Bonneville America Forums Forums Technical Forums Performance Mods simple tasks have me guessing.

Pat or any other carb Guru: I have the same similar problem ,I know one cyl.is burning richer than the other. I've read some posts somewhere that one could balance F/A (pilot screws) that way(Like Pat described) The feedback wasn't good for that post or something about stressing the other cylinder with the other coil wire off.At this point I could care less about their views I'll tell you what if it has your endorsement I'm going to do that too!You've had more hands on,then I'll ever have.Already Mercury balanced the carbs,Had a little trouble trying to get them dead nuts in fact I couldn't.I switched lines over 6 times.One was always up 1/8" over the other. I tried right,I tried Left and back around. Was trying to be careful,a little fearful of that mercury ,it started getting hot,blued my pipes a bit, the RPM"s crept up on me during the procedure ,caught me unaware(close-2800) I was trying to watch both instruments,Had panic attack;was waiting for mercury to come flying out of exhaust,promptly took it down to a safe level ,anyway I'm working on getting it Dyno'd , not so easy to find around these parts ,For people(Business) that of which are willing to 'run'-dyno a Triumph that is, they claim different connection? However, if you say doing what is described above(pilot screws) is going to get me closer to the ballpark, then great! My settings are as follows ,are 40's large enough?
Pilot screw adjustment:
Start the bike with one side plug wire pulled with idle about 1100-12oo rpm. Adjust the side running pilot screw in until it starts to stumble, then back it out until it starts to rev a bit higher. Set it in the middle of these two points. Shut down bike and then do the same with the other side and then the carbs will be tuned the same at idle...OR THIS.....With the engine warmed up fully, start on one side and adjust the mixture for best idle speed.

Any time the idle speed gets much over 1100 RPM, adjust the idle speed control to get it back to just below 1000. If you let the idle speed get too high, it will start pulling fuel from the transition jets and that will confuse your adjustment. When you have optimized the idle speed, in hot weather, richen the mixture 1/8 to 1/4 turn so the engine will run a little cooler.

Once that cylinder is done, readjust the idle speed and do the same on the other cylinder.

Follow up by rechecking the balance and adjust as needed.

If you have added a balance hose between the manifolds, be sure to remove it and cap the fittings before you try to adjust the idle mixture or you will end up with your head hurting. ...Note: last night when riding w/wife we noticed a faint smell of gas coming to a stop at idle speed.Does this then qualify for the masking tape on the throttle "witness" mark procedure?

sounds about right, if you smell gas at a stop the bike is probably rich or leaking a bit of gas. when i had my stock carbs they were both on slightly different settings so dont be afraid if they are not dead on the same. how many tunrs out are you at now? seems most people runs the stock 42 pilots with the occasional running 45's

Frank

All good except there is really no compelling reason to pull the plug wire for the other cylinder. Back in the days of the carburetted dual plane V8's, we wouldn't think of pulling plug wires to make it run on 4 cylinders at a time. You just adjust one carb to make it run the best that will, then repeat on the other. The optimum adjustment is when the engine runs the fastest at idle, but readjust the idle speed as needed to keep it below 1100. In summer, give it another 1/8 - 1/4 turn richer so it will run cooler.

Frank- I'm 3 turns out. Stock-40 pilot jets,however I have brand new 42's out in the garage but didn't install them at that time.Don't the pilot jets do their thing from idle thru 1/4 throttle ? Maybe should have put them in?..........................Greybeard , thanks a million. that's the clarification I was hoping for!

From looking at your set up in your signature 40 is too small 42 might do it since you have the stock air box still if not then 45. Greybeard is correct adjust 1 carb for best idle with both cylaners firing then same for second carb. Then back your idle down to where it should be. When balancing find the biggest fan you can or 2 even and put them in the front of the bike to blow air across the engine to prevent over heating.

Yeah, Dog 33, I have the stock airbox w/Polaris bellmouth. What is it or better yet, how can you tell that the pilot jets are too small. Daz told me I should probably do the 42's,Jenks mentions that most riders settle with 125 to 130 mains and often with 42 pilot jets, but what is the factor up to 1/8 throttle going size up on the pilot jets? More Air passing the butterfly? Or beyond that more Fuel?...............yes, by the way next time I sit and make adjustments on bike like that ,I'm going to put a helicopter in front of it,about had a meltdown,very stupid mistake. Won't assume that one again.It got extremely warm.

the pilots still work above 1/4 throttle and add fuel to the stream. I am not saying 42s are not what you want depends on how restricted your pipes are I have no experience with Tbike pipes. Adjust the pilots then a dyno is best way to see where you are at what specific RPM.I suspect 42 is going to be fine for your set up. adjust 1 mixture screw at a time to get the best idle once you have the best idle move to the 2nd screw and do the same. Don't worry about 1 having a slightly different setting than the other. If the difference is dramatic check your balance. Once you have them adjusted then adjust your idle.

I am not sure what you are asking with your last question.

The belmouth I don't feel does anything when installed on the stock air box. The theory is that it makes the air flow smoother but since it still has to pass through the filter I really feel it doesn't do any more than removing the snorkle. A bellmouth works very well on the back of a carb.

O.K. Then upsizing the pilot jet strictly feeds more fuel..... polaris bellmouth? I know. At least it might divert water.

yes and yes it may divert water although not sure on that one.

After quite a bit of thought lately , tweek this turn that,Swap this pilot for that ,Drill this and that ,I'm postponing the inevitable;I'm going FREAK and be done with it ASAP. ...Would this set-up go w/Freak 155-160/42....1T.....2 shims TBS needles? This is what Tigwelder is running on his 05' with the exception of Thruxton needles.

Personally I think the Freak is the way to go. But ask for something around a 150 or 155 jet when ordering the 160 will be too rich.

Hey Dog 33 , I'm leaning that way more and more , need to get the money up though. Did you Freak your bike? If you mentioned it I must have missed it. It sounds to me like your sold on it.

Yep I did my bike and Wendys bike we both love it. Power increase and sound are both very good. Last I heard the kit was still coming with 160 mains and many , including myself have found that to be too large a main jet.

After I got it I found it wouldn't be too hard to make one but was too lazy and ordered one for Wendys bike!

Yep...It's me again,3 more questions, Are you two rolling on Speedmasters or other? The reason I ask Is this; Firing angle - 270 degree (speedmaster) Firing angle-T100 (360 degree) Dazco has asked this question and I thought I would as well. It seems for some hands on modifying the 360 seems to fair out pretty well.I don't know if it has to do with the Camshaft positioning or whatnot beyond that ....Do you think the speedmaster will have noticeable results[H.P.or Torque]if I do the freak kit because of that fact? Hows the mileage?

I have the Freak on my 03 SM and the power gain is absolutely noticable. I also have Specialty Spares (more open exhaust), and rejetted to 150 mains (still have 42 pilots). The bike runs good nad strong. Mileage actually went up a bit!

I would imagine doing the NARK on a T100 or Bonneville, rejetting, and aftermarket open pipes would gain the same.

Who the he11 is Dazco? I've never seen him post here???

mine is a Speedmaster Wendy has an America,power is definately noticable. I image gains are similar between T-100 and our bikes.

O.k. that's what I wanted to know power gains 360 .vs. 270. Daz is a triumphrat member from L.A. He may not no it but he has taught me a lot about these speedmasters. Never had a U.K.bike. From what I understand he's had dozens of bikes and was never afraid to turn a wrench on a modification to squeeze out a little more H.P.. I may go all out here.and get the hard saddle bags w/locks/LED lights and freak kit w/Blk/slipover pre-filters going to have to order those mains separately.I can get it Dyno'd at Life cycle kalamazoo,Mi.

same here I currently have 18 old brits and 2 new ones. Been wrenching on them for about 30 years.

Holy Cow,Dog,I just seen your profile under hobbies. Think you ought to open up a museum alongside your Towing Co....LOL..At any rate I'm still in junior High when it comes to bikes,know more about old style autos,currently taking up an online course [Penn Foster] Motorcycle repair to try to get myself in the Ballpark.Thanks for all the valuable Info on the above-said,Will consider it all. Oh, by the way I'm sure there might be a few more questions down the road......Keep the rubber on the ground! Speed.

Considering that the older engines produced the same power and torque, and the 270 version had a bit milder valve timing than the 360 engine, I can't help thinking that the 270 degree one has the potential to produce a little more power at the same engine speed. The gotcha is that the 360 produces half as many sparks per revolution, so it could be made to turn much faster before running out of spark, giving it a potential to produce quite a bit more power.

Grey,correct me if I'm wrong...360 degree ..Both pisons rise and fall in their respective cylinders together...keeping in mind 720 degrees rotation of the crank... one power stroke every 2 revs of the crankshaft (or 4 piston strokes)......270 degree the pistons are offset in thier relative positions It would almost seem to me like there is a lot more action going on there because of the indifference ...you know..intake..,compression..power(ignition)... exaust It would seem like those valves left to right are going overtime or do I have that backward via the 360 , both rising and falling....is that what you meant by milder duty by the valves? [Spark]:I could envision that.The pistons in the 360 are drawn out of thier holsters together firing on different rotations ; as where the 270 has 1 gun out and the other half drawn? Therefore more consistent spark?Could you define the 270 has more potential to produce more power at the same engine speed.