potheadpixi Posted April 6, 2009 Report Share Posted April 6, 2009 Has anyone tried setting up carbs using a CO meter on the road / track ? I've got a project 837cc track bike based on a '97 VFR750... It's running the standard RC36 CV carbs with stage 1 dynojet kit, RC30 airbox, K&N and a race can. When I fitted the 837cc big bore kit I had to reduce the main jet size back to std to resolve a loss of power at the top end. The engine now pulls strongly, but I feel that it's still running too rich in the mid range. I live in the Channel Islands and we have no dyno facility here. Has anyone tried / had success setting up carbs on the road / track using a CO meter ? I have access to a decent portable unit and would like to have a go improving my fuelling using this equipment on the road. What I'd like to know is (roughly) what CO readings I should be looking for at different speed ranges during roll ons / constant RPM. Hopefully I'll be able to try a few needle position changes / swaps, improve the power delivery. Can anyone help ? Cheers. Link to comment Share on other sites More sharing options...
porter_jamie Posted April 7, 2009 Report Share Posted April 7, 2009 http://www.perfectpower.com/Technical_info/afr.asp table of co v. afr personally i think this is a load of bollux. if you want to get it right, there is only one way, and that is a wideband lambda, a dyno, and an operator who knows what he is doing. Link to comment Share on other sites More sharing options...
spacemonkey Posted April 8, 2009 Report Share Posted April 8, 2009 http://www.perfectpower.com/Technical_info/afr.asp table of co v. afr personally i think this is a load of bollux. if you want to get it right, there is only one way, and that is a wideband lambda, a dyno, and an operator who knows what he is doing. I would suggest this is not the only way but certainly the easiest way. - And it doesn't require that you learn all about carbs.... Link to comment Share on other sites More sharing options...
V6Jon Posted April 8, 2009 Report Share Posted April 8, 2009 I live in the Channel Islands and we have no dyno facility here. Not sure where you are, but I am in Guernsey, and it pisses me off that there have been two proper dyno's installed over here, and they have never bothered getting anyone trained to use them for anything more then producing power graphs. Am considering a full systems / filters etc, but just can't afford to take the bike to the UK to get it done properly at the moment I am also puzzled at the number of modified bikes over here, they can't all get taken to the UK to get set up shurely J Link to comment Share on other sites More sharing options...
spacemonkey Posted April 8, 2009 Report Share Posted April 8, 2009 Not sure where you are, but I am in Guernsey, and it pisses me off that there have been two proper dyno's installed over here, and they have never bothered getting anyone trained to use them for anything more then producing power graphs. Am considering a full systems / filters etc, but just can't afford to take the bike to the UK to get it done properly at the moment I am also puzzled at the number of modified bikes over here, they can't all get taken to the UK to get set up shurely J The trouble is that the quick power curve/Power Commander monkeys make more money than a guy that takes the time to muck around with stuff and engages his brain. Not many people are happy to pay for a real professional to spend hours on thier bike to fix what might be a very minor but difficult to isolate problem. Link to comment Share on other sites More sharing options...
potheadpixi Posted April 8, 2009 Author Report Share Posted April 8, 2009 Not sure where you are, but I am in Guernsey, and it pisses me off that there have been two proper dyno's installed over here, and they have never bothered getting anyone trained to use them for anything more then producing power graphs. Am considering a full systems / filters etc, but just can't afford to take the bike to the UK to get it done properly at the moment I am also puzzled at the number of modified bikes over here, they can't all get taken to the UK to get set up shurely J In Jersey mate ... I knew that there was a dyno over on your rock for a while, last I heard it was decomissioned and gathering dust, which is a real shame. To be honest i'd like to buy it, but I don't think the owner is willing to sell. I'd love to have one just to learn with as I am a mechanic. Realistically, I don't think that there is enough demand to justify having a modern, calibrated dyno here in the islands - you'd need to hire an experienced operator to get good resuts for a start, and once you've set up John Smiths GSXR you probably won't see him again for a long time. We had one in Jersey about six years ago, but he went bust before he really got going and the equipment was sold off by the receivers. (to UK). I know what you mean about getting the bike over to the mainland just for a set up... Condor Ferries prices are sky high - About £400 return for a van + 2 passangers ! Then B&B, food, risk of bike getting nicked by spotty chavs etc. Re our modded bikes... I know a few guys who have made the effort and got them setup in the UK - mostly track or race bikes though. The rest seem quite happy to spend £££ on tuning parts and then charge about with a less than perfect setup. I believe there is a Kawasaki dealer in Rennes (France) with a dyno, but they only use it for power checks and not for set ups. Just been looking at wideband air / fuel monitoring equipment - a much better method than using a CO meter... Some of the equipment out there looks pretty good and less than the cost of a return ferry ! I'm partilularly looking at the Innovate LM1 / LM2 systems - which allow real time monitoring of multiple sensor inputs - including wideband lambda, and a data logging facility to record the measurements during road or track testing... this would allow me to fine tune the fueling, and will also calculate any performance increases gained by measuring the time it takes to accelerate between two points in the rev range. I'd be really interested in hearing from anyone out there who has had the opportunity to use one of these types of units. Cheers ! Link to comment Share on other sites More sharing options...
potheadpixi Posted April 8, 2009 Author Report Share Posted April 8, 2009 The trouble is that the quick power curve/Power Commander monkeys make more money than a guy that takes the time to muck around with stuff and engages his brain. Not many people are happy to pay for a real professional to spend hours on thier bike to fix what might be a very minor but difficult to isolate problem. I agree... You never got all this before fuel injection came along. No USB port on a set of flatslides ! Link to comment Share on other sites More sharing options...
porter_jamie Posted April 8, 2009 Report Share Posted April 8, 2009 dynojet wideband commander - google it, some outfit called superbike toy store has them for 277 quid. i think that is really cheap, since it uses a bosch sensor, and has built in logging of afr, RPM, and tps, so more or less everything you need. also, it has an analogue dash gauge of AFR, so you can ride it about and get a real time measure of what is going on - this really helps in my experience. the only 'issue' is because you can now see your afr at all times, you start to obsess about it! it even comes with a boss to weld on the exhaust for the sensor. it works well and uses exactly the same sensor as the dynojet wideband modules on the dynos Link to comment Share on other sites More sharing options...
spacemonkey Posted April 8, 2009 Report Share Posted April 8, 2009 I was going to suggest the LM1 logging lambda, wheel speed, rpm and TPS as an alternative. I used the LC1 into an AIM mychron dash on my own bike in the past logging the channels listed above - you need something that allows you to reference what load the engine was under when you look at your logged lambda, hence the wheel speed and rpm to allow you to work out what gear you were in and TPS to tell you whether the engine was labouring or keeping up. Yeah, I should have suggested that... I've used an LM1 with great success. I just logged TPS voltage, Wide band Lambda and engine speed. Cheap compared to a large number of dyno runs! As Pothead says... No usb port on carbs.... But they aren't so complicated as long as you think about it.... Link to comment Share on other sites More sharing options...
vfroem Posted May 16, 2009 Report Share Posted May 16, 2009 You have to 'open' the airbox to get the maximum Hp's. The engine needs much more air than standard. Best carbs for your bike are the RC30 carbs with (dyno)kit. (tried really everything -with dyno!-; Keihin FCR39 Flatslides, RC30 and RC36 airboxes, 4 K&N filters) My VFR837F engine: JE pistons Flowed head VFR800 inlet valves VFR750F modified outlet valves Reshaped cams (quicker profile) RC30 carbs with HRC mods K&N panel filter Custom made Durbahn airbox Ignition changed Link to comment Share on other sites More sharing options...
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