The Varastorm Dyno run (VTR cams)

[Varastorm]

You want more.

I have very similar notes, are you sure we're not related or see the same therapist

Here is a pic (trying) to showing the difference in needle lengths, around 3mm .

Top one (2nd groove down DJ needle) is what's in now (Best ever midrange, pulls like a train).

Bottom one is a Std needle.

This is why I think not many have tried running #50's / #52's pilots with the needles this low

[Varastorm]

The new pilots arrived today so stripped & fitted the #50's, as a random guess I turned both pilot screws out 2 turns.

It started first time with a little choke (which is always a good sign) & it warmed up nice & cleanly as I finished rebuilding it.

There was no stumbling or any blipping needed during this process to clean it's throat or to avoid any stalling.

Once warm it idles at 800rpm smoothly, with no "is it going to stall" thoughts.

Been out for a 50 mile slow country road ride & feel the jetting is really close now, there is still a slight, & I mean slight lean stumble at 2000rpm in top (25-30 mph) going through villages, so I opened the choke very slightly & it went away, so it's still a little lean low down.

When leaving the villages I nailed the throttle to the stop (testing purposes only) the acceleration is faultless & so hard now it really does surprise me.

Going to strip it again now & open the pilots another 1/2 turn to 2 1/2 turns out each.

Just had a look at the #52 pilot in the bag & they sent me a set of #48's in error. quick phone call, no problem sent me out another set straight away & a returns stamp.

Will update with the new pilot setting

[VTRDark]

I have very similar notes, are you sure we're not related or see the same therapist

Now that did make me chuckle.

3mm difference in length. That is masses in the jetting world. Well done on your persistence, I'm looking forward to seeing how you get on with the bigger pilots.

(:-})

[Varastorm]

Yesterday I screwed the pilot screws out another 1/2 turn to both 2 1/2 turns out.

Just been for a 40 mile ride & 7 miles in the fuel light came on so I had to really take it easy as I had no money except the coin in the Bagster

But what it did do was eliminate all high speed riding & it highlighted more flaws in the pilot jetting which did go away once again when the choke was opened a little.

So once the #52's arrive they are going straight in, with a guess of around 1 1/2 out on the pilots.

Like you mentioned Carl, 3mm is masses in the jetting & dropping the needles as low as I have done, has had a major impact on the pilot side.

At the moment it can idle smoothly at 750rpm all day (too low tbh) & it will pull through villages at 30mph in top (@ around 1750rpm).

I feel am being really picky describing the fuelling now & under normal riding conditions you would hardly notice.

Will update.

[sirch345]

I absolutely admire your enthusiasm and determination Phil and what a brilliant dyno read out, you must be delighted

Fingers crossed for the #52 pilot's,

Chris.

[Varastorm]

Fingers crossed for the #52 pilot's,

Cheers Chris,

I am making it my goal to sort this rich mid range problem on my bike.

It is time consuming but the results are worth it

Its a shame I am doing it with the Ducati stack mod, because I don't really know if anyone could copy my setup running Std stacks.

But I really feel I am on to something with the needles being too short.

The next time you look at someone's dyno you'll see what I mean, they are all too rich between 5000-6000rpm.

I am relying on hard evidence from the dyno graphs, not just my butt & the results are brilliant

Hopefully on the next dyno sheet the fuelling, torque & power graph should prove me right

[NZSpokes]

Fingers crossed for the #52 pilot's,

Cheers Chris,

I am making it my goal to sort this rich mid range problem on my bike.

It is time consuming but the results are worth it

Its a shame I am doing it with the Ducati stack mod, because I don't really know if anyone could copy my setup running Std stacks.

But I really feel I am on to something with the needles being too short.

The next time you look at someone's dyno you'll see what I mean, they are all too rich between 5000-6000rpm.

I am relying on hard evidence from the dyno graphs, not just my butt & the results are brilliant

Hopefully on the next dyno sheet the fuelling, torque & power graph should prove me right

I believe the key is to slow the needle lift speed a bit more. Restrict the slide hole or pre-load the slide spring.

[Varastorm]

I believe the key is to slow the needle lift speed a bit more. Restrict the slide hole or pre-load the slide spring.

I think I have tried close to all the configurations possible with these carbs & I don't think the rich midrange has anything to do with the slide speed tbh.

The main problem is the needles are too short, way too short. You'll need the longer DJ needle's & a foil hat to try it/prove my theory (not too sure about FPro needles).

But when you do try it, it'll run like crap under 4000rpm because your leaning out the pilot system also. This is the stage I am at the moment, trying #52's maybe have to go to #54's ?

I would highly recommend people try it, it cost nothing if you have DJ needles .

If your running big bell mouth trumpets try the clip in the 2nd or if Std trumpets 3rd groove from top with DJ needles.

Btw, I don't think it will work with #45's, but if you have #48 pilots in, wind the pilots out as much as you dare (3 1/2 - 4)

Try it, you will feel a huge improvement/difference mid range. I guarantee it.

Also, if I am talking crap you can shame me here

[Varastorm]

The envelope from Allens arrived with one #52 jet in it, ffs.

Called him & explained, their posting another one to me (Sorry about that Duck )

So, whilst I wait for the other #52 to arrive to fit. I've decided to give the #50's one last go, so I've opened them another whole turn to 3 1/2 out.

I feel this amount of turns out on the fuel screw is on the limit, but is purely just to see if it will bring me closer to, or over the required pilot setup.

With all this testing, I really feel the answer will be with the #52's

Here is a picture of a plug from the non thrashed sub 4000rpm (no petrol or money) above run

[bigtwinthing]

Rich!

[Varastorm]

BTT you are correct, too rich

I feel have tried all fuel screw setting with the #48's + #50's to try & rid the bike of the tiny lean splutter @ 3000rpm.

So am going back to a nice idle (#50's+11/2 out) & stop playing with the pilots, as I feel the answer is not there.

But am going to try & richen the afr with emulsion tubes, failing that I am going to look into the throttle cutaway.

Here's the plan,

Factory Pro recon you can lean the "cruise" by using two rear emulsion tubes.

I am planning on going the other way, I am going to use two front emulsion tubes to hopefully richen the 3000rpm "cruise" zone.

I just hope their use of the word "cruise" is around the 3000rpm zone.

Factory pro recon

2.For persistent over richness at cruise, you can use another rear emulsion tube to lean out the front cylinder. The higher holes delay the onset of fuel delivery. Diagnosed by the need to have the front fuel screw almost closed for best idle - That's a superb test for pilot jet size.

Here they are



What do you recon?

[NZSpokes]

Im still putting my money on slide speed. It something i will work on soon.

[Varastorm]

Update on the jetting

I do feel I was barking up the wrong tree by trying to richen the 2500rpm to 4750rpm zone by using different (richer) pilots.

£20 down the pan I know I should of listened But now I know for sure.

I have also tried NZSpokes's ideas also, by slowing down the slides, firstly by using the Std cv springs & then using 2 & 3 holes on the slides.

No difference btw Spokes, we're both wrong.

This is the start/finish fuelling zones on the VTR carbs. Pilot circuit = 0rpm to 2500rpm---Needle 2500rpm to 7000rpm---Mains 7000rpm to max rpm.

Now this lean 2500rpm to 4750rpm problem I have, comes under the needle zone & I know lots will say "just raise the needle".

But when you do that, you get a rich issue & power loss from 5500rpm to 7000rpm, just look at anybody's Std dyno run sheet.

That 6000rpm to 7000rpm is where many will mention the "2 stroke effect" It's the burst of power that you feel when the mixture hits the perfect 13/1 ratio, before that it's way too rich & the engine bogs down. You don't really feel it bogging, only the burst of power when the mixture hits optimum.

If only we could get the mixture to maintain 13/1 from 2500 to max revs. I recon it's a built in restriction of some sort as I can't see Honda cocking this up.

So, I recon its the DJ needles & the Std needles that are wrong, too lean low down & too rich higher up. (I've measured them both & they are virtually identical, apart from being able to raise & lower the DJ needle)

So here's what the Dj & Std needles have to offer.

You can have a perfect 2500rpm to 5000rpm. But 5000rpm to 7000rpm is way too rich (boggy).

Or, way too lean ((surging)my problem) 2500rpm to 5000rpm. But perfect at 5000rpm to 7000rpm.

So, has anyone got any Factory pro needles to measure up?

Failing that, know where to file a needle to richen the 2500rpm to 5000rpm zone?

Help

[VTRDark]

Just had a quick scan through the post I have missed. Interesting stuff.

Its a shame I am doing it with the Ducati stack mod, because I don't really know if anyone could copy my setup running Std stacks.

Not really as although it may get someone close, as you know every machine is slightly different and it's the fine tuning that counts. So don't knock yourself.

Phil we may have to change your username to Man On A Mission Shame about the 52's but it was something you had to try. I think you going about things the right way and you right the carb circuits do cross paths. It may be time to go back to the drawing board....step away and clear the head. Emulsion tubes could be worth a shot though. Change only them and see what affect it has. As far as I know the position of the holes in the emulsion tube controls the timing of fuel drawn from the float chamber. IIRC the lower the holes, the sooner the fuel flows/sprays through.

A second rear emulsion tube put in the front carb I believe is FP's equivalent solution to HRC's one slide hole approach. Two solutions to a problem from different directions kinda thing.

(:-})

[Stephan]

Tbh I don't understand why you do it, posted chart looks really good. Only thing I would consider is to try stock 2 slide holes, nothing more.
Seems to me you do massive changes to good running setup.