The Varastorm Dyno run (VTR cams)

[8541Hawk]

if there was a needle issue it would have been found a long time ago.

8541Hawk, I feel that it's pointless answering/arguing with you with my thoughts on filing needles as you can come across quite aggressive in getting your point over.

But obviously I do feel the needle profiles can be changed so they work better for me & my bike.

All I am looking for a linear'ish 13/1 AFR in the needle fuelling zone & I do believe it's the needle profile causing the lean issue around 3000rpm & not the slide speeds like you do.

I also recon that there are other ways to solve the problem, but I have chosen this way. Ways skin a cat & all that....

We obviously have differing views & while I respect yours & am grateful for the information you post, I am keen to continue on the path I have chosen at the moment.

I do apologise for being a little rude not answering your questions as I was hoping to of posted the dyno graphs up by now so we could all see them & comment on the outcome for ourselves

The I guess it's pointless to try to help you.
That is what I have done, though you don't appear to feel that way.
More like I have to prove I can do it a different way than everyone else.

So here's a deal. You stop telling folks they need to this or that to their carbs and just say what you are doing to your bike, as it is a different system than what anyone else is running.
And I won't post up saying that I believe you are wrong and why.

Sorry you think that is aggressive because I give reasons for the points I am making, I have always thought you should say why you believe something when talking a technical issue not just Oh I recon your wrong.

With that good luck......... and I'm wrong again if I say at 3K the slides haven't opened yet

Though I don't think you even read any of my stuff as the questions about the XL parts was also ignored and that can be a major player in getting things to work.

Carry on

[Varastorm]

8541Hawk, here is the spec of the bike.

It’s a 2000 model carby Varadero, running VTR carbs & STD air box with paper filter, pair removed, Ducati 916 intake trumpet mod with a slightly modified snorkel to avoid water pipes.

STD headers, with Renegade link & straight through silencers.

It was running well for years (your specification) but I was getting poor mpg.

Then I heard about a Dyno that had opened close to home & promptly booked my first Dyno run. It highlighted over fuelling issues which I didn't realise I had, so have been attempting to sort it out since.

Here's the pick of the run & link to the thread.



http://www.vtr1000.org/phpBB3/viewtopic ... 36&t=35924

Since the first Varadero cam run, I have changed to the setup in this thread & have gone down the road of attempting to adjust one fuel zone at a time to achieve my 13/1 goal. But also realising they all have an effect on each other.

Firstly I went down the road of fitting various main jets & tried all combinations of 168's, 170’s, 172's, 175's,178's all with high speed runs to pinpoint the best performing jets.

Then, in my eyes the graph pointed to the needle area being rich. So with the Std needles as low as possible, it left me with no choice but to dig out the DJ kit I had previously given up on & try again with them.

What I found was that the needle, when lifted or lowered did not give good linear afr results across the fuelling zone & I thought it should.

It was either one or the other, a trade off you might say.

Good low 3000rpm, but poor 6000rpm (4th groove)
Or poor 3000rpm but good 6000rpm (2nd groove)

This was tried for days, going back & forth with needle heights, to home in on exactly what changed what & when. Nothing else was being changed during this process .

This is when I came to the conclusion, that if I can get the bike to run fantastic in either fuelling zone's with only slight modifications to clip groove height. It has to be the needle.

The difference in acceleration at 5000rpm with the clip in the 2nd groove is very impressive & something I want out of the bike.

That has lead me to try & sort out the 3000rpm lean issue by attempting to use larger pilots to manipulate & help the situation. Even to the point that it was practically flooding the pilot circuit with #52's.

Since the Varadero cam Dyno run I have sanded/de flashed the intakes (finger ported )as far as the valve guide.

I have also fitted VTR camshafts & timed to the specs in Carls excellently written Cyborg links: thumbup:

It is also running a lightened flywheel: thumbup:

I appreciate the VTR also has double valve springs to avoid bounce at higher revs. But seeing that the peak power of the VTR cams comes in under the Varadero's rev limiter, I have not looked into splicing the VTR loom into a Varadero's......Yet

Since the last VTR cam Dyno run I have filed the needles as you know & do feel I am there now only requiring a Dyno to see if I have achieved my goal of a 13/1 AFR.

BTW, Phoned the Dyno again today, still no answer

[VTRDark]

That's a superb explanation of all the mods and processes you have been going through. Far from standard ay You know what, this may very well turn into one of those things you will be always chasing as there are so many variables here and like you say there's the ignition side of things to consider too. The fun is in the chasing.

I for one thank you for all your trials and tribulations and posting descriptive posts including dyno runs etc. I look forward to the next one and it's something that maybe we can all learn something from. It certainly will be interesting to see what the dyno makes of them needles. I think we can safely say you have entered the world of Black Art

(:-})

[8541Hawk]

The one question no one seems to want to ask is why do I feel that filing the needles is a last resort and not a place to start.

For me it has to do with how the system works.
You have a round needle with a taper in a round tube and are using the clearance between the needle and tube to meter the fuel.

Now you put a flat spot on your needle. For discussing sake lets say you end up with 20% of the needle O.D. with a flat spot just for an example to keep it easy.
What happens when this bit tries to control the fuel flow, 80% of the needle will be flowing one rate with one size droplets and the the other 20% will be flowing at a higher rate with larger droplets due to the larger opening to flow through. What will this difference due to the atomization of the fuel and how much will just drop out of suspension due to being too big of a droplet for the airflow at that range to pick up?
Also what issue can be caused by all the larger droplets being concentrated into one small area?

Which leads me to believe, IMHO, that yes you can make your own needles but it also can add a whole new list of issues to deal with or to me, the last resort.


Now I asked about the rest of your set up because you have to look at the whole system, especially when "strange" issues pop up.
First what do we know about a FireStorm?

The important bit is that they are extremely sensitive to intake and\or exhaust changes.
We have all seen the exhaust experiments and have seen that most have issues and end up with a hole somewhere in the power band and the stock 2-1-2 is what the bike wants.

Another way to look at it is by doing something as simple as going to the high mount exhaust will loose you on average of 2HP due to the slight increase of length of the exhaust system.
Doesn't sound like much until when put into the perspective of: If you install cams and high comp pistons in a VTR, you will see and average gain of approx 10HP.
Now that 2HP loss is 20% of what you gain by pistons and cams....or a pretty big deal in my book.

Start messing with the airbox and you can be in for a world of fun.

So now lets look at the bike that is up for tuning.

We have system that started out as a VTR lump and then was optimized to make peak power at 7K RPM.
Honda didn't just do a cam swap but also, like I said. optimized the intake tract, exhaust and ignition curve for that RPM.

Now you take that system and install cams that make peak power around 8-8.5K

Do you think this mis-match might or could cause issues?

Until this issue is addressed, again IMHO, you will never know if you are truly dealing with a carb issue or is the problem a timing issue and the true cause is an exhaust pulse hitting the chamber at the wrong time and just blowing the mixture back out into the intake.

There are 2 ways of dealing with this.
Either bring everything else to VTR spec for a system that makes power at 8K or retard the cam timing so that they make peak power at 7K and the system you have can work with the new cams.
Then address the carbs.

Well I guess there are actual 3 ways, with the third being figuring out some way to get the carbs to meter correctly with whatever is actually going on in the combustion chamber

[Varastorm]

I totally agree with you about filing my own needles, it wasn't a road I was eager to go down either (filing needles, what does he think he's doing. Honda made them, cost them £1000,000's & he thinks he can do better in his shed.. bla bla bla..) I was with you guys too. But I do feel that I have exhausted all other areas before looking into modifying & filing them.

I accept this is not the proper way to get the fuelling correct, pretty far from it tbh. But I have never stated it as so either. But if it solves my lean fuelling issue at 3000rpm, I am going to run with it.

Please remember, its only a very small flat of 0.2mm removed from a 2.84mm dia needle, not 80% removed as used in your example. That would be 2.27mm removed from a 2.84mm needle & we both know that's bonkers

Initially, I was going to use a watchmakers lathe, wet & dry or scotch pads but came to conclusion the amount of metal to be removed would be close to insignificant to the eye, but not to the fuelling. To work out & remove that amount from the diameter accurately for a matching pair of needles would be close to impossible by hand (for me anyway).

So that's why the file came out.

What ever the outcome, I have never stated this will work for any VTR. But it might work if you have a VTR carbed & cammed, Ducati stacked Varadero

But if you have any clip & groove type needle, Dyno jet or Fpro etc., have a go at lowering the needle. The 3000-3500rpm will be hopeless, but you'll have an idea of why I am doing this at 4000-7000rpm

I'm so looking foreward to getting this thing on a dyno, you wouldn't believe it

[Varastorm]

Just had a chat with dyno man Paul, he had been on holiday, up north to watch the Scottish games.

He's lost the keys to open the main doors & only has keys to the office

Hopefully will have a run this afternoon, if he can access the dyno. Fingers crossed

[Varastorm]

Its pouring with rain & blowing a gale. I've just got back from the dyno run & I'm soaked to the skin, but unfortunately that's the least of my problems.

A little/very disappointed tbh, especially the mid range section

We both put our heads together & decided that when I increased the mains from 172F-175R to a Std 175F-178R, that it had a knock on effect to the needle zone & richened up the already rich needle area.

Here is the disappointing graph They are both blue, don't ask.

The darker one is todays run & the crappier afr is also todays.



The plan is to lower the needle a groove so the clip is located into the uppermost groove. If it still feels too rich, then I'm going to remove the washer under the clip

But we think this will have a knock on effect on the mains & the pilot. So maybe then try 178F-180R & file some more needle

Carbs on & off at least 30 times, all for 0.92HP.....

18th of July @ 10:30am next dyno run (£15.00), Charity dyno run for North wales air ambulance, will update

[macdee]

keep up the good work varastorm
you'll get there in the end

[Varastorm]

keep up the good work varastormyou'll get there in the end

Thanks Macdee, I will sort this afr problem out, even if.....

Bit more information on the runs, now I've had time to warm up & calm down

We did 6 runs altogether, 4 with the lambda down the right exhaust & 2 down the left. Just to see what's what. No real difference tbh so we scrubbed them from the graph.

All runs were done from 2000rpm in 4th gear & throttle slammed open right the to the rev limiter when the signal was given.

The plan is, I am going to leave the mains alone this time & concentrate solely on the needle. I know that leaning out the needle again will cause more problems, but I am thinking of running the clip only in the top groove & working around things then.

Paul (dyno man) thinks doing this with the needle might lean the mains again & cause me to run 178F-180R or bigger, which will in turn richen the needle again

There's me thinking I had solved the needle & mains

The chart at 8500rpm highlights the difference between 172F-175R to 175F-178R Main jets = 0.5 on the afr scale

[Varastorm]

Just stripped the bike & adjusted the DJ needles so the clip is in the highest groove No 1# slot = the lowest possible setting for the needles. With no washers at all under the clip.

I also filed the needles again going 1mm lower down the taper & also removed 0.15mm just from that section, but obviously blended it all together nicely.

Been for a ride & it definitely feels like a lean powerless surge at 5000-5500rpm now, give it a little choke & it smooth's out.

What I have noticed is that when you give it the beans say to 7500rpm & then close the throttle slightly to cruising speeds, the engine braking is very noticeable. It feels as if someone has turned the ignition off, its that noticeable.

Every other fuelling area seem okay, starts nice & idle's spot on, 3000rpm & top end. It's the 5000rpm cruise now, so I am going to put a washer back under the needle again, but leave the clip in the top 1# groove.

Will update

[NZSpokes]

Just stripped the bike & adjusted the DJ needles so the clip is in the highest groove No 1# slot = the lowest possible setting for the needles. With no washers at all under the clip.

I also filed the needles again going 1mm lower down the taper & also removed 0.15mm just from that section, but obviously blended it all together nicely.

Been for a ride & it definitely feels like a lean powerless surge at 5000-5500rpm now, give it a little choke & it smooth's out.

What I have noticed is that when you give it the beans say to 7500rpm & then close the throttle slightly to cruising speeds, the engine braking is very noticeable. It feels as if someone has turned the ignition off, its that noticeable.

Every other fuelling area seem okay, starts nice & idle's spot on, 3000rpm & top end. It's the 5000rpm cruise now, so I am going to put a washer back under the needle again, but leave the clip in the top 1# groove.

Will update

You have just reached a danger area. Thats what I was getting with FIL. You have lost control of the slides and are going extremely lean.

This condition will cost you the motor if you leave it this way. It burns exhaust valves and you will end up dropping one.

[Varastorm]

After the previous test ride I adjusted a few things again

I filed the needle once again. another 2mm lower but only slight metal removal 0.07ish, a slight blend if I could call it anything.

Just to give the 5000rpm a little more fuel. I did fit a Std needle washer under each clip (still in the highest groove btw.)

I also sealed one slide hole in each slide (the extra DJ hole) so both slides are now running only 2 Std holes & replaced the DJ springs with standard ones.

Just back from a test.

I feel that the 5000rpm issue is close to gone, but have noticed that the initial pickup at 2-3000rpm is now sluggish compared to the previous setup.

I would love to see what's what on the dyno

So the next plan is to swap out & put a slightly thicker washer under each needle to eliminate the new ever so slight 5000rpm lean surge.

Not too sure where to go with the sluggish low throttle response, either 2 holes & DJ springs or 3 holes & Std springs

Ideas anyone

[Varastorm]

This condition will cost you the motor if you leave it this way. It burns exhaust valves and you will end up dropping one.

Sorry NZSpokes, never saw your post

Like you mentioned, I'm going to adjust & address the lean issue @ 5000rpm

Advice taken

Btw, how fast are these VTR's supposed to go?

My current gearing is 15 front 43 rear running a 180-55-17

[VTRDark]

Wow loads gone on since I last checked in. Thanks for posting Vara. That dyno run was bit disheartening I expect but at least you know which direction to go in now. Changing the slide holes and springs will have now changed things again. As for the softness down low that is down to the pilot circuit.

You mentioned engine braking in an earlier post. Don't forget the lightened flywheel has an immense affect at higher cruising revs/speeds on engine breaking. It more noticeable at them speeds than lower down.

(:-})

[Varastorm]

That dyno run was bit disheartening I expect but at least you know which direction to go in now.

Yea, I was a bit miffed tbh. But back on track again now

I stripped her again yesterday & replaced the thin (0.5mm) washer for a thick (0.75mm) washer, the clip is still in the top #1 groove btw.

But since I was in there, I had another go at the needles. I filed another 0.15mm from the mid section of the needle (hopefully the 5000rpm lean zone), then blended it in all nicey nicey.

Hopefully the metal removal & raising the needle 0.25mm should help the afr in the lean 5000rpm zone.

The main reason for the slide/spring change is because of the cheap £15 dyno run as it will allow me to see what's what for not a lot of cash.

Hopefully it will reveal an answer to the lean 4000rpm as seen on the graph & the sluggish feel it has given the acceleration. Then maybe I can either replace the DJ spring or open out a slide hole, to give me back the urgency it once had.

If all the above works then it looks as if I am going to have to concentrate on the pilots again. If you notice on the last run, we started at a lower 2000rpm 4th gear roll on, just to highlight any issues before the lean 4000rpm bump & tbh the fuelling looks way too rich on the pilot