Removing Camshaft Sprocket

arch · Jan 12, 2018

I am having difficulty removing the camshaft sprocket. The nut is off and it’s me against the sprocket.

I have the proper Norton puller but the sprocket will not budge. I have applied heat from a propane torch with no success.

I am contemplating splitting the engine cases with the cam / sprocket still in place and trying separate them with a press but I fear damaging the engine case.

Or handing it off to a machinist friend who can apply more heat than my torch.

Any suggestions

Hobot · Jan 12, 2018

Nothing gained if nothing risked so try way MO HEAT than most girlish pensive nortoneers can stand, flashing oil vapor to flames then air impact wrench to savage sense of self worth before given up to shop pro's. I've had to take stuff to air impact wrench equipped pro's for once in life Commando hang ups. In some cases destructive release is only relief to start from new again. I've a TS cover cut to protect pinion gear shaft seating on hi torque take offs and put on's, ping if care use it to try hobot desperado method.

oldmikew · Jan 12, 2018

penetrating oil repeated applications.. and then tighten the tool and hit the centre bolt head of the extractor with suitable hammer.. or better still use a slide hammer if you can find one with jaws that will grip behind the bolt head..

RoadScholar · Jan 12, 2018

Your idea of splitting the cases then using a press won't buy you much as the sprocket key won't permit the cam to move very far and may ruin the timing side cam bushing.

Using a lot of heat can cause collateral damage as well. I suggest that you use a Dremel or die grinder and split the cam chain. With the cam chain removed you'll get a much better "purchase" on the sprocket with a puller. Protecting the end of the cam, install the puller and load it, a few taps on the puller bolt should start the sprocket moving, once it starts moving you'll have it.

Beware that, if your cam is made from cold steel (a close cousin to cast iron), too aggressive with the tapping can, literally break the cam in two pieces. ANs new cams are made from cold steel, not sure what the original factory cams were made from.

marinatlas · Jan 13, 2018

+1 with roadscholar, cut the chain, your puller will work better , then buy a Andychain cam chain, cheap and better than oem........

concours · Jan 13, 2018

A pair of 4mm allen wrenches padded with rag bits made great tiny pry bars, popped out nicely.

carlo · Jan 13, 2018

hobot said:
Nothing gained if nothing risked so try way MO HEAT than most girlish pensive nortoneers can stand, flashing oil vapor to flames then air impact wrench to savage sense of self worth before given up to shop pro's. I've had to take stuff to air impact wrench equipped pro's for once in life Commando hang ups. In some cases destructive release is only relief to start from new again. I've a TS cover cut to protect pinion gear shaft seating on hi torque take offs and put on's, ping if care use it to try hobot desperado method.

:
this remedy has worked better and more faithfully than anything, 50/% acetone 50% transmission fluid, shake it up apply to softly heated part..let it sizzle till cool, add again, 1hr later , add again, over 4 hrs of adding a few drops- tap tap tap with a soft blow between applications with a small ballpeen. you can also try the wax thing, but this has always worked best.. even on rusty exhaust manifold studs.

Hobot · Jan 13, 2018

Ugh thot was just the cam nut jam not stuck on cog, thought one leads to the other. A nod to using allen wrench as pry bars. I have a tiny 4-5" long pair of flat carpentry type pry bars, long leg has chisel end the 3/3" long short leg end forked nail puller. Allen ends are too thick to slip behind some Norton items. ATF/acetone or candle wax are famous home remedies. Heat cycles and impacting is also a standard I've restored too while trying not to plan meaner escalations - and sometimes works. Freeing/saving stuck up stuff is skills I rate above the fine predicable machinist feats to me. Still air impact has freed stuff I wouldn't believe if not seen fairly freq on my non cycle hang ups. On that note, had to resort to big hammer and chisel to get some pass buggered fasteners off. So far have not had to weld on to studs or crack nuts off on Nortons, but have taken cutting torch to remove swingarm with trapped spindle wear lips.

htown16 · Jan 13, 2018

Propane torches a lot of times won't get it hot enough. Get a MAP torch and ditch the propane.

seattle##gs · Jan 13, 2018

make VERY certain the two jaws of the puller are even. If it is trying to tilt the sprocket it will be harder to move. I can't imagine what is making it impossible to remove, usually it will slide right off or by using two levers 180 apart gently.

worntorn · Jan 13, 2018

I use a cheap air impact hammer. Works most of the time.
Apply max pressure with the puller then put the bit of the impact hammer somewhere near the centre, but on the item being pulled
One blip of the trigger and the sprocket/gear/pulley comes off with a bang. No heat needed.
I've used this method on bikes but also on some really heavy duty items on the tractors and the crawler.
Last was a rusted on ujoint that would not come off the rear differential input shaft on my F350. One sideways blip from the air impact and off it came.

Glen

arch · Jan 13, 2018

Thank you for all the suggestions. I will continue to work on this. My economy Harbor freight impact doesn’t seem to have to power it used to have. I may need to replace it.

I have no idea what is holding this sprocket on. I have done this a few times before on other engines using just a cheaply 2 arm universal pullers.

Hobot · Jan 13, 2018

Realize you are not alone on facing what I call blank staring Brit Iron states. There are exceptions to the rules some of us hit so normal level wisdom and advice are not sufficient. I mention because of what i faced in often nasty feedback asking advice on forums about situations no one else encountered. At some point must decide cheapest easiest thing to sacrifice to carry on. If yours was used to max outs in past may be distorted combustion strikes black smith forged together. One last try before destructive escalations would be about incandescent heating nut/cog while holding dry ice on shaft end. Has worked for me saving my sense of incompetent Commando mechanic.

Dances with Shrapnel · Jan 13, 2018

Never had the difficulty you are experiencing. When you removed the nut can you tell if the previous owner may have used a bearing compound like LocTite Green on the cam spindle and drive sprocket? Any chance someone stuffed a washer behind the nut and that washer is smooshed in there and it is binding things up?

You need to make sure the puller is pulling square. I used a puller on at least one occasion but you need to grab beneath the chain (top & bottom of gear) if your puller jaws can fit in there. If you cannot pull square then as mentioned before; cut the chain and get behind the gear.

What I found works well is tightening down on the puller while someone else is rapping away at the puller spindle. By feel of the wrench you will know if you are making progress.

Hobot · Jan 13, 2018

I miss Commando wise Wesley backing me up on miserable stuck tight Commando hang ups. But if solo ...

The main risk torquing on cam nut is pinion shaft pulling out so old nasty TS covers are cut to support it or custom supports created/sold to focus the scary distorting forces on the cam nut only. Ping if can wait for my pinon protector back up to stave off sense of helpless Commando newbie I had till proper tool on hand.

arch · Jan 14, 2018

Yes Hobot, I am aware of that issue and will to proper precautions. It may be a few months before I put engine together.

I need to get it apart first. Thanks for your offer. I may take you up on it.

Will the Andover Norton pinion support tool adequately protect the crankcase from damage?

arch · Jan 15, 2018

I won the battle.

I split the cases and was able to tap the cam away from the sprocket with a small ball peen hammer. It didn’t really take much force with the hammer. ( I tried a padded hammer first with no luck.)

Once freed I tried to slide the sprocket back on, no way was it going on.

This engine was rebuilt way back in the 80’s after the rocker oil feed line gave way. A new camshaft was part of the rebuild. The cam does have a higher lift than stock and valve pockets were cut into the piston. ( this is an 850 engine )

Once I get a new chain and sprocket I will determine if the cam is useable.

The sprocket shouldn’t be a press fit.

Hobot · Jan 15, 2018

Alrighty a new way to work around this area w/o any forum help, my respects. Next hang up, is it sprocket or cam as item at fault, or both or method of ham fisted fastening or over rev events blacksmithing to junk once perfect fitting parts. Commandos and Chiropractic taught me just attending to obvious faults, symptoms, like flat tire fixing, may need repeated obvious fixing/replacing till figuring cause like too many screws still in driveway. May never know so carry on regardless.

arch · Jan 16, 2018

I tried some of the suggestions. Got map gas, cut the chain and tried using an impact wrench on the puller all to no avail. Splitting the cases was the last resort. If I had know a few taps with a hammer would separate it I would have done that sooner. (It has been quite a while since I rebuilt the bottom end of a Commando. )

The engine was assembled by a respected Brit bike shop that is still in business. I never abused the engine rarely went over 6000 rpm. I will purchase a new sprocket first and go from there.

Then there is the issue of the quick change cam bearing. And the compatibility of using a stock Norton cam with roller bearings. I will save that for a new thread.

Removing Camshaft Sprocket

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