82 Seca xj650rj Intake boots

I have noticed that I have cracks on both sides of the intake boots on the outboard cylinders of my bike. The cracks don't appear to go all the way through the rubber but not really sure though. These are the boots closest to the cylinder heads. My bike fires up perfectly cold but once I have been running for a while and I try to start it again it is very sluggish to fire up. Once the bike is running again it idles very well.
How would I know if my bike is running too lean? If it is recommended to replace them I have noticed that there are two different kinds of boots in my Haynes manual, it looks like one set of boots goes on cylinder 3 and 4 and a different set on cyliders 1 and 2. If I replace them I assume I replace the gaskets as well.
I have had the carbs off in the past for a rebuild when I stored my bike for a quarter century but that is a different story altogether. So I am resonably confident I could do this myself.
Is there anything else I need to know or anything I am missing?
I would appreciate any or all feedback from the forum.

 

There are a couple of threads here about inexpensive ways to repair those boots. Smearing them with RTV or, as Hogfiddles has suggested, cutting collars of a tight fitting inner tube and stretching over the boots. Len at XJ4EVER has the new boots and if you make sure he knows which XJ you have he will get you the right ones. Yes, there are 2 styles of the boots. Earlier XJ's have all 4 the same, later models have different boots, left and right. The biggest problem I have had is the socket head screws that secure them to the head being seized. Those are spectacularly easy to break off rather than unscrewing. The screw in question will act like it is turning slightly as you try to work it back and forth to free it and suddenly just snap off. Soaking in penetrant like Kroil, PB Blaster, WD-40 for extended periods, great, gentle care and holding your tongue just right and good Karma are all helpful. Good luck.

 

Snapping one or more of the hex bolts is a new nightmare I haven't yet dreamed about yet. Thanks for the input maybe a chat with my local bike shop might be in order.

 

Actually, that's not entirely correct. It's only the orientation of the bolts that hold the manifolds to the head that are the same on the "early' (non-YICS) engines, but the left side and right side manifolds are always different from each other, regardless of which engine you have:

NOTE: the non-YICS (1980-81 XJ650 Maxim/Midnight Maxim and 1982 XJ650RJ Seca) left side (cylinders #1 and #2) manifolds differ from the YICS (1982-84) manifolds in the orientation of their mounting:

* non-YICS engines have the intake manifold mounting bolt holes in the cylinder head aligned in this manner:

<#1 \ \ \ \ #4>

* YICS engines have the intake manifold mounting bolt holes in the cylinder head aligned in this manner:

<#1 / / \ \ #4>

This is why the left side (cylinders #1 and #2) intakes differ between the YICS and non-YICS engines, and why they are the same for the right side (cylinders #3 and #4) on all XJ650 non-Turbo engines!


And you can't just "flip" a LH manifold upside-down (which would achieve proper bolt hole orientation) and then install them on the right-side cylinders (or vice-versa), as the rubber portions of the manifolds have compound curvatures to them (and never mind that the "flipped" manifolds will have their vacuum nipples facing towards the ground, either):

NOTE: all intake manifolds differ between the left side and the right side versions in two critical manners:

* intake manifolds, when installed on the engines, "curve" inwards towards the centerline of the bike.

* they also curve "upwards" (as well as inwards).

This combination of both upward and inward curvatures of the intake manifolds is why it is not possible to simply swap left side (cylinders #1 and #2) and right side (cylinders #3 and #4) intake manifolds.....some people think that you can just "flip upside down" a right side manifold and it will become a left side manifold (or vice-versa). This would be true if there were only the "inward" curvature to the manifolds; however, the "upward" curvature prevents such swapping from occurring (as the swapped-side manifold would be curving "inwards and downward")...........and you'll never get the carbs to fit correctly into such mis-aligned manifolds, and on the slim chance that you do get them to fit, you'll end up with major vacuum leaks at that joint.

 

@chacal, Thank you Len. Well explained. At least I was close.