kbart1 wrote:so bottom line is the cams have to come out. all 4 cams or just the offending bank? remember the other caps i removed looked SWEET. i read somewhere the hot set-up for the '81's was to use '81 exhaust and '79 intake cams? more lift on the '79's i believe. if i'm in there why not.
kent
Kent, the cams are not he problem. They will work fine and probably were not hurt. Still need to be checked for galling. The cylinder head will most probably have to be replaced.
There are no 81 exhaust cams. Your 1981 has 79 exhaust- and 81 intake-cams, which is an excellent set-up together with the crossover exhaust for mid-range torque. This is what you will feel while riding. Not 105HP at 9,500 rpm.
Kent:
My advice from here would be to take a breath and learn as much as you can about how these are put together. You really need to get a shop manual and study it very carefully, especially the areas that you will be working on. You absolutely cannot do any maintenance on these without one. We try here to describe things, but by no means is it a substitute for a maunal. Things like the alternator are pretty basic if you have the manual and can see where all the parts go.
Now for the really bad news - what EMS was trying to tell you is that if ANY cam bearing surface is scored/worn beyond tolerance, the entire head is junk and you will need to find another one. Doesn't matter if it's only one - it's a boat anchor. Good news is that there seem to be lots out there, what with several late models being parted out on eBay recently. But then you need to determine why the bearing surface got ruined in the first place. Lots of things to consider and check out. It will take time and thorough homework on your part to learn these engines. And of course, we'll help all we can from here.
I'd suggest running ANY new discoveries by us here before proceeding further, as you have been doing. We will try our best to help you make the right decisions.
Kent, the cams are not he problem. They will work fine and probably were not hurt. Still need to be checked for galling. The cylinder head will most probably have to be replaced.
hey guys, sorry i dont know how to highlite the above info from your previous reply but to respond to above. the bearing surface on the cam at caps 1 and 2 is pretty scored. there are some big grooves cut into the surface. i am pretty sure i will need a new cam there, and a head. i do have the manual and it's proving pretty handy. i will start ripping the top end off the head and try to see what else is going to pop up????? had to bail on today and take the wing up to whistler to ponder the situation.
here's and update and appreciate your input. top end is stripped off and yes the head is shot. i will definitely need a new one along with the cam(s) as the left side exhaust cam is shot as well. combustion chamber looked pretty good. piston tops have a little carbon on them but look good also. cylinder walls are smooth as a baby's butt, which i THINK is good. someone said they should not be a mirror like finish which they are??? one easy question is how do you pull these guide dowels out of the head and cylinder etc.? you can't just grab them with your fingers and i don't want to mark them up with needle nose pliers. the manual just says "remove them". any practical tips here? i imagine you could heat around the dowel with a heat gun to expand the head and the dowel may pull out easier? clutch and all associated gears chains etc. are out of the right side, except for the primary shaft (the one above the clutch). everything in there looks good and don't SEE any signs of material from the cam / alternator migrating down there. that being said i am still trying to figure out what the sludge was that was stuck to the case below the alternator plates? it definitely was metallic as my magnet picked it up when i passed it through it. i thought it may be some material from the plates wearing but i really don't know. anybody have any ideas? have the cylinders all ready to pull off however i think the gasket and dowels are not wanting to give it up, you can't just "pull" it off and i don't really want to whack it with my rubber mallet for fear of damaging it. any ideas?
here's the big question now. i really don't want to split these cases if i can avoid it. is there any telltale signs i can look for to tell me the bottom end (crank and main bearings etc.) should be in good shape, or bad shape for that matter? other than the issues with the cam and sludge in alternator cavity things LOOK pretty good. with oil pan and all covers off everything looks pretty good in the lower end. the oil pickup screen had nothing major in or on it for what that's worth. when i look at the manual it looks as though the main bearings are the same as the cam bearings, line bored with no removable bearings? so if these surfaces are shot that means the case is an even bigger boat anchor than the head correct?
i look forward to your suggestions. so much for a fresh tank of gas and a spray bomb resto!
Kent:
You do not need to bother removing the cam cap dowels since the head is junk. Your replacement head has to be complete with those and the cam caps or DO NOT buy it. I see lots of used heads on eBay - many do not have the matching caps.
The block sometimes sticks where the 6mm stud goes through the cases in the front. You did remove that nut didn't you? If so and it's still stuck, position the engine so that you have clear access to the area of the block right at the 1047cc logo. You can whack right in that area pretty hard with a hardwood block and hammer. It will come loose eventually.
Again, study your shop manual and you will see that the main and rod journals indeed have babbit bearing shells. They are replaceable and still available from Honda. It's probably worth taking a chance of just re-doing the top end and seeing what you have then. The cases can be split without taking the top end apart, but the crank cannot be serviced without the top end off.
Find yourself a good head first and it has to be an '81 or '82. Reason is that the center four studs are larger that the early models and the early heads won't go on without some machining.
yes the nut in the front of the cylinder is removed. i will try your hardwood block trick and see if i can break it free. was at the honda shop today having a new tire put on my wing and investigated the bottom end situation. main and rod bearings are going to be close to 500.00 up here but i figure i'm this far into it i might as well go the distance and split the case anyways. 2 reasons, piece of mind and also i just like knowing whats in the motor i'm riding so what better way is there to find out. as i am obviously going to be needing a new head do you know of any tips to not buy someone elses junk? obviously the dowel pins need to be there AND the original cam caps. hopefully the seller will be honest about any scoring of the cam bearing surfaces??? i am going to drop a note to the fellow in Florida (usedcbxparts) to see what he has in the way of pro-link heads, couldn't get much further away for shipping but hey, what can ya do?
Kent:
I'd only buy a head that could be returned for full refund if it did not check out OK. If you can find someone parting out a running engine (don't like to hear of that, but it happens), that's the way to go. Might have to be patient looking. I'll keep my eye out. You might even consider buying a whole engine for parts.
I'd really check out the bearings before replacing them. They are good for 100,000 miles or more with decent care. I just picked up a complete set of main bearings today for $165 from my local dealer. Rod bearings would be one set less, so $300 would buy the complete main and rod set here. Your guy is ripping you on that.
well, tried the hardwood and the hammer on the cylinder at the 1047cc mark. didn't budge and i was hitting it pretty hard. i thinks that's an omen. i'm going to gamble and leave the bottom end as is. i am thinking with all the covers off and oil pan removed etc. i wouldn't mind flushing something through the case and down the cam chain openings etc. to flush away any potential nastys that may be hiding on any surfaces in there. obviously not a de-greaser as i want to keep all the bearings etc oiled. i thought i might warm up some new oil on a stove for example and pour that throughout the motor and into a large drip pan to flush anything out. any thoughts on that? my thoughts are now to get into the shop manual again and learn the path the oil takes to the head and then where it goes in the head and drains back into the case. those # 1 and 2 cam bearing surfaces had to fail for a reason??? and i agree, it would be cool to find a complete motor for parts, i will be keeping an ever present eye on e-bay for example. thanks for your help and advice here.
Looks like we are both engrossed in the resurrection of CBX's.
I just split the cases on The Travesty, she is a 79 model with 21,000 miles on the clock. I suspect she was abused. Here is what the bottom case looked like.
Mike
When given the choice between being right or being kind; choose kindness. W. Dyer
kbart1 wrote: my thoughts are now to get into the shop manual again and learn the path the oil takes to the head and then where it goes in the head and drains back into the case. those # 1 and 2 cam bearing surfaces had to fail for a reason???
kent
Here you go Kent ...
CBX Lubrication.jpg
Good luck, Aris
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hello all
getting back into this now. picked up a used 82 head and cams. plasti-gauged the journals tonight and all good. found one issue in that the #14 cam cap has a stripped thread in the head, will need to get that fixed up. removed the carb boots, they were pretty brittle however i am hoping i can re-use them. anybody have any tips on reconditioning or "softening" up the rubber on the boots? the head is missing a few (6) exhaust studs so i was planning on removing 6 from my old head to use them but couldn't budge them, any tips? tried heating the surrounding head with a torch but still no go? taking the head into a local machine shop who has done some cbx head work before to do valves, seals etc. HOPEFULLY GUIDES ARE FINE. getting the top end sorted out though. one other question, it doesn't say in the manual the torque for the 6 bolts on the clutch, the ones you use in conjunction with the springs. anybody have any ideas of the torque spec'd? don't want to over tighten them as the alum strips easily, as i'm sure you know. frame is in for powder coating now and should have it back by end of week and then can REALLY get going on putting things back together. toying with the idea of building a naked pro-link but not sure about wiring and headlight bucket. anybody confirm you can use an 81-82 wiring harness and run a 79-80 headlight/indicators or do i need a different harness? also, any thoughts on natural alum. engine covers (valve, cam, crank covers etc.) want to either polish or chrome them all, i think chrome will be less maint. however i am concerned about heat on these parts, any thoughts? more to follow
For the missing exhaust studs, I would go with new ones and buy yourself a heli-coil kit to install them. You *might* be able to screw some of them into the original threads in the head and have them hold, but as you discovered, the stock ones are well stuck in there . . . . unless someone has pulled out the threads overtightening the exhaust collar nuts and that's probably what's happened to the 6 you have missing
A new stud in a heli-coil will fix you up good as new . . . . better than new actually
Polished aluminum looks beautiful, but you'll have lots of work to keep it that way. Chrome is the easy way, but it's a bit expensive. All the covers on my bike are chromed and so far, so good. The heat isn't a problem . . . . you can even chrome the exhaust collars if you want. Tims now does chroming on most CBX parts at pretty competitive prices . . . . you send him your pieces and he returns the same ones chromed
kbart1 wrote:found one issue in that the #14 cam cap has a stripped thread in the head, will need to get that fixed up.
kent
Kent, I could not agree more with Don.
Invest in one or two helicoil kits, read the instructions, apply care and consideration and you will never look back.
As suggested, your bad / tired threads will become much stronger than original!
2 pics to show you how I prepared for an iffy cam cap thread on my Z head:
P1070723 (1).jpg
P1070726.jpg
Aris
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so i am getting ready to install my freshly painted motor into my 81 prolink. think the motor install itself should go pretty smooth the way i have it worked out. i have a couple questions re carbs and airboxes etc. looking for any input or suggestions and these are not in any nesc. order. i have the carbs ready to go onto the engine AFTER i have it installed on the lower hanger bolt. i thought i may install the throttle and choke cables to the carb linkage OFF the bike and pass them up through the frame while installing the carbs? then attach them to the throttle housing after carbs are mounted. also, does anyone have any suggestions on the airbox to carb connection? thinking of installing air box to carbs while motor is tilted forward so when tiliting engine back you only have the 1 large opening to the aircleaner housing to contend with. also, i would like to replace some of my valve cover bolt rubbers, i have a number of rusted bolts but the rubbers are good and i have some nice chrome bolts with bad rubbers. i was hoping to swap rubber bolt seals around but they look as they may get destroyed while trying to remove or install them? anybody have any practical tips here? any input or advice would be much appreciated. once i get the motor back in place i will post some pics so you can see whet the heck i'm up to.
i am thinking with all the covers off and oil pan removed etc. i wouldn't mind flushing something through the case and down the cam chain openings etc. to flush away any potential nastys that may be hiding on any surfaces in there. obviously not a de-greaser as i want to keep all the bearings etc oiled. i thought i might warm up some new oil on a stove for example and pour that throughout the motor and into a large drip pan to flush anything out. any thoughts on that? my thoughts are now to get into the shop manual again and learn the path the oil takes to the head and then where it goes in the head and drains back into the case. those # 1 and 2 cam bearing surfaces had to fail for a reason??? and i agree, it would be cool to find a complete motor for parts, i will be keeping an ever present eye on e-bay for example. thanks for your help and advice here.
