Lean condition 2000 to 4000 rpm

[hymey]

I am seeking advice from experienced vtr owners. I am an Efi tuner from aus. I have owned my vtr since 2007. All I have done is a set of pipes. I have done a lot of dyno work with several jet combos. The issues I am having is lean condition at low rpm when I roll on throttle say 2000 to 4000 rpm. I have experimented and fitted very large mains ie 200 to find where the main jet has most influence and I found it goes super rich at 5000 rpm, but still has a major influence on low rpm wot. I started with a dj kit, 180 185 main 4 th clip, 48 pilots stock air box and filter. The bike ran very well, but on the dyno was super rich 11.0 to 1 afr, very flat fuel curve from 5000 to rev limiter. By this I can see the air jet is correct size. I leaned it out and found to get afr back to 12.5 to 13 to 1 where it makes best power I had to drop down to 165 170. The issue then being the lean condition from 2000 to 4000 rpm region. I increased pilot to 50 but was then to rich at idle with fuel screws all the way in pretty much. I then raised needle further to clip 5 still no good. Was 17 to 1 afr and backfiring . I tried the extra lift hole made it worse and caused hesitation at 5000 rpm. Went back to stock needles and springs. This seamed to work better but did not eliminate the lean hole. I again raised the needles to the point the engine was pulling fuel thru the needle jet at idle and causing hunting. I give up then. I went back to 180 185 clip 4 and 48 pilots and just left it as is. After reading the cv tuning section I found the float height has huge influence in this case. Looking at the float arrangement from memory they are non adjustable. I know in Holley carbs etc raising float height does richen low end. As it says in the tuning guide. Has anyone else experienced this. I will keep playing till I solve it, going bigger main to solve it is just a band aid so I will work on it till its right, any advice will be appreciated.!

[sirch345]

This link might be worth reading if you've not already:-
http://www.vtr1000.org/phpBB3/viewtopic ... 31&t=14214

And some more here:-
http://www.vtr1000.org/phpBB3/viewtopic ... 31&t=28922

Chris.

[leevtr]

I am by no means a tuner, but from experience of owning 3 storms, all with DJ kits fitted, not had one yet running badly, and all made good power on the dyno. Each time the pilots were left as standard, used 180 jets in both carbs & 4th clip on the DJ needles.( Basically the set up on the instructions supplied with the kit, EXCEPT drilling the slides, left them alone ) It's worked on 3 bikes for me, so maybe worth a try for you, isn't going to cost you anything. Oh, and always with standard air filter, mixture screws 2 turns out.

Hope this helps

[hymey]

Hi Lee. Does your bike run 48 pilots? And do you run 180 jet in rear too ? I have been looking at what the hrc kits have . They block air jet and run smaller mains around 150 from memory ? And use 40 thou shim under needles. And block one lift hole in front carb.

[leevtr]

Hi Lee. Does your bike run 48 pilots? And do you run 180 jet in rear too ? I have been looking at what the hrc kits have . They block air jet and run smaller mains around 150 from memory ? And use 40 thou shim under needles. And block one lift hole in front carb.

Not sure of the pilots mate, aren't they 45's out of the factory ?? Haven't touched them either way. Yes, both carbs fitted with 180's, as supplied in the kit. As far as lift holes, the kits instructions say to drill an extra, although the general consensus is to ignore that. I've never drilled the extra hole and its always worked well. This is my Dyno chart from the last 2 bikes, both set up in this way. The bike with better power had approx 37000 miles on the engine. The lower had 12000. Havent dyno tested my current bike as yet, but it feels good.

[hymey]

Lee . That is good results and I agree 180 ish mains and 4th clip seams to work with mine too. After going through and messing with carbs so much. The things I have found is they have poor atomisation. Due to being oversized. That is noticable from not being so fussy with air fuel ratio (AFR) mixtures. They do not tolerate lean conditions at all. Like 14.7 to 1 will cause surging and popping from poor atomisation. Hence needles have to be raised. Larger pilots and mains to compensate for lean low end. What I am going to do. Is switch to efi. With aftermarket ecu on the stock engine and eventually run 11 to 1 pistons and cams and cyl heads. I will be using closed loop for cruise. With injectors mounted under butterflies with excellent atomization means will tolerate closed loop 14.7 to 1 . I believe 50mpg is then acheivable quite easily. With the better atomization means the engine will start to show gains from leaner fueling conditions ie 13 to 1 across the board . I expect a 15 to 20 hp gain. With good torque increases. Very smooth curves and with a accel pump tables dialed in and aggressive power enrichment settings the bike will be super responsive. I will also implement closed loop in pe. With auto tune to dial afr in whilst riding on the road. I have a design in mind where I will mount fuel pump and reg and ecu. It will be a few months before I start. But looking forward to the mod.

[gl_s_r]

I think there will be a few people looking forward to that mod with the 20BHP increase your expecting... and the 50mpg.

I hope you get it to work as personally reading that meant absolute nothing to me.

[leevtr]

Lee . That is good results and I agree 180 ish mains and 4th clip seams to work with mine too. After going through and messing with carbs so much. The things I have found is they have poor atomisation. Due to being oversized. That is noticable from not being so fussy with air fuel ratio (AFR) mixtures. They do not tolerate lean conditions at all. Like 14.7 to 1 will cause surging and popping from poor atomisation. Hence needles have to be raised. Larger pilots and mains to compensate for lean low end. What I am going to do. Is switch to efi. With aftermarket ecu on the stock engine and eventually run 11 to 1 pistons and cams and cyl heads. I will be using closed loop for cruise. With injectors mounted under butterflies with excellent atomization means will tolerate closed loop 14.7 to 1 . I believe 50mpg is then acheivable quite easily. With the better atomization means the engine will start to show gains from leaner fueling conditions ie 13 to 1 across the board . I expect a 15 to 20 hp gain. With good torque increases. Very smooth curves and with a accel pump tables dialed in and aggressive power enrichment settings the bike will be super responsive. I will also implement closed loop in pe. With auto tune to dial afr in whilst riding on the road. I have a design in mind where I will mount fuel pump and reg and ecu. It will be a few months before I start. But looking forward to the mod.

You lost me at 4th clip !!

[VTRDark]

Well this will be a first...fuel injection on a Storm. Mmmmm I wish you luck with that one.

(:-})

[8541Hawk]

Hi Lee. Does your bike run 48 pilots? And do you run 180 jet in rear too ? I have been looking at what the hrc kits have . They block air jet and run smaller mains around 150 from memory ? And use 40 thou shim under needles. And block one lift hole in front carb.

While these are the setting that come with the kit, it is not what is run on the street with the HRC bits.
Blocking the air bleeds plays hell with the bottom end that you need for a street bike.
In my dealings with HRC and Moriwaki it was stated that blocking the air bleeds is only for running no air filter or in ram air set ups.

Also they state to run 1 shim on the front needle and 2 shims on the rear needle.

[8541Hawk]

Well this will be a first...fuel injection on a Storm. Mmmmm I wish you luck with that one.

(:-})

Well I do have one lead on this subject, though it is a bit different.
What was done was to turn the carbs into throttle body injectors.

I can dig up the info if you guys might be interested.

[hymey]

Mounting injectors is easy bit. I have done a lot of efi conversions and tune full time so I guess its doable for me. Ill be putting them in kits and running e85 aswell with a GM flex fuel sensor which automatically compensates for fuel changes.

[hymey]

Guy's. I am looking at using the haltech sprint 500 ecu. I will use this in conjunction with a haltech wideband with twin sensors. And closed loop control so I can command 16 to 1 at cruise and 13 to 1 peak power. With a good base map and the wideband trims the mixtures for different climayes and altitudes.

[gl_s_r]

Seems someone beat you to it and they sell firestorm injectors on eBay

http://pages.ebay.com/link/?nav=item.vi ... 1350874825

[Virt]

Seems someone beat you to it and they sell firestorm injectors on eBay

http://pages.ebay.com/link/?nav=item.vi ... 1350874825

Oh dear god, is it just me or is that description a formatting nightmare?