175 replies to this topic

[Udo]

Been looking at fitting soom Yamaha R1 carbs for a while now and have finally got round to doing something about it.

Got the carbs a while ago and have split them down into the two required.

Moved the choke bracket into the two carbs which have the throttle cable linkage between them.

Got an ITG filter and base plate and used part of the standard filter box to secure the filter to the carbs

Have also made up the inlet manifold using a spare head and exhaust manifold to make sure it fits

Rolling road booked for in a couple of weekends time.

Looking to get the following from fitting them

Reduced intake noise over the Weber 45

Reduced fuel consumption (Bike carbs are basically a moden SU so will give better metering etc than the pump jet of the Weber - well thats the plan!)

More BHP as the carbs are 40mm straight thru whereas the Weber is reuced from the 45 due to the chokes (34mm)

Attached Files

•  inlet1.jpg   33.54K   352 downloads
•  cable_bracket.jpg   30.15K   157 downloads
•  carbs_on.jpg   31.65K   265 downloads
•  filter.jpg   30.41K   144 downloads
•  inlet2.jpg   26.67K   164 downloads

[miniboo]

awesome

[minifrench]

I like the sound of this, was it easy to convert? will be interesting to read the outcome and how much work involved in the setup. do you think it would work with different bike carbs like maybe one from a big single ?
Al.

[Dog]

Interesting!
Keep up posted.

[Udo]

Cheers Miniboo but we will see for sure after the RR

Minifrench - As with anything a bit different there has been quite a bit of fiddling to adapt things from the four to two carbs such as the choke cable and throttle cable, removing the water heating pipes that are on the carbs as standard and finally the fuel connections

Not sure about different carbs I was advised by the guy who does my RR and he knows bike carbs to go for Yamaha R1 or Blackbird carbs as these are the ones which are 40mm diameter

If any body wants any detailed photos i'll take them for you

[ed4ran]

Did you not want them slightly further apart so the manifolds could be straighter or do they need to fit into the weber box?
So will you be working on these when im on the rollers?

[Dog]

Would be interesting to see how different lenth manifolds affect them.

[miniboo]

pleaes put up more detailed pics!!!

[Bungle]

sounds interesting lets see some more pictures and let us know how you get on

did you rolling road this engine before you fitted the carbs so that you know the difference in BHP ?

[Udo]

You can space the carbs further apart, which may still be required, this is still testing phase if you like, but then you have to start making your own linkages fuel pick ups, choke activating bar and independant breathers as, for those unaware, the R1 carbs all sort of piggy back the previous items with two long bolts thru all four carbs to hold it all together. Not impossible but a lot more work.

You also have to try and keep the carbs at the angle they would be a a bike to allow the fuel floats to work properly so I can't angle them down into the weber box (shame) It will be very close to the edge of the scuttle panel as it is once the filter is on so longer manifolds isn't really going to be possible.

Will take some more pictures tomorrow and stick them up.

Ed - Was going to be helping working on them but Phil who does the welding down there had finished them Sat but I will be down there to pay them. (Not my brazing/welding - tried it cant do it!)

Current setup has been on the rollers at the same place so should have a good comparision to before and after on the BHP and noise but fuel econ will take a few runs to figure out.

Not fitted to the car yet need to drive to the RR then fit them, dont want to do any damage as the settings are going to be way out

Cheers for now

[Udo]

Photos as promised

First one shows the altered fuel inlet. The standard is a pipe which is fitted, and can't be removed, into the side of the end carb.

First I got a brass inlet from an old fuel regulator, machined off the threads then formed a groove for an 'O' ring. The piece of alu holds it in place although it is already a tight fit, the bolt holding the alu in place is one of the two that bolt thru all the carbs to hold them together, this bolt also had to be shortened and rethreaded.

Attached Files

•  fuel_inlet.JPG   107.78K   152 downloads

Edited by Udo, 09 January 2007 - 12:46 AM.

[Udo]

This is the choke mech

The spring horizontally in the middle of the picture should be on one of the carbs i'm not using so had to be moved

The choke bar, the yellow bar horizontally, also went across all four carbs so had to be shortened to just two

Top left is the breather, again had to reduce the connections to this down to just the two carbs

Central betwen the two black rubber rings which connect the carbs to the inlets is the throttle cable connection and just below that, the little black bit, is the idle adjustment screw. Again this had to be altered as in standard form it exits thru the bike fairing to allow adjustment on the move via a flexible shaft. The shaft was cut off and a nut welded on to allow adjustment just using your fingers

Left of the picture is the TPS which will be connected up to my Megajolt system once the carbs have been fitted

Edited by Udo, 09 January 2007 - 12:18 AM.

[Udo]

For some reason I cant do two posts with different photos so heres the second photo

Attached Files

•  rear_view.JPG   111.88K   240 downloads

Edited by Udo, 09 January 2007 - 12:47 AM.

[markrally]

I am really impressed with this little project as i can appreciate the fiddly work and injunuity that goes into attempting something like this,
First thoughts is that the heat from your exhaust manifold may affect the bike carbs as they are not normally run over a hot manifold like a su is designed to maybe need a heat sheild fitting before any initial tests just make sure the heat isnt messing with your testing on the rollers as there wont be alot of air circulation provided by the fan compared to on the road.

Cheers and keep us posted!!

[Udo]

Thanks for the coments

Agree about the heat but in normal bike use they are confined within the frame fairing etc so not exactly out in the open.

The rolling road I use has variuos fans and the last rr i did the temp with the fans running never went above normal

For when on the road I as have bonnett vents above the carb area one for cooling and two for air into the carb

Cheers