Honda CX 500 Forum banner
1 - 18 of 18 Posts

·
Registered
Joined
·
810 Posts
Discussion Starter · #1 ·
Has anyone widened the two oblong mount holes of the pump so that you could get more use out of a stretched chain?



Last fall I noticed a rattle sound at higher rpm and recently decided to pull the front cover and adjust the chain and change a leaky cam oil seal.



I found that my oil pump chain is so loose that it has been hitting the clutch basket. The pivot adjust wont pick up much slack at all.



I have ordered a new chain but am curious if others have opened up the mount holes some to work with a less stretched chain.
 

·
Registered
Joined
·
5,563 Posts
Has anyone widened the two oblong mount holes of the pump so that you could get more use out of a stretched chain?



Last fall I noticed a rattle sound at higher rpm and recently decided to pull the front cover and adjust the chain and change a leaky cam oil seal.



I found that my oil pump chain is so loose that it has been hitting the clutch basket. The pivot adjust wont pick up much slack at all.



I have ordered a new chain but am curious if others have opened up the mount holes some to work with a less stretched chain.
ill be the first to admit,i have.got the tip from one of the OZ guys.the problem,is that both bolts do not bottom at the same time.so,i used a rat tail file,a few good rasps at only one bolt hole.now both bottom at the same time.2mm play on the chain.

ISmith from OZ,also showed that there is very little difference in a new and used chain
 

·
Registered
Joined
·
810 Posts
Discussion Starter · #3 ·
I do hope there will be a difference between my current and a new chain. I don't think I could file the holes out enough to get a fit close to the reccomended slack. It is interesting that the slots don't bottom together.



I guess the po's never had the front cover off this machine. I should have done this last year when I did the cam chain and found how that had worn into the case.
 

·
Registered
Joined
·
5,563 Posts
I do hope there will be a difference between my current and a new chain. I don't think I could file the holes out enough to get a fit close to the reccomended slack. It is interesting that the slots don't bottom together.



I guess the po's never had the front cover off this machine. I should have done this last year when I did the cam chain and found how that had worn into the case.
Linny,you would be surprised how much 1/2mm can make to the play in the chain,its the geometry of it.

compare your old and new chain[when it arrives].post the difference
 

·
Registered
Joined
·
1,241 Posts
If there's no real difference between a new or a used chain (ie not stretching) then what causes it to loosen up if it's NOT stretched ?



Is this some kind of design flaw where as what holds the chain in place wears out instead with no way to adjust for the wear ??



I've not opened my front cover yet....so this half of the engine is still Greek to me.
 

·
Registered
Joined
·
810 Posts
Discussion Starter · #7 ·
Hi Rickbert. It does wear. The slots in the pump housing allow only a min of movement to pick up slack.

As I read what Bandit said 'you'd be surprise how much 1/2mm can make'. That is why I ordered a new chain and will file the holes to match.

I would recommend pulling the front case to adjust the chain and clean out the sump screen. My screen was dirty.
 

·
Super Moderator
Joined
·
15,416 Posts
It's kind of hard and easy to explain.



The chain doesn't really have any stress on it. The oil pump is a non stress unit. It easily rotates. Since there is a lack of adjustment on the oil pump unlike the cam chain tensioner.



When putting on a new chain it is set to 3mm loose. That 3mm is the difference is what you get when you lightly push down between both gears on the chain. After 55,000 miles my chain wasn't much farther than that.



I don't know if you ever tested the stretch of a cam chain but when you put a new one next to a dead one the difference isn't completely noticed until you hold them sideways and the one hangs down a little bit and the other you would think it's imitating a U. The oil chains are pretty similar.
 

·
Super Moderator
Joined
·
23,831 Posts
Perhaps some of the mechanism for chain wear is a loss of diameter of the chain rollers, allowing the chain to snug further into the sprockets.



No chain actually stretches, this includes rear wheel drive chains. Even though the old chain may be quite obviously longer than the new one when laid out side by side on the bench no link has actually stretched.



The wear is in the inside and outside of the rollers, this is what allows an old chain to be bent sideways to a fair degree.
 

·
Super Moderator
Joined
·
11,455 Posts
My input is purely speculative, but I wanted to add to what Stitch said. The oil pump chain is not really working hard to give motion to the shafts. No real heavy load to move. If it is whacking the clutch basket, there might be something else beside the chain at fault. Perhaps misfiring over time has caused unusual wear on the sprocket gears, and/or undue wear on the brackets. Just a thought.
 

·
Registered
Joined
·
1,241 Posts
Thanks for Oil Pump 101 class




You're right though, seeings how I've done all the "obvious", "common" restore type of stuff and have nothing else on the pallet I should probably open up that front cover and clean up and inspect etc just for good measure as Linny has done. However I'll probably go all out and replace the clutch workings while I'm at it.



COULD the oil pump chain be the source of what some people think is clutch noise ? I saw above it mentioned that the chain could be slapping the clutch if it's loose ?
 

·
Registered
Joined
·
8,422 Posts
Out of all the CX engines I've stripped I've only seen one with gouging in the Clutch basket from an oil pump chain and that engine was a real wreck so I would say that it's not commonly a cause of sounds similar to,"Clutch" rattle which is pretty easy to fix in an evening or afternoon.





http://globalcxglvtwins.hostingdelivered.com/viewtopic.php?f=7&t=694







HTH
 

·
Registered
Joined
·
810 Posts
Discussion Starter · #14 ·
Got the new chain today. Not a really big difference in length. I still had to use Bandits tip and widen the pivot slots. To me the sprokets don't look bad but must be worn in. The following are of the new chain in place. The last pic shows the old chain on the left.









 

·
Registered
Joined
·
5,563 Posts
hi Linny,and thanks for taking the time to post pictues and follow up.

my eyes tell me your sprockets are fine for a 30 year old bike.



the chain,it shows about 1/2 link difference.more than ISmith had on the old forum.im at home,with no manual to hand,but i think it calls for 2-3mm slack,measured on the longest length.

a question Linny.......can you get 2mm with the new chain?.......i doubt it.



the tip i posted above was not mine,its not from a new member,but a guru from the OZ board,he knows what he is talking about.



here is my take on it......people think,because honda or suzuki,what ever, designed it....it must be right.i dissagree.i have 2 doubts[only 2] this topic and the expansion bottle,whereby,the engineers/designers got it wrong,or over designed their thinking.

i also wonder if a sloppy chain amplifies wear
 

·
Registered
Joined
·
810 Posts
Discussion Starter · #16 ·
Bandit, when I first put the new chain on the slack was still way too much as you can see in my 4th pic. After filing the slots a bit I was able to get the slack to spec as shown in the 3rd pic.
 

·
Registered
Joined
·
5,563 Posts
Bandit, when I first put the new chain on the slack was still way too much as you can see in my 4th pic. After filing the slots a bit I was able to get the slack to spec as shown in the 3rd pic.
yes,i know Linny,just needed you to write it.lol


4-6 pushes with a rat tail equals spec. as per manual



hope your buttoned up and back on the road Linny
 

·
Registered
Joined
·
810 Posts
Discussion Starter · #18 ·
Not yet. The new seals I ordered should be delivered today! I hope to get it buttoned up tonight. Not that it matters as we still have lots of snow and ice. I suppose it'll be a couple more weeks until I will be able to get out for a ride. Please feel sorry for me. In the meantime I'll keep reading about the great rides so many of this board are having!

You're a good Spaniard!
 
1 - 18 of 18 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top