[KLR Kool-Aid!]

You never owned a RX-7? Man, you missed out! Those engines loved to rev and weighed much less than an equivalent power piston engine. They didn’t get very good gas mileage though. But they made up for it with fun factor.

That's what I'd heard - fun, fast, and nimble; all the same, it probably kept me out of trouble..

 

[KnowledgeLackingRider]

And we’re baaaack with another episode of Carnage Time!
Carnage Time theme song plays

Got the cam chain tensioner off which did, indeed, give me the needed slack in the cam chain to access the balancer chain mangle.


Photos:

Teeth on the cam chain tensioner look great! Will inspect internal spring & test it all for functionality today.

Lower cam chain guide/area got torn up pretty good:

(do I need to deburr this?)

Cam chain links broke open

Balancer chain guide (the other one looks about the same

Balancer sprockets. Teeth actually look alright visually but the hard black..rubber? got shredded on 2/3 sprockets.

flat surface scoring doesn’t look as bad as I feared

Are the light-colored links in the balancer chain for timing purposes, or is this a sign somebody Frankenstein’d it?

Next Steps:

• I’ve yet to closely inspect the LH crankshaft assy.
• I think it seems wise to open the clutch cover side to check the RH counterbalance weight & whatever’s around it in case of any related damage there.
• I’ll obviously be disassembling the top end, checking camshaft sprocket teeth, valves, etc.
• I’ll be reinspecting the rotor to be sure it’s in good shape.

Current Parts List:

• Rear tire
• Balancer chain
• Starter clutch
• Counterbalance sprocket/weight assemblies
• Balancer chain guides
• Cam chain
• Lower cam chain guides
• Spacer/washer for lower cam chain guide
• Potentially LH crankshaft assy.
• Top end = as of yet unknown

Keep those tensioner bolts adjusted, boys!
More updates to come.

 

[Six8five]

You’ve made a lot of progress!
RMATVMC has been a great source for OEM parts for me. Their prices are less than list, it adds up when you have a long parts list.
eBay can sometimes be a good source for used parts. Ive had good luck.
I do have a starter clutch in good shape . Let me know when you start part hunting it’s yours.
You’ll be riding soon!!

 

[Reveille]

The marks on the chain are for timing/clocking alignment. It will be covered in the manual. You're making progress!

 

[KLR Kool-Aid!]

So far so good, man! This won't be as bad as it sure could have been, and it'll be adding to your knowledge base (and ours!). Good luck!

 

[DPelletier]

the balancer rubbers are what the chain actually rides on and are needed to be in good shape to allow the lever to have decent adjustment range.

Dave

 

[pdwestman]

I don't see any damage to the LH end of the crankshaft or its roller bearing. Vacuum out the tiny rubber bits.

I'll suggest that there is nothing to inspect on the RH balancer weight. Owners often mess up the coolant pump oil seal during reassembly or strip the threads on the coolant pump shaft when reinstalling the coolant impeller nut.

The rubber cushions on the sides of the balance sprockets many times degrade with time & mileage and are caught by the oil pump filter screen, below the clutch, inside the clutch cover. So some that missing rubber may already have been missing.
If people use too much RTV sealant on used LH cover gasket when replacing the doo-hickey, the excess RTV is also caught by the screen, broken off OEM doo spring tips are also caught by the screen.

If I was going into the clutch cover to clean the oil pump screen I'd perform the PDW 100% oil filtration mod on the oil filter cavity. the crankshaft oil control orifice in the 6:00 oil port and the oil flow improvements to the external oil pipe banjo bolts. Here is the best write-up of those mods, Post Page

 

[PeteK]

I recommend that you pull the clutch cover while you're at it. The main reason is to clean out the oil screen. With all the rubber bits torn off the balancer sprockets, you're sure to find a lot of junk in the screen. You're into it this far, so clean out everything you can reach, short of splitting the cases.

 

[KnowledgeLackingRider]

Thanks everybody! My weekend starts today so it’s back to the bike. Working outside again because at the moment I’ve got nowhere indoors to do this. I do recognize I’m committing a mortal sin there, but I’m working with what I’ve got.

Cylinder head disassembly/inspection is the main agenda item for today.

@DPelletier thanks for the info Dave. Sprockets with damaged rubber will be replaced with eBay parts (or potentially new ones if the price is manageable with everything else)

@pdwestman thanks Paul. Vacuuming sounds like a great idea. And that’s good news on the RH weight—I didn’t wanna do it anyway. I’m intrigued by the 100% oil filtration mod—have been since I read through all of @Tom Schmitz’s blog posts last year. Now that I have some mechanical experience it doesn’t look all that intimidating anymore, so I’ll definitely give it a shot once I get there. Maybe I’ll create a separate post for it when I do, especially since this one’s title is already so far off from the actual issue lol.

@PeteK I’m mildly embarrassed to admit I hadn’t even thought about the oil screen until Paul & you mentioned it. Definitely on the list, hopefully today.

 

[pdwestman]

I’m mildly embarrassed to admit I hadn’t even thought about the oil screen until Paul & you mentioned it. Definitely on the list, hopefully today.

I wouldn't pull the clutch cover to clean the screen unless I was going to perform the 100% filtration mod at the same time.
No sense in pulling the clutch cover Twice in my line of thinking.

 

[KnowledgeLackingRider]

Update #932:
Cam system is removed, including the cam chain, cam shafts, and cam chain guides (all except the longest one that’s seated between the cylinder & cylinder head).

Upper cam chain guide is fine. Lower guide is obviously wrecked and the rear guide appears to have cracked from the force of seizing up. Photos later.

Cam shafts and cam shaft sprockets look visually fine to me. But given the drama so far, I’ll likely post some photos and measure them with a caliper.


Valve/TDC Questions:
Am I safe to proceed with removing the cylinder head with the rotor/piston/valves in their current positions?

I guess I’m unclear about the exact chain of events that takes place with each revolution. Are the cam lobes physically moving their respective valves in & out when they rotate & come in contact with the shims/valve lifters? If so, I’m thinking it’s probably best to remove the cylinder head as-is, inspect the valves, and then bring the piston up to TDC when I’m ready for reassembly. But if I’m missing something I’d rather know ahead of time lol. Thanks

 

[KnowledgeLackingRider]

No sense in pulling the clutch cover Twice

Very good point, thanks!

 

[pdwestman]

I guess I’m unclear about the exact chain of events that takes place with each revolution. Are the cam lobes physically moving their respective valves in & out when they rotate & come in contact with the shims/valve lifters? If so, I’m thinking it’s probably best to remove the cylinder head as-is, inspect the valves, and then bring the piston up to TDC when I’m ready for reassembly. But if I’m missing something I’d rather know ahead of time lol. Thanks

With the camshafts removed you can now remove the head & cylinder. There is an Allen bolt hiding under the front of the cam chain tunnel at the cylinder head. There are 2 acorn nuts under the front & back of the head. The starter motor has to be removed to access the rear cylinder base acorn nut, one at the front of cylinder also. There is also an Allen Bolt hiding at the cylinder Base in the cam chain tunnel, under the front cam chain guide that slides up & out (don't loose the little rubber horseshoe at its top pin).

 

[KnowledgeLackingRider]

Copy, thank you!

 

[terry_g]

Did you check the valve clearances? If the clearances are within spec then you probably
don't need to pull the head. if the clearances are above spec you may have bent valves.
If the cam chain was still keeping the cams timed so there should be no damage.

 

[KnowledgeLackingRider]

Did you check the valve clearances? If the clearances are within spec then you probably
don't need to pull the head. if the clearances are above spec you may have bent valves.
If the cam chain was still keeping the cams timed so there should be no damage.

Didn’t check clearance since cam lobes were pointing inward, and I couldn’t turn the rotor before removing the balancer chain, which required de-tensioning the cam chain.

Honestly, I probably could’ve still done the trick Paul mentioned—holding tension on the cam chain manually while turning the rotor. The cam chain has a couple missing pins, but I think it still would’ve been intact enough to do that. It just didn’t cross my mind until after I had already removed the cam shafts.

 

[KnowledgeLackingRider]

Alright.
Cylinder head is off.
Here’s what we got so far:

Couple questions:
1. Is it normal for the exhaust valves to have only grey carbon buildup while the intake valves are black?
(Keeping in mind that the head was re-machined last year when the RH Intake valve was replaced)

2. Does the fact that the exhaust valves are slightly open indicate trouble or is it possible they are in that position due to my not having set TDC?

Thanks!

 

[DPelletier]

valves have contacted the piston (due to the KLR being an interference engine) and are now bent.

Dave

 

[KnowledgeLackingRider]

Oh cool! Real cool. Super sweet. Love it.
I guess at this point what’s the difference lol might as well throw 2 valves into the mix.

Thanks for the quick reply, Dave!

 

[DPelletier]

...sorry bud.

Dave