Hello everyone,

Here is my first post, i have been creeping on this site for a couple of weeks. I recently purchased a 1981 IH with 5k miles on it. Previous owner said that he cleaned out the carbs. Bike was running and then stopped. He thought it may be the coil. SO, I recently purchased a coil, plugs and wire.

She fired right up but then died. The bike only starts if the choke is fully pulled..it will run reving really high, has some black smoke coming out of the exhaust and it back fires a little. It also had some fire and white smoke coming out of the carb. I checked the exhaust and the rear pipe was loose. so I tighten it up. I have the manual which was included in the sale. I know i need to check the for intake leaks which i plan on doing tomorrow morning. Couple of questions what should i gap the plugs too?

Everything appears to be stock with the exception of the pipes.

Any help would be appreciated. I am a total noob but i am really committed to get it going and on the road.

Thanks again

 

Clean the carb thoroughly and check timing. As far as revving high on startup check that throttle isn't stuck open/idle screw to far and check for leaks around intake. Also check your valve adjustment.

 

Thanks Redwood seems like everything i have read points to what you just mentioned. I am going to try in the morning and report my findings

 

After morning check..new symptoms:

Front compression is 110
Rear under 40PSI

Do i need to rebuild, change a gasket or adjust rockers? I dont know where to start.

Do i burn it?

 

Front pipe gets hot and rear pipe is warm to the touch

 

at 40psi most of the gases escape before igniting.

you can check the pushrods. There is a youtube video that shows you how to do that. Both juggs are low...tho the front just might be the way you did it or the equipt you are using.

If the pushrods are adjusted fine and there is no improvement then time to pull the head and see what the problem is.

 

Okay update: I adjusted the pushrods and it increased the psi from 40-50 and i put some oil in the rear and it bumped it up to 90psi

Any suggestions would be helpful, if the motor needs to redone how much should i expect to pay for someone to do i for me vs I try doing myself.

 

do I pour some in and start it or pour some and let it sit? 1800 is way out of my budget. How much to fix it my self

 

For a valid compression test you must ...
1. have the engine at full operating temperature
2. have the throttle held wide open while cranking the engine

Note: if you have electronic ignition there must be grounded spark plugs in the caps while cranking the engine.

I'll bet you a good Canadian Tim Hortons doughnut that that 40 psi cylinder has a tight pushrod. Repeat the adjustment following these instructions, then you owe me the doughnut, eh ...

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.

 

you can open it up. Check the spring hight, pistons, rings, cylinder bores and valves. clean the heads, lap the valves and hone the juggs yourself. You will need some basic tools that also will have to include a C clamp and a socket that you can cut almost in half to remove the spring retainers, honing tool (not expensive at auto parts store--but you get what you pay for, so don't go too cheap), lapping compound and a drill (or lapping tool), industral cleaner, dish detergent, compressed air, assembly lube, gaskets and a torque wrench. (fresh oil and filter)

If the pushrods can be removed easily when the adjusters are screwed down, you don't likely need to worry about the seats or valves...but that can not be assessed until it is apart. The guides can't really be checked without some measuring.

You can get together the tools you need for a few hundred dollars...it is worth the expense to have them. You will use them again and again. You are able to measure the compression...so, you may already have some of these other tools too.

If you don't have one, get yourself a service manual. None of this is difficult.