 Dyno run reveals dodgy carbs. :(
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Joined: Mar 2007
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3/4 Throttle
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Hi, guys. I was really excited last night as I was due my first (ever) dyno today. Now, I aint so happy. According to the meter, it was running rich, very rich. So, we pulled the carbs apart to change jets and, upon removing the emulsfier tube, the needle seat falls out. (Both carbs) The dyno bloke thinks this is strange, as they're generally a snug fit. Indeed, the dynojet kits come with a special tool for removal/insertion and also glue to hold it in. So, after consulting with the dealer (service manager, no less), I'm taking it in to be looked at. Here's the printout. Blue (first run) had the AF meter stuck into the left zorst; red, the right.  Pipes: TORS. Filter: stock Snorkel: present Carbs: stock AI: removed Altitude: sea level. Any comments? EDIT: Stock main and pilot jets.
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 Re: Dyno run reveals dodgy carbs. :(
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Joined: Jan 2005
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Loquacious
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Loquacious
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whats your jetting, and get rid of that snorkel
Frank
(Former)05 BA tbike pipes, ai removed, Freak, mikuni hsr 42's, 904, ported/polished head, 1mm oversized valves
NOW-2010 silver and black tbird
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Re: Dyno run reveals dodgy carbs. :(
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Joined: Sep 2006
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Learned Hand
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Learned Hand
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They fell out of mine, too. I don't think anything holds them in there. I've heard of other people's falling out as well.
Edit: Isn't ideal A/F mixture closer to 13? Looks lean, not rich. According to your mods with stock needles and jetting, should be lean.
Last edited by Lonzo; 07/29/2008 6:15 PM.
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Re: Dyno run reveals dodgy carbs. :(
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Joined: Mar 2007
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3/4 Throttle
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OP
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When I called the dealers before, the service guy didn't think it was right that they just fall out so he asked a technician who also thought it strange. Then I got put onto the service manager who agreed and said to put it back together and bring it in as soon as.
As far as I'm aware, the ideal mixture is 12.6:1 for power and 14.6:1 for cruising. That is, you'd tune your pilots and needles slightly lean for economy when you're cruising but when you wanna 'get it on' and crank the throttle, bringing the mains into play, you want 12.6. The top line of the A/F chart above is 11.6, which is very rich and the whole curve is below that figure. It drops to 10.3 in places, which is soopa-rich. With my set-up, it *should* run lean but the plugs, the pipes, the dyno and the way it rides all say rich, hence I'm taking it back to the dealers.
A/F ratio. Basically, the bigger number represents the amount of oxygen molecules to every fuel molecule. Therefore, 12:1 is richer (less oxygen) than 14:1.
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Re: Dyno run reveals dodgy carbs. :(
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Joined: Jan 2005
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Learned Hand
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Learned Hand
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Thats interesting, I wonder if the AI was back on the bike would this burn the unburnt fuel in the headers ( as I think it is designed to) and so give you a leaner reading at the exhaust exit?  This would mean that our bikes actualy come standard rich. I have been tampering myself, 865cc, 07, carbs standard, AI removed, TOR short, stock filter. I first removed the snorkle and the bike sounded a bit louder, and popped a bit more on decel. I thought this was a sign of running weak so I inserted a .8mm shim below the needles (a couple of 3mm brass washers I had) this I thought made the bike feel a too rich and I was getting the odd blow back to the air box when bliping the throttle. Did not want to blow that to bits so I removed the shims and bunged the snorkle back in. I did not notice any actual performance improvment with the snorkel out to be honest regarding rolling the throttle on from just open to 1/2 anyway ( just noise ) So now I am back to standard without AI I checked the plugs after 70 miles with the snorkle out and there was just a hint of tan on them by the way. My dealer had set the C0 at idle on my last service, and I don't have a D tool so have not messed with the pilot screws yet.
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Re: Dyno run reveals dodgy carbs. :(
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Joined: Apr 2007
Posts: 286
Adjunct
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Adjunct
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Maybe they come with different jetting in the UK, but here in the USA, they are lean from the factory and need adjustment if you pull the snorkle. A shim under the stock needle isn't a bad place to start, but you can end up too rich unless you use a really thin shim. Try a thinner shim and you might end up where you need to be. Also turn out the mixture screw a few turns and consider going up one size on the main jet. Sometimes trial and error is the only way to get it right. Oh yeah - as everyone else on the forum has told me - make one change at a time.
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Re: Dyno run reveals dodgy carbs. :(
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Joined: Jan 2005
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Learned Hand
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Learned Hand
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In will tinker again, need to get a D tool first though.
Like you say 1 thing at a time.
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Re: Dyno run reveals dodgy carbs. :(
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Joined: Feb 2007
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Fe Butt
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Fe Butt
Joined: Feb 2007
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You can make a D tool by flattening one side of a piece of metal break line or you can get the needle out with small needle nose pliers or hemostats and cut a slot in the head so you can use a screw driver. I did the latter.
I learned all I need to know about life by killing smart people and eating their brains.
Eat right ,Exercise ,Stay fit, Die Anyway!
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Re: Dyno run reveals dodgy carbs. :(
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Joined: Feb 2007
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Fe Butt
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Fe Butt
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altitude, temperature, and humidity play a role in jetting too so what is a perfect set up for me isn't good for another person in a different location. Also if my jetting is perfect in spring it won't be in mid summer but would still be within a reasonable range. I like to jet my bike for peak riding season so it would be then OK for the whole year. I run 155 mains and 48 pilots with stock needles and no shims. I also have K&N pods and gutted stock exhaust with no AI. My set up is almost perfect for my location but wouldn't be for say Brokenfixed since he is at a much different elevation than I. I used Tom as an example because I know where he lives and his approximate elevation.
I learned all I need to know about life by killing smart people and eating their brains.
Eat right ,Exercise ,Stay fit, Die Anyway!
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Re: Dyno run reveals dodgy carbs. :(
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Joined: Jan 2005
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Learned Hand
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Learned Hand
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Any news Neill?
I just ordered 125 jets for mine and a D Tool.
Like to know if bits are going to fall out of the carbs.
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Dyno run reveals dodgy carbs. :(
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Joined: Mar 2007
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3/4 Throttle
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OP
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Still waiting to take it to the dealers. They're fully booked up til 2nd Sept, due to the new registration coming out on the 1st. It's still rideable so not a huge problem.
The jet's are the same regardless of where the bike's being sent to.
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 Update: Dyno run reveals dodgy carbs. :(
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Joined: Mar 2007
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3/4 Throttle
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Had the bike in the dealers today. The tech says my carbs are fine and they often 'fall apart', as mine did. He did mention a few things: Installing free-er flowing pipes doesn't automatically lean the mixture out. Removing the AI can alter the mixture. And a few more things that contradict what passes as common knowledge around here but I forget what. :S So, given the results of my dyno, it looks like I'm fitting smaller jets. (Or installing PODS, yay!) Oooh, my cush-drive has gone...AGAIN! 
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Re: Dyno run reveals dodgy carbs. :(
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Joined: Sep 2006
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Learned Hand
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Learned Hand
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Quote:
Like to know if bits are going to fall out of the carbs.
If you hold the tube with a 5/16" or 8mm wrench while removing main jet, nothing will fall out.
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Re: Dyno run reveals dodgy carbs. :(
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Joined: Apr 2007
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Loquacious
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Loquacious
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With the jet assemblies falling out, more fuel would have been burned than the standard 120 mains would normally be able to supply hence the rich readings on the dyno run. Try the bike again on the dyno now that the rich condition has been corrected for a proper benchmark. Then pull the snorkel (plural on older models) and be ready to insert a 125 to 130 main jet. You should also notice a lean condition in the mid range which can be corrected with shims under the needles or switching to TBS or Thruxton needles or both. I'm running 135 mains with TBS needles with 1 shim with 42 pilots and the plugs are still white. I pulled 3 snorkels out of my airbox though. Power improvement on the butt dyno was substantial.
Have fun.
12 Rocket Roadster
03 Bonneville America
69 BSA Firebird Scrambler
73 Yamaha TX 750
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Re: Dyno run reveals dodgy carbs. :(
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Joined: May 2008
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Adjunct
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Adjunct
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When I rejetted my carbs, one side fell apart and one side didn't. Teck from the shop said that was normal and as long as I got all the parts in correctly it would be all right. It seems to be just fine and I've been running all summer without a problem.
Chip Sciarra "07" America, N.C.Switch Blade windshield, Moto Lights, Tri. Off Road pipes
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Dyno run reveals dodgy carbs. :(
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Joined: Mar 2007
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3/4 Throttle
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OP
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I'm getting conflicting advice and I dunno what to do. I spoke to warranty at the Hinckley factory today and the bloke I spoke to (Mark, I've spoken to him before and he seems sound) advised against changing jets and just use the adjusters on the carbs to correct the mixture. He said that, with the mods that I've done, there should be no need to change anything internally. Thoughts? PS I've still not checked the plugs: am I right in thinking that it's a 18mm plug socket? Seems hyooge!!
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Re: Dyno run reveals dodgy carbs. :(
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Joined: May 2008
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Adjunct
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Adjunct
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18mm thin walled socket is correct.Its a PIA to get them out. 
Bill.
"I spent a lot of money on booze, birds and fast cars. The rest I just squandered."
-George Best
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Re: Dyno run reveals dodgy carbs. :(
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Joined: Jan 2005
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Monkey Butt
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Monkey Butt
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Put some iridium in Neill, around £15.00 for two, eBay
Ray(UK)
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Re: Dyno run reveals dodgy carbs. :(
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Joined: Feb 2007
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Fe Butt
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Fe Butt
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With TORs and stock filter and box you may not need to re-jet depending on the condition I mentioned earlier , such as altitude. You may very well be able to adjust the mixture screws to bring it into an acceptable range. That being said our bikes come lean from the factory to get through emissions. The dyno doesn't lie taking it for granted that it isn't out of calibration for what ever reason. If you end up more than 3 or so turns out you should increase the pilot jet and adjust again. Keep in mind the pilot feeds gas with the main as the main opens so a change to one may the cause the need for a change to the other, weather that be a shim or tweek to the screws until you are good across the board.
I am wondering (from the post above me) if maybe the different plugs could have anything to do with the ignitor problems. I have never opened the left side engine cover to change my pick up gap (not even when I adjusted my valves) and I am at just about 20,000 miles on my original spark plugs. They have never been changed but I have pulled them to check the gap and to check condition. Each time all I did was put them back with no need to clean or adjust anything. I have never had an ignition problem.
I learned all I need to know about life by killing smart people and eating their brains.
Eat right ,Exercise ,Stay fit, Die Anyway!
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Re: Dyno run reveals dodgy carbs. :(
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Joined: Jan 2005
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Loquacious
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Loquacious
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Quote:
18mm thin walled socket is correct.Its a PIA to get them out.
Spark plugs? Break them loose with the 18mm socket and slide a 6" piece of 1/2" OD tygon tubing over the plug insulator and twist it out - makes it real easy. Take a plug to home supply store to make sure the tubing fits snugly (i think it's around 3/8" ID). Use the tubing to screw the new plug in.
Smaller sizes of tubing are great for carb bowl screws also if you converted to Allen screws.
Ride Safe,
Dennis
Triumph, it's how I live and what I ride.
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Re: Dyno run reveals dodgy carbs. :(
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Joined: Jan 2005
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Check Pants
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Check Pants
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My bike, bought used, had TOR's and stock jetting. Bella Corse recommended 125 mains. Stuck with the stock 42 pilots and although I never dyno'd it, the bike ran great (pretty much sea level here in MD). So, I think you are on course.
Al
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Re: Dyno run reveals dodgy carbs. :(
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3/4 Throttle
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Update: pulled the plugs today and they seem fine and it's certainly not running rich. I tried to take a picture but it didn't come out right but the plugs were clean; the electrode was grey with a trace of tan, the white bit was clean and in good order. If you look at this table, it was like the plug in the top picture. (Mine was more grey) Plug condition tableSo, given that the carbs are OK and the plugs are OK, what are my options? Regarding the dyno., the place I took it to race their own bikes and they'd had one of their own bikes on the dyno that morning and that hadn't shown any abnormal readings so I'm assuming the dyno is OK, too. I'm going to speak to the dyno operator to see what he says but I thought I'd run it by you lot first. Incidentally, if it was running slightly lean, what would the plugs look like? As I've described mine? If it was running very lean, what would they look like?
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Re: Dyno run reveals dodgy carbs. :(
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Joined: Jul 2007
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Adjunct
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I've been wondering bout rejetting since I put a set of Madaz pipes on my 08 America, my plugs look exactly the same as the Normal ones according to the Plug Condition Table"- I've pulled out the Airbox Snorkel, removed the AI, otherwise the rest is Stock Standard. I'm going to get it Dyno'd anyway just to be sure. It feels that I've got more power now but I don't know if that's the motor just freeing up (6500 kms) or I'm getting a bit more confident of the motors capacity of handling a bit more hooning on my part, be interesting to see what the dyno tells me
2x Norton Commando Roadsters
08 Triumph America
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Re: Dyno run reveals dodgy carbs. :(
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Adjunct
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lean = white. Rich = black. Correct is a light tan, though our bikes seem to run more grey. Not sure if with all the changes to gas over the years, if tan is still considerd the benchmark.
Hoffo, if you pulled the snorkle and added an aftermarket pipe, I would guess that turning out the mixture screw and going up to a 125 main would give you more power. maybe try the TBS needles.
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Re: Dyno run reveals dodgy carbs. :(
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Joined: Dec 2006
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Oil Expert
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Oil Expert
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Hoffo, I think you are pretty well on track with what you've done so far so maybe it would be a good idea to dyno your bike as it is now and forget the tbs needles. For what it's worth, it's been said by a few on here now that keeping the stock needles is preferable to the TBS and unless a comparison is done to say otherwise, I agree. Looking forward to seeing what the dyno says too but again, the owner's backside is still the best dyno. 
Staintune Pipes, K&N Pods, 45 pilots, TBS needles and 145 mains.
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Re: Dyno run reveals dodgy carbs. :(
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Joined: Mar 2007
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3/4 Throttle
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OP
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I'm still confused. Had the bike back on the dyno today and it's still showing very rich. Despite this, I had 126 mains put in and it gained 2 hp at idle and just off it, but lost 2 hp from 6k rpm onwards (WOT) It also smelt rich.
Based on the readings, he would recommend a 110 main and 2 shims on the needle.
I've not heard of anyone going smaller from stock so if anyone can offer advice/suggestions, please do.
Incidentally, I left the 126's in on my ride home but it was raining so I couldn't open it up, to see if they cured the top end problems I've been having, that is, not being able to hit the limiter, despite trying. I'll try tomorrow.
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Re: Dyno run reveals dodgy carbs. :(
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Joined: Jan 2005
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Should be Riding
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Should be Riding
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Read This FactoryPro.com: Quote:
To properly tune, you MUST:
1. Have selected the BEST main jet for full throttle power (not just a "good" main jet - we mean "the BEST main jet" for power at high rpm).
That eliminates the common severe tweaking of the midrange and lower tuning ranges to compensate for a "wrong" main jet.
2. Then - select the BEST needle height / clip position for power at FULL THROTTLE / MIDRANGE after selecting the BEST main jet -
That almost eliminates weird problems at cruise caused by tweaked needle heights that were required because the main jet wasn't correct.......
3. Then, adjust the BEST Float Height for BEST FULL THROTTLE / LOW rpm (many Honda's excluded because floats are not adjustable) -
You should be able to apply FULL THROTTLE at LOW RPM in TOP gear without ANY misfire of bogging or stumble.......
If you follow that order, you will have:
1. Best topend.
2. Best midrange.
3. Best low rpm power.
Then - all you have left is dialing in the pilot circuit - i.e. mixture screw and pilot jet size - That's IT - Don't tweak needle heights and throw away full throttle midrange to try to fix a cruise issue!!! (Unless you want to!)
Blowing gravel off rural roads
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Re: Dyno run reveals dodgy carbs. :(
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Joined: Nov 2008
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Member
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Member
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Have you checked the fuel levels/float heights? If you have a float way off whack it will cause odd fuelling problems.
If you've pulled the needles out, when you put them back in the white plastic spiders must sit correctly located in the bottom of the vacuum slides. If they don't then the needles can flutter and bounce. Also if not corrrectly fitted it's possible for a leg of the spider to cover the lift hole.
Try removing the air filter or snorkel, even the air box cover, and see what difference you make to the AF ratio. If you are truly at 10 - 11/1 then it is too rich. You don't want to run it way rich, as much as you don't want to run it way lean.
The AI will give a false reading of AF ratio as it is making the exhaust lean......removing it would give a true reading, surely?
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