exhaust back pressure, or lack of.
 

I recently bought an 83 Roadster that had been sitting for a couple of years. It supposedly has an 1150 kit installed, has an aftermarket air cleaner and 2" drag pipes. It had a big flat spot between 3 and 4 thousand rpm. When it came up to 3 grand it would just lay down and take a long time to get up to 4 grand and then it would take off again. Also has a big hesitation or hiccup when you wick the throttle open at once. Kinda like it was starving for gas until you let off of it andthen roll back into it again.
I had the carb taken apart, cleaned and the accelerator pump checked out. It's all good. I also did the lollipop washer thing in the pipes. Now the flat spot from 3 to 4 grand is gone and it runs much better except that the hesitation or hiccup is worse. It will kill the engine if you don't back out of the throttle when it hesitates. It sometimes pops back through the carb especially at low speeds and just off idle. It will surge and sometimes pop through the carb at steady highway speeds. To me it acts like it's running lean but the inside of the pipes are really black.
I guess next I'll check the intake rubbers,timing and new plugs and wires. Am I on the right track here trying to sort this out? Do you think the lollipops are good enough or better than torque cones?
I also have a oil smoke issue at idle or when I let off of the throttle but I can't tell how much it smokes while riding.

A hesitation when you twist the throttle usually points to the acc pump or the slow jet/pilot screw system. What jets are in the carb, and how many turns out on the pilot screw?

The first steps in a tuneup are:
checking for intake and exhaust leaks
cleaning the carb
setting the pilot screw
adjusting the pushrods
setting the ignition timing

Here are some notes:
Intake And Exhaust Leaks Tests

You cannot get a good tuneup if there are intake leaks or exhaust leaks.

1. Check for Intake Leaks

With the engine idling spray propane gas or WD-40 around the carb/intake/cylinder head joints. Propane is best because it leaves no mess, and is most easily sucked in thru leaks. WD-40 is said to work well because it has very fine spray droplets. Be careful to not allow any of either to get sucked in thru the A/C as this will invalidate the results.

Any change in engine RPM is a leak which must be fixed.

EDIT: Experience is that this procedure will identify larger intake leaks, but it may miss very small leaks that also must be fixed. And that propane is definetly the better choice.

2. Check for Exhaust Leaks

Pour about 1/2 ounce of oil into each cylinder thru the spark plug holes. Run the engine at idle. You will get lots of smoke for about 5 minutes.

All smoke should come from the ends of the exhaust pipes/mufflers. Any other is a leak which must be fixed.

Setting The Pilot Screw on Your IronHead

If the carb is old and dirty the pilot screw passage may be gummed up such that you will not be able to "gently seat" the pilot screw reliably. If this is the case remove the carb from the bike and clean it up. Some guys try to do carb work with the carb in the bike. IMO this is a very bad idea.

In the pilot screw passage there should be, in this sequence: screw, spring, washer, o-ring. [Often POs have installed these parts in the wrong sequence; remember that the purpose of the washer is to protect the o-ring from being damaged by the spring]. The screw usually comes out easily. The other parts may require some work. The best technique is to stick a pipe cleaner in the hole, twist it around, and, like magic, out come the other parts on the end of the pipe cleaner.

1. You need to have easy access to the pilot screw, easy enough to reliably judge "screw it in until gently seated". Loosen the front fuel tank mount bolt; remove the rear fuel tank mount bolt; prop the rear of the fuel tank up on a piece of 2X4; on some bikes this will not be necessary.

2. With the engine cold [so you do not burn your fingers] turn the pilot screw in clockwise until it is gently seated. Count the number of 1/4 turns as you do it; write the number down. Back it out to the original setting. You may need to return reliably to this setting after experimenting.

The "normal" starting point for this process is 1,1/4 [according to the 79 - 85 FM] or 1,1/2 [according to usual practice] turns out.

EDIT: An old HotXL magazine article recommends for Keihin butterfly carbs between 1/4 and 1,1/4 turns out. My experience is that this works best. If you are more than 1,1/4 turns out your pilot jet is too small.

3. The engine must be at full warm up. It will have very hot parts; to avoid burned fingers have a well lighted, comfy place to work.

4. Set the engine idling at about 1000 RPM. You want it to be idling at the slowest speed that is consistent with a smooth idle so that you can hear or feel slight changes.

5. Turn the pilot screw in clockwise until the engine idle becomes worse; tending to stall. Count the number of 1/4 turns as you do this. Then turn the pilot screw out counter clockwise until the engine idle gets good, then becomes worse, tending to stall. Count the number of 1/4 turns as you do this.

6. The best setting for your bike will be somewhere between these two settings. The FM says to use the leanest setting [most screwed in] consistent with a good idle quality. Some guys say to go between the two settings.

It should be between 1/2 and 1,1/2 turns out from gently seated. If it is not within this range you should change the slow jet.

EDIT: I follow the advice from the old HotXL mag article - set it between 1/2 and 1,1/4 turns out.

7. You may have to adjust the idle speed.

8. Make sure that the spark plugs are clean, then ride the bike around your neighborhood for 10 minutes. Keep it under about 15 MPH so that you are on the "idle port", not the "idle transfer ports", the "mid range port", or the "main jet" [see carb diagrams in FM]. Hopefully the plugs will come out a nice medium gray or tan color. If they are too dark you can screw it in another 1/4 turn; too light screw it out 1/4 turn, and try the ride again.

9. If they are really light or really dark the problem is not with the pilot screw setting. For example, too light might mean an intake or exhaust leak, and too dark might mean the pilot jet is too large [among other possibilities].

10. My experience with this process is that after making a change i have to clean the plugs and go for a good ride [say, an hour or more] before i can trust that the new results are reliable.

Ironhead Push Rod Adjustment

Do this procedure with the engine stone cold. I usually do it first thing in the morning.

1. Remove the spark plugs. Remove A/C to make room to work.

2. Using a flat blade screwdriver pry the spring keeper off of each push rod; the bottom of the keeper pops out first, then the top. Alternately, use a 3/4" open end wrench to push down on the top of the spring retainer, then pry out the spring keeper with the screwdriver.

3. The lower push rod covers may be stuck tight against the bottom o-rings, but they can be loosened by pinching between thumb and finger [or carefully using a shop rag and a pliers] and twisting or rotating. Lift these up and secure each with a tall-S-shaped piece of 12 or 14 gauge household wire [not cable] [or a long piece of Plumbers solder such as 95/5 hooked over the rocker cover and under the push rod cover.

4. Jack up back end of the bike so that rear wheel is off the ground, shift to 2nd gear, rotate wheel until it clicks, repeat until you get to 4th gear. Now by rotating the rear wheel you are rotating the engine. Almost impossible with the plugs in; very difficult in lower gears.

5. To adjust a particular push rod, its valve must be fully closed [the valve spring is relaxed]. Valve position for a particular cylinder is determined by observing the corresponding push rod of the other cylinder. For example, when the rear cylinder intake valve tappet is raised [valve fully open, spring compressed], the front cylinder intake valve is fully closed, and the front intake push rod can be adjusted.

6. Check [and adjust if necessary] the push rods:

[a] use the rear wheel rotate the engine so that the rear cylinder exhaust push rod tappet is fully raised. The front cylinder push rod is adjusted correctly if it has no vertical or horizontal play, and you can just rotate the push rod between thumb and forefinger with no trace of binding or dragging.

[b] to adjust if needed: hold the adjusting screw in place with a wrench; with another wrench loosen the split locknut. Then turn the adjusting screw using fingers only until the pushrod's ball end is seated in the tappet with a "slight amount of play". Then tighten further as follows:

Option 1: Adjust on the tighter end of the range: There should be no vertical or horizontal play, and you should be just able to rotate the push rod between thumb and forefinger with no trace of binding or dragging.

Option 2: Adjust on the looser end of the range: Set the adjusting screw to finger tight so that you cannot turn the push rod between forefinger and thumb. Undo it a tiny bit so that it is just barely loose. Then loosen it 1 "side" for an exhaust or 1/2 "side" for an intake. "Side" refers to one side of the 6-sided adjusting nut.

EDIT: Experience here is that Option 2 is the better and most likely the correct choice.

[c] hold the adjusting screw in place with the one wrench; with the other wrench tighten the locknut.

[d] recheck the adjustment; it is common for the adjustment to go out as you do step [c], in which case [b] and [c] must be redone.

[e] repeat for the other push rods.

7. Use a flat blade screwdriver to push the upper push rod covers up, and seat them into the upper o-ring or cork washer.

8. Install the spring keepers, top end first, by prying them in under the bottom with a flat blade screwdriver.

Setting The Ignition Timing on Your IronHead

1. Checking vs Setting the Ignition Timing

You can check the timing without changing anything. Changing the timing can be done by one person but is easier with two. The ignition module or points is on the right side of the bike, the timing hole is on the left side. Easier with one person on each side than to go back and forth. Standard advance for the 1980 XL is 40`. I have mine set at about 35`. At 38` i get pinging.

2. Equipment That You Need

You need an induction timing light which you can buy at any auto supply store. Best to get the "dial back" type. These allow you to set a number [like 35`] into the timing light and then adjust the ignition module/points backplate until you are there.

If you have very well insulated spark plug wires the timing light may not sense the signal thru the wire. If this is the case then open the gap on the spark plug to 050 or more. Reset it to your normal gap [030 for points or 040 for electronic] when done with this procedure.

It also helps to have a throttle lock as the timing should be checked/set with the engine at 2500 to 3000 RPM.

You will need a piece of rubber oil line hose about 1 inch long. Press one end up against the side of a stone grinding wheel [or whatever] to make sure it is perfectly flat.

3. Front Cylinder: TDC Mark vs Advance Timing Mark

The TDC [Top Dead Center] mark is used with a dial back timing light to check the timing, or to set the timing at a specific degree, such as 37`. The advance timing mark is used to set the timing to the factory setting, such as 40`. Best is to use a dial back timing light to check or set timing.

4. To Identify Your Front Cylinder TDC Timing Mark

Remove spark plugs. Rear wheel off the ground, shift to 2nd gear, rotate wheel until it clicks, repeat until you get to top gear. Now by rotating the rear wheel you are rotating the engine. Almost impossible with the plugs in; very difficult in lower gears.

You want the front cyl to be at TDC. You can see in thru the spark plug hole, especially with a flash light; you can try inserting something soft like a pencil and watch it rise and fall as you rotate the engine with the back wheel but be careful it does not break or get stuck! You will have to hang on to the pencil with left hand while rotating the rear wheel with the right. Helps to have a good wingspan, or an extra person.

With the piston at precisely TDC look in thru the timing hole. You should see a drilled dot or a line. That is your front cylinder TDC mark. Once you know for certain what the TDC mark looks like you can check the timing.

5. Procedure, Checking The Timing

Begin with the engine at operating temperature. Remove the timing plug from the left side of the engine. Insert the 1" hose smooth end first, right tight up against the flywheel. I use a needle nose plier and twist it in there as firmly as i can. If it is not smooth and tight against the flywheel oil will spray out while you are working.

Start the engine, have it at about 2500 to 3000 RPM [it will be extra noisy with the timing plug out], set the timing light at 40`, aim it into the timing hole thru the hose. Click it down one degree at a time while you look for the timing mark. If you don't find it you may have to work up from 40`.

If it is in the 35` to 40` range and there is no pinging then you may wish to leave it as is. With pinging on acceleration you may want to retard it by about 1/16 of an inch or less [see Math below].

6. Procedure, Setting the Timing

Remove the points cover from the right side. You will be rotating the back plate so first mark it so you can get back to the current position if needed. Make a scratch mark or use a permanent magic marker, or better still a small bright red or whatever color paint mark.

To change the timing loosen the two standoffs holding the points/ignition module and rotate the backplate. Clockwise advances [larger degree number] counter-clockwise retards [smaller degree number].

7. Some Math, How Much to Rotate

The backplate has a 3" diameter = 1.5" radius.
The circumference = 2 * pi * radius = 2 * 3.14 * 1.5 inches = 9.42 inches
The circumference = 9.42 * 16 ~= 151 sixteenths of an inch.

One rotation of the backplate corresponds to two rotations of the engine, so it is like a circle that has 2 * 360 = 720 degrees. 720 / 151 ~= 5

Therefore a rotation of the backplate by about 1/16 of an inch results in a timing change of almost 5 degrees!

Surging and popping/spitting back through the carb are usually caused by being too lean. Intake leaks & correct jetting first. Also, 2 inch diameter pipes will never work well as the large diameter slows the exhaust gas velocity so much it can be pulled back into the intake, fouling the cylinder charge, especially if that hot-rod 1150 kit has a set of cams with significant overlap. If money is tight, at least get a set of el-cheapo 1-3/4" drags, and use the lollipops. Back the accelerator pump setting off so that it barely shoots a squirt in the throat. get everything else right, then adjust the pump setting so you get the best throttle response. Use some oil and check your compression to see if your rings or guides might be the oil smoke causing culprit.

The 1 3/4" pipes seem to work the best,40" long sometimes without loli pops or baffles.

Yep, and my bad for typing 1-7/8 'cause I meant 1-3/4. Old-timer's disease!

Okay, you guys have given me a lot to do. It may take me a few days being as I'm also right in the middle of trying to install forward controls which have turned out NOT to be a simple bolt on mod. It seems like everything I try to do with this older bike turns into a train wreck.
I was hoping I could make the 2" pipes work with washers or baffles and because they're almost new. The look of the bigger pipe has grown on me but.....I might have to go back to 1 3/4".
I have no idea what jets are in the carb now. I'm not sure if the mechanic made note of that or not either. His first response was that I should junk that carb and put an S&S on it.
Other than tearing the engine apart is there anyway to tell if this actually has an 1150 kit in it or not? I trust the guy that I bought it from but the guy he bought it from is the one who had the work done. My guy bought it and didn't put but maybe 1,000 miles on it in three years. I bought it off of his front porch where it sat 99% of that three years. According to the owner before him it is supposed to have about 2,200 miles on the engine work, including the 1,200 or so miles I've put on it since I bought it about 4 weeks ago. But who knows? It could be a bunch of BS too.
I got a million things going on and time is a little short but I'll check this stuff out when I can, appreciate the help.

An 1150 kit probably has stroker flywheels. Follow the instructions for setting the ignition timing - remove the timing plug, get rear wheel off the ground, shift to 4th gear, rotate the engine using the rear wheel. Watch the series of flywheel marks thru the timing hole, write them down and post them here. We will be able to determine if they are stock flywheels or something from S&S or whatever.

In my experience there is no such thing as forward controls that are straight bolt-on and go for IronHeads. They all require a lot of time, modifications, etc to work well. Even the ones from Kraft Tech which are among the best.

If the carb that is on the bike is the original Keihin then it is a good carb. It would be worthwhile to remove it, follow the cleaning etc instructions, and record and post here the jets and the number of turns out on the pilot screw.

The carb is a Keihin and it is the same as what my Clymer book says should be on this year of bike but without going out and looking I couldn't tell you the model number. Aren't the mixture screws plugged off on these so that they can't be adjusted?

I have controls from Custom Chrome. I think I can make the shift side work by drilling a new hole on the foot peg mount halfway between the middle mounting bolt hole and the foot peg hole and then moving and mounting the shift lever there. It will be a little high above the foot peg but I think I can live with it.
On the brake side.....I can't relocate the master cylinder to the inside of the forward control mount because it won't clear the exhaust pipe. If mounted on the outside then it's way out of alignment with the brake pedal lever. I don't know what I'm gonna do about that yet.

I like the look of the 2" pipes to,tryed a set when I first saw them on ebay never could get them adjed close. used the baffles also..no luck. they are in the junk pile now.
Post up a few pics of Your Roadster when Ya get time please?

The plug can be easily removed. With most bikes it has already been done. The pilot screw is in a passage on the top of the carb, about the middle. I have not had to remove one of these plugs myself but apparently, you can drill a small hole in it [without going thru too far!], turn a screw into the hole, and pull it out.

Post a pic of those forward controls and i will make suggestions. You should be able to use them with the master cylinder in the stock location. I have used a piece of 5/16" threaded rod for this, and covered it with a piece of chrome plumbing line from Home Depot - works very well.

The final position needs to be such that you do not have to lift your foot [much] from the footrest to brake or to shift. They should work well in emergency situations.