hi all I'm new here, i dont know if I'm in the right place but I've got a 1.3 mk1 golf (dont hate me haha)

I've got a standard 1.3 engine in it, its been fully rebuilt so its as good as new really, i just want somthing abit quicker without a bigger engine, I'm not looking for anything mega quick just to give it abit more, i was thinkin bike carbs but i have no idea what I'm looking for

what would i need and how easy would it be to do??

cheers

sam

the problem with bike carbs is that its just too much messin around but well worth it because webbers or other carbs go out of tune all the time and are more expensive to source and fit and get running properly and i have heard loads of old cars i.e mk1 golf's mk1 fiesta's and nova's with bike carbs on and they sound awesome and some produce more power.

They'll produce more power if the twin carbs are incorrectly set up, but obviously you dont want that. They dont go out of tune all the time either.

most of the ones i've seen have a throat plate which opens with the needle operated by vac/pressure, no idea where these are attached to when used on a car mind. this changes the flow area/velocity, as well as the butterfly.

Polo d, has you car been on any rolling roads yet? be intregued to see what effect chokes that are way too large for the engine does to the torque curve.

i`m afraid not , its somthing that will come in time as the whole build has been done on the cheap , the whole car running cost me under £200 so splashing out on rolling roads is a bit extravagant at the mo

the plan is to get it some where close to good and then get it set up , it does run rich and dont have a 4 branch on it yet , but it does suprise me how well it goes (mk1 golf with 1.8 16v worried to 100 and a bit ) but a g60 raped me but he did say that it quite suprised him

i`m constantly playing with the timing as the vac advance is not conected , but if i was to g uess a power figure i`m going to say about the same as maybe bit more than a stock gt . but i can feel the potential for more

Fire - bike carbs are safest because they use lower fuel pressure than any other fuel system,as they only need enough pressure to fill the reservoirs.

Safer that is,unless you pump fuel into them too hard..

I put the carbs on the return line,so they only get the return's back-pressure. No regulator needed this way - no pressure wanted anywhere.

Size - they use needles in vacuum diaphram controlled vertical slides,so they are throttled down to relevant size at lower rpm. So 40mm bodies will only be 10mm at 2k rpm on a 1.3. Also,the fuel is vacuum-sprayed off the outside of a needle instead of squirted from within one,so you get better atomisation.

Economy - they work by the vacuum from the combustion chamber. So they only give as much fuel as the engine will suck from them. Jet them right,and they're very efficient.

Compatibility - they can be adapted for vacuum ignition advance. I've now done this,using all four carbs,by daisy-chaining tubing through the coolant casting points which are the cylinder head side of the butterflies.

Manifold - i didnt use one,I've just used industrial vacuum tubing and connected it to the head by bolting four top-hat flanges to it. This makes my 'manifold' universal fitment.

Extras - i used an early MK2 choke cable,Golf MK3 T-pieces,VW constant tension spring clips for the fuel pipes,and a Facet pump with Ford Sierra EFi fuel cut out switch for safety.

Cost - carbs cost me twenty five quid a couple of years ago when it was a relatively unknown practice.

Tubing was free - got some off-cut from work. I made the top hat flanges on a lathe. Choke cable and cut switch were a tenner from breakers.

Fuel pump was dearest at fifty quid,now cheaper.

Still cost less than a ton altogether.

Any chance you fancy making me a set of top hat flanges for a manifold? :p Have you got any pictures of your setup? Sounds niiice man

i haven't got my vacum advanced fitted, what difference will it make

this is my set up on a 1.3 gt engine

£30 for cbr 600 1998 model

£00.00 for my manifold (made it my self)

£60 for new electronic dissy of a mk2 polo

£30 for ignition module a coil

£60 for facet recurcitating fuel pump

£35 for filter king regulator

£20 for filters

so all in all cost me £235 which isnt bad i didnt think but obviously if u can't make a manifold bogg brothers makes one for around £200 i think

took the car on the rollers and had 100bhp which I'm happy with, car drived fine only bad point is the throttle is a bit sensetive

i haven't got my vacum advanced fitted, what difference will it make

I haven't either and neither has Heg123. Apparently is just for tick over/low revs but mine idles fine and pulls from nothing :)

The vacuum advance takes affect whenever there is a vacuum in the inlet manifold big enough to pull the diaphragm in the saucer on the dizzy.

It increases the spark advance so that the (slower burning) mixture on small and lower open throttle positions has more time to burn before pushing the piston down. It helps economy and lower down response.

Saying that i never ran it, i just kept shagging dizzies when i connected it up. My fuel economy was never going to be good, anyway.

Any chance you fancy making me a set of top hat flanges for a manifold? :p Have you got any pictures of your setup? Sounds niiice man

There's a pic of them in the 'GT engine cover' post,when it was an eight-valve. I'll get a pic of them on the 16v head tomoz.

I no longer have access to a lathe,and dont want to sell my two other sets as they're different sizes.

Might aswell add to the 1,000,000th bike carb thread :p

I have the full setup (and then some) waiting to go onto my aav. From the vast amounts of reading i've done about carb conversions onto 1.3 (or there about) engines i've seen the overall opinion regarding main jets is that most bike carbs intended for 600cc bikes contain main jets too large to be used on 1.3 engines such as mine. My main jets in the carbs i have (yamaha yzf600r) are 1.55mm. I briefly contacted bogg bros and was advised main jets of around 1.3mm would be more suitable.

I already have an innovate wide band sensor wired in to monitor my air fuel so i can see the various stages of fuelling through the rev range, and where possible, tune accordingly. Obviously the first thing to get right though is the main jet sizing so my question is, from experienced people having used 600cc carbs on a 1.3 similar to mine, is it worth running smaller jets as i have planned? Or is the fuelling ok with the standard jets?

I'd really like to get this right 1'st time round so i dont have to spend much more money through trial and error.

Thanks, Ian.

Edited 22 May, 200917 yr by evans.I

You do need to adjust the jets for you engine. as standard tits normally out to 1.45-1.55 depending on your engine.

What I totally recommend which lots of people running bike carbs don't seem to do is have them set up on a RR. My manifold and carbs (CBR600) were set up by Bogg Brothers and the car will run without having a session as mine did but on the RR they realised it was over fuelling low down and running lean high up. On the the RR they re-soldered the jets and re-drilled them.

It did cost just over £200 but it is well worth it and it is something everyone should factor in the costs of fitting and running carbs.

My set up.

How fast does yours feel now max? Looks a very good setup

Anyone supercharged bike carbs? Cause I'm considering it!

H&S

You do need to adjust the jets for you engine. as standard tits normally out to 1.45-1.55 depending on your engine.

What I totally recommend which lots of people running bike carbs don't seem to do is have them set up on a RR. My manifold and carbs (CBR600) were set up by Bogg Brothers and the car will run without having a session as mine did but on the RR they realised it was over fuelling low down and running lean high up. On the the RR they re-soldered the jets and re-drilled them.

It did cost just over £200 but it is well worth it and it is something everyone should factor in the costs of fitting and running carbs.

Setup looks good man :)

As i understand from your post, your standard jets have been filled then re-drilled to a smaller bore to fuel more appropriatly. At least this confirms my existing jets will be too large. I will order the 1.3mm jets and of course, if they are to small i can redrill them to a larger diameter (far easier than starting with jets too large).

Thanks for your reply, Ian.

Edited 22 May, 200917 yr by evans.I

Jet sizes are not that simple. Yes,the FZR600 jets are bigger,but so are the needles. CBR600 jets are only 1.32 as standard.

Eight valvers,particularly ABD and AEE,benefit from the more torque-biased needle profile of 900/1000cc carbs,wheras our sixteen valvers or long duration 8v's are more suited to the screamer 600 needle profile.

Anyway,here's mine as it is today,as promised yesterday. Bit of a deja-vu pic after Max_crox's but differences more relevant than the hybrid 1.6 bottom end and extra long ratio 4+E box include a ported head to accept round 40mm internal diameter pipe flanges (held to head with clamp plate),70A late type alternator,return fuel line take-off to omit regulator and thus excess fuel pressure,and reverse dizzy (requires cam to be drilled) so that vacuum advance can be used.

Jet sizes are not that simple. Yes,the FZR600 jets are bigger,but so are the needles. CBR600 jets are only 1.32 as standard.

Eight valvers,particularly ABD and AEE,benefit from the more torque-biased needle profile of 900/1000cc carbs,wheras our sixteen valvers or long duration 8v's are more suited to the screamer 600 needle profile.

Anyway,here's mine as it is today,as promised yesterday. Bit of a deja-vu pic after Max_crox's but differences more relevant than the hybrid 1.6 bottom end and extra long ratio 4+E box include a ported head to accept round 40mm internal diameter pipe flanges (held to head with clamp plate),70A late type alternator,return fuel line take-off to omit regulator and thus excess fuel pressure,and reverse dizzy (requires cam to be drilled) so that vacuum advance can be used.

I've now got, and fitted the 1.3mm jets so i'll see how it goes with that. The needles (from what i gather) have adjustment notches in them to adjut the fuelling? lower notch allowing more fuel in due to the taper of the needle.

The good thaing about my wideband is that i will be able to see instantly what ther doing fuel wise so i'll know whether its running lean or rich :)

Hopefully its about right straight away though!!

I'll update once fitted

Ian.

Sorry what i meant about the jets was bogg brother enlarged them to about 1.55 or something like that. But when it went on the RR they reduced them to about 1.48 or something like that. Bogg brothers set them up so it the car will run but they still need setting up so they can be fine tuned.

How fast does yours feel now max? Looks a very good setup

Well its far faster than i thought it was going to be. The engine just keeps pulling up to and beyond 7k rpm. Not that its been done. Too sacred.

..Not that its been done. Too scared.

You will though - its like not wanting to step in a puddle with new trainers on.