Ironhead 70 xlch tuneup and intake manifold

[Wilkinson949]

So i just bought this bike a few weeks ago, 70 xlch. Going over some issues. Since it is a new bike to me I feel like I should give it a complete tuneup, valves, pushrods, points, plugs, carb, oil change. 1st question, would that be the best order to do it in.

The intake manifold support bracket I noticed is missing. No biggie, I'll just get another; but then I notice that the S&S Super E shorty is being held on by some aftermarket hose and clamps; not the original bands, clamps, or orings.

The bike fires up but runs horrible, which is why I want to give a complete tuneup. The intake manifold no where nearly lines up with the intakes on the heads. I've read that I could adjust the heads to help, but i mean it is no where even close. The current aftermarket hose and clamps appear to be holding strong; so I'm just curious if this misalignment is a big deal or not if there are no leaks?

Rear head:


Front head:

[doodah man]

if it were my bike the first order of business would be to get the correct o-ring manifold and o-rings in there, then the carb brace. you don't want to attempt to do any tuning with the possibility of intake air leaks. then do the other items - valve adjustment, points gap, ignition timing...

[Pickss]

Looks like a "tite seal" kit to me.

https://www.lowbrowcustoms.com/tite-...sportster.html

or it could be someone's homemade version. very cheap to do yourself with some silicone intercooler piping cut up and some metric hose clamps.

I would do the easy stuff. start with cleaning the carb, carb brace and then check for intake leaks. new plugs and points. adjust pushrods and check the timing. throw in changing all the fluids in there too.

I like to change the oil immediately when i get a new bike. doesn't have to be the best brand oil, because i change it as soon as i get the rest of the bike sorted out.

[Toejam503]

My first order of business would be to get the old oil good and warmed up, and change it. Clean out the fuel system, then I would try and see if I could get it to run better before tackling your list.

[bustert]

hard to say from pic but can you feel the miss alignment through the rubber boot or is it just the way the boot is squeezed out by the clamps.

[ryder rick]

That manifold seal is a hack job.
I'd fix that first as it will come back to haunt you.
You have to take the carb off to do that so go through the carb per the S&S instructions.

Start with a 29.5 low speed and a 72 main jet or in that neighborhood. (S&S instructions are very lean)
(a small motor will not necessarily need smaller jets as it does not suck as hard)
Final jetting will be determined by riding it.
Idle mix setting is very sensitive on this carb 1/8 turn is a fairly large change.
Set it to lean best idle with a hot oil tank. (hot oil tank is like a 30 minute ride)
Lean best means, turn the mix screw in 1/8 turn at a time until the motor slows down, then back it out 1/8 turn. That is your best idle mix setting and will keep you from fouling plugs.
No less than 950rpm so it gets good oiling.
I set them a little faster so it doesn't stall so easy when colder.
Use very little accelerator pump, it only needs a little mostly is a starting aid.
Do not try to tune for best sound free reving, you will wind up way rich.

Lastly do not try to tune around the flat spot that drag pipes have, fix the exhaust. (see the 2 into 1 topic) http://xlforum.net/forums/showthread.php?t=1815664

[Wilkinson949]

Originally Posted by bustert

hard to say from pic but can you feel the miss alignment through the rubber boot or is it just the way the boot is squeezed out by the clamps.

I can see and feel it. Huge uneven gap on both front and rear. I'm hesitant to go and buy an new manifold if that is not the issue since i've read here to align the heads to meet the manifold.

[Ferrous Head]

A couple of options here. They make "kits" to covert o-ring style manifolds to band style. I have one, haven't used it.
Simply because the o-ring set up does work ok if a bit fiddly to install. We've all been using them for many years with minor issues. The band style is obviously a better design.
If it was mine I would just buy the correct o-ring manifold and some new o-rings. Your then at a known good starting point.

[IronMick]

Originally Posted by Wilkinson949

... i've read here to align the heads to meet the manifold.

In the FSM it recommends to get a slightly better alignment you can rotate the cylinders - this, of course, assumes that you have left at least one side of the base gaskets with no sealant, and have not yet final tightened the base nuts.

Some of us have done the same technique with the cylinder heads, although this one is not in the FSM.

These each allow a small amount of adjustment, considering the amount of oversize in the bolt holes.

[Wilkinson949]

Originally Posted by Ferrous Head

A couple of options here. They make "kits" to covert o-ring style manifolds to band style. I have one, haven't used it.
Simply because the o-ring set up does work ok if a bit fiddly to install. We've all been using them for many years with minor issues. The band style is obviously a better design.
If it was mine I would just buy the correct o-ring manifold and some new o-rings. Your then at a known good starting point.

I agree. I was speaking with a buddy of mine and he says most likely its the wrong manifold on the bike. It may be a shovel or some other, but to get the correct manifold and go from there. May have to align the heads, cylinders, and manifold all in one step.

Thanks for the feedback.