V7 Classic Carb Conversion

[acrata]

Hi all, would it be possible to convert a FI V7 to carburettors? I've done a quick search, but can't seem to find any info on it...this is my first post, so if this is not the right place to ask, please do let me know and I'll move my question...

Cheers

 

[chris a]

Possible but it would cost a bucket (allthough that could be offset by selling the ignition and injection system),take a considerable amount of time so one has to wonder why ???!!!!!!

 

[acrata]

Possible but it would cost a bucket (allthough that could be offset by selling the ignition and injection system),take a considerable amount of time so one has to wonder why ???!!!!!!

What would it entail? I'm by no means an expert, but I've come across this site today and wondered whether it'd be possible to do similar thing on the V7...

As to why...well, why not? Keep it simple...or back to basics...or cheaper tuning...or just for the pleasure of doing it...take your pick

 

[john zibell]

Possible but it would cost a bucket (allthough that could be offset by selling the ignition and injection system),take a considerable amount of time so one has to wonder why ???!!!!!!

What would it entail? I'm by no means an expert, but I've come across this site today and wondered whether it'd be possible to do similar thing on the V7...

As to why...well, why not? Keep it simple...or back to basics...or cheaper tuning...or just for the pleasure of doing it...take your pick

Why would you want to in the first place? The FI system is good on the small blocks. It would take some sort of ignition system, old instruments, different harness. You might as well just buy a used small block that already has carbs. It would be cheaper that all the parts you would have to buy to do a proper conversion.

 

[acrata]

Why would you want to in the first place? The FI system is good on the small blocks. It would take some sort of ignition system, old instruments, different harness. You might as well just buy a ued small block that already has carts. It would be cheaper that all the parts you would have to buy to do a proper conversion.

Ok, I was hoping that somebody would have been as curious as me or be willing to share their knowledge as to how to accomplish this. I didn't start this topic as a discussion on "why", but "how". I love the looks of the V7 and I'm considering buying a second hand one. I understand its engine has been around for a while (using carburettors, although I might be wrong about this) and wondered how easy/difficult it would be to do a conversion, differences between a carb'd and FI'd engine so that I can learn something along the way...that's all. I haven't seen any such information anywhere around the web, except for the site mentioned above.

Does anybody know in more detailed how to accomplish this? Does the V7 engine share parts with older carburatted Guzzi engines for an easy swap? Is the "why" so important?

Regards

 

[draidt]

IMHO DONT

 

[Carl Allison]

You seem rather adamant about applying a solution to a problem that doesn't exist but we can give it a go.

You'll need the points section off of an old V65 Guzzi or something (if you're going to regress to carbs, you might as well forgo modern ignition as well). There's precious little space under the V7 Classic tank for coils and I'm not certain that the FI coils are suitable for a points system so you may have to source some coils and find another location to mount them. You won't be needing the fuel pump/filter/fuel level sensor in the tank so you'll need a new plate with a fuel tap on it. That's in a piss-poor location for a shut-off valve petcock so you're going to have to rig some sort of remote fuel line with valve. That's going to be a bit messy but if you're going to regress that far, why would you want an electric petcock anyway? It's electric, so it must be unreliable. Outside of that, you'll need some carbs and mount adapters. It's probably going to be too complex to make the factory fitted air intake system fit the carbs so you can ditch the air filter and associated intake plumbing in favor of filter pods. That's not all that bad, the air filter in the small blocks is a bitch to change. Next you'll have to adapt the cables for throttle and choke from those provided for the FI system. Okay, with the carbs adapted and wiring modifications done for the points and coils, you're pretty much only going to have to do jetting for your custom installation. If you're an expert at this and love spending hours getting it right - kudos to you. If you get it just right (at one altitude), you'll be about 90% as good as a well set up FI system (like the V7 Classic has) but unlike the carbs, the FI will work without intervention at any change of altitude. No re-jetting necessary for FI bikes. If you're really into the regression mode though, you can investigate using a magneto to replace the points and coil and there are some fine bikes at various museums with kerosene headlamps that you can emulate so you can get rid of that pesky electric headlight.

Don't take this personal because I'm being a bit sarcastic. There have been some Guzzis with absolutely dreadful FI characteristics and some owners did revert to carbs. The Sport 1100i is probably the worst of the bunch in that regard. The real problem of those was a combination of poor ECU programming/mapping and timing stutter caused by a loose cam chain tensioner. For the most part, FI was applied to that bike to try and get by the equally horrible performance of the carburation on the preceding Sport 1100. Getting the FI on the Sport 1100i's and some of the other spine frame Guzzis has been the holy grail of a lot of owners and there has been good progress there. With the current Guzzis though, the FI system is pretty mature and with the factory providing update maps as required the reasons for reverting to carburation pretty much whittle down to appearance. There is no performance increase with carbs that would merit the cost of the conversion. Or... if it ain't broke - don't fix it.

 

[moto]

What in blazes is wrong with you people?

The man wonders about what would be involved in converting to carbs, not whether you think it is a stupid idea.

Why would he have to convert to points ignition "if you're going to regress to carbs"? I didn't change to fuel injection when I moved from points to electronic ignition! Why mock him some more and suggest he doesn't want an electric petcock??

It seems to me he needs two used carburetors, throttle cables and a throttle. And he would like to know if the intake manifold is still appropriately made for accepting the old carbs. If not, he'd like to know whether he can change the manifold to the old one that took the carb.

If there is some feedback from the throttle position sensor that he needs to get the ECU to function then he'd like to know about hooking that up to the throttle cable somehow.

What he doesn't need is your collective churlishness.

I'm sorry to say I have no information for him.

Moto
(John Logan, Madison, WI)

 

[john zibell]

What is boils down to is this. If he likes the looks of the V7 classic, but wants a bike with carbs, it would be easier and more cost effective to take a v65 or similar and put V7 classic trim on it. The work and expense involved in going the other way is both technically and financially challenging. I'm not even sure it could be done without an extensive parts inventory and machine shop access to modify parts of the bike.

 

[Mark111]

Wasn't going to buy in to this but here we go.
Moto,
A bit harsh.

I think the comments from the others should be read in context.
This is a major undertaking and the costs involved would be prohibitive and I think the other guys are just trying to give him a warning and emphasise what he is in for.
Acrata
The reason you haven't seen info anywhere else is because it is a mammoth task not necessarily because it can't be done, probably no one has been brave or ...... (insert word of choice) enough.
The last post from John is the most viable way of achieving the desired result but would still be very expensive unless you have access to very cheap parts.
If it is going to be used as a track bike it would be an interesting exercise but I can't see any way it would generate better performance than a similarly modified and well set up Fi engine.
I'm not sure what the registration requirements are elsewhere but in Australia you wouldn't get this conversion registered for road use as it would not meet the pollution standards for a modern bike, worth checking out before you start.
In regard to the injection side of things I personally don't think carbs will make the bike simpler to tune and maintain.
Many people still have a phobia about FI but I pose this question in response, how many cars, trucks, bikes etc run trouble free and neglected on a daily basis with fuel injection and many run 10 times the mileage that a bike will do?
I don't actually know the answer but I would confidently say it would be in the 10's of millions so the technology is well proven and in real terms trouble free.
Anyway good luck if you have a go at it, your much braver than me.

Mark

 

[Penis Rotor]

There is also the fact that the dash won't work without the ECU and visa-versa. The dash also controls functions like the indicators.

If you were to try to do this you would need to swap the cam and the timing chest casing to enable the fitment of a points or Dyna S setup along with advance weights and all the other points crap. You'd basically have to re-loom the bike or at the very least fit a sub-loom to cope with the stuff no longer required.

It would be a significant undertaking, not one I'd be willing to undertake but perhaps you have significantly more time, money and energy for such a project than I do?

As for the simplicity and reliability statement I think this was summed up almost perfectly for me on two separate occasions in the last few years. A fair number of years ago when I too was still an FI neophyte with deeply held suspicions about electronics Cliff Jeffries of myECU fame came up to my workshop and talked me through his My16M computer. I was impressed but said to him in my typical whiny way that the great thing about carbs was that all you had to do was change out a few bits of brass and alloy and you could eventually make them run sweet. He looked at me as if I was deranged and slightly mentally defective and said "Yes. But if you do that you SMELL!!!! It was a 'Come to Jesus' moment for me. I realized he was quite right. I would no longer have to regularly wallow around in carcinogens and filth! all I needed to do was punch buttons on a keyboard!!!

The second was only a few weeks ago when a mate with a Stelvio came around and we were discussing the, as we saw it, rather odd fixation with obsolete ignition and fueling technologies. His statement was that the great thing about points and carbs was that you can fix them at the side of the road. This he pointed out was a good thing as that is invariably what you do end up doing! Fixing 'em by the side of the road.

Certainly if you do proceed with this endeavor I wish you the very best of luck but I counsel you to think long and hard before you embark on such a project as it will be difficult and costly..

Pete

 

[Brian UK]

It seems to me he needs two used carburetors, throttle cables and a throttle. And he would like to know if the intake manifold is still appropriately made for accepting the old carbs. If not, he'd like to know whether he can change the manifold to the old one that took the carb.

If there is some feedback from the throttle position sensor that he needs to get the ECU to function then he'd like to know about hooking that up to the throttle cable somehow.

Moto
(John Logan, Madison, WI)

You have conveniently omitted the bit about removing the fuel pump assembly from inside the tank and providing another fuel feed with petcock for the carbs.
It is also unknown whether the existing ignition system will work on it's own without the FI part.

How about taking a late carbed 750 engine and putting it into the V7 frame? You may even get more power from it.

 

[ghezzi]

Mate, one of my dreams has been to take the original V50 Monza at 153kg dry, add a motor from the new 750 range and tune it to with in an inch of its life on carbs etc.

I reckon adding carbon wheels from a GP125 bike (plus other mods) would help get it down to 125kg, just a light weight toy for the track that looks like a vintage 250.

If your carb conversion appeals to you what does it matter what it costs, its your dream, your pleasure, your baby.
Most of my mates have been smoking and pissing a $200 a week up against the wall for most of their lives, all they've got to show for it is a fat gut and heart disease. Fuck the naysayers here, go and do it.

Todd can reflash standard computers, or you can throw the ECU away and get a motec or whatever and Smiths Chronometric guages, hell its only a couple of months worth of piss and drugs to the average bloke.

Pioneers get more critisism than support, but you will find your supporters and go for it.

Hey, I've got an Aprilia RS250 in the shed that's cost me close to 25k so far and its still not going.
Its got an RZ350 (banshee) based engine at 485cc. My mate has just got his going, it sounds like 50hp at idle.
Anybody who hears it for the first time falls over pissing themselves laughing ............................... its wild. :evil:

 

[Carl Allison]

Since I made pretty snarky post earlier, I'll delve into what I can actually speculate (not verify) would work to change over to carburetion on the V7 Classic.

There is also the fact that the dash won't work without the ECU and visa-versa. The dash also controls functions like the indicators.<snip>
Pete

These are the Norge dash connectors functions as compared to the V7 Classic dash connector.

Actually, the ECU is pretty much stand-alone from the dash on the V7 Classics. While the ECU provides a pulse for the tach input, pretty much everything else is just indicator functions or turn signal outputs. On previous FI model Guzzis, the tach pulse has been the opposite polarity from the pulses from a coil system and probably is on this one as well. That's not something that's very difficult to flip over with some additional electronics. BTW, I missed labeling the function of pin 8 on the V7 dash. It is an error indication for over-voltage on the O2 sensor. I'm 99% certain that the dash could be made to work with a carburated setup. Murphy owns that other 1% though...

Ditch the ECU itself and use a Rec-Ignition Module and gain the ultimate flexibility in triggering, dwell and advance funtions for the coil. Since it has variable dwell settings, you should be able to use it with the stock FI coils. Big Plus there. No TPS required either, just dial in the advance curve you want.

I'd use whatever type of carbs were on the V75 of years past, that should be better matched to the input requirements of the V7 engine. I hope. Lord knows I'm not a carburetor kind of guy.

With a little experimentation, it might be possible to just remove the pump from the tank flange and allow fuel to just flow through the ball valve tank fitting. You would want to put a fuel valve downstream from that as well as a fuel filter designed for the low pressure of a gravity fed system. Don't use the filter in the tank, it's designed for 42 psi or so and for a gravity fed system, is probably too restrictive.

That pretty much leaves wiring interfacing and adapting the cables from the handlebar switch assemblies to function as choke and throttles instead of partial throttle advance and TB controls.

If the carbs can be adapted to the FI air plumbing - good. If not, go pods.

That leaves jetting, something I am infinitely not qualified to go into.

What's the total cost? The Rec-Ignition module and carbs and bits and pieces to adapt hardware plus time. Perhaps some wiring connections and associated connectors. If the harness on the bike has to have the ECU connector removed to splice in the alternative ignition system (doesn't matter what kind here) - there will be no going back to stock in any reasonably simple fashion.

 

[acrata]

Dear all, thank you very much for your replies...it's taken a little to get this topic going, but I'm satisfied with the answers, so thanks a bunch.

Just to clarify a couple of things...I usually don't take sarcasm personal..not worth it. As moto said I was only trying to get some information on a subject which is no such taboo (for lack of a better word) in other motoring circles - i.e. converting a FI 2.1 VW engine to carbs. I do love the V7, but I'm not as knowledgeable when it comes to bike mods as I am with VW T3 Syncros (mind you, not an expert on it either), so I wanted to get a better understanding of the work involved. In addition, I never said I was going to go ahead with this mod...only wanted some info on the topic as I thought it might be a common/not too difficult mod and hadn't seen any info around, so I was curious. I tried to put that point across on my first two posts, but I'm a straight talker and sometimes folk think I'm being sarcastic when I'm not.

Anyways, I got a lot of useful info so thanks to ALL contributors of this topic

Best
Rob

 

[Corn Oil Kid]

I'm not being sarcastic or anything but genuine, when I ask why you would think such a mod might be common?

 

[acrata]

I'm not being sarcastic or anything but genuine, when I ask why you would think such a mod might be common?

That's because I wrongly assumed that what applies to cars will probably apply to bikes too...I realise now this is not the case, but I had to ask in order for me to know...it's all down to my ignorance on the field, really...

 

[acrata]

What in blazes is wrong with you people?

The man wonders about what would be involved in converting to carbs, not whether you think it is a stupid idea.

Moto
(John Logan, Madison, WI)

I greatly appreciate your words John

 

[Carl Allison]

Well Acrata, you got us all to exercising the grey goo in our skulls.

 

[Corn Oil Kid]

Good enough answer for me, I guess I'll put this box of rocks I was going to start chucking at your head down. :lol: :lol: