Megacycle Cams

[davidd]

Megacycle makes a racing cam for me and I ordered a few more recently. I thought it would be relatively easy to have them replace the phosphor bronze bushings which they use in the Vincent cams with the correct Oilite bushings. It was not. As a result, I asked them not to install any bushings as I know of one person who bought a cam from me who forget to change the bushings to Oilite.

I have been told by others who purchased and installed Megacycle cams that they had seizures which caused lots of damage as a result of not knowing about the bushings Megacycle installs.

If you have purchased Megacycle cams for your Vincent and have not installed them, please be aware that they should be replaced with Oilite bushings.

If you are ordering Megacycle cams you can ask them not to push in the bushings. They agreed to do so for me. I think this a good solution because there is a possibility of forgetting or re-selling that may cause problems.

If you have installed these cams as provided, I would replace the bushings at the soonest convenient time. I installed my cam while on the road during the racing season and I clearanced the Megacycle bushings to "nearly worn out." After three years of running the cam seized. Even generous clearances and years of wearing-in may not prevent a seizure.

David

 

[Gene Nehring]

This sounds very much like running straight bronze in the gear box bushings.

Thanks David.

 

[Howard]

Just a thought. Oilite bushes are made to size, not intended for reaming. The bush bore will depend on the bush fit in the cam. Check cam bore with Oilite requirements and Megacycle tolerances.

H

 

[Bill Thomas]

Morning David, Do you know if the Small end Bush, In a Carrillo Con Rod is OK, Looks Bronze to me. Cheers Bill.
Anybody in the UK have a pair of Stroked Flywheels to sell, Twin or Comet, Please P.M. me, Cheers Bill.

 

[passenger0_0]

Carrillo rod small end bushes are silicon bronze - a tough material well suited to this application if you feed it the right oil and have the correct clearance to let the oil in. Neglect this last point at your peril. I've gone over the handlebars after the small end snapped off one a Carrillo in a badly prepared engine (not be me I might add). Good luck Bill with that stroker.

 

[davidd]

Morning David, Do you know if the Small end Bush, In a Carrillo Con Rod is OK, Looks Bronze to me. Cheers Bill.
Anybody in the UK have a pair of Stroked Flywheels to sell, Twin or Comet, Please P.M. me, Cheers Bill.

I will defer to Passenger0_0 on this one. I have never had a problem with the small end, but years ago Carleton asked Carrillo to increase the small end clearance on the small end 0.0005" because of excessive bluing on the pin in the single. It seemed to do the trick and I use that spec in my singles.

David

 

[davidd]

Just a thought. Oilite bushes are made to size, not intended for reaming. The bush bore will depend on the bush fit in the cam. Check cam bore with Oilite requirements and Megacycle tolerances.

H

Howard,

I thought that we discussed this in an earlier post about Oilite. I believe I posted machining instructions for the bar stock and rod stock that is sold by Oilite to be machined. I found the information at:

https://www.oilite.com/bmp.asp

The reamed Oilite cam bushings have been seemingly happy in the racer for several years.

David

 

[Bill Thomas]

Yes when I was racing, My Small Ends were very Blue, Like you , I just had to run them a bit slack. Cheers Bill.

 

[Mark Fisher]

Megacycle makes a racing cam for me and I ordered a few more recently. I thought it would be relatively easy to have them replace the phosphor bronze bushings which they use in the Vincent cams with the correct Oilite bushings. It was not. As a result, I asked them not to install any bushings as I know of one person who bought a cam from me who forget to change the bushings to Oilite.

I have been told by others who purchased and installed Megacycle cams that they had seizures which caused lots of damage as a result of not knowing about the bushings Megacycle installs.

If you have purchased Megacycle cams for your Vincent and have not installed them, please be aware that they should be replaced with Oilite bushings.

If you are ordering Megacycle cams you can ask them not to push in the bushings. They agreed to do so for me. I think this a good solution because there is a possibility of forgetting or re-selling that may cause problems.

If you have installed these cams as provided, I would replace the bushings at the soonest convenient time. I installed my cam while on the road during the racing season and I clearanced the Megacycle bushings to "nearly worn out." After three years of running the cam seized. Even generous clearances and years of wearing-in may not prevent a seizure.

David

David as you know I'm one of the unfortunates that didn't realize that the bronze bushings that megacycle cams fit to their cams can cause a problem. I really, really wish I had known though. Basically last year I replaced both cams and all followers after 20k miles as they looked a little tired due (probably) to lubrication issues. These were Megacycle cams that I had fitted with bushings from Coventry spares rather than those which were supplied. I can't remember why I did this, but it meant that back in 2008 I fitted oilites without realizing it or the significance of doing so! Anyhow I fitted the new cam and followers etc ( and yes I did check that the bushings weren't too tight on the spindles) then went for a test ride and initially all seemed well until I lost the front cylinder at about 15 miles, went home on 1 pot and put bike on bench. on inspection I found that the front cam had seized solid on the spindle and the gearwheel was spinning on the cam with predictable results. The rear was also close to seizure and the bush had turned blocking the oilway! I had to buy a new cam, cam gear, O/S spindle and of course (having figured out the cause with advice from those more knowledgeable than I) new oilite bushings in both cams. I had Glenn Bewley check the head as there had been evidence of contact with the piston, but all was well luckily. So a cautionary tale then, a small part that if ignored can cause carnage!
mark

 

[litnman]

An interesting note on Megacycle's site says that "All cams will have new bushings installed and honed after grinding" . Maybe they aren't sure how to size oilite bushings.