Broken Cam Cap question - Kawasaki KLR 650 Forum
1987 to 2007 Wrenching & Mods For maintaining, repair or modifications of Generation 1 KLR's. 2007 and earlier.

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post #1 of 12 Old 05-03-2018, 08:39 PM Thread Starter
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Broken Cam Cap question

Hello all,

I've read through the threads asking where to buy a cam cap alone (to get new cam caps, you have to buy the whole cylinder head assembly for $900). However, I have a different question.

Backstory

I had a local shop install a helicoil on one of the threads where the valve cover attaches to the header. I am convinced they are the ones that stripped it when tightening a loose bolt, but I can't prove that. Later events detailed below would lead me to believe the owner of this shop is a crook. On the way home from picking up the bike the bike suddenly started making a loud knocking noise from the cylinder head area and lost most of its power. I pulled over and had a buddy trailer the bike back to the shop immediately. The next morning, the owner of the shop calls and tells me I have to buy a new head assembly (the part they just repaired) because the guide lip on one of the cam caps broke... $900. Then he told me they were going to charge me $100/hour to look for the little piece of aluminum down in the engine, which may take 1 hour or may take 10 hours. He quoted me at somewhere between $1000 and $2000 for the whole fix. I paid $1,200 for the bike... He claimed the cam cap breaking had nothing to do with the fact that they had taken the cylinder head apart less than five miles before it failed. I called b.s.

I felt I was being swindled, so I went down to the shop and asked him to explain what was going on. He gave me the same story and was a condescending jerk about it. He recommended I post the bike on Craigslist for $500 and cut my losses. He then pointed at the Doohickey and recommended that I upgrade it while we had the bike apart. He assumed I knew nothing about KLR's. I told him that the bike had an eagle mike aftermarket doohickey. He said, "No, this is stock". I then proceeded to pull the stock doohickey out of the pannier which embarrassed the hell out of him and he walked away knowing he'd been busted.

At this point, the jr mechanic turned to me and said.. "Don't give up on the bike, this thing is sweet and you'll get a lot of mileage out of it. We don't need to replace the cylinder head. The guide lip on the cam shaft is not necessary. The bike will run fine with the broken part. Also, we found most of the aluminum piece. The rest is probably ground into tiny bits (we had found one such tiny piece) and sitting in the oil pan. They will come out with your next oil change. I recommend we put the bike back together and you ride it.".

Since I had no intention of burning $2K on mechanic labor for a $1,200 bike, I went with option #2. I've put about 50 timid miles on the bike since then and she seems fine other than a burning smell here and there (I'm guessing from oil residue on the exhaust from taking her apart) and she sometimes makes a popping sound out the exhaust when decelerating (is this normal?).

The Big Question

Is the second mechanic right? Can I ride the bike with the broken cam cap? There are no cracks or imperfections on the internal surface. Unfortunately, I didn't get a picture of the damage. It is the rounded lip on the top outer surface of one half of the cam cap that broke off. Is it true that these caps were made to fit into only one head assembly? That seems crazy to me that Kawasaki would do one-off machining like that on a mass production bike. If I find a used set of cam caps, can I use them to replace mine?

I appreciate you reading my story and any advice you may have. I am brand new to motorcycles and this has been a rough intro.

Cheers,

Ben
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post #2 of 12 Old 05-03-2018, 09:48 PM
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Yes, The camshaft bearing caps fit the original cylinder head PERFECTLY! Because they are Part of the Original cylinder head. Line bored & honed to perfection. For about .0008" - .0025" bearing clearance, stock & standard.

Maximum clearance is .006", but the dowel pin placement may be a larger issue! But, possibly not,
As long as there is .0008" clearance around the tightest area of the cam journal all should be operable.

The cam bearings are only 'loaded' for half a rotation when the valves are opened. Yeah, I know it ain't 'Perfect'! So What?

pdwestman
Modify at "YOUR OWN RISK"!

Still riding my 1987 KL650-A1. 84,000+ miles & counting
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post #3 of 12 Old 05-03-2018, 09:56 PM Thread Starter
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So, given the current damage to the raised lip, do you think I'll be okay to ride it?
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post #4 of 12 Old 05-04-2018, 09:58 AM
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Paul's got more experience on this that I do, so listen to what he says.

- yes the cam caps are matched to the head.....a mismatched set can be re line bored but that'll cost a fair bit too. No easy fix here.

- I normally wouldn't worry about the damage to the lip, but I'd be concerned as to where the broken pce went and what damage was caused by the "loud knocking noise".


OTOH, you have little to lose by running it now as long as it all sounds normal. Eaglemike has talked about a fix for this in the past; I'd recommend giving him a call to get his opinion.

2 cents,

Dave
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post #5 of 12 Old 05-04-2018, 10:12 AM
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I wouldn't advise riding it. The cam sprocket needs to be kept in-line with the chain & the lobes need to stay centered over the tappets.

A loud knocking noise & loss of power seems to be more than just a broken guide flange on a left hand cam bearing cap.

I'm pretty certain that Eagle Mike has welded a few broken or cracked bearing flanges on KLR's. Give him a call, Eagle Mfg & Engineering
Also, Engine Dynamics has repaired many cylinder heads of all kinds, ENGINE DYNAMICS

We can't see your parts.

pdwestman
Modify at "YOUR OWN RISK"!

Still riding my 1987 KL650-A1. 84,000+ miles & counting
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post #6 of 12 Old 05-04-2018, 11:05 AM Thread Starter
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Dave!

Thank you for your response. I have done more reading and have abandoned the idea of buying a new cap (which it seems people are calling a "cam journal cap"). Mostly, I was just frustrated with this "throwaway" design. In looking at the valve cover, these grooves on the outer edge of the four journal caps do not fit into anything and as such do not appear to be a guide of any sort. The caps are attached via two bolts and those bolts keep the caps snug and aligned. This leads me to believe that these grooves are simply for reinforcement, which makes me a little more nervous that the journal cap will break eventually.

Regarding the loud "knocking noise": the mechanic assured me that the noise was the result of the engine going out of time as a result of the part failure. It is no longer making this noise as he re-timed everything. He inspected all of the gears and chains and assured me that there was no damage. The piece of metal is clearly very soft aluminum. Seems odd that a bearing surface of this importance would be made of aluminum. I rode the bike into work this morning and she seems fine. I'm guessing he is correct in his assessment that the pieces are down in the oil pan somewhere. My only worry is that they get into the clutch plates. Maybe that isn't even possible, but I'm now very paranoid about this bike. I suppose we'll see what happens.... After all, if she blows up or disintegrates, I'll just become a guy without a motorcycle, which is what I was three weeks ago. I have nothing to complain about.

On a more serious note, are there symptoms I should be looking for regarding the cam journal cap wearing out or breaking? I would like to avoid the cam seizing up on me.


pdwestman,

Just saw your response. I will call Eagle Mike today and see what they have to say. It would be awesome if they could weld the flange. Can you weld aluminum? I will take your advice and not ride for the meantime (except to get home from work today, of course).

Thank you all for your responses. It's awesome having a resource like this!
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post #7 of 12 Old 05-04-2018, 11:11 AM
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Yes, you can weld aluminum. :-)

Dave
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post #8 of 12 Old 05-04-2018, 11:33 AM Thread Starter
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Okay, just talked to Eagle Mike himself. What a cool guy! For the help of future info seekers I will post what he said.

Regarding riding the bike with the broken flange. This flange prevents left/right play on the journal cap. If you don't get it fixed, you run the risk of the cam operating out of alignment which can cause more serious problems. He recommends one not ride the bike without the fix.

He also confirmed that the only way this part broke is that it was assembled out of alignment by the mechanic. I urge you to avoid "House of Motorrad" in Boulder, CO. His shop guys are good people, but the owner is a crook.

I am going to send the part into Eagle Mike. I will post a pic of the part once I remove it. Luckily it's sitting right there on top.
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post #9 of 12 Old 05-04-2018, 04:42 PM Thread Starter
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Hello again,

After contacting Engine Dynamics (trying to get as much information as possible), it became clear that people may be misunderstand exactly what is broken. Here is photo (not my photo) to help. I will take a photo of the broken cam cap once I get the bike taken apart.

The red arrow is pointing the "lip" I am describing. Note, this lip does not have any contact with the cam shaft. The part that prevents the left/right play is the flange/groove on the left side caps. The outer lip on the left front cam cap is what is broken. I believe this is why the mechanic believes it is okay to ride as it has no interaction with any other part of the engine. I believe these lips are only present for structural reinforcement. Again, I will take a picture once I get her apart.





EDIT: Not sure why I am still unable to post pictures. It seems that the process to post photos on a forum hasn't changed since 2003, and remember not being able to figure it out then either.

I guess for now I will just post a link to the imgur photo. Again, this is not a photo of my cam cap. It's just to point out the raised lip that broke off. Rode the bike home today with no issues.

https://imgur.com/Hq6lm2E


Last edited by Tom Schmitz; 05-04-2018 at 07:20 PM. Reason: insert photo, using the 'insert photo' tool in the tool bar. Use a URL with a .jpg extension.
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post #10 of 12 Old 05-04-2018, 08:39 PM
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Quote:
Originally Posted by pdwestman View Post
I wouldn't advise riding it. The cam sprocket needs to be kept in-line with the chain & the lobes need to stay centered over the tappets.

A loud knocking noise & loss of power seems to be more than just a broken guide flange on a left hand cam bearing cap.

I'm pretty certain that Eagle Mike has welded a few broken or cracked bearing flanges on KLR's. Give him a call, Eagle Mfg & Engineering
Also, Engine Dynamics has repaired many cylinder heads of all kinds, ENGINE DYNAMICS

We can't see your parts.
I understood exactly what was broken. Therefore others could understand also.

pdwestman
Modify at "YOUR OWN RISK"!

Still riding my 1987 KL650-A1. 84,000+ miles & counting
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