Carb settings with high comp. pistons & cams
 

I recently installed 11.5:1 JE pistons, Webcams cams (grind #189), and cleaned up the heads a little, stock ignition rotor, lightened flywheel, sub gear delete, and F.I.L. mod.

My question is, do I set up my carbs differently than I am running now with high comp pistons and cams? I'm assuming, I will need slightly larger pilots and possibly mains as well. I tried searching for this, but didn't find anything, even when searching with the term "stage 1", but my Search fu sucks. I know quite a few people have made these engine mods. What were thier carb settings?

keep in mind that with new cams, you have longer opening, delivering more fuel into cylinders.


Just for interest, my experience:


before HC pistons and new cams: 48 pilots, 178+180 mains, Dr Honda stacks, stock filter


after stg1 assemly (including ported heads): 48 pilots, 182+185 mains, stock filter - it was way too rich


after dyno: put Pipercross filter, which makes it significantly leaner everywhere, 48 pilots, 188 mains


Question is about slide holes, I tried setup with one (HRC), but two slide holes works much better. I also think that I could use 45 pilots, will see on anothher (hopefully final) dyno run.
I have no idea how FIL will affect the things, probably it will be leaner than stock airbox with Pipercross.


Another thing to consider from my experience: longer needles (FactoryPro in my case, I assume Dynojet will be similar) makes leaner condition on the top (WOT), so this is not fully applicable for stock needles, which can make richer condition at top revs.

The FIL thing is an unknown but the ones I have done I have just gone up one size on the mains for a starting point.

The slide hole issue has more to do with running a full exhaust system than a STG1 issue IMHO.

slide holes was side point from me, not really relating this topic :-)


Another thing to consider, Roger D recommends two slide holes everywhere except of full race setup (3 holes). But this don´t devaluate other ways (HRC, Dynojet) ...

Hey guys,

There is always much debate about the jetting on our bikes.

With high comp pistons a little bit of head work, standard filter, no cams, lightened flywheel, 4 degree advancer , no anti rattle gear, electric water pump with water pump gear and chain removed , no pair , plus a couple of other tweaks ,Dynojet needles 48 pilots 180 in the front and 182 in the rear and modded exhaust my bike runs great.

Never been on a dyno, my butt and brain tell me things are good.

Revs like a banshee and runs great.

All this was done to get my bike to run as it does now and I drilled the slides only to put standards back in.

No two of our bikes are the same, and what I have may not work for you, all I know is that my Bro can't catch me on his Suzuki TLS 1000 that has some similar mods so I am happy!

Good luck chasing the holey grail, I for one believe I have found it and apart from the odd carb sync and valve adjustment I am leaving well enough alone for now!

Thanks guys. So it sounds like my 48 pilots, FP needles and 205/210 mains should be okay to start out with. I would hate to drill my mains to 210/215, if I don't have to. However, my Flo-Commander was almost turned all the way in before my bike was tore down, meaning I probably needed to up the mains anyways. After engine break in, I will find out.

That should get you close enough to get it running.

One of the nice things about the VTR is that she will tell you that things are running lean (we all know the lean "pop" if you have done a bit of tuning with this bike) long before you get to a dangerous lean condition. ;)

You can try to seal the air jets, as it is setup for open airbox. I assume mains would go some size down.

Just revisiting this, since my bike will be back together and running soon. I am very curious about what Stephan mentioned. I also heard this mentioned by someone when I was in the infancy of tuning the FIL mod.

When my bike first fires up, I am not going to touch the carbs, so it will be at the same settings as mentioned above. However, if it does need to go bigger on the mains, would plugging the air jets be the way to go and tune from there? Or, should I continue to drill out my mains?

I'll try searching for a thread about plugging the air jets.

EDIT: I found a post by Mike that says this about HRC and air jets (bleeds?)

I find this very informative, since my bike is likely to see 90% of its life on the street.