Where the carb attaches to the intake there is [or should be] a paper gasket, usually held in place with some sticky gasket sealer. In its place [or in addition] you can install an insulator that is the same shape as the gasket but is about 1/2" thick. This is to prevent the heat from the engine migrating thru the intake to the carb, and boiling/evaporating the fuel from the carb float bowl.

I believe [but i do not know] that this was common on shovelheads; i do not know if it was ever installed on IronHeads from the factory. Someone else might comment on this.

It is worth a try if you think fuel evap from heating of the carb is a problem.

 

Even the tinyest intake leak will cause a serious tune up problem. The propane technique i described will find most intake leaks but will miss a very fine one. Some guys use WD40 but the propane is better - finer mist and less mess.

There is one, and IMO only one, way to prevent intake leaks, and that is to follow the factory manual procedure for installing ther intake manifold. That is: install and fully tighten the intake manifold before final tighten the cylinder head bolts. This ensures full mating of the intake mani surfaces with the cylinder head surfaces. Plus: you must use a carb support bracket.

Some guys keep the cylinder base nuts rather the the cylinder head bolts loose and this appears to work as well.

So if there is an intake leak, the proper solution may involve removing both cylinder heads and reinstalling them with new gaskets. First tho i would, as already suggested, install new rubber seals.

 

There are no exhaust gaskets. Some guys put a ring of the very thin and soft pop can metal between the head flange and the pipe; others use even thinner sheet copper or whatever.

I use a little Permatex Ultra Copper Gasket Maker on the head flange before sliding on the pipe.

Another common technique is to cut another groove in the header with a hacksaw. Some of the aftermarket pipes are not grooved well enough and will not seal regardless of how much you tighten the clamp.

Some of the aftermarket clamps will not seal. There are some really nice looking, extra wide, chrome exhaust clamps - i could not get them to seal, even with the Permatex. The best clamps are the OEM ones.

 

I don't know which problem I should address first If there is boiling evap is there any way to test for this. Now for carb maybe I should adjust the idle mixture when she is hot and see what happens

 

The idle increases as the bike gets hot and she doesnot misfiresdoes this help I also just checked the s&s carb there is a block between the carb and the intake.the carb is bolted to the intake. I am goig to take the bike out today weather is only 45 deg. we will see if I can duplicate it today Any more sugg Thanks

 

Insulator block for S&S carbs J&P P/N 401-273 Need a catalog call 800-397-4844 These blocks keep the engine heat ( big time on ironheads ) from transferring to the carb body or slows it down somewhat It is made of a composit material Heat will effect the idle on a carb!

 

Can this part go bad? Any other part can cause this problem including intake or exhaust parts Thanks

 

I took the bike out for a little while and she rode good. Now I let her sit in idle and then took her out again and she rode great ,well the weather is cooler but then I was thinking that when I did take her out when it was warm the idle would go down if I gave her gas real quick trying to do it today is going to be a problem

 

Don't get sidetracked by too many issues. Here is what you should do:

1. test for exhaust leaks; correct if found
2. test for intake leaks; correct if found
3. determine which S&S carb you have [there are several models], what jets are in it, number of turns out on the pilot screw; report results here

My feeling [not scientific] is that it is a carb tune up or adjustment problem.

If it idles high but returns to normal when you blip the throttle it could be a throttle cable adjustment or lubrication problem.

 

md, you are right ,I am jumping around. I am going to check the intake then exhaust,then work my way down your listSometimes I want it to be the easiest instead of the worst. Now as for the cables they are working fine and retracking fine i will lubricate the throttle cables. I do have a s&s e carb. The only problem is the weather a little chilly here Thanks Charly