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Affordable 904 Kit and Performance Cams

30K views 135 replies 26 participants last post by  Biker_CC 
#1 ·
Hey guys,

I have put together an affordable 904 kit and want to see if anyone else is interested, as the more the merrier when it comes to minimums. Perhaps some of you have something to add as well? *cough* 904 Tune *cough* Or some words of wisdom on how to handle all this awesome power.

I will be using:
Arias; 92mm Pistons with 11.5:1 compression, lightweight wrist pins, etc. $330
Millenium Technologies; Bore and Nikasil coating. $350
Wiseco; 904 Kit Gasket. $111

In addition, if you would like to have your cams reground:
Web Cam "813" Regrind. Proven to be the best performing cam available without changing shims. $495

If you guys want any other services such as porting or valve enlargement, Millenium Technologies does this at the highest level.

This setup has been proven to be the most effective way to increase power in our beloved motorcycles and these suppliers have a proven history of making parts for our bikes. I have done a lot of legwork in tracking down machine shops who can supply us with these parts. These guys make parts for a lot of the "retailers" that we know on here, but also deal directly to customers and have for decades.

If you are interested in jumping on board please feel free to email me.
BSGrimes@gmail.com

There is tons of info on these kits on the forums, so don't forget to search before you ask a question.
 
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#3 ·
Also, if you just want to get the pistons now and then wait to have your cylinders bored you can do that too. Arias wants to do as big of a run as possible. Millenium will bore you out any time. It's also a 4 week lead time on custom cylinders.
 
#11 ·
Just got the final pricing for the Arias Pistons and have begun the process of placing the order. $383 shipped in the US. Rings, offset lightweight wristpins, and all that other good stuff included. Speak now or forever hold your peace. We have eight guys on board at the moment.

Also the gaskets we are going to use come from Cometic and will be around $50.
 
#13 ·
Just got the final pricing for the Arias Pistons and have begun the process of placing the order. $383 shipped in the US. Rings, offset lightweight wristpins, and all that other good stuff included. Speak now or forever hold your peace. We have eight guys on board at the moment.



Also the gaskets we are going to use come from Cometic and will be around $50.


Hey Bryan I need to confirm extra shipping to Australia can you ask Elmer to contact me with extra shipping costs so I may make payment


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#12 ·
Also, for posterity, according to the invoice the Arias Piston specs are as follows:

TRIUMPH 2CYL
BORE 92MM = 3.622
STROKE 68MM = 2.677
ROD L 4.784 WITH .748 HD PIN
C H 1.006 @ 0 DECK
GASKET .043
C R 11.0 = DOME .175 = 0.5CC
HEAD CC 38.4
CID 55.17
Part: MCMD4

The rings it lists out as:
1.0x1.2x2.8x3.622 GNH RINGS
 
#15 ·
Also, for posterity, according to the invoice the Arias Piston specs are as follows:



TRIUMPH 2CYL

BORE 92MM = 3.622

STROKE 68MM = 2.677

ROD L 4.784 WITH .748 HD PIN

C H 1.006 @ 0 DECK

GASKET .043

C R 11.0 = DOME .175 = 0.5CC

HEAD CC 38.4

CID 55.17

Part: MCMD4



The rings it lists out as:

1.0x1.2x2.8x3.622 GNH RINGS


Hi Bryan I have made payment via PayPal to Carmen for the amount you required and if any other shipping costs to Australia are required for I will make another payment to cover.

Thanks again for all your help making this group buy happen!

Regards.

Greg


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#14 ·
#20 ·
Yeah! Fantastic thanks Bryan!


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#23 ·
Fantastic Bryan! Hope all the upgrades go well for you as soon as the valves and heads get back and look forward to hearing your performance and dyno results.




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#28 ·
At the end there was the 813S and 813SC, from my humble knowledge, the 813S (which I have, is a good cam for stock motors and the 904 with stock carbs/tbs and heads and work well with head work and bigger carbs/tbs.) and the SC cams were designed for big carbs and head work and a 904 or the 865 hi comp kit.
I don't personally know how much more hp/tq they net.
 
#29 ·
Sounds like the 813sc is the way to go for us!


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#31 ·
A little late, but I would be interested in a set of pistons!

Has anyone given thought to getting them coated?

I have the tops of my Norton pistons coated with Swain Tech's TBC - Thermal Barrier coating, I wanted the skirts coated but my barrels had already been bored, so I gave it a miss! Ideally I would want the tops in TBC with the skirts in PC-9. Having said that my brother did the same and the added coating, combined with the fact that the person boring the cylinders did not take it into account resulted in a trashed DR650 (711cc)!! I have a set of fully coated ZRX (1109cc) pistons, but they are still on the shelf, awaiting a reason to take the engine out of the old girl. Valves and springs can benefit as well. And it's "free" horsepower ... well sort of!
 
#33 ·
A little late, but I would be interested in a set of pistons!



Has anyone given thought to getting them coated?



I have the tops of my Norton pistons coated with Swain Tech's TBC - Thermal Barrier coating, I wanted the skirts coated but my barrels had already been bored, so I gave it a miss! Ideally I would want the tops in TBC with the skirts in PC-9. Having said that my brother did the same and the added coating, combined with the fact that the person boring the cylinders did not take it into account resulted in a trashed DR650 (711cc)!! I have a set of fully coated ZRX (1109cc) pistons, but they are still on the shelf, awaiting a reason to take the engine out of the old girl. Valves and springs can benefit as well. And it's "free" horsepower ... well sort of!


Expensive and for marginal benefit. I'm sure a coated valve train and pistons would outperform one that was not, but not enough to justify the cost in my opinion. Would love to see before and after dyno numbers though.


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#38 ·
I contacted Web Cams and have been advised the 813 cams are all the same specifications so no difference


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#39 ·
Yeah, that's what they told me as well....maybe TPUSA just used 813S and 813SC as a marketing ploy???
But I have also been talking to others that are in the know and so should know, and they say that the 813SC cam definitely exists, but that there may only be a few of them made. So I am a little bit confused.

The 813 cam was marketed at being best for 865 to 9994ish cc's. The 813SC was marketed as being for 994 to 1200cc, I will need the 813SC if I am going to get the best out of my motor.
I don't want just any cam, I want the right cam for my build. I think I will keep looking for now. There are others who have done cams that may be just as good or better, I want to see what they can sell me by comparison.
 
#50 ·
Huzzah! Good Work! Looking forward to news of your results!



:)


Bryan has his bike going again after performance upgrade and in the process of having it fine tuned on dyno.

Can't wait to hear results as well.

Nick is in process of installing upgrade....myself we'll have all components apart from headwork just need so time signed home to real estate to sell after many months hard work renovating and business travel which is increasing so free time is limited until we move closer to business region in Nth East Victoria.

Can't wait to work on my bike!



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#53 ·
Fantastic result Bryan and as discussed hopefully with some velocity stacks and ported matched manifolds will even be stronger.

Congratulations again mate well done!
 
#54 ·
Make sure you keep an eye on the oil temp if you use that power, mine soon pushes the oil filler cap mounted temp gauge over 115*c (240*f) if i ride it in the upper rpm for more than a few minutes in the british summer (warm rain lol). i'm using motul 7300 15/50 fully synth oil, fully synthetic copes with the heat better.
 
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