new intake boots

well i did the spray the wd-40 on the carb boot trick and the RPMs went up. so i didnt bother with it and ordered new ones. i just got the old ones off and they looked pretty good. should i be concerned? could it have been the deal against the block? or could there be hairline cracks in the boots?

It could have been both hairline cracks and a bad seal against the engine causing the vacuum leak(s).

Ya gotta remember that they're mearly rubber, and after 20+ years the rubber itself will start to break down and warp due to the engine heat and simply old age.

i cant remember if someone had mentioned this before, but would anyone recommend some type of sealent between the boot and the block?

kzrider.com/component/option,com_joomlab...id,3/id,69591/#69591

alright, this will be the last time i ever remove the carbs. i havent finished yet, but i had to stop because i am beyond pissed off. it took nearly two hours to slide them back into place in the engine side, then the rubber boots in the airbox got pushed back, and it is impossible to pull them back out to where they lock in place. i am so angry with this setup. who in their right mind ever thought up this setup? it is the most rediculous, unneccessary half ass contraption i have ever seen. so i guess this leads me to my next point.....

with k&N pods, what jets will i need with stock pipes? and stock carbs.

As long as your boots are not as hard as concrete just fold the boots over on themselves. This gives you another 3/4 of an inch and it makes a world of difference in installing carbs. When carbs are in just unfold the rubbers back over the carbs. If your boots are too brittle to do this buy new boots. Try Z1 Enterprizes. It really makes carb removal and replacement easy. No more flinging tools around the shop or bug stomping.

finally after many hours of frustration, its on. and WHAT a difference. its incredible. idles like a dream, runs awesome. its amazing that those boots that looked fine caused all that problem. i love it

I got a nice looking set of 34mm intake manifolds with a set of carbs I bought off eBay. They were a bit old and hard but no cracks. I wanted to put some sync tubes in them and use them to synchronize a few different types of carbs that have no sync port built onto the carb bodies. It took me about an hour to remove the sync tubes from an old junk set of carb holders and then install in the new carb holders. They leaked like a sieve... the rubber was just too hard and wouldn't seat against the cylinder head. If I had used some sealant between the cylinder head and carb holders they probably would have done OK but since I change the carb holders frequently, I didn't want to clean up the mess. You can see leaking easily with vacuum gauges.

when i put carbs back on i usually have the air cleaner tubes off. when the carbs are in place i boil some water and throw the air cleaner tubes in there for a minute or so. wear gloves, they come out squishy as can be an pop right in to place with minimal cussing or fussing

You can see leaking easily with vacuum gauges.

Or like happened to me a couple of hours ago, if you happen to be looking directly at the carb holder and you see flame inside the carb holder when it pops back through the intake

After a closer examination, I believe I could slide a .020" feeler gauge between the head and the carb holder, guess I'll dig through my spare parts and see if I can find a couple in decent condition tomorrow after work.
I'm determined to have this bike (79 KZ750 twin) licensed, insured, and be riding it next weekend.