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post #1 of 19 Old 05-09-2017, 02:47 PM Thread Starter
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Rebuild Questions

First time posting in awhile. Bike died on me a couple weeks ago riding 2 up, hadn't checked the oil in awhile and it was almost a quart low (wasn't showing on the window at all with the bike standing straight up). Pulled the motor a couple days ago after she failed a compression check (gauge was showing a little under 60 psi); I had planned on cracking open the engine and fixing it myself, but I was reading through the service manual and it looks like I'd need 300+ dollars in tools buying new (tension stopper, valve spring compressor and its attachment, guide reamer/driver) so I'm starting to think buying a second engine to swap in instead of rebuilding this one might be the way to go. Is there anything I can do without specialty tools before I pull the trigger on another motor? Also, can I get to the piston/piston rings without messing with the cam/valves/etc? Manual says to pull cam before pulling the cylinder head...

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post #2 of 19 Old 05-09-2017, 06:02 PM
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The only one of your questions I can answer is that YES, you need to pull the top-end before you can get to the piston and rings.


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post #3 of 19 Old 05-10-2017, 08:46 AM
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Quote:
Originally Posted by trentr View Post
First time posting in awhile. Bike died on me a couple weeks ago riding 2 up, hadn't checked the oil in awhile and it was almost a quart low (wasn't showing on the window at all with the bike standing straight up). Pulled the motor a couple days ago after she failed a compression check (gauge was showing a little under 60 psi); I had planned on cracking open the engine and fixing it myself, but I was reading through the service manual and it looks like I'd need 300+ dollars in tools buying new (tension stopper, valve spring compressor and its attachment, guide reamer/driver) so I'm starting to think buying a second engine to swap in instead of rebuilding this one might be the way to go. Is there anything I can do without specialty tools before I pull the trigger on another motor? Also, can I get to the piston/piston rings without messing with the cam/valves/etc? Manual says to pull cam before pulling the cylinder head...
Yes as the S/M states, you do have to remove the camshafts in order to remove the cylinder head.
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post #4 of 19 Old 05-10-2017, 12:06 PM Thread Starter
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Couple more questions; I've read that you can add a little oil to the cylinder and test for compression again, and if it increases this indicates bad piston rings. Will this work on an engine that hasn't ran in several weeks? And if so, can I attach the loose battery directly to the engine to crank it for the test? I'm thinking that if I have a piston issue I still might be able to fix things myself, but if I've got a valve train issue I think it might be more cost effective to swap motors [I'm assuming work on the cylinder head at a shop/dealer would be a lot of money, and this is the first time I've had an engine out/apart and I think I might be in over my head a bit if I try taking the head apart myself (but maybe not? was going to until I saw tool prices)].

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Yes as the S/M states, you do have to remove the camshafts in order to remove the cylinder head.
Can I pull them without buying the tension stopper, and any reason(s) not to if so?
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post #5 of 19 Old 05-10-2017, 12:10 PM
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The first question to answer would be why was your oil low.
I've now been riding on my bike for just over 4 years and I've never used oil like never, always on the top line. Good luck with the rebuild.

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post #6 of 19 Old 05-10-2017, 12:21 PM Thread Starter
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The first question to answer would be why was your oil low
She was a few months overdue for an oil change, and admittedly I hadn't checked the level in awhile. Hadn't seen any spots from a leak in the garage. She's at about 6k miles if that matters. Oil filter wasn't on backwards. Seemed to be running okay to me the day she broke down, never noticed temps going above 3 bars. Oil didn't look too bad to me when I drained it but there was also a fresh quart mixed in with the old stuff (from me hoping she'd fire back up with more oil).
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post #7 of 19 Old 05-10-2017, 01:16 PM
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She was a few months overdue for an oil change, and admittedly I hadn't checked the level in awhile. Hadn't seen any spots from a leak in the garage. She's at about 6k miles if that matters. Oil filter wasn't on backwards. Seemed to be running okay to me the day she broke down, never noticed temps going above 3 bars. Oil didn't look too bad to me when I drained it but there was also a fresh quart mixed in with the old stuff (from me hoping she'd fire back up with more oil).
Many small engines will pump oil from the crankcase breather into the air box from high RPM running. The issue with the CBR is it doesn't carry much volume of oil to begin with, so any amount of loss shows up quickly.

Because it was an oil-related failure, I would say there's more damage than just a set of rings is going to fix. The top-end cam journals, rod bearings, and the cylinder itself may have damage that would need to be repaired.

There are a few threads in here that show some of the typical damage from oil-starvation - usually it's caused by the incorrect installation of the oil filter (duh Honda).

At this point, I would say a different engine would be the most economical alternative.
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post #8 of 19 Old 05-10-2017, 09:29 PM
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...but you should be encouraged to dig into the old one, once you are back on the road.

Most special tools can be worked around with home-made tools.
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post #9 of 19 Old 05-11-2017, 04:44 PM Thread Starter
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Update: Went ahead and ordered another engine from "The Motorcycle Guys Inc" (wasn't having alot of luck looking locally the last couple days). I was also wondering if learning/doing wheelies (clutch-ups in first and attempts at them in second) on her could've contributed to the failure? Hadn't done one in at least a couple weeks before the breakdown, and I don't think I've ever got the front much higher than a foot off the ground, but it hit me last night that that might've had something to do with it.

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...but you should be encouraged to dig into the old one, once you are back on the road
I definitely want to, I've been thinking that if I get the bike running with a second engine and could get the first running again after I could use the spare for a shifter kart build (when I have a little more money to burn anyway).
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post #10 of 19 Old 05-11-2017, 06:25 PM
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Update: Went ahead and ordered another engine from "The Motorcycle Guys Inc" (wasn't having alot of luck looking locally the last couple days). I was also wondering if learning/doing wheelies (clutch-ups in first and attempts at them in second) on her could've contributed to the failure? Hadn't done one in at least a couple weeks before the breakdown, and I don't think I've ever got the front much higher than a foot off the ground, but it hit me last night that that might've had something to do with it.
Maybe. If the oil level was low anyway it may have moved it away from the pick-up and sucked air into the oiling system.

Doesn't really matter. Just keep an eye on the oil level.

I would use a better oil than the usual Hondaline GN4 10W-30. At least a semi-synthetic like Rotella T5 10W-30 or a full synthetic 10W-30 like Redline or Motul. Check it and change it often. The recommended 8000 mi or whatever is crazy, especially with a high(er) revving engine and small oil capacity.
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