . I just moved my butt farther off the  seat  on the inside . It worked great.

[Rikugun]

Well, I guess that will get you around a turn - but what do you do when you encounter one of these? Good front brakes might come in handy!  ;D

[Rick G]

Actually its not the donkey thats the problem, its the meadow muffins . Fresh ones are quite slippery.
I had enough brakes to stop,   but  the front pulsated badly .
A worse hazard are cattle . This is  open range (no fences)  and they like to congregate on the road ,at night to enjoy the warmth,on cool nights . More than once I have come upon  a small herd  , standing like ghosts in the dark, with big blinking eyes, causing me to do a quick stop!

[treedragon]

Just thought I should mention that the fuel economy is no way impaired while delivering the extra grunt.........  8)  8)

I ended up ditching my new airbox/filter arrangement as it wasn't flowing enough air at speed making things too rich and boggy. Surprising really as there was a large filtration area and the conclusion was that it needed the flow around the headstock to "charge" the area under the tank. At speed the flow under the tank rather than being available to the carb seemed to be acting with a very mild venturi/strangle me zone.  I will do a MKII version that blocks off the base of the under tank area and use the vents up front to charge the "airbox" thus created via the headstock area.

So I guess it is just borderline rich and 'feeding it more fresh air should be the way to go, and easiest  ;D

I got in a 700k overnight test run with the boys and it returned 18k per litre on average. I expect much better is possible should I ever get the urge to take it easy and do the "responsible thing".

On the trip away there is a particular hill with a long straight up it, a top gear run that provides a good indication of power for small to mid sized bikes..........  and it did. I had just passed the 160k (100mph) mark and accelerating harder than it has ever done before just there when I got a bout of the clutch slips..............  :( :(  I will attend to that methinks. For the rest of the trip as I had agreed to be somewhat civilized I never quite created a high speed run but the indications are good.



 

[Rikugun]

Sounds like you're getting some good feedback from the test rides. The fuel economy would indicate efficiency with power gains which is a beautiful thing and proves they need not be mutually exclusive.  :)

Funny how adding power quickly finds the next weakest link - in this case a clutch in need of attention!

[sunburnedaz]

yes they are.

I'm thinking when we get into the hi rev territory with the new crank the bike just might need stronger valve springs to stop valve bounce.......

It seems crankcase scavenging is some of the cheapest extra horsepower available and fairly straight forward to do.

On high performace cars they found that the valve float was being caused by the springs getting in resonance with the RPM they were going not that they were too weak. They fixed that with the progressive or beehive springs. Have you though about swapping to those to fix any high RPM valve issues?