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Discussion Starter · #1 ·
I created a thread about this a few weeks ago, asking if I should use my spare engine for parts and build up my current engine, or build up the spare and then just swap. While it'd be most logical to just build mine up, I decided that the most convenient option will be to just build up the spare, as everything that it needs done to it is something I would do to my current engine anyhow.



Now, I want to know if I have the right idea of what all to do with it. I want to make it as perfect as I can. I know that these engines don't take kindly to modding, so unless I find some easy mods that have little risk to negatively affecting my performance, it'll be a stock rebuild.



So far, my list of things to do/get is:



Gasket Kit

Mechanical Seal

G8 Stator

Cam Chain+Tensioner

Piston Rings

Lap Valves

Inspect entire engine, and decoke everything possible.

Clean out and/or replace oil pump

New clutch kit, if current one isn't serviceable





Is there anything else that I should consider, or did I pretty much nail everything?



Oh, and there was a bit of rusty water that came out of the cooling pipes when I removed the radiator. I was told that this can be flushed out after the engine is rebuilt, and put back on the bike. Is this true, or can I get it flushed out before putting it on the bike, so I can get it "perfect?"



Thanks for the advice. This is still a bit off in the future...but the first thing I'm going to do is get the heads serviced (the valve lapping and whatnot) and get my gasket kits. Then I'll slowly do everything else until it's ready.
 

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If the engine's bottom end and pistons/compression are/were ok then don't touch them and also leave the gearbox alone and just do what you intend.



See this thread as well,



http://choppercharles.com/cs/forums/126066/ShowPost.aspx



As a check also look at the Cam followers from down top and hopefully they have not been changed and fitted incorrectly.They can be fitted with their cup angles wrong presenting the wrong angle to the push-rods.This causes premature Cam shaft and cam follower wear.



Obviously take the front engine case off and check/service the oil pump chain and assembly and clean the sump area underneath.
 

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Discussion Starter · #3 ·
If the engine's bottom end and pistons/compression are/were ok then don't touch them and also leave the gearbox alone and just do what you intend.



See this thread as well,



http://choppercharles.com/cs/forums/126066/ShowPost.aspx



As a check also look at the Cam followers from down top and hopefully they have not been changed and fitted incorrectly.They can be fitted with their cup angles wrong presenting the wrong angle to the push-rods.This causes premature Cam shaft and cam follower wear.



Obviously take the front engine case off and check/service the oil pump chain and assembly and clean the sump area underneath.


I'm unsure of the history of it, thus my want to replace the rings and etc. I've heard that checking compression should be done at WOT...with this engine being detached, does that mean I need to hook some carbs up to it, or is there a separate method to checking compression?



It does turn over just fine when jumping the starter motor, I don't hear anything out of the ordinary, but that's just turning over. I was told that merely inspecting the pistons and crankshaft will require me to replace the rings, which is why it's on my list.



I'll definitely look out for the cam followers, and thanks for that thread.



When I finally get around to working on this engine, I'll use this thread, and post lots of pics
.
 

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I'm unsure of the history of it, thus my want to replace the rings and etc. I've heard that checking compression should be done at WOT...with this engine being detached, does that mean I need to hook some carbs up to it, or is there a separate method to checking compression?



It does turn over just fine when jumping the starter motor, I don't hear anything out of the ordinary, but that's just turning over. I was told that merely inspecting the pistons and crankshaft will require me to replace the rings, which is why it's on my list.



I'll definitely look out for the cam followers, and thanks for that thread.



When I finally get around to working on this engine, I'll use this thread, and post lots of pics
.
only one real/practical way to check comression.engine in turning over, warm and at full throttle[kill switch set to off].mmm.thats pretty deep going in to look at crank,pistons,bearings and rings.

good luck on that,if you feel its needed to be done
 

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I'm unsure of the history of it, thus my want to replace the rings and etc. I've heard that checking compression should be done at WOT...with this engine being detached, does that mean I need to hook some carbs up to it, or is there a separate method to checking compression?



It does turn over just fine when jumping the starter motor, I don't hear anything out of the ordinary, but that's just turning over. I was told that merely inspecting the pistons and crankshaft will require me to replace the rings, which is why it's on my list.



I'll definitely look out for the cam followers, and thanks for that thread.



When I finally get around to working on this engine, I'll use this thread, and post lots of pics
.




Well...thinking this over.....what does WOT give you? IMO you'd get the same airflow without carbs on.



I'd check the valve clearences and run a compression test on the engine. (to make sure valves are closing all of the way)



I have not had the bottom end apart on my bike so I do not know about it. (my engine's bottom end is untouched)



Worse case would be compression test comes out fine. Put the motor in the bike and find out it needs lower end work. IMO it's not that hard to drop the engine.



If you do end up doing the full overhaul, lots of pics please!
 

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Discussion Starter · #6 ·
I don't really want to do the rings and etc, but my uncle who'll be giving me assistance with the rebuild says that "I don't know a single person who has an out of frame engine, and doesn't change the rings while they're in there." He says that it shouldn't be too hard, and all I'll have to take into consideration is that I'll have to break the new rings in.



I figure that I have plenty of time, so it shouldn't be too big of a deal to do. Unless my current engine finally blows up. Then I really need to hurry this one haha.



Now, if I were to just ignore the rings and whatnot, what symptoms will appear if there is something wrong in the crank? Knocking, clicking, or something worse?
 

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I don't really want to do the rings and etc, but my uncle who'll be giving me assistance with the rebuild says that "I don't know a single person who has an out of frame engine, and doesn't change the rings while they're in there." He says that it shouldn't be too hard, and all I'll have to take into consideration is that I'll have to break the new rings in.



I figure that I have plenty of time, so it shouldn't be too big of a deal to do. Unless my current engine finally blows up. Then I really need to hurry this one haha.



Now, if I were to just ignore the rings and whatnot, what symptoms will appear if there is something wrong in the crank? Knocking, clicking, or something worse?
in my opinion,you and uncle are wading in too deep too quick.your rings and bottom end may be just fine.do a rear and top end rebuild,and see what you are dealing with then.

jmo


and it is odd,i do not know a single mechanic who would even think about replacing rings just because the engine happens to be on the bench.i certainly would not.




if you decide to go down that road.mm,i wish you guys good luck
 

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I don't really want to do the rings and etc, but my uncle who'll be giving me assistance with the rebuild says that "I don't know a single person who has an out of frame engine, and doesn't change the rings while they're in there." He says that it shouldn't be too hard, and all I'll have to take into consideration is that I'll have to break the new rings in.



I figure that I have plenty of time, so it shouldn't be too big of a deal to do. Unless my current engine finally blows up. Then I really need to hurry this one haha.



Now, if I were to just ignore the rings and whatnot, what symptoms will appear if there is something wrong in the crank? Knocking, clicking, or something worse?




I'd look/listen for poor oil psi, and noise.



I wonder if your uncle is used to working on air cooled bikes? IMO they need to be overhauled sooner than a liquid cooled engine.



On my bike with 39,000 miles, I don't get any smoke on start up and it uses very little oil.
 

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in my opinion,you and uncle are wading in too deep too quick.your rings and bottom end may be just fine.do a rear and top end rebuild,and see what you are dealing with then.

jmo


and it is odd,i do not know a single mechanic who would even think about replacing rings just because the engine happens to be on the bench.i certainly would not.




if you decide to go down that road.mm,i wish you guys good luck
I'd tend to agree with Bandit here, if everything rotates by hand smoothly and you can visually inspect some of the parts you might skip the bottom end tear down. One important but small thing I didn't see mentioned so far are the oil seals. Easy to replace but a PITA if they fail, especially the rear cover one behind the water pump. Two years ago I replaced the cam chain and tensioner along with some other small bits, but I overlooked the front cam shaft oil seal and sure enough, it started leaking just last week.



Also, I know this is your spare engine but you may want to order a new fan along with all the other pieces. Either that or convert to an electric fan.
 

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With all due respect to your uncle, he knows nothing of CX engines. What he says holds VERY true for about 95% of the bikes that were circulating when the CX was new. On my old BSA I was lucky if I didn't have to do piston rings and head gasket between oil change intervals.



The bottom end of a CX is a very robust, long lived and forgiving thing, just leave it alone if it ain't broke.
 
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Well, I have to join the group on this one as well. I have had my engine out twice (now doing a triple bypass plus a bit more). I have done rings in many engines, but I have not even attempted it on the CX engine mainly for the reason of very limited availability of parts you may need. Rings you may find, pistons and bearings probabaly not, and if you do they will probabaly run you more than the whole bike. Unlike other bikes (see, i didnt say Harley) these bottom ends are really rugged and if maintained last a hell of a long time. I WOULD (and did) lap the valves as its very easy and makes a huge difference, but leave the pistons and cylinders alone (and resist the temptation of removing that little ring that gets formed at the top of the cylinder walls lol).



If you are concerned about the rings, make sure the valves are seated properly (after lapping would be best) and run a compression test on each cylinder and compare the two values (they should be close to the same +/- 15psi max). Just make sure you have a bit of oil still on the cylinder walls when you reinstall the heads. (I prefer to put oil in even if I have to drain it again just to play safe).



If you KNOW the valves are seated well and the gaps are OK, the compression test will tell you right away if you should even consider messing with the pistons.
 

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Discussion Starter · #12 ·
I'd look/listen for poor oil psi, and noise.



I wonder if your uncle is used to working on air cooled bikes? IMO they need to be overhauled sooner than a liquid cooled engine.



On my bike with 39,000 miles, I don't get any smoke on start up and it uses very little oil.


Yes. He's only ever worked on one water cooled bike, an older Goldwing, which he never pulled the engine out of. Him and his friends are big on KZs and the old Kawasaki triples, his main bike is a Z1. I'll mention it to him that the CX engine != his old Kaw engines then lol.



My current engine (the non-spare one, that is) seems to be using quite a bit of oil lately. I'll get some clutch slip, look at my dipstick, and the oil is right at add. I'll put in like maybe 1/4th of a court (enough to bring it up to the first diamond) and then maybe a week or so later the clutch will start slipping again and I'll check the oil, and it's back to add again!



No smoke noticeable from the pipes. Once I did see white smoke, but I think that that was from water. Haven't seen any since the one time.



I'd tend to agree with Bandit here, if everything rotates by hand smoothly and you can visually inspect some of the parts you might skip the bottom end tear down. One important but small thing I didn't see mentioned so far are the oil seals. Easy to replace but a PITA if they fail, especially the rear cover one behind the water pump. Two years ago I replaced the cam chain and tensioner along with some other small bits, but I overlooked the front cam shaft oil seal and sure enough, it started leaking just last week.



Also, I know this is your spare engine but you may want to order a new fan along with all the other pieces. Either that or convert to an electric fan.


Thank you! I'll add them to my list. I want to replace everything that can fail due to age or whatever.



I already have an e-fan that I'm going to probably stick on my current engine before even beginning to work on my spare engine. Though I am using the spare engine to fit it, so I don't waste an entire day trying to make it work while I can't go anywhere or something.





With all due respect to your uncle, he knows nothing of CX engines. What he says holds VERY true for about 95% of the bikes that were circulating when the CX was new. On my old BSA I was lucky if I didn't have to do piston rings and head gasket between oil change intervals.



The bottom end of a CX is a very robust, long lived and forgiving thing, just leave it alone if it ain't broke.




No offense taken. He's just trying to make sure I don't cut corners like I've been doing, and he knows very little about water cooled motorcycles. He does know that when I cut corners, usually my bike will end up stuck in his yard for several days until we think up a fix.



What you say makes a lot of sense, and makes me understand what's going through his head a little bit better. This'll make things a hell of a lot easier rebuilding the engine. I'm basically just doing a triple bypass+valve lap, and complete gasket/rubber bits replace.
 

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Yes. He's only ever worked on one water cooled bike, an older Goldwing, which he never pulled the engine out of. Him and his friends are big on KZs and the old Kawasaki triples, his main bike is a Z1. I'll mention it to him that the CX engine != his old Kaw engines then lol.



My current engine (the non-spare one, that is) seems to be using quite a bit of oil lately. I'll get some clutch slip, look at my dipstick, and the oil is right at add. I'll put in like maybe 1/4th of a court (enough to bring it up to the first diamond) and then maybe a week or so later the clutch will start slipping again and I'll check the oil, and it's back to add again!



No smoke noticeable from the pipes. Once I did see white smoke, but I think that that was from water. Haven't seen any since the one time.







Thank you! I'll add them to my list. I want to replace everything that can fail due to age or whatever.



I already have an e-fan that I'm going to probably stick on my current engine before even beginning to work on my spare engine. Though I am using the spare engine to fit it, so I don't waste an entire day trying to make it work while I can't go anywhere or something.











No offense taken. He's just trying to make sure I don't cut corners like I've been doing, and he knows very little about water cooled motorcycles. He does know that when I cut corners, usually my bike will end up stuck in his yard for several days until we think up a fix.



What you say makes a lot of sense, and makes me understand what's going through his head a little bit better. This'll make things a hell of a lot easier rebuilding the engine. I'm basically just doing a triple bypass+valve lap, and complete gasket/rubber bits replace.
a very wise decision,in my opinion.

here is a list of all the part numbers that you may need




http://choppercharles.com/cs/forums/149387/ShowPost.aspx

hth
 

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Oil Usage:



The last work I did on this present engine was to fit new valve stem guides and seals and new valves.Quite an expensive job but had the money at the time.This helped reduce my oil usage however I also run my engines on Molyslip,



http://www.ebay.co.uk/itm/MOLYSLIP-...arts_Vehicles_CarParts_SM&hash=item2a122e984d



Which does not seem to have caught on in the US.I've been using it on older engines for over 30 years.After around 3,000 miles of use my compression is up and my oil usage down.It can take quite a few thousand miles to show any improvement but does help quite a bit.This is a case of the more miles I do the better the engine gets.



It's based on Molybdenum Disulphide

http://en.wikipedia.org/wiki/Molybdenum_disulfide

http://www.engineersedge.com/lubrication/molybdenum_disulfide_characteristics.htm



which is used elsewhere in the engine/bike as in Moly paste for running in Crank shafts and cam-shafts and Moly grease for drive boxes etc.It causes NO clutch slip.My engines are made of high mileage parts so any help I can give them,I do
 

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Shep, would you suggest use of this Moly Slip stuff in my rebuilt FJ engine (sorry to Hijack!)? I re-honed the bore and installed 2nd hand (low hours and mileage) high comp pistons and rings.



Also in my CX and running FJ?



Cheers, Matt
 

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Cheers Shep,



The daily rider FJ is a little over 70k miles. It does smoke, especially when it gets cained but I expect its those valve stem oil seals as they're notorious on these engines for drying out. Especially when they've been stood like this one had before it was mine. Bores and pistons are generally very tough on the FJ, I know living examples that have done more than 175k on the original pistons and rings. Bit like the CX engine! Tough as old boots!



 

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Ok, so an intial top up of 240 ml then 120 ml from then on. How often tho? At oil change intervals?



Cheers for the info.
 

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Discussion Starter · #20 ·
I feel like I've asked this already, but don't see the post o.0. Does the Molly stuff go straight into the oil, or does it have to run through the gas?







Anyhow, back to the engine
.



Since it's been raining all day, I decided that I didn't want to head out and work on my suspension, as planned. I actually love rain riding, but I don't love rain working.



So I started to take apart the spare engine. I removed the fan shroud, and realized that one of the top bolts wasn't the same size as the other. It didn't have a flange on it either. Upon closer inspection, it actually was smaller than the flanged bolt (which is one of the proper bolts) and was coarsely threaded instead of finely threaded. Hmm. Strange, I didn't remember my engine having that. Then it dawned on me that the hole was helicoiled....to a smaller, and incorrect size of course -.-. Oh well, as long as I find another bolt that fits and has a flanged top I should be fine.



Anyhow, I turned the left cylinder to TDC on the compression stroke, and then removed the coolant drain bolts. Out came enough fluid to pool up, and drip on the floor. Maybe, I dunno, half a cup or so, if even that much. I soaked some up with a paper towel and it smelled just like normal water. No other scents detected. Now, it's obvious that the PO ran this thing with water instead of coolant because of the rusted up coolant pipes, but should I be worried that water came out after removing those drain bolts, or is that to be expected?



I hope I don't run into too many other "surprises" along the way. The fan shroud bolt hole imo is a very strange one to have stripped, or have a broken off bolt in. Dunno why it was helicoiled. But it seems to be aligned properly, so I guess I'll leave it.



Now I'm about to actually remove the head. Let's see how badly I screw it up
.
 
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