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Unitrak Cams

Posted: Tue Dec 06, 2016 7:38 pm
Author: Julian_Boolean
In my ongoing rebuild I have noticed that the cams in my uni head have R3 stamped into the inlet cam and R2 stamped into the exhaust cam, is this normal for Uni cams?

Posted: Tue Dec 06, 2016 10:50 pm
Author: zed1015
All my Unitrack cams have R7 and R8 stamped on them and also a raised letter 'A'

Posted: Tue Dec 06, 2016 10:51 pm
Author: Julian_Boolean
I think mine have got a raised H on them

Posted: Tue Dec 06, 2016 11:24 pm
Author: zed1015
Might not be uni cams then.
You need to measure the lift.

Posted: Wed Dec 07, 2016 1:21 pm
Author: Julian_Boolean
Found this

http://oldschoolperformance.com/forum/v ... 656d1398ea

With comments from Zed1015 on it, now I've no idea what cams I have, and my bike might have had the cams round the wrong way as the R2 cam was definitely the exhaust cam and R3 the inlet. Cam sprockets have Z1100A on them by the way.

Is there an easy way to tell an inlet cam from an exhaust cam?
I'll measure my lobes, but I'm not sure I've got anthing accurate enough to tell the difference of 0.05mm in overall cam height.

Posted: Wed Dec 07, 2016 3:47 pm
Author: zed1015
Exhaust cam has a blank raised section instead of the tacho worm.

Inlet and exhaust cams can be swapped over if they are the same profile or maybe the exhaust cam from another model has a higher lift you could use it on the inlet.

My uni cam sprockets are Z1100B.

My uni cams are 1983 but judging by the OSP thread it's probable that later cams and sprockets have different markings but the spec is the same.

All the info for lift etc is in my posts in the OSP thread so it should be easy enough to see if yours are uni.

Posted: Wed Dec 07, 2016 6:17 pm
Author: Julian_Boolean
Cam sprockets actually say Z1100B, I was wrong when I said they had a B
The cams look identical apart from inlet is stamped R3 and exhaust R2, all lobes are 37.8 mm, both cams have what look like blanks for the tacho drive to the right of the sprocket.
CMSNL shows exhaust and inlet cams on Unitraks and Z1100Rs having the same part no.

You can tell the inlet from the exhaust by the position of the sprocket.

Posted: Wed Dec 07, 2016 6:43 pm
Author: zed1015
Julian_Boolean wrote:The cams look identical apart from inlet is stamped R3 and exhaust R2, all lobes are 37.8 mm, both cams have what look like blanks for the tacho drive to the right of the sprocket.
CMSNL shows exhaust and inlet cams on Unitraks and Z1100Rs having the same part no.

You can tell the inlet from the exhaust by the position of the sprocket.


Yes! both cams have the same profile with any slight height difference down to factory tolerances and wear.
37.8mm is Uni spec cams then.
1100R uses the uni engine.
Cam sprockets are both the same with different positions for in and ex.