Tec Cam

cupoftee

Well travelled
Location
Hampshire UK
Well after a very long wait, the Tec cam was available.
Last weekend I decided to fit it.
Firstly the cam was lets say is a bit cheap looking, still rough casting marks own the larger diameter. Although not an issue still showed where the machine couldn't remove material waste due to the lack of it!
Fitting the pin, done by covering up the cam to protect it, making a 5mm thick plate drilled to take the pin so that it had good alignment. Once that was done the removal of the old cam was completed.
I also checked out the holes in the cam for loose swarf, yes there were some and blew them out with my air gun.
A word of warning, when the cam cog , bolt and plate was unbolted, I kept a magnet close by just in case the anything slipped and the magnet would get it.
What surprised me was when the locking plate was removed, the alignment pin from the gear shot out and stuck to the magnet. Bit on the loose side!!!!
A bit that did annoy me was when I put the new cam in was upon rotating the engine I noticed there was a small amount of oily swarf picked up in a couple of the holes. I forgot to check the holes for sharp edges!
They had scraped the bearing surface, not a lot but enough to piss me of as I should have looked, or the seller should have checked before sending!
The cam lobe holes were deburred but the journal faces were not.
So I did the best I could in situ.
Another problem was as the locking plate was returned , I noticed the pin was too long resulting in having the plate bow around it.
Close the lid and crack on, set the tappets and rotated the engine by hand as in the You Tube instructions, then fired her up and out for a long ride.
Impressions are after 150 miles , a spritely engine but nothing to write home about. Not sure it was worth the money and the fuss of doing the job. The sealer if your interested is about £9 for a tiny 50ml worth, I saw £40 for the larger one but I'm sure any high temp sealer would have done !
I do on the other hand think the MPG was a lot better but I am running under 4000 revs.
In the lower revs , pulling away the bike gets bogged down then starts to pull. I have the smaller front sprocket, a free flowing exhaust, the DNA filter and alloy front clamp around with drilled holes in the side panel , iridium plug also a booster plug. Short of getting the free flowing down pipe I'm sure I've covered all areas to make the engine breath.
I contacted the Tec company and they weren't too worried about the bearing surfaces getting marked by the drill holes stating they never had any complaints and all should be OK. In the video however it is stated never get any marks on the bearing surfaces!
Shame they don't guarantee their products for this only if it broke, then it would be argued of the installers confidence and professionalism in the trade!
Overall, I was going to buy the cam for my Triumph, after this I'm not .
Now I know that a lot of folks are going to say that their bike is a revelation with this cam and I will complete the running in for 300 miles then see if its better.
My mate has a cam to go in his bike and on our ride out, I'm sure his bike has a lot more power than mine standard but we will see , at least he is more the wiser through my experience fitting one.
 
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cupoftee

Well travelled
Location
Hampshire UK
The Royal enfield build quality is very good but not to the tolerances of say jap aircooled bikes from the 80s.
Their tolerances are reasonable but as an example I know of someone who is fitting a tec cam to his and the cam is exactly the same size as the gear, we know this as he has measured it on a cmm machine, so tolerances are a bit wide.
 

Roy Gavin

Well travelled
Good review, nice to hear a candid review.
Cam tolerances and timing were always a problem with Brit bikes, the cams profiles were rarely better than +- 5 degrees then add in tolerances in the keyways and gears and on the twins you could have the timing out over 20 degrees, side to side.

So , just sorting them both so you had the correct profile and exact timing sometimes gave you more than TEC claim for their revised profile.
So, just a precise reworking on the OEM cam and a adjustable sprocket might have worked almost as well.
FWIW my local Brit bike specialist, MDA, also has a nice sideline making adjustable sprockets for current Jap hot shot single MX bikes---!
Did you notice any difference in starting without the decompressor - I know that the TEC site talks about the difference in timing reducing the compression, but no one has actually ever been able to verify that theory, it is one of these things only "clever" people know!
 

cupoftee

Well travelled
Location
Hampshire UK
Yes on a couple of occasions, hot and cold, it will not turn over on the button! A second go and it fires up, a little inconvenience but nothing as bad as my Harley, that does need decompressors.
I feel from your explanation that an adjustable sprocket would be benificial but where do you stop?
 

Roy Gavin

Well travelled
Yes on a couple of occasions, hot and cold, it will not turn over on the button! A second go and it fires up, a little inconvenience but nothing as bad as my Harley, that does need decompressors.
I feel from your explanation that an adjustable sprocket would be benificial but where do you stop?
S&S supply one with their cam for the 650 twins, perhaps if they ever do a cam for the Hima it will have one too.
They do get a lot more out of the twins with their cam/sprocket than we do with either of the Hima cams.
 

cupoftee

Well travelled
Location
Hampshire UK
A mate of mine is in the process of fitting a cam.
He just told me that the sprocket dowel hole and the original cam hole is 0.2mm out of position 😳
The Tec cam is also out so the sprocket is out of tolerance.
 
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Bluestrom13

Well travelled
Location
UK
He just told me that the sprocket dowel hole and the original cam hole is 0.02mm out of position
OR, to put it another way, 0.0007874016", so less than 1 thou in old money.
Even Rolls Royce work to tolerances.

NOTE - OP has edited #9 since I posted this.:rolleyes:
 
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cupoftee

Well travelled
Location
Hampshire UK
2 things were an issue, 1 was the sprocket wouldn't fit the new cam because of the pin hole misalignment, 2 the overall bore dimension of the sprocket was the same size as the new cam. He had the sprocket ground to fit the new cam and had to grind a flat on the pin to make it fit the cam.
 

Bluestrom13

Well travelled
Location
UK
OK....So it sounds like TEC need some feedback.
If the old cam fitted the sprocket, and vice versa, it's the TEC component that's the variable.
Mammoth had no problems, judging by his report.
And feedback on YouTube comments show nothing like the above.
See how mine goes in...Just plucking up courage to start.
 

Bluestrom13

Well travelled
Location
UK
He just told me that the sprocket dowel hole and the original cam hole is 0.2mm out of position
How the heck did it go on????

That's not an interferance fit....It's a "won't fit". (Unless the hole in the cam is 0.2mm oversize for the dowel?)
 
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Roy Gavin

Well travelled
Just realised that I have got the error wrong, it was 0.2mm and not 0.02mm.
Which now makes more sense.
Which is why some of us old fellows like to stick to inches and thousands of an inch, you are not alone in getting the decimal point in the wrong place, it seems a good proportion of guys quoting metric make the same mistake.
Or claim to be measuring to half a ten thou with a $ 10 - caliper which rounds of to the nearest thou!
 

Dool2

Well travelled
When I have installed Cams in the Himma I notice that the Timing is not correct, the Horizontal lines that should be level with the Gasket Face are Not.
Because the Cam Chain Tensioner only works on one side and that means as your chain stretches the Timing will be more Retarded as the Slack it taken up.
Solutions, Fit more Base gaskets( and lose compression) Make an adjustment on the front side of the Cylinder to compensate OR an Adjustable Timing Chain Gear
Im working on the Latter to be incorporated into the Cam itself at manufacture.
 
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