QUOTE

Bike Carb FAQ Index
Pg1: Information, Carb size to engine size guide, Mk2 polo ignition loom with Amp and useful links
Pg2: General Info
Pg3: T-piece Fuelling, Plug layout for Mk2 Ignition loom.
Pg4: Bogg brothers manifolds, Carbs will work at silly angles, difference between fuel pressures on twin 40’s and bike carbs, picture of T-piece setup
Pg 5: General Info
Pg6: Humer’s How-To, Carb needle/spring setting
Pg7: Needles and jetting
Pg8: Fuelling, Attaching Throttle cable
Pg9: CBR 600 pipe diagram, water heating for carbs, brake servo take-off’s
Pg10: Homebrew manifolds, The diffrence in mechanical & Hydraulic head dizzy’s, Motorbike ETKA
Pg11: Ignition Coil Wiring
Pg12: General Info, Coil wiring
Pg 13: Facet Fuel Pump wiring
Pg14: Fuel Pumps, Homebrew Manifolds
Pg15: Basic settings, Rev Counter signal wiring, Ignition loom wiring, Basic fuelling methods
Pg16: Fuel Pumps, useful link, T-piece fuelling setup
Pg17: T-pieces, Importance of Return Lines, Vacuum Take-offs
Pg 18: Fuelling, Bike ETKA Link, Engine to Carb size, T-piece method explained, Dismantaling 94 CBR600F carbs
Pg19: Vac Advance Dizzy’s, Rant about lazy people
Pg20: Fuel Hose’s, Air Filters
Pg21: Rev counter issues, ECU Basics
Pg22: T-pieces and fuelling methods/problems
Pg23: General info, Dizzy’s
Pg24: General Info

400cc motorbike carbs(doesnt matter so much what from but that is the optimum size)

A manifold either home made using an inlet gasket as a template for the flange or call bogg bros to make you one

some fuel hose

A T peice

a mk2 vaccuum advance dizzy

And get them PROPER set up by a carb specialist with a rolling road.

Edited 30 March, 201610 yr by Cymro
Adding Index

recomendations for specialists who can set up carbs properly please

Ant

You'll also need the whole ignition system from a mk2 polo aswell as the dizzy

recomendations for specialists who can set up carbs properly please

Ant

Bogg Bros are probably the most well known in the midlands, but I'm sure there's others around as capable, phone around

Don't really need the huge post that was here, plenty of info added since so it's just wasting bandwidth.

Edited 17 August, 201313 yr by MikeyMK

I fitted bike carb to my kitcar a few years ago and the best place for info i found was www.locostbuilders.co.uk. The kitcar boy have been doing it for years and the forum is full of info on every aspect of the conversion and its populated by a lot of experienced people. :-)

400cc motorbike carbs(doesnt matter so much what from but that is the optimum size)

For a 1.3 or below i assume? What if your using something larger, say 1.4 or even 1.6

Any one know of a wiring diagram that includes the coil, ignition amp & mk2 dizzy.

Didnt get the loom with mine, only wiring i got was about 6cm's from the ignition amp plug.

I understand 90% of the system but just need to check what wires i need to put in and also which wires on the ignition amp go where, did read heg123's one as he's fitted a round coil to replace the standard mk3 coil pack and kept the ECU but cant make sense of how he did it.

Should have dismantled the car this weekend to check it out.

Edited 23 August, 200917 yr by Cymro

400cc motorbike carbs(doesnt matter so much what from but that is the optimum size)

For a 1.3 or below i assume? What if your using something larger, say 1.4 or even 1.6

Then bigger,from a 600-900cc,though that's not to say bigger is better universally. They have vaccum-operated flat slides,which govern the throttle dependant of what the engine can draw at any time,so you can go for bigger bodies without notably loosing low-rev efficiency.

But obviously there's no point going much bigger than the ports (bar compensating for the drag from the butterflies and needles),and the jet sizes required for the needle's taper can be too big if the standard jets are too big for the engine (900cc carbs are too much for a 1.3 8v,but would be okay for a 1.4 16v).

Basically,you want to match the same fuel/air draw as the bike,across it's range,for minimal jet compensation. So 1400cc from 900-6,000rpm is drawing about the same as 600cc from 2,000-14,000rpm.

I suggest the following as a guide,though a more precise fine-tune will be needed,preferably on a rolling road,and depending on the state of tune of the particular engine:

1.0 8v - 400cc carbs with standard jets possibly having to be opened a fraction during tuning.

1.3 8v - 600cc carbs with standard jets possibly having to be opened a fraction during tuning.

1.4 8v - i ran CBR600F-X carbs with the jets drilled out from standard 132 to 145.

1.4 16v - another member has reported running CBR600F's,jets drilled from standard 132 to believed 148.

1.6 8v - i ran CBR600F-X carbs with the jets drilled out from standard 132 to 155,and 900 needles.

1.6 16v - I'm running CBR600F-X carbs,jets drilled out from standard 132 to 165,and 900 needles.

Any one know of a wiring diagram that includes the coil, ignition amp & mk2 dizzy.

Its well covered in the revised MK2 Haynes manual,but basically consists of the coil,TCi-H amp unit and the distributor. These are joined by a semi-independent loom,and to ignition and battery.

This includes keyed multiplugs for the amp and dizzy,so you really need to get this loom from an '86-90 Polo.

If your loom doesnt fit/reach,its probably from a Golf,and you'll have to adapt it.

thanks mikey.

got no issues with adapting the loom or even making one from bits, plus got a photograph now as well of the amp loom and i think it makes sense, but may try and source a mk2 loom just to be sure.

Edited 23 August, 200917 yr by Cymro

Thats spot on,Polo one. The amp goes just behind the firewall panel,just under the plastic rain-drip tray,the rubber grommet's for that. There's actually a bracket on the later MK2 to mount it on,but it's fine screwed to the panelwork as mine is. Black wire to battery earth. Then the black plug is for the dizzy and white are for the coil.

They just hang across the bay,as you can see in pics of MK2 bays,though I've used flexi conduit.

so in theory I can bin off the ecu and all associated wiring in my gt when the vac advance dizzy and carbs are fitted ?

Antoni

Yep no need for the ECU

Same with a mk4 aswell

Maybe another point to mention, with the rev counter (I did this in a mk4, but I would assume its the same in a mk3??) the wire coming from the instrument panel goes to the middle wire on the hall sender plug on the distributor.

Just so you guys know, I am doing this conversion too and plan to do a bit of a guide on doing it, should help others when they start it as it does seem quite daunting.

anyone ran airfilters on cbr600s in a mk3 bay ? reccomend wich ones maybe

Also i think proof of power increases of rough guestimates would be good

Ant

any idea if cbr600fx carbs would run on an AFH "out of the box" well enough to get me to the rolling road?

any idea if cbr600fx carbs would run on an AFH "out of the box" well enough to get me to the rolling road?

CBR900s would be better,perhaps even spot-on. But I'm wondering if the 600s needle profile would suit the revvy 1.4 valver better. The 600 jets will be too small by at least 0.15mm and it'll run too lean - but as long as you keep the revs sensible,you should be okay to get to the rollers.

Id run 900s.

only got about 20 miles to go, if that, to get to the RR , will stick to the slow lane on the way there

budget and time are both running out now so i'll have to make do with the 600's for now and see how it goes

thanks for the answer :)

i'll post up some details of my conversion when it's all up and running

if it works, i've been told about a nice cheap way of making an inlet manifold for a valver lump, which has so far cost me £16.99! i think it was hummer who told me about it, dont want to steal his thunder!

Edited 27 August, 200917 yr by skapunk1

Here are the best shots i have of my flanges/plate/tube method. Thirdly,I've included the shot of my old smaller flanges i made for the ABD.

I've since discovered that Ikea sell cheap bathroom handrails,and B&Q sell rubber/jubilee bathroom/kitchen sink wastepipe joiners and washers for the handrail ends. They also sell hacksaws,and that's your ingredients for a cheap and easy,off the shelf,manifold solution (depending on engine and carbs).

Can anyone tell me the colour of wires I need to connect to retain my rev counter on my polo gt ?

Am doing the conversion saturday morning and getting a tad scared It wont work

400cc motorbike carbs(doesnt matter so much what from but that is the optimum size)

For a 1.3 or below i assume? What if your using something larger, say 1.4 or even 1.6

Then bigger,from a 600-900cc,though that's not to say bigger is better universally. They have vaccum-operated flat slides,which govern the throttle dependant of what the engine can draw at any time,so you can go for bigger bodies without notably loosing low-rev efficiency.

But obviously there's no point going much bigger than the ports (bar compensating for the drag from the butterflies and needles),and the jet sizes required for the needle's taper can be too big if the standard jets are too big for the engine (900cc carbs are too much for a 1.3 8v,but would be okay for a 1.4 16v).

Basically,you want to match the same fuel/air draw as the bike,across it's range,for minimal jet compensation. So 1400cc from 900-6,000rpm is drawing about the same as 600cc from 2,000-14,000rpm.

I suggest the following as a guide,though a more precise fine-tune will be needed,preferably on a rolling road,and depending on the state of tune of the particular engine:

1.0 8v - 400cc carbs with standard jets possibly having to be opened a fraction during tuning.

1.3 8v - 600cc carbs with standard jets possibly having to be opened a fraction during tuning.

1.4 8v - i ran CBR600F-X carbs with the jets drilled out from standard 132 to 145.

1.4 16v - another member has reported running CBR600F's,jets drilled from standard 132 to believed 148.

1.6 8v - i ran CBR600F-X carbs with the jets drilled out from standard 132 to 155,and 900 needles.

1.6 16v - I'm running CBR600F-X carbs,jets drilled out from standard 132 to 165,and 900 needles.

i fitted CBR600 on my AFH and drilled the original 114 jets to 148/150, but found it over fueled anything above 3000 rpm and killed the motor, so i fitted some 132 i had lying about and it is now runing excellent, still needs setting up, but i am more than happy with how it is performing.

hope that is of some help

The original size is so important,because its about the needle. A smaller jet means a thinner needle,and if you drill the jet too much over standard then the needle will no longer match the jet.

The drilled jet needs to be as close to the original size as poss without going under,which is why id use a set from a 900cc on a 1.4 valver or 600cc on a 1.3 8v.

How are those flanges attached on that ABD? I dont see any nuts

And also, whats that ally plate running along the inlet on the other too, between the head and the carbs? Is that your method of mounting them?

Those allen bolt just hold them in place, I'm assuming here that he put a lip on the inside do they would slot in then the bolts to stop them falling out again.

TBH the ABD ones are a good idea. Simple but effective.

The ones currently on there are no different to the brass ones,they're just bigger and aluminium.

I've inset rubber seals into them as a gasket,like an 'O' ring. Otherwise they're flush with the head,the shoulders were enough to hold the brass ones secure,but the AFH bolt pattern didn't allow me to do this so i had to make a plate.

This is the best pic i have of the ABD with the carbs on those brass flanges..