Bike Carbs Or Webers

[rally_kid 0]

Im in the process of building the new engine for the rally car, Ive decided that its going to be on carbs of some sort as the budget doesnt stretch to bodies atm. THing is which is best for all round gains? BIke carbs - If so which are best to use or webers, i was thinking 45's

 

its going to be on a 1.9 gti 8v engine

 

Ive had nothing to do with carbs as such befre so any information would be gladly taken

[mattbenselin 0]

Hi mate, I'm in the process of building my 1.9 8v with some bike carbs. They have 40mm butterflies so I guess are a match for Weber 40s. The guy I bought them from reckoned his 8v had made 152hp on the rollers (Hi-Tech in Birm.) with just the carbs, Piper 270 cam, Kent vernier and Premium juice. So I think they are a good alternative to webers, they are supposed to be easier to tune and maintain, sound the same but to me they look neater and are so simple to setup.

The common choice is Yamaha R1's but there are lots of bikes to choose from! I wouldn't get anything with less than 39/40mm bores. The ones I have are Kawasaki ZX-9R spec. C.

PM danpug he had a set of R1's with a Bogg brothrs mani for sale a few days ago, good price too!

 

But I'm with you if any one has any thoughts....?

[swordfish210 20]

The Yamaha carbs are the Kehin type ones which arn't the best really. The Mikomi carbs as fitted to the GSXR range of bikes are much better built and easier to tune.

 

The bike carbs are the cheaper choice and can (if tuned properly) give as good a result as webbers.

[mattbenselin 0]

Don't mean to hijack the thread but...the ones I have are Keihin and I read that that the Mikumi ones can sometimes be the more problematic? I'm not sayin your wrong cause I'm new the carb stuff but a lot of people fit R1's so there is a lot of knowledge out there if you ask around.

[Baz 421]

Webers everytime, they're meant for a car.

[rally_kid 0]

Hi mate, I'm in the process of building my 1.9 8v with some bike carbs. They have 40mm butterflies so I guess are a match for Weber 40s. The guy I bought them from reckoned his 8v had made 152hp on the rollers (Hi-Tech in Birm.) with just the carbs, Piper 270 cam, Kent vernier and Premium juice. So I think they are a good alternative to webers, they are supposed to be easier to tune and maintain, sound the same but to me they look neater and are so simple to setup.

The common choice is Yamaha R1's but there are lots of bikes to choose from! I wouldn't get anything with less than 39/40mm bores. The ones I have are Kawasaki ZX-9R spec. C.

PM danpug he had a set of R1's with a Bogg brothrs mani for sale a few days ago, good price too!

 

But I'm with you if any one has any thoughts....?

 

Cheers, Im after sometihng that is a similar match for 45's rather than 40's, not sure what extra power increast this will give though, the other thing im after is as much torque gain as possible it being in a rally car, i need to be able to pull myself out of corners alot. I was thinking the 285cam on vernier pulleys.

 

If i were trying to match similar to 45's what bore sizes would i need? 45's??

 

The Yamaha carbs are the Kehin type ones which arn't the best really. The Mikomi carbs as fitted to the GSXR range of bikes are much better built and easier to tune.

 

The bike carbs are the cheaper choice and can (if tuned properly) give as good a result as webbers.

 

HEy, what is the difference between the Kehin and the mikomi carbs, is it just build quality? if so mikomi seem the ones to go for, as for the gsxr, are they from the 1000's or the 1100?

 

cheers

[projectpug 0]

I would go for Twin Weber 45's been done lots of times before on a 205 off the shelf inlet manifold too.

[mattbenselin 0]

I agree with projectpug that webers are a natural choice, plenty of people have done it and parts can be sourced fairly easily. However theres nothing wrong with bike carbs, they cost pennies in comparison and yield similar performance, bang for buck they're awesome!

 

I'm going with 285 cam with my set-up too, seems the right choice for me anyway with using the car on the road a lot. You could maybe think about going a little harder...eBay item: Kent PT27.

 

You can get bike carbs with everything from 34mm-51+mm bores. The Suzuki hayabusa has 46mm I believe, but they are TB's not carbs. I'm sure they some big carbs out there though.

[swordfish210 20]

Don't mean to hijack the thread but...the ones I have are Keihin and I read that that the Mikumi ones can sometimes be the more problematic? I'm not sayin your wrong cause I'm new the carb stuff but a lot of people fit R1's so there is a lot of knowledge out there if you ask around.

 

 

I'v got Kehin carbs as well (from an R6) so it makes it all the more meaningful when i say the Mikomi's are better. Think of it as a Weber Vs a Solex carb. The Mikomi's are built better and are a more high performance carb, like i said they are also easier to tune but they do need to be looked after which is why you have probably heard they are problematic.

 

I think a lot of people fit the R1 carbs because they are so readly available (lots of scrapped/crashed R1's) and there is the impression that they are one of the fastest bikes around so they must have the best carbs. However i'm just speculating there

[rally_kid 0]

I agree with projectpug that webers are a natural choice, plenty of people have done it and parts can be sourced fairly easily. However theres nothing wrong with bike carbs, they cost pennies in comparison and yield similar performance, bang for buck they're awesome!

 

I'm going with 285 cam with my set-up too, seems the right choice for me anyway with using the car on the road a lot. You could maybe think about going a little harder...eBay item: Kent PT27.

 

You can get bike carbs with everything from 34mm-51+mm bores. The Suzuki hayabusa has 46mm I believe, but they are TB's not carbs. I'm sure they some big carbs out there though.

 

Thanks, yeah sorry had the wrong cam in my mind when i was wrting that, im gonna try and go with the harshest cam i can, the hayabusa carbs may be woth looking into

 

Dont supose you know any reliable guides to doing bike carb / tb conversions

 

Also with the bike Tb's what sort of gains do you get out of them compared to the ones from carbs. as you can prob tell im a complete novice with carbs/tb's

 

cheers

[mattbenselin 0]

Check the main website there are 2 articles regarding carb/TB conversions, some useful info there for sure. Do searches on here with some patience you can find a lot of info. I am doing mine having never done it before, with just the experience I have gained over the years, lots of asking questions and some common sense! (some!)

With TB's you need some sort of ECU to control it all like Emerald, Megasquirt, etc. This means with other mods you can really get the best out of the TB's, but really depends what you do to the engine. What I can say is that you will see more power with TB's than carbs for sure, but at a lot more cost to install. Ask Sandy on here he has a lot of experience with this stuff and knows his butterflies from his trumpets!

Depending on your current car spec. you may need things like electric power steering pumps so make sure you take into account the hidden complications. Keep me updated with what you decide, and I'll let you know how I get on.

[rally_kid 0]

Thanks, ill be sure to keep you updated, i havent actually started any of the engine work at the moment as im still trying to gather all the inf that i need before i start to save me buying unnecessary things.

 

cheers

[mattbenselin 0]

 

Day 1 - I made a right mess!

Edited October 26, 2008 by mattbenselin

[projectpug 0]

The outright poewr difference between well set up carbs and TB isnt much. Its more to do with tractability,fuel economy/emission and they are also fairly fit ,map and forget where a weber set up like mine requires constant fettling to get the best out of them. I have had them RR tuned 3 times this year at a cost of about £180 and thats on brand new carbs i also had a venturi vibrate loose that i had to replace. So there are benefits of both i am quite old school despite being fairly young so i still like good ol 45's

[mattbenselin 0]

Well so I've been told and get the gist...bike carbs are less maintenance and easier to maintain when you do need to. which is plus point in my book.

[rally_kid 0]

 

Day 1 - I made a right mess!

 

 

aaah thats not too bad im uploading pics of mine at the moment, gonna get one of those photobucket jobbies on the go

[mattbenselin 0]

That was the tidiest bit. you should see the rest of the drive, garage, kitchen, stairs, garden....smells like an oil rig!

[rally_kid 0]

atleast this didnt happen

 

Cut finger

[Baz 421]

The outright poewr difference between well set up carbs and TB isnt much. Its more to do with tractability,fuel economy/emission and they are also fairly fit ,map and forget where a weber set up like mine requires constant fettling to get the best out of them. I have had them RR tuned 3 times this year at a cost of about £180 and thats on brand new carbs i also had a venturi vibrate loose that i had to replace. So there are benefits of both i am quite old school despite being fairly young so i still like good ol 45's

 

TB's and carb differences aren't about the power output, there's many other pros and cons. And a properly fitted carb setup, properly setup doesn't and shouldn't require constant fettling at all.

 

There's another argument between proper carbs and bike carbs here though.

[rally_kid 0]

There's another argument between proper carbs and bike carbs here though.

 

 

Which is?

[Baz 421]

Carbs for cars and carbs for bikes?

[boldy205 74]

I think a set of Webers /Dell'ortos are the best bet, bike carbs are not that much cheaper, unless you make your own inlet, and have some one who is familiar with both the carb and the car you have (and i feel there is a lot in that) to set it up well. Plus there is the linkage, and some/ most bike carb spacings (to suit the inlet ports) need to be altered. At first the bike carbs seem to be a cheep route, but overall, i dont think they are. (By the way, i looked into both bike carbs and Webers, and took the Weber option, though Dell'ortos are just as good i belive)

Plus the bike carbs are, i think, a fixed choke size, so you are limiting your self before you start, unless you know the choke size you will need and can pick a bike carb to suit.

Matt

[mattbenselin 0]

Getting hold of a manifold is the tricky bit I agree, Bogg Brothers do a very good one but they often have a long waiting list and they cost about £200. If you measure up correctly and can weld its not too bad, lucky me had one made by a friend. Sourcing good bike carbs isn't that hard and you can get some with 40mm chokes for £50 from the bay of e. The throttle linkage is not too hard either if you know your maths and have an imagination. I'm using a lever system to extend the 1" of travel at the carbs to suit the GTI pedals, mounted on the middle bolt of the cam cover.

With the bike carb option there are many obstacles to overcome but for me the challenge of this and the satisfaction I'll have when it works plus the sound will be unbeatable!

[boldy205 74]

judging by what you have posted you seem made up with the bike carbs, and thats good that you want to do it that way. im just saying i think Webers etc, are the easyer way or doing it.

Hope all goes well with the conversion.

Matt

[mattbenselin 0]

Cheers mate I was just lucky I guess, got my carbs and manifold for a good deal and I'm always keen to try new things (I know its been done before, but not by me!).

I'm sure webers are easier but that's part of the attraction doing something which is different. Once I get going I will start a project post to show the progress and hopefully inspire some others to do the same!