The Varastorm Dyno run

[Varastorm]

My Big day & here are the specifications

Pilot
Front------1 turn out.
Rear-------1 1/4 turns out.

Pilot jets
Front------#48
Rear-------#48

Needles
Front------no washer at all.
Rear-------1 Std washer.

Mains
Front------#175
Rear-------#178

Slide holes
Front-------1 open.
Rear--------1 open.

Air filter------Std.

Ducati stack mod.

Varadero cams.

No porting.

Not too sure why the poor picks They are spot on before transferred to Photo bucket







The discrepancies are down to me Because I was the one running it on the rolling road

4th gear full throttle power rollons from 2000rpm to limiter, with Std cct installed

What a hoot

Bit of a problem at 6000-6500 Rpm any advice appreciated

[NZSpokes]

On my computer I cant read the dyno runs.

[lloydie]

Same here

[VTRDark]

Bit of a dip in the fuelling there but nice torque curve and it's best to tune these to torque. Not sure what to say about the dip but I had a similar dip myself in one of my runs. I couldn't notice anything on the road though. I put mine down to my exhaust which has a slightly narrower link join between the left can link and the header outlet. My custom bodge.

That's what I would call abstract photo's Looks like the files have got corrupted along the way.

(:-})

[Varastorm]

That's what I would call abstract photo's Looks like the files have got corrupted along the way.

Or it might be me using the wrong setting on the camera

Bit of a dip in the fuelling there but nice torque curve and it's best to tune these to torque. Not sure what to say about the dip but I had a similar dip myself in one of my runs. I couldn't notice anything on the road though. I put mine down to my exhaust which has a slightly narrower link join between the left can link and the header outlet. My custom bodge.

I was thinking along them lines Carl.

If there was such a significant hole in the fueling, then where is the fault in the power/torque graph

I have taken some photo's more of the sheets Hope there ok

Here goes

[Varastorm]

I have been busy reading about various jetting setups & thinking about what step next.

I am not too sure about the hole in the fueling @ 6000-6500rpm so will leave that for the moment. (hope its a fault like Carl pointed out)

The fueling is definitely rich across the range, so this is what I'm thinking.

I think the Ducati stack mod has vastly increased air flow into the carb mouth & is causing the engine to run rich.

The pilots are around a turn or so out, the needles are as low as possible & the mains are Std & its still rich.

This is the plan.

Pilot
Front------2 turn out.
Rear-------2 1/4 turns out.

Pilot jets
Front------#45
Rear-------#45

Needles
Front------no washer at all.
Rear-------1 Std washer.

Mains
Front------#172
Rear-------#175

Slide holes
Front-------1 open.
Rear--------1 open.

I plan to refit the #45 pilot jets, purchase & fit a #172 main for the front & around 1~1.25 extra turns out on the mixture to compensate the smaller pilot jets.

This will be the new base setting & I will take her for another run to cross reference & report back

I think the rule of thumb is if you are 3 turns or more out, go to the next larger sized pilot jet, or 1 turn or less out, go down 1 size.

Any advice welcome

[VTRDark]

That all seems logical to me. More air=more fuel drawn through so a tad smaller on the mains. Up one size on the pilots and open the A/F by 1 turn out.

Yep pilot fuel screw should be ideally between 1 and 3 turns out, though I have seen them with/and have experimented with only 1/2 turn out and 3.5 turns out. What is interesting is the different feel from having say, larger pilot jet and lower needle from having a smaller pilot jet and higher needle.

I think it's the fuel screw position that makes the most subtle changes. To me there seems to be a very fine borderline between to rich and booggy to being to lean and getting coughing and spluttering. Also the bike can feel more snappy/responsive with 50 pilots and only 1/2 to 3/4 turn out on the fuel screw against being less snappy/responsive but smoother with 48's with 1.5 to 2 turns out. These kind of things don't always show up too well on a dyno but out on the road seat of the pants it's very noticeable.

I have a feeling you might find yourself going too far the other way now. It's not easy to get things spot on. These CV carbs are a bit course so to speak. To get such fine tuning one needs to start looking at the transitional area between pilot and needle which happens to be the area where people complain about carb cough spitting back and also where K&N seems to stumble the majority of the time. So that's then moving onto the slide cutaway and/or the size and/or amount of lift holes in the slide. Food for thought there.

For now I think your going in the right direction. But guess what.....if you go playing with your cam LSA your most likely going to have to start all over again with the carbs

(:-})

[Varastorm]

Again, big thanks Carl for the mental backup.

Just pulled the bike out ready for stripping again & thought about how much does a (performance) aftermarket filter lean out things? Anyone know?

Preparing for the run yesterday, I gathered all my bits (spare slides, jets, Dynojet kit & tools) together in case there was time to change a few settings. Then I remembered about an old Std paper air filter which I had butchered & replaced the paper with RamAIr foam & glued in with E6000 glue from EBay.

A few years ago this is what I wrote in the XRV.org forum about it.

Ramair Filter mod.

I just thought that some of you might find this tip useful as a K&N or Pipercross hover around the £50-£70 mark.
I have done this modification to quite a few of my own and friends bikes and all are happy with the results and price.

1.The next mod is my own Pipercross type air filter. I purchased a sheet of some Ramair filter foam for £5 off EBay and some E6000 glue (again from EBay) this glue will not harm the foam! Motocross guys swear by it.
2.Firstly you need an original (dirty) air filter and cut away the entire paper element. Cut your foam to the required shape with a scissors (Patience needed). Make sure you have it fitting snug with no gaps or buckles (too tight). Remove foam and run the glue about 3-4mm thick/wide around the frame were the foam filter will sit/Touch. Position the foam in place for an air tight seal.
3. Full strength of the seal is 72 hours.

It did work, but how much? If at all, it leaned the mixture, only the dyno will tell.

Personally I am not too keen on K&N's, But It would be interesting to see how much a K&N does lean things out, anyone done any tests?

BTW, best place for a ~172 main jet?

tony.mon wrote:
If you want to buy genuine Keihin main jets you need to get jet type: KEIHIN 99101-393

[VTRDark]

More free flowing airfilter is getting into this territory. Some interesting results later on in this thread over the pond especially with regards to fuelling, but it's all experimental.
http://www.superhawkforum.com/forums/mo ... lid-31606/

As for main jets make sure they are Keihin N424-Serias 21. You can find loads on the bay but not necessarily the best quality.

Here we go some more info.
http://www.vtr1000.org/phpBB3/viewtopic ... 15#p342511

(:-})

[Varastorm]

Just an idea, I have the carbs off & have changed the #48 air jets to #45 & Pilots out 2---2 1/4 respectivley.

Before (whilst I have a cuppa) I put it all back, I was thinking of replacing the Std needles with Dynojet needles (That's all I have) to enable me to lean in that sector. If I did, what height clip groove does any one recommend?

I appreciate the needles are totally different, but they are all I have to work with & its way too rich at the moment any way

BTW I am only going to use the DJ needles

Help appreciated

[VTRDark]

Dynijet say to put the clip on the 4th clip (from blunt end) with their setup but yours is not that same setup as theirs. I'm running Factory pro needles which have 1 less clip position compared to Dynojet and I'm on the 3rd clip. That don't help much I know. All I can say is that it's trial and error but I would start with the 4th clip.

(:-})

[Varastorm]

Thanks for the advice & the links Carl.

Time was against me as the bike was in bits outside, so I decided to leave the needles/mains & run it with the free flow (homemade) Ram Air filter instead.

All back together now with #45 air jets fitted, Pilot~ 2 turns out front, 2 1/4 out rear.

Seems easier to start & snappier throttle also. You could say it sounds raspier, nastier too

Had enough today so will update with a seat of the pants test asap.

Hopefully it will run okay & will be interesting to see what's what on the Dyno again

Big thanks

[NZSpokes]

I can confirm the bike richens up a lot with running DR Honda trumpets. Mine did.

But Im on the FIL mod now running 210 mains........

[Varastorm]

can confirm the bike richens up a lot with running DR Honda trumpets. Mine did. But Im on the FIL mod now running 210 mains........

210's Can you remember what carb setting you where running before you did the FIL mod

Do the setting I have used sound similar Thanks in advance


Out of interest. Can anyone give me an idea of how much of an improvement I will see if I can get it closer to 12.5 A/F ratio

[Varastorm]

Update on the modified dyno jetting setup.

Just an idea, I have the carbs off & have changed the #48 air jets to #45 & Pilots out 2---2 1/4 respectively.

I also swapped the Std filter to a free from foam (ram-air) modded one.

Firstly the bike now requires choke to start & setting off out of town on low rpm seemed fine (cold engine, high gears & low speed).

A quick squirt down the carriageway seemed fine also, but on the slow roundabouts it felt poor, as if it wasn't clearing its throat low down.

Through the 30mph villages it now will not hold or pull from top gear at 30mph. It used to, fine, its as if the chain is jumping teeth on the sprockets. Really poor (eight stroking?).

During one of the 30mph top gear runs I tried pulling some choke, thinking it was too lean after the jetting change & I would see/feel an improvement. But it was worse, I had to quickly clutch in before it stalled on me.

So, after reading (lots) more on the pilot jet side of things I feel that I am a bit lost as which way to read the air pilot jet. I have exhausted Google & I cannot find an answer, only what peoples settings are.

So just to clarify.

I know that to increase the main jet & give it more fuel you increase the number on the jet
I know that if you want to give it more fuel on the pilot screw you unscrew the pilot screw
I know what happens when you play around with the throttle slide cutaway radius
I thought I knew what happens with the air pilot jet

Going from #48 to #45 pilot jets seems to of richened the pilot circuit.

Am I right to think that the bigger the number on the air pilot jet = the more air it flows?
Or the bigger the number on the air pilot jet = more fuel it flows?

The Std Varadero carbs have got #42 air pilot jets so was thinking of fitting them & seeing what the outcome is, before I order #50's but then I have read that the Std air pilot jets carry the same number but have different hole heights...

Any help appreciated as I am going to start stripping it again in a minute