FairWeatherFellow Posted April 10, 2017 Share Posted April 10, 2017 Ok guys so I've been busy dialing in the viffer. I got it dyno'd when I first got the bike and was running a bit rich, but the power curve was good and it ran great. I fixed the busted main header on cylinder 3, put on a non restrictive mid pipe, plugged the air box mod hole, put in a Piper cross air filter. Hoping I'd lean out a bit. I dyno'd it the other day and I'm even a bit richer that before. Dyno tech informed me that having better airflow could help make a richer environment for I'm pulling more volume and air which pulls more fuel as well. Which means I have carb work in my future. He said start by going down 5 on the main jets. I understand what that entails; so what size are the factory jets? Also I don't know if there was prior carb work done, if they aren't factory jets how would I tell the size of them so I could go down from it. I'm newer to carb work but I've been researching how they work and to better understand what I'll be doing. Just unsure of the specs for them. Any info helps and is much appreciated! Bottom chart if the first run on the dyno, top chart is the run I did Saturday. Also they changed the software and there's a 5% accuracy difference in number. So no I haven't lost power, I just have to lean her out a little to better my numbers. Link to comment Share on other sites More sharing options...
douglasthecook Posted April 10, 2017 Share Posted April 10, 2017 You can find jet kits for the VFR, but they're not as common as they used to be. There was a company by the name of Factory that sold them, you could check them out. That's where I got my jet kit from, SEVERAL years ago.....You'd be changing jets and adjusting the heights ofthe needles. It isn't a difficult job, but is kinda tedious... http://www.factorypro.com/ Link to comment Share on other sites More sharing options...
750 Posted April 10, 2017 Share Posted April 10, 2017 Whatever you do, do NOT go with dynojet. Get a kit with factory pro. 130 are the mains, I THINK...not 100% sure. You'll likely need 126 mains like I have, my set up is very similar but I have a left exit exhaust with no rear manifold or collector box. I also have a standard air filter but was advised I'd benefit from a K&N etc. Factory Pro will actually be able to tell you what they'd recommend for your setup - but you won't be needing larger jets from my experience. Link to comment Share on other sites More sharing options...
750 Posted April 10, 2017 Share Posted April 10, 2017 Oh and don't forget you'll likely need to shim the needles Link to comment Share on other sites More sharing options...
FairWeatherFellow Posted April 10, 2017 Author Share Posted April 10, 2017 Awesome thanks for the info. Do you know how to check the size of whats in there, are there marking of some kind? Also wouldn't shimming the needles make it richer? Thanks, Miles 1 hour ago, 750 said: Whatever you do, do NOT go with dynojet. Get a kit with factory pro. 130 are the mains, I THINK...not 100% sure. You'll likely need 126 mains like I have, my set up is very similar but I have a left exit exhaust with no rear manifold or collector box. I also have a standard air filter but was advised I'd benefit from a K&N etc. Factory Pro will actually be able to tell you what they'd recommend for your setup - but you won't be needing larger jets from my experience. Link to comment Share on other sites More sharing options...
FairWeatherFellow Posted April 10, 2017 Author Share Posted April 10, 2017 Also what stage kit would that be? Stage 1 2 or 3? Not sure what each stage entails. It also doesn't say so in the info ? Link to comment Share on other sites More sharing options...
coupedupsubie Posted April 10, 2017 Share Posted April 10, 2017 Most jets are stamped with the size if they are aftermarket, don't recall if any factory ones I have seen are stamped. Link to comment Share on other sites More sharing options...
750 Posted April 11, 2017 Share Posted April 11, 2017 I've got some standard ones in a box, I'll check them out for you. Unsure if you'd need to shim, you'd only be able to tell where you're at with a dyno run anyway. Unless you're fat, 55, bearded and pretend to be able to tune carbs by ear? :) Link to comment Share on other sites More sharing options...
FairWeatherFellow Posted April 11, 2017 Author Share Posted April 11, 2017 16 hours ago, coupedupsubie said: Most jets are stamped with the size if they are aftermarket, don't recall if any factory ones I have seen are stamped. Awesome, thanks! 1 hour ago, 750 said: I've got some standard ones in a box, I'll check them out for you. Unsure if you'd need to shim, you'd only be able to tell where you're at with a dyno run anyway. Unless you're fat, 55, bearded and pretend to be able to tune carbs by ear? :) That'd be great, I appreciate it! Haha unfortunately I don't appear to fit the stereotype! Trying to work a deal with the local tuner, paint his race bike to get the viffer all tuned up ? Link to comment Share on other sites More sharing options...
The Phantom Posted April 12, 2017 Share Posted April 12, 2017 Factory jets are 125 main and the factory jetting is rich - you need a serious exhaust system (full system) to need to go bigger than factory. Standard headers and aftermarket muffler, you can get by with factory jets. Link to comment Share on other sites More sharing options...
Member Contributer slo1 Posted April 12, 2017 Member Contributer Share Posted April 12, 2017 At 4k altitude we had to go down a step or two from stock, even with a full TBR system...... Link to comment Share on other sites More sharing options...
coupedupsubie Posted April 12, 2017 Share Posted April 12, 2017 I was told mine was rejetted when the TBR full system was fitted, based on the exhaust smell I am running slightly rich still. Link to comment Share on other sites More sharing options...
Member Contributer slo1 Posted April 12, 2017 Member Contributer Share Posted April 12, 2017 23 minutes ago, coupedupsubie said: I was told mine was rejetted when the TBR full system was fitted, based on the exhaust smell I am running slightly rich still. That's what happens when people assume they need to "Re-Jet" and just go bigger........ Link to comment Share on other sites More sharing options...
FairWeatherFellow Posted April 12, 2017 Author Share Posted April 12, 2017 Hmmm...Makes sense. Wouldn't surprise me if someone has been into the carbs before. Had a UMI filter, air box mod, and full TBR system when I got it. When the UMI was in it with the box open I had lots of pops on deceleration. Then I discovered the filter was completely deteriorated...Might of had something to do with it. Luckily for me I'm painting a race bike for the owner of a renoun NW bike tuner for trade work on my bike. Gonna let him do his thing ?. I'll be sure to post a fallow up with charts ? Link to comment Share on other sites More sharing options...
750 Posted April 13, 2017 Share Posted April 13, 2017 Never known anyone to go bigger on jets when fitting a race system (which mine is) - it's always a case of going smaller. Fairweatherfellow - I forgot to dig out the jets but it seems your question's been answered anyway. Can't remember what size are in mine now but they're smaller than stock. I'll double check over the weekend Link to comment Share on other sites More sharing options...
FairWeatherFellow Posted May 15, 2017 Author Share Posted May 15, 2017 I had some issues with the carbs recently (different maintenance question I posted about) I had to dive into the carbs and give them a good cleaning for the first time. I found some things that apply here too though. I saw how my bike was jetted for the first time, and it seems odd. Cylinder #2 just was unmarked but maybe factory? Not sure. Link to comment Share on other sites More sharing options...
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