CVH On Carbs
 

After trying to fit my engine and having some space issues with the manifold on my CVH CFi, I hoping to now get rid of the manifold and replace it with bike carbs. From what I've managed to read so far, a majority of people seem to be using some variation of zx6 carbs but are there any others worth considering which aren't too expensive? Also where have people sourced theirs from?

Some seem to come with tps and some without. I'm I read somewhere that tps is good when it comes to the megajolt. Can anyone explain what tps is as it seems to be alot more expensive? http://cgi.ebay.co.uk/ZX-636-ZX6R-03...em33669 a250a vs http://cgi.ebay.co.uk/j1-model-carbs...em1c1d4 823a9 ?

Also I think I've also read that I need a fuel pump from the same model bike as my carbs but is there anything else I need besides the carbs, pump, and a megajolt for this setup?

Is this roadster building lark starting to keep you awake at night! questions about carbs at 3.25am :D

Basically when running a megajolt it will run a preset ammount of ignition advance at certain rpm this is known as running in 2d mode

With a tps the (throttle position sensor) the megajolt will know how far open the throttle is and change the advance to suit the current throttle position/rpm, this is 3d mode

Definately worth using carbs with tps

You will also need an filter and base plate

Tps seems to be better than manifold pressure for megajolt.
Don't buy throttle bodies, they are not carbs they need a full fuel injection installation. I think lots of other carbs can be used.

Lol I was up early before going on holiday :) so how can I tell if the carbs have tps as I'm guessing the link I posted above isn't actually carbs?

If you open your second ebay link, and look at the second picture. The carbs are actually upside down in this picture. To the right hand side of the picture, on the end of the butterfly spindles you can see a little black item with white writing on it. This is the TPS sensor.

Most bikes from around 1998 onwards that still ran carbs will have a TPS sensor, but if buying from ebay and you are not certain just ask them the question.

Cheers

Dave

I run bike carbs with MAP, map reads actual manifold pressure and is in my opinion more accurate than tps, both work with bike carbs, tps probably easier to fit

Excuse my ignorance here but is the cvh engine being refered to here the same unit that used to be in the mk3 escorts?

Bob

The escorts used 1.6 or 1.4cvh which are different from the 1.8 found in the sierras

If it is a 1.6 then mk 3 & 4 escort, mk 2 & 3 fiesta. Basically xr2, xr2i, xr3, xr3i models.
If 1.8 then sierra only.

Yup its a 1.8 cvh from a sierra I've got, one of the later ones that came with an early form of fuel injection (CFi). The inlet manifold is massive and has stuff like exhaust gas recirculation which gets in the way of the chassis rails hence why I'm going down the bike carb & megajolt route to reduce space and hopefully get a bit more power out of it :) im guessing though you could do something similar with the smaller cvh's by using carbs from a smimilar bhp bike?

Hi guys, can you have a look at these 3 links and let me know if you think they've got TPS? Am I right in thinking any 1998 ZX6R model G or later has TPS? Also is this about the right sort of price to be paying at £60ish?

http://www.ebay.co.uk/itm/1998-KAWAS...em3a681 9abf8

http://www.ebay.co.uk/itm/KAWASAKI-Z...em19c74 c0f99

http://www.ebay.co.uk/itm/ZX6R-G1-98...em51914 ca914

I paid £30 for my zx6r tps carbs and got trumpets and rubbers with them. £70 + postage is a total rip off!

Did you get yours from ebay deezee? If not where from? :)

Yup, got mine from Ebay. In fact I got 2 sets as they were so cheap. Have used one for spares when servicing the other. I also got the loom of the bike for 99p + postage so I had the correct plugs.

That was lucky, I'm not finding anything on fleabay for under £60 that isn't badly damaged. Been trying to work out alternative models that had tps and struggling a bit there. From what I've worked out a suzuki bandit would be ok as it's also a horizontal fit but the honda cbr isn't as it's more vertical, and the yamaha ones cost a small fortune :(

You just need to sit down with ebay and manually go through the listings each week. The ones I found were listed as carburetors, not carbs. So less people were bidding on them. I only ever got them from auctions, not Buy It Now. If you go through, you can get a complete engine for the same price as some people charge for a set of carbs!

ZX6R G1 complete engine

Just tried calling a few local bike breakers and lowest price I was quoted was £80 for the carbs and they then wanted another £20 for tps :O I'll just have to keep an eye out on ebay.. I'm guessing it's not possible or too expense to take a non-tps set of carbs and put a tps on it?

Another quick question on this setup, when i put my exhaust system back on will I still need the lamda sensor as doesn't that normally connect directly into the orginal donor ecu?

Your lambda is redundant if your not running fuel injection. So as your going onto carbs, you can fit a blank into the hole (normally M18 fine)

So what does the wideband lamba option that you can get on megajolt do?

A regular lambda on a production car is measuring a very narrow range, giving either a lean, ok or rich result (simplified) A wideband lambda can read a complete range and therefore allows you to help tune an engine.

the out put from a narrow band ranges from .2-.8v with a tight transition at a afr of 14.7 around .45v and the ecu is set up to make it flip flop from high to low at the transition point
good enough for basic mapping and running closed loop for cats

widebands need a seprate controler as thay operate at a totaly diffrent voltage range (some contolers can emulate a narrow band tricking ecus to run a diffrent afr) unless its linked to an ecu thats designed to use it that is

What have you guys done about re-routing the coolant that normally goes in via the thermostat part of the donor manifold?

I made a housing which has the two sensors in it and bolts onto the exisiting thermostat housing

I though the existing thermostat housing was located on the end of the orginal donor inlet manifold kind of on the front side near cylinder 1?

It is, I'm using bike carbs sohave modified the water outlet

Ah I think I get you now, so you've used the thermostat & housing that was on the bike carbs rather than modifying the donor one to fit onto the bike carbs?

I'm a bit lost with this now. I've got a set of zx6r carbs with tps, the wiring loom from the bike, and a fuel pump. I'm a bit stuck with how to make the manifold as my cvh head has the coolant coming out just behind the 4th cylinder in a sort of large square shaped hole. I'm guessing I need to make a pipe outlet of some kind on the manifold i make and then re-route the coolant out of this pipe into the donor thermostat housing somehow?? There's also a lot of electrical connections on the top & bottom of the donor manifold so do I need any these and if so where do I move them to? Starting to wonder if I've bitten off a bit more than I can chew with this one and maybe should have stuck with chopping up the chassis to make the donor fit as is :(

Dont be disheartened, its easy! very easy.

You can forget about ALL the electrical connections on the donor manifold if you are going megajolt

You dont need the bike loom really apart from the connector that fits the tps and the fuel pump

The manifold you need for the carbs should only have holes for the inlet runners, the square coolant outlet needs to be blocked

So basically a flat plate with four tubes to match the carb spacing

Then you remove the core plugs on the end of the engine and the coolant will flow from here instead via either a 1.6cvh thermostat housing (which fits straight on) or a home made outlet, if you make one weld in a small boss for your water temperature take off

Shame i took my cvh out otherwise i would have taken loads of pics for you, i will see what i can find on my laptop

I found a couple of pics, just keep asking if you are stuck!

Thanks mark, I'm struggling with this bit!

The only electrical connections I need to keep are the ones that go onto the thermostat (think there's 2).

I don't need any of the vacum hoses either that went on to the donor manifold?

So the plate I make to bolt onto the engine for the manifold I just don't cut a hole for the coolant and that blocks it enough?

When you say remove the core plugs on the end of the engine have you got a picture of what these look like or where they are as it's hard to see in your coolant outlet picture.

Will the thermostat I've got from my 1.8 cvh (injection one) work? It bolts onto the front of the manifold by cylinder 1. So again I'm a bit confused about how this gets connected to the core plug outlets mentioned above.

At the flywheel end of the engine there are 3 round plugs in the end of the head, you can see them in my pic just below the dipstick, thats where you need to fit a thermostat housing

Your 1.8cvh wont fit you need one from a 1.6 front wheel drive escort, i think davedew is doing this so may post a pic for you to clarify what you need

You will only need 1 temp sender in the water system for your dash temp guage

You wont need any of the vacuum take offs

Yes you are correct just dont cut a hole in the manifold flange for the coolant outlet and this in conjuction with some thick gasket paper/sealant will make it water tight

Just take it one job at a time and ask questions as you go, dont worry about things that are too far ahead

Get your engine and gearbox in make your inlet manifold and get a thermostat on it then take it from there

Nice one, thanks a ton for the help mark :)

My engine/gearbox is in now and bolted in. Got the loom out and have layed it all out so things are in the right sort of area.

I'll have to source a thermostat from a 1.6 then, is it only escorts that had a 1.6 cvh? Any idea what year range had them? If you could post a pic of one davedew or anyone else it would be appreciated!

For the inlet manifold, is 3mm plate good enough to make the engine & carb plates? Also for the connection pipes, what kind of thickness pipe should I use? I'm guessing the inside diameter needs to be the same as the carbs (36mm) and should it be bent into a more oval shape to match the holes on the engine head?

3mm wont be thick enough, personally i would want at least 8mm for the engine side as you want it to be as flat as possible, nothing to say you cant go less as long as its perfectly flat once its finished

2/3mm for the carbs pipes will be fine as you say just match either end with carbs/inlet ports as closely as you can

Are you using the carb rubbers off the bike? i used silicone hose on my cvh install but when i made a new manifold for the new engine i used the bike carb rubbers & it seems a better job as you dont have a lip inside where they join the carbs as you do with silicone, much more secure too

The carb rubbers are also fuel resistant whereas only specialist silicone hose is and is quite expensive

Also i have heard stories of carbs falling off when mounting them with silicone, mine never did but theres not much stub to mount them on the carb side

Ok makes sense I need something really thick for the plates.

My carbs didn't come with the rubbers but thanks for the heads up, I'll try to source these as well and avoid the silicon route.

I believe the thermostat housing from the 1.4 cvh fwd also fits. I think that's what I used.

Picture time.

Below is a picture showing the back of the head with the core plug that you need to take out. It is the one with the three tapped holes around it.



The next picture shows the fwd thermostat housing bolted to the back of the head.



Any further questions just ask.

Cheers

Dave

Nice one, thanks for the pics dave, that makes a bit more sense now! I'll need to take a trip down the breakers to try and get a thermostat at some point. Any idea which years escorts had them in, and if there's an easy way to tell the engine size by looking at it? (wasn't there escorts made around the 1.1-1.2 range which I'm guessing won't work?)

Also I've been looking at sourcing the CHS to make the manifold and I'm struggling to find something with 3mm wall and an inside diameter of 36mm to match the carbs. Would it be better to go slightly bigger say 42mm OD/39 ID or something a bit smaller like 38mm OD/ 35mm ID?

Basically if its a cvh and front wheel drive the thermostat housing should fit.
The housing was the same across the Mk2 XR2 & Mk3 XR2i Fiesta as well as the Escorts. Age range would be late 80's to mid 90's I think.

The tube I used for mine was 42.4x3.2 CHS. Closest like you say to the 36mm of the carbs. If you get stuck let me know as we keep it at work. I could post you some, or seeing as you are only in Bristol it isn't to far to come down to have a look at mine & Gus's car if you need.

Ok thanks for the info once again about the thermostat, should help narrow it down a bit.

It's ok for the steel, I got it from bej engineering on ebay as they had a good price for 1m of 42.4x3mm chs and a couple of steel bars to make the plates out of. I was more wondering if it would be better to having something wider or smaller as no one seemed to do anything with 36mm id.

Out of curiosity at this stage, once I've got my 2 plates made with the tubes connecting them, how do the carbs get attached? Surely they're not only held on by the rubbers?