hi I'm collecting parts for a abu engine with bike carbs and was reading pvw and that mk1 polo is running mk2 16v golf ecu anyone no how that would work ,what parts they used ,other than using all those mk2 polo ignition bits?

thanks

hi I'm collecting parts for a abu engine with bike carbs and was reading pvw and that mk1 polo is running mk2 16v golf ecu anyone no how that would work ,what parts they used ,other than using all those mk2 polo ignition bits?

thanks

Actually I was thinking why they were using the Golf ECU.. Would be interested to know the answer as well.

Well the 16v uses ecu just to control ignition, so it could probably be used.

ok I've been to the breakers today ,3 local to me and only saw 1 mk2 polo and have got a dizzy and coil but am short of a module and loom was allready gone

nearly there on the parts collecting :-D

and a quick one where does one get cheap silicon hosing for the carbs,my local car junk shop sells big lenghs for 30 quid but its massive .

thanks

oh and I've had the float bowls off and removed jets and cleaned i assume the jets you drill are the small ones adout 5mm of thread only

Edited 7 November, 200916 yr by bmwe30init

Hi all,

Just a quickie... Would this ignition system work on the AFH engine for a bike carb conversion? The engine is going in a MK3 Ibiza though...

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?Vie...e=STRK:MEWAX:IT

Cheers

John

yes it would have done!

hi again i was wondering if anyone had a pic of cbr carbs with the float bowls off to point out which jets are the ones that need drilling when required? thanks.

the main jets are the ones with the biggest hole, search bike carb conversion on club gti and jolfa hs posted a pic up of which jet to drill on there.

the main jets are the ones with the biggest hole, search bike carb conversion on club gti and jolfa hs posted a pic up of which jet to drill on there.

cheers humer :-D

Yeah they're the ones in the middle,on the big tower (very unofficial description),they unscrew and have the original size stamped into the side of them.

Unscrew them from their tower (flathead and 8mm hex) and they're tiny,that tiny thing is the one you drill. It'll be easier drilling it in its tower though,holding it nipped in a wood-jawed vice/clamp,just take care.

It'll probably have 130/132 or there abouts stamped into the side of it (138/140 if they're 900s),which is the size you'll invalidate.

right, drilled my jets today to 150 instead of 132 and now my car pulls like a train to around 3k ish and then power starts to drop and plummets after 4k. i have disconnected the vac advance and its made it a tad better so do we reckon the timing is mucking up all the new fuels entering the engine?

engine is an afh with straight through exhaust and cbr600 carbs

Ant

needles are wrong (or a mix of too big on the jet and too thin on the needle) fulthrottle at full vac (as in air speed through the carb meaning the diaphram is al the way up) is all mainjet, anything under this is needlespring type (the spring controls how open the diaphram is atany given vac, the needle attached to this controls the air fuel ratio) alot of these settings can be relativly passive (ie mainjet if at full revs/throttle) or mix at idle, the MAIN factor is the needle and slide spring. its near impossible to just tell you what needles to run altho the springs will be fine I'm sure.

put basicly, the needle needs to be leaned out from 1/4 to 3/4 open then set your main jet size again.

you can hold a mirror behind the carbs to see into them at full throttle then note at what rpm how far open the carb slide comes. this wil give you a much better idea of what part of the needle is ajusted to correct fueling at any given rpm, altho when you labour the engine (drive in too low a gear) it will show up as a little on the rich side..

the opperating range of these carbs is alot broader than on a car engine (as in, bike engines can rev twice as hard) so the old lean rich lean condition caused by conventional carbs when pushed past there opperating rpm's is seriously reduced.. again this is why the main jet is so passivly set and its more to do wiht needles..

I've playd wiht slide/cv/su carbs for over 10 years and still learn daily.. nothing beats the experience of an old guy wiht a rolling road and 40 odd years experience, it has been said a few times in here befor but if you cant get yourself to borg bros then any decent mini centre with a dyno will be more than able to set these up perfexctly.. as for not having a timing advance, thats just stupid.. if it makes no difference obviously your ether timing it for top end and correcting the bottom with overfueling or its set for low revs and again jetted around for high rpm.. ether way you NEED some varying in the timing from 1 up past 5000rpm or it plain looses power here and there. this is what causes heavy flatspots and horible pop's and farts whendecelerating.

gonna sling a set of carbs on the breddy once i have the new engine in, will be making my own manifold (flange to flange in cds) so can report back once i figure 1, what engine I'm actually putting in and 2, got them setup nicely. great info from all tho :)

rriiigghhttt, what i dont get is that the guys at bogg bro's set up my last set and I have just copied there settings onto these set of carbs as they are exactly the same.

the needle you speak of is it the one that goes directly across the carb when you look into it ?

And as for vac advance the old geezer at bogg bro's told me to get rid of old one as it is of no use when timing is set correctly

Ant

I had to cut my springs (i think 5 off a 30 coil spring) to make them open properly over the rev range. If you cut too many coils you can stretch a little,but the slides must all open totally evenly.

Revving the engine out of gear isnt ideal,as they'll be like half open at a stable 7k rpm yet further open under load at 5k rpm.

I used 900 needles with the torque-biased 1.6 8v but I'm sure the 600 needles suit the 1.4 16v very well because the power curve should be similar over the capacity rpm.

I'm using 600 needles with the 1.6 16v because the 900s ran lean near top end and i melted a piston,but i think the 600s profile would suit the more progressive 1.4 16v even better - neither are perfect for the 1.6 16v's curve.

I had to cut my springs (i think 5 off a 30 coil spring) to make them open properly over the rev range. If you cut too many coils you can stretch a little,but the slides must all open totally evenly.

Revving the engine out of gear isnt ideal,as they'll be like half open at a stable 7k rpm yet further open under load at 5k rpm.

I used 900 needles with the torque-biased 1.6 8v but I'm sure the 600 needles suit the 1.4 16v very well because the power curve should be similar over the capacity rpm.

I'm using 600 needles with the 1.6 16v because the 900s ran lean near top end and i melted a piston,but i think the 600s profile would suit the more progressive 1.4 16v even better - neither are perfect for the 1.6 16v's curve.

To answer a couple of your questions Ant,yes that's the needle and you remove it by taking the top off and removing the diaphram that operates it. And the Bogg's know their stuff but mine barely idles with no vac advance when timed correctly,it often stalls and shakes about on its mounts.

well it seems I may be a little out of my depth here.

So i need to remove said needle, chop 5 coils from the spring that operates it and throw it back in and see how it goes?

Easy/hard? anything I need to know?

Thanks for all help

Ant

no, no and no.. you dont cut/bend springs... lots of people seem to like stretching there springs out (idiot superbike owners) thinking it will help with things...

as far as springs go.. you want to look into the carb as you hold a certian rpm.. at full rpm the slides should be fully open, at half revs the slide should be half open.. this obviously tewlls you 2 things, if they open too late then the springs are too strong for your engine opperating rpm=velocity through the carb.. if they open fairly early in the revs there too soft.

so first things first, throw the drilled jets away and go buy some proper sized jetsa.. unless you clock them in a mill its NEVER gonna be the size your aiming for (unless of course your hands are steady to 0.1mm) throw them in and see if firstly the slides are opening fully at full revs.. if so then trim the main jet size (by obviously keeping it at a high rpm and listening for lean/rich sound) you can work out if its lean as it revs yet go's quiet.. if its rich it will sound verry deep and wet. once this is correct you can start figuring your needle position/type.. half revs = half open on the slide = half way up the needle inside the atomizer (dependant on carb) so, if its range is closed at 1000rpm and fully open by 5000rpm then 3000 rpm is richend/leaned out by the middle of the needle.

there are MILLIONS of springs/jets/atomisers/slide's (yes they have different cutaways and drop rates) avalable from any dynojet centre (how do you think drag bikes are setup? drilling jets? no no no, big old box of them) no need on bodging your carbs by drilling jets. no need atall. way too inacurate for somthing as critical as fueling, especially when using multipul carbs.

another problem cv type carbs suffer wiht when run in banks of 4 is wear on the slides meaning they drop at different ratees, there are ways of timing this and swapping slides from carb to carb to get them as equal as possible altho its only to correct downshifting to full throttle pickup, plus most of this is spring vs vac so for the most part you can ignore this.

put bluntly, take it to somone who knows what there doing, with a dyno.. its the only way you can really load an engine in any gear at any rpm and get a good mix reading. you can get them close but its SO easy for them to be overly rich at bottom, way lean at top and "seem" ok on the plugs.. 2 weeks later and BOOM there go your rings/piston's.

I've try'd to be as simplistic about this as possible just to give you an idea WHAT part of the carb SHOULD be ajusted for more air or fuel.. theres no such thing as a boilt on setup with a few jets.. at bear minimum you need to get yourself a carb balancer (verry cheap) and a colourtune, even then you cant test it under load and cars revving in nutural are rarely fueled correctly as there setup for driving, not revving in nutural.

have fun, find yourself a dyno with bike carb experience/parts in stock.. if they dont stock jets/needles/springs they REALLY shouldent be offering the work they do.

thought id throw up a couple links to make things easier... here is the dell spares link, there is also a link to the dell needle profile range (yes its confusing as there not numberd lean to rich)

http://www.dellorto.co.uk/merchandise/prod...artsectionID=51

the numbers and needle's will be different in different carbs but this is just to show that these parts are READILY avalable from your local stockist (will have a sighn outside.. most bike shops are dell stockists) keihin/mikuni are even easier to find parts for.

oh, grab some vernier calipers aswell.. your never gonna be setting/ordering needles correclty unless you can messure them accuratly.

also i thought id throw up this link, i know there cabl;e slide but the theory is the same, you just have to imadgen there is a butterfly befor the slide that opens on the throttle and the slide works under a vacumm... http://www.ducatimeccanica.com/dellorto_guide/dellorto.html

again, most carb's work the same, if you understand how YOUR carb works IT can tell you if its happy or not.. its not impossible to jet wihtout a rolling road.

Edited 22 November, 200916 yr by MiNoR cOnFuSiOn

as for timing, theres no point in advancing the timing if its set correctly? at what rpm is this set correctly as timing wil NOT be correct between 750 and 7000 rpm (yes bike carbs will fuel well over this)

he has obviously set them for your peak power at the cost of low down fueling, it will run fine but use fuel/smell (or set the idle speed differnetly and have it lean = dodgy piston conditions in traffic)

ALL engines have an advance (with the exception of chainsaws) is your car a chainsaw? LOL

vac advance is a must to get EVERYTHING right (yes you get the same peak but i prefer my fueling correct at any rpm at any throttle position) some ignore this..

most "grasstrack/stox" run no advance.. simply becausew they couldent care about fueling. I've seen some STUPID things when racing (liek airfilters that are more restrictive than an airbox)

has anyone actually used a bike airbox on there bike carbs? the airbox does more than keep the air dry.. it also has rezonant frequencies just like a 2 stroke expantion chamber.. usually nice an small too..

but ye, I'm waffeling away, spelling teribly and fumbeling at my keyboard now so ima shutup

just remember, go by the correct needle profile names (there on the needles) and BUY replacment needles jets and springs to suite your application.. yes you can bodge somthing together that works but vw's can last 200,000 miles.. id like to keep it this way WITH fueling upgrades

one more while I'm in the linking mood...

the sole uk distributor of all keihin carbs (also a mikuni stockist) http://www.allensperformance.co.uk/index.html

used them lots in the past.. always good service altho the new keihin carbs (if bought new) are chineese made NOT jap carbs (yes i sent a 190 quid carb back and bought a better quality german copy but hey, thats just irelevent)

ether way you can work out what you need (harder/softer springs) quote what bike there off and they should be able to tell you what springs you have/what's best to run..

again, dont go cutting springs.. its an impatient way of bodging things.. same with drilling jets. they have everything you want/need in stock. oh and the r1 has advance/retard on the ignition (just checked) as does your stock car, every other car on the planet, touring cars, f1 cars (asked a friend on the honda f1 team) so yes removing any advance is just lazy tunning at the expence of fuel/engine life. its there for a reason

hey Ant, thats why they were drilled to 130! had the same problem when i took them out to 150 and couldnt fathom it! sounds like the gent above certainly knows his stuff.

stick with it! and come see me when its done. take me out and show me what it does now.

good luck

Rick

hows Saf getting on?

jebus, things always seem easy untill shit gets technical, just drill them out and it'll be fine I though. How wrong was I.

Well it seems I am heavily out of my depth here so I think a phone call to mike anics and bogg bros is in order tomorrow and I need to get booked in asap

It wont be untill weekend though so I am very tempted to give this choppy spring method a quick wirl as I pretty much have nothing to loose curently :(

thanks for your help guys and I am currently going through all of your link mister 'MaJoR cOnFuSiOn'

Ant

this is why cars have injection... it does it all for you

this is why cars have injection... it does it all for you

When it works properly. I've had more grief getting injected cars through emissions than carbs.

Still,all this talk of using proper parts is true,but drilling is fine as long as its done carefully,cut springs are fine as long as they work.

I couldn't find standard replacement parts,let alone custom ones,so i dont agree its so easy. And you'd have to have all the different sizes there on the rollers - money.

Modifying what you have works fine,on a budget. If you have the cash for the session Minor Confusion says should be done,then of course that's the best way.

But you could drill them out with a masonary bit in a hammer drill and put ball point pen springs in there,and it'd still run better than the average Pierburg!

just ordered a set of 135 jets for my carbs from allen performance, getting wideband within a few weeks so I will be back at this, I am intent with cracking this damn witch craft

.

Ant