Hi Folks , The title says it .. after a particularly dozy move on my part where i scraped the cam lobes turning the engine over without shims in on the exhaust cam i am thinking i need a replacement rather than a repair. The cam is cheap enough on flea bay . My confusion is which year to get .. My guess is any outlet gs 500 cam with the splindes for the rev counter would work but really i dont know .. i hope someone ib gs world does . Als wonder if it maybe worth simply carefully filling any burrs and carrying on with the cam I have , opinions sought ... and yeah , Im a twit for scoring my cam lobes it was one of those days where i kept getting stuff i the wrong order :confused:...love and light
I have heard that the cams are machined to match the head they are in. It would be better to find a used head cheap as running mismatched head and cams could cause interference issues.
I had a cam lobe with a scratch in it likely caused by a tool like a screwdriver.
TBH, cam caps and end bearings wear together, I would rather just run the scratched up lobe over a swap.
A scratch you can see will take up oil, it will bear against the shim and between the 2 it will smooth out. Post a pic if you like.
I had a V shape on mine and in the 40k+ I had it it would look fainter with every valve adjustment but even at 48K wasn't causing a problem.
Cool.
Buddha.
Quote from: Bluesmudge on February 06, 2021, 10:05:09 AM
I have heard that the cams are machined to match the head they are in. It would be better to find a used head cheap as running mismatched head and cams could cause interference issues.
No, that means you disturb the base gasket seal and its worse. Just run it, I had a scratched cam, didn't do nothing.
Cool.
Buddha,
Thanks for the replies . I will get a picture when the weather allows , hopefully soon . I have some fine needle files so I will see if i can reduce any burs and a magnet to remove any tiny bits of metal etc .It would be great to simply keep running that cam . The bike has 60k miles on it and its got some wear generally so if i did get a head it would be sensible to do the bores as well etc and i just dont want to go that far when a replacement engine is not a fortune .Thanks for the advice , I willcarefully tidy up what is and post a pictureand hope its good enough though its a bit of a mess right now , cheers ...
A cam from 89 to 03 should have the tach drive.
I don't see any issue swapping another good used cam in.
As far as running the scratched lobe. As long as it's just a couple scratches that are below the surface, going around the circumference. it won't hurt anything. If there are raised burrs beside the scratches, de burr, but I would NOT use a file on the lobe. Use some 400 to 600 grit paper, followed by crocus cloth.
hi sporty , ok , wet and dry it is, ordered some as the hardware shop is covid closed so a small delay ... From memory its more than the odd scratch , if the weather is kind tomorrow i will go have a peep and a picture . A decent looking cam is as little as 20 quid delivered so no biggie ... Thanks for the advice
ps ,,, what is crocus cloth ? cheers
Very fine sanding cloth, almost polishing. It comes in sheets and rolls.
This is a description https://www.mcmaster.com/crocus-cloth/
You only need a little bit (not whole roll of it) , but if you don't have it, no worries.
Thanks , not sure if its available in the uk but there will be something similar , thanks again
A check on the part numbers says the cam was used from 89 to 2000.
£30ish on ebay £200ish brand new but at 60k I wouldn't worry too much about a slight scratch, there is bound to be wear elsewhere.
The other thing to think about is that a used cam may have wear on the lobes meaning you will have to check the valve clearances and if the journals are worn the clearances in the bearing surfaces will increase. So by replacing the cam to solve a problem you could be introducing further new one.
Thanks for the continued advice , I took a look and it didnt look as damaged as i remembered , I decided to run the engine and then take another look and it looked better again - certainly not ideal but only two problem areas and no burrs/ raised areas that i could feel so Im just crossing my fingers .. On the bright side i am a lt faster at getting the valve cover off and on etc ... It would be useful to know what to look out for .What are the signs that a cam is failing? .. as you say they are cheap . Tried taking a picture but it didnt work well enough t be useful so snod it - running the old girl ...Live in hope ! have breakdown cover !
I'd say examine your oil carefully for 'colour' when you change oil, but cam wear would become evident if you measure valve lift, - a dial gauge is ideal for this. The highest point of lift to closed valve is what you need to know. Though you'd need to shim up clearance with valve closed, then compare with a measurement at full lift - that'll give you the total lift -difference between the 'back' of a lobe, to the highest point of the lobe. I doubt that you'd have a problem unless the scratch causes further damage to the case-hardening, in which case rapid wear will result.
Thanks Jools , I will take that advice on the next oil change and measure stuff as well ... Cheers ,,,
Quote from: jackinacabin on February 06, 2021, 10:41:50 AM
Thanks for the replies . I will get a picture when the weather allows , hopefully soon . I have some fine needle files so I will see if i can reduce any burs and a magnet to remove any tiny bits of metal etc .It would be great to simply keep running that cam . The bike has 60k miles on it and its got some wear generally so if i did get a head it would be sensible to do the bores as well etc and i just dont want to go that far when a replacement engine is not a fortune .Thanks for the advice , I willcarefully tidy up what is and post a pictureand hope its good enough though its a bit of a mess right now , cheers ...
I would absolutely not go in there with a file. Just run it, worst case, it will wear on that shim a tad. Next valve check look and see if that shim shows a pattern of where the cam was. Replace shim with correct and run. I ran mine from 8K to 48K and the crows foot scratch never did much of anything. It takes up oil and so does the shim.
BTW no, you wont see crap in the oil from your scratch on the shim. If you see crap in the oil, you killed something unrelated.
Just ride it. Just ride it. Just ride it.
Cool.
Buddha.
Hi Buddha , yeah thats what I am doing , its back together ,,, when the plague lets us all out to play and my crap health allows I will ride Mavis the Motorcycle , she is ace . Right now farting about with the fairings , tidying , cleaning , painting adjusting , turning the gruntfuttock into less of a skip , shiny shiny shiny -in fact she,s going to look pretty cool for an old heap ... Thanks for the advice .. next step after the continued turd polishing will be tuning starting with the diy advancer ... cheers :thumb:
OMFG ??? There's plague also they've unleashed already. Plague 20 ???
Cool.
Buddha.