ok i have a set of cbr 600 bike carbs. i also have 4 individual k&n induction kits to go with the carbs. all i need now is an inlet maniold. i am doing a college project and i have £273 left. if i get an inlet manifold made it will cost around £200. but i still have to buy other small bits for my project. is it possible to make the inlet manifold my self. has any one done it? how hard is it. also to clean and rejet the carbs. will this be doable for a person who has never done it before?

or the other option is sell what i have and just set up the car with an ECU.

any help is appreciated. cheers

cant help you with the carbs etc but just want to know do the college provide you with the funds

Can you weld? you need to be able to weld to make up an inlet manifold... so I wouldn't recommend trying if you can't. I'm getting my dad who can to make up a manifold. What other bits do you need anyway?

Also I though I read you don't really need to rejet the carbs from a cbr600??

Not for the car to run, but getting the jets exactly right can only help. I'd probably be tempted to jet it slightly lean in fact. Although, with an adjustable fuel regulator, you get the best of both worlds. After a lot of farting about, anyway.

There's only one thing putting me off bike carbs right now, and that's the economy. The manifold is no problem, I know enough people that could do one for me if I can't. Sourcing the carbs, piece of piss.

But fuck 15 to the gallon from a bad setup - I'm struggling with ~25 mpg, hence going down the MPI route! Although, that's not working either

hi my list of recipts

carbs £70

manifold £188 £270 with carb re build and re jet

mega jolt ecu £57

edis ecu , coil pack , £40

fiesta plug leads £12

trigger wheel £22

new crank V belt pully £50

pully adapter and trigger wheel machining £50

facet fuel pump £40

filter king reg £25

yes economy is shit but induction noise is well worth it.

There's only one thing putting me off bike carbs right now, and that's the economy.

But fuck 15 to the gallon from a bad setup - I'm struggling with ~25 mpg, hence going down the MPI route! Although, that's not working either

Surely it can't be that bad? Stop putting me off haha... I sold all the old bits from the GT conversion ages ago, starting to regret that now.

No, not if you get it set up well! I'm just saying, if you leave it jetted rich, the economy will be shite. Rolling road is almost a definate!

i got a set of yamaha 900 carbs sitting around! dunno what to do with them lol "impulse buy"

as far as econemy goes i was going to run them 12:1 constant any way which is probably not the best idea. but i dont think i have the money to finish this unless i can get a manifold made cheaper. i may have to put more money into the project.

answer to the first question is no i pay for the funds. unless i do a college project

yes economy is shit but induction noise is well worth it.

ITB's + MPI...best of both worlds.

If you are on a tight budget why not try making something using cheap + stock parts...rather than something that's really custom-orientated. I am sure there are manifolds available for bolting the likes of Weber 45's to a Polo?

What college course are you doing? What was your budget and what's the aim of the project?

Edited 7 January, 200818 yr by Tav

I wouldnt expect the economy to be all that shit to be honest, keep the standard cbr-600, 132 jets and all should be fine

I've been doing a lot of research into bike carbs for an e30 recently but that dried up due to a wierd running issue.

Basically to answer your question, you can make your own manifold without having to be a master welder. It wont be pretty but it will work. Essentially what you have to do is remove the inlet off the car and remove the carb, cut the inlet where the carb attaches so you just have the 4 bits which bolts onto the engine.

Measure the size of the venturi on the carbs and the size f the inlet ports. Geet a hold of some coolant pipe from any company who you trust. www.pirtek.co.uk re helpful and i think the tube is a tenner a metre which should be ample.

Get some good quality jubilee clips and clamp the coolant pipes onto the inlet and onto the carbs, the length of tube will have an effect on the power band so be prepared for some messing about (generally longer = more low down torque).

Rejetting the carbs is a piece of piss have a look at this PDF from Bogg Bros which shows how to take the carbs to bits, what you will find and what to remove. I dont know the calc they use for Jet sizes though, I'd be interested if you find out http://www.totalvauxhall.co.uk/resources/t...4.tech60697.pdf

if you do get the carbs on the car and it running, it is better to have it running rich as opposed to lean, which is the opposite to whats above.

Bogg Bros will do a set up for the carbs for around 80 quid which is well spent as they will resize the ets you have by drilling them when you are there to make sure they're running right.

Hope that makes sense and helps

They say a picture speaks a thousand words, knew I had these knocking about somewhere

This is what I meant by using coolant hose, 2 different people I've found have used them to no detriment to the running

CBR600 carbs should be 36mm throttles, you can buy jets for these from most good bike dyno centres, see yellow pages. Absolute doddle to fit new jets to, or yo could buy a Dynojet kit for about £80, these include air correction jets as well as the main jets and new diaphram springs and needle valves. Talk to your local bike tuning centre or call PDQ - dynojet experts. Hope this helps.

p.s. the std cbr fuel pump will do the job nicely, my dad races bikes!