Twitchy

Hi guys, long time lurking here (got some very excellent thumb screws from Jack Flash), been a member on vtr1000.org for a while, and thought I would introduce myself here, and expose myself to additional ideas/expertise.

Here is my build thread at vtr1000.org;
www.vtr1000.org ? View topic - VTR Down Under

I am having some issues with carb setup that I just cannot get my head around. I have read many articles by 8541Hawk, cybercarl and many others in working through my issues, but can't seem to make any progress.

This is a rundown on where my bike is at, at the moment.
Standard new air filter
Standard new little foam filters in airbox
Jardine RT One high mount exhaust
PAIR removed

Front;
DynoJet needle 3rd clip from blunt end +1 shim @ 0.5mm (0.020")
#48 pilot jet
Keihin #180 main jet
Standard diaphragm spring
2 holes in carb slide (was 3 when I bought it - blocked 1)
Jack Flash thumb screw 2 1/2 turns out

Rear;
Dyno jet needle 3rd clip from blunt end +2 shims @ 0.5mm each - total 1.0mm (0.040")
#48 pilot jet
Keihin #182 main jet
Standard diaphragm spring
2 holes in carb slide (was 3 when I bought it - blocked 1)
Jack Flash thumb screw 1 7/8 turns out

Carb balance done at approx 1900 rpm
Idle then set to slightly fluctuating 1250rpm
TPS then set to 498 ohms

Front plug;


Rear plug;


The bike runs like a pig in slow and stop start traffic. (yeah, I know, its a v-twin etc etc, but this is not right). Considerable popping out the exhaust when gearing down (not as bad on the weekend so not sure its the gaskets). Still getting the 2000-ish rpm hangup when blipping to 3000-ish rpm. According to many articles here, this means I am too lean on the pilots, but yet to find out how much effect the other circuits have on the idle and the lower end of the rev range.

I am still getting relentless cutting out/surging whatever at steady and light throttle position, feeling it badly chugging along in crawling traffic and feeling it at 80km/h revving at 5000rpm, and I am thinking it may be the TPS position. I believe 8541Hawk has his set at 430 ohm. Some others have put theirs back up to 840. There is a lot of info about lean conditions and rich conditions, but zero about incorrect TPS position. Nothing to say 'if this is happening try increasing/decreasing the ohms to blah blah blah'. Everyone just whacks it on 500 and leaves it.

My 2 most urgent things I want to know are about the TPS and potential of going down to 430 or up to 840, and how much overlap is there between circuits? How much effect does the mains have at idle/light throttle if any? My bike always smells very rich, but the blip test always hangs up so I am confused. There's a bit to trawl through there, but would much appreciate any assistance or positive input to help me get the best out of this awesome machine!

Jack Flash

Your problem is not TPS related. You can stop worrying about that one. To me, your issue is you're way too rich.


In your case my first move would be to bring down idle jet to #45. But then again, you have Dyno jet kit, and I know many people here have had problems with this kit. The word is, they are too rich. Perhaps someone here with one, or has had one can chime in and confirm this info. If so, they can guide you much better than I can as to which direction to go.


I would also bring the needles down, and put the stock main jets back in. I don't know if you have all stock parts available or not, but if you do, IMHO, I would go back to stock carb setup. Which means you put back slides, needles, mains, and idles back in. Then work from there on.


My 2 cents.

thedeatons

Yah, as soon as you mentioned Dynojet kit you lost half the forum members lol.


James

Twitchy

Only DJ needles left as it was recommended they *should* be able to work with standard jetting.

I currently have new floats and OEM needles on the way from partzilla as it seems the profile of the OEM needle is different to the DJ unit. With a high flowing exhaust, not sure how it will end up though. When I bought the jets from jetsrus.com I order 1 each of 175, 178, 180 & 182. After suggestions I think I will pull the carbs and drop the jets down to 178 front & 180 rear. Not sure about dropping the pilots back to 45s as I am 2 1/2 turns out on screws and maybe 45s too small?

Twitchy

Sorry, I should clarify when I bought the bike it had K&N air filter, DJ 180 mains front & rear and 45 pilots, and 3 holes in the slides, DJ needles set at 4th clip from the top.

Jack Flash

You mentioned that you had many problems on the lower end of the power band. With the number of turns out on the screws, and the idle jets you are running, you are too rich.


Put back the 45's and lean the screws. I am sure you will see a difference in response.


How did it run with this set up ? Pretty bad I'm sure.

VTR1000F

Yeah, there went the other half, James.

Twitchy

Believe it or not the bike ran fine. When I bought it, the bike had done 130kms in 2 years. The clutch fluid had turned to gel, and the brake fluid not much better. A mate told me to pull the carbs and give them a good clean out as well. That was my biggest mistake! It has never run the same since. I am tempted to put the K&N and Dynojet stuff back in to see if I can get it to work but at the moment I just want to ride!!

(With the K&N and DJ gear it never smelt rich, or surged or farted - can't say the same for the OEM & Keihin gear!)

Twitchy

But how about the slight hangup at 2000rpm after blipping to 3000? I thought that meant too lean? Going back to 45s will lean it out more I would think.

thedeatons

LOL...

NZSpokes

Normal rules dont apply to the VTR. Biggest production CV carbs on a motorcycle....

kenmoore

There are so many variables with our bikes.

That is one of the things I like most about them.

I tried various set ups when I Dyno Jetted it, drilled slides and the like only to return to normal slides 180 and 182 jets and D.J needles.

I have J.E pistons, and a 4 degree advancer plus other engine mods and my set up is sweet.

Based on what you are saying if it was me I would go to a dyno and then go from there.

To me your front plug looks lean and your back way to rich.

Why? I don't know but something is out of whack!

Go back to the start mate, otherwise you will be chasing your tail forever and never get to enjoy the bike for what it is.

Here are my plugs, once I achieved this I have left well enough alone except for the odd synch.



It can be done.

erno

Yeah mate ,I tossed the K&N and fitted a BMC ran alot better after that.But I also have the Airbox mod
Are you on the ozfirestorm site?

Jack Flash

Car Owner : You scratched my car washing it !
Car Washer : The scratches were already there.


CO : Car was fine when I bought it 2 years ago !
CW : Did you ever wash it ?


CO : No.
CW : Well, that's why you never saw the scratches. Car was too dirty.


Get my point ?


Perhaps, as you mentioned the bike sat for some time, the carbs became varnished. The varnish obstructed the jets. Cleaning the carbs up, opened the fuel circuit, and voilà, you now have a rich condition. So cleaning up the carbs was not a mistake, it was the right thing to do. However, you now need to sync the carbs as well. These carbs are sensitive to being played with. I have never played with my carbs, were I didn't have to sync them. They had unbalanced every time.


This is just my thoery. I am just going on what you are saying, and have not seen the bike. I'm just a dude on the internet pointing out the obvious to me.


Kenmoore's suggestion, along with what I have told you also is sound advise. Go back to base setup, and work from there. There is nothing wrong with moding the carbs, you just need to know where you stand everytime you are going to make a change. And when you do make a change, you do it one at a time, so if something isn't right, you know what it is that's now wrong.

Twitchy

Thanks for the input guys. I did notice when I installed the new float valves, the slot on the float where the valve sits had a bit more play on the rear than the front. I wonder if this is contributing to the rich rear. I have an order coming from Partzilla which contains OEM needles, OEM floats, new choke cable and o ring gaskets for airbox surface and fuel bowls. It was after I put the order in that I saw the comments about the emulsion tubes ovalling/wearing.

I guess I am a bit puzzled why it ran well with the DJ gear, but down sizing the mains and blocking the 3rd hole on the slide and lowering the needle has made it richer, and not running nice at all. But once more OEM parts come hopefully it will all come together!

matt365

Are you still running the DJ springs? They're shorter, and seem weaker to me. If you plugged one of the slide holes, I could see the slide slamming open rather than getting on the main slowly...

Twitchy

I installed new OEM diaphragm springs when I converted everything back from DJ to OEM (except the needle). The old springs were 300mm long (12"), whereas the new OEM springs are 270mm (10 3/4"). I don't recall the new ones being any stiffer than the old ones.

**The 'OEM' diaphragm springs came from Partzilla. Surely the U.S. springs wouldn't be different???**

Twitchy

So while I wait for UPS, I thought I would have an experiment. You guys wont agree, but I returned the bike back to almost as it was when I bought it. K&N air filter back in, Dynojet 180 mains front and rear, needle back on the 4th clip with 1 shim each, 45 pilots, left the new OEM diaphragm springs in and left the slides with 2 holes, and fuel screws on 2 turns each. The bike started surprisingly well, balanced up nicely, a barely noticeable hangup below 2000 rpm. Left TPS at 497 ohms. The exhaust note did sound different, maybe not crisper though.

Went for a ride and it seemed better than before though it did get the low throttle lean surge thing under 3500ish. Today I pulled the plugs and this is what l found, front is on the left and rear is the right plug;

Now I dunno about you guys, but I was pleasantly surprised to find those colours. BUT.... the 2 little foam filters in the airbox? Well I am missing one!! Had a look down the carbs into the intake ports and no sign of any melted foam. Without pulling the exhausts off I don't see a way of checking the other side.

And on that topic, I think I will cut the triangular filter bits of the used OEM filter I have and see if I can fix the pressure differential at the diaphragms.

Tonight I set the fuel screws out about 1/4 front and 1/8 rear and put the TPS back to 827 ohms (it was 824 when I bought it).

So after the aforementioned comments about losing the viewers with my K&N and DJ stuff I am expecti g to cop some flack, but to fully understand the bike, I am going to try it how it was. I was fresh off a 250 so scared to give it a fistfull but the bike definitely did not buck around at low throttle/revs so that is where I am starting. If it all goes pear shaped then so be it.

thedeatons

Experimentation is good. Good to know what does what.

Do you understand how to properly do plug chops?

James

NZSpokes

Plug on the right is still way to rich.

Twitchy

I have read that a plug chop is only accurate if the bike is shutdown at the revs & throttle position where the mixture is not right. I am not sure I need to go there just yet.

With the K&N filter not having the triangular sections to retain the little foam filters, the bike will be sucking in unfiltered air through those points, which will affect the mixture. Once I cut out the sections from my old OEM filter and put them in, then I will have a more accurate representation of whats happening.

But yes, it probably is a tad rich.

kenmoore

Twitchy,

Your last comment is an understatement for sure.

The plug on the right is a good indication of where your problem lies.

I am no expert, however the difference is vast!

If I saw that with my bike I would be worried and would definitely target the carb that relates to that plug.

The difference is too great!

Any progress?

NZSpokes

Well they are both too rich but one is far worse. Will be a lot of carbon building up in that motor.

Twitchy

OK, a couple of operational questions;
1. If the bike runs kind of nicely for the first 5 - 10 minutes, but then develops a bit of the surging/hunting issue, does that mean its running too rich, or too lean?

2. When I stopped a the first red traffic light this morning, the bike died within 2 seconds of me stopping. No stumble and die, just died. Any thoughts as to the cause?

3. When people refer to rerouting the carb overflow tubes, do they mean the 2x 10mm (3/8") tubes that poke from the outside of the main plates into the centre of the plates and towards each other? If so do I just let them hang down towards the base of the 'V', either side of the coolant overflow bottle?

4. Are these 3 issues all somehow connected?

Thanks.

Cadbury64