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Discussion Starter · #1 ·
Ok, went to startup my '69 cb 350 after mounting new mufflers on it and she fired right up after two or three kicks. The bike ran like usual except:

1. there seemed to be some back firing when I gave it some gas.

2. there was a bad oil leak on the left side

I turned the bike off and went to see where the leak was coming from. It seemed like near the points so I turned the bike back onto check. I walked to the left side of the bike and by the time I went to look the bike died. It died quickly after making a vacuum sound like "foooom"

I went to turn the bike back on and I now have no pressure at the kick starter. The kickstarter just goes down by hand with no pressure.

I have no idea what this problem is. Please help.

Thx.
 

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Doesn't sound good, but strange for this to happen just by changing the exhaust. Is that all you did? Have you pulled to spark plugs to see if you can see the pistons moving with the kick or electric starter? Do you have a compression tester?

The mufflers weren't packed with anything for shipment were they? Just wondering if they were not allowing the exhaust to flow creating a lot of backpressure.

Any strange noises during this time?
 

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Discussion Starter · #3 ·
I added new shorty mufflers and torqued the head cover bolts. I didn't have the leak before I swapped the mufflers and torqued the bolts.

There were no strange sounds before or after. The backfiring happened before and after the changes so I wasnt too concerned I figured I just had to balance the carbs.

The exhaust was packed but I removed everything from it. Lol

I didn't look to see if the valves were moving since I was utterly frustrated. Lol I'll do a compression test and get back to you. Any ideas on what might have happened?

Thx.
 

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Discussion Starter · #4 ·
Ok so I just kicked the bike and noticed the valves are not moving at all. What does that mean? Thx

Ffffff I also seem to have lost the compression adapter for my plug type. I will have to borrow one some other day.
 

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If the valves aren't moving then you've got a broken cam chain, unless the cam sprocket is held onto the cam by bolts and those are sheared off..


GB :mrgreen:
 

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Discussion Starter · #6 ·
WTF?!?! So what caused that? I replaced the cam chain tensioner with the racing type that has no moving parts, is that busted too?

WTF?!?! Aaaaaarrrrggggghhhhhh
 

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Bird76Mojo said:
If the valves aren't moving then you've got a broken cam chain, unless the cam sprocket is held onto the cam by bolts and those are sheared off..
Sorry if I'm misunderstanding something, but it seems to me that if he had a broken cam chain he would still feel the kicker engage the crank shaft and pistons... if the valves were closed he would still feel the compression; if the valves were stuck open the pistons would bind against the valve at some point... right? He says:
bk69cb350 said:
The kickstarter just goes down by hand with no pressure.
Doesn't it sound like the kick start isn't engaging in some way, either in the kicker itself or where it meshes with the transmission?

@ bk69cb350: can you see the pistons move inside the spark plug hole as Perry asked?
 

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As for your oil leak that occured after you torqued the exhaust to the head, you may have cracked your head. have you taken a closer look since?
 

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Discussion Starter · #9 ·
I'll have to check the pistons tomorrow.

As far as the leak goes, it happened after I torqued the head cover bolts on. I have to take a look, but I think it is coming from where the points are mounted.

Damn I was ready to check my float height today.
 

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I may have missed something in his post but if his valves aren't moving WHILE the kickstart is actually working correctly, then he's got problems. He may have other issues.. Who knows?

If the pistons are moving then that's a good/bad sign in itself..



GB :mrgreen:
 

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Discussion Starter · #12 ·
Ok so right now I can tell the pistons move when I use the kickstarter.

Still haven't found a compression tester and am looking for the source of the leak.

Any ideas?
 

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Discussion Starter · #13 ·
Ok so I think I found the problem. I moved the head cover and looked inside and noticed that the cam sprocket isn't connected to the cam. Basically it spins without turning the cam shaft. I can't see how bad it is yet but that's what I am seeing without pulling the head cover completely off which i can't seem to do without pulling the motor.

I am wondering how this may have happened?
 

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Discussion Starter · #15 ·
So it looks like the bolts sheared off. I am in the process of pulling the motor now, but I am wondering why did the bolts shear off? Were they just old? did I put them on wrong? Was something else causing to much pressure for the bolts to remain on?

This f*****g sucks man. Lol

Oh and thanks for all the help everyone.

Question, does that racing cam chain tensioner need different adjustments? I mean I just adjusted it like the original is adjusted. Was that wrong? Is there a write up on that?

Thx again.
 

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You probably overtightened old bolts. Easy fix I think.
 

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Discussion Starter · #18 ·
Man this is incredible. So the bolts sheared off and blew holes in my cam case. There are two holes and one is right threw the bottom of the cam case which was causing my leak. It was right over the upper fins that are right behind the spark plug. I've posted some pics below.

So, uh, does anyone have a cam case I can buy?


This is the sprocket and cam. You can see the mounting holes are not aligned.



This is the cracked part of the inside of the cam case. You can see right in front of the left side of the spring there is a chunk of cam case missing.



Now this is the one that hurts! It's about the size of a quarter. F me.


This is the shrapnel from the lower hole. You can see the bolt head and piece of metal from the cam case.

I found the other bolt head lying next to the sprocket. From what I can tell, the camshaft, sprocket, chain and rockers are fine. I will double check but I think they are all good to go. Also, from what I can tell, the fins are all good to go. So I think destroyed bolts, holes in my cam case and threaded bolt ends stuck in my camshaft are all the damage. I hope I can pull the remaining bolt pieces from the cam shaft without destroying it.

Let me know what you guys think and if there is anything else I should look out for.

Thx again.

Edited this post to name the right part. It is the cam case that has the hole not the head.
 

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You've probably got some bent valves so check those if you plan on reusing them. Also, check the tops of the pistons for cracks or damage.

Did you use a torque wrench when you tightened those cam sprocket bolts?
 
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