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Discussion Starter #1
I searched this forum but came up empty handed on alternate suppliers for head and base gaskets for our machines. My thought is to gain whatever I can in compression by running the thinnest head gasket I can (no worries...I'll check valve/piston clearance to be certain it's at least 0.036 inches).

Anyone find an alternate vendor for these? I know I can get base gaskets from Cometic (they also do 0.005 material)...

Triumph Bonneville 2002 Motorcycle
.010 Spring Steel BASE GASKET
Cometic Gasket Part Number: B0644010S-C

...but haven't researched the head gasket. Anyone encounter a thinner option?

Thanks,

--Rich
 

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Discussion Starter #3
be very carful there not much room to play with .Think about this to changeing deck changes cam timming to.
Yeah...I'm not looking to make any sweeping changes in compression using this method. Just going to spend my head gasket $$ for the one that works the hardest for me!

And I've got a 50/50 chance that the cam timing will move in the *right* direction! With my normal luck, though, it'll reverse any gains the increased compression makes...!! Only one way to find out I guess...

Cheers,

--Rich
 

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Hi ,wouldn't lovering the head retard the cam a small fraction as the cam chain pulls from the front of the bike so a shorter distance to the cam would turn the cams back ? This would be so small an amount a worn cam chain would make more diffrence . Though I might be wrong .
 

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Hi ,wouldn't lovering the head retard the cam a small fraction as the cam chain pulls from the front of the bike so a shorter distance to the cam would turn the cams back ? This would be so small an amount a worn cam chain would make more diffrence . Though I might be wrong .
as would worn rockers/shims/mushroom valve stems/hammered seats/cam lobes=increased gap...so there's a couple variables at play that takes strict theoretical science into the realm of fudge reality.

as far as gasket thickness, you need to consider what the swell of heat expansion demands...and thin would mean aluminum smoosh...that's supposed to be compensated for by the gasket.

what's wrong with stock?
 

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Discussion Starter #6
as far as gasket thickness, you need to consider what the swell of heat expansion demands...and thin would mean aluminum smoosh...that's supposed to be compensated for by the gasket.

what's wrong with stock?
There's absolutely nothing is wrong with stock. My original purpose was just as I originally stated. I do wish, however, that Triumph would sell complete upper end gasket sets since everything is bought one bit at a time.

From what I can tell from the replacement part pricing structure, Triumph is clearly trying to make some serious $$ via the spares market or, otherwise, is encouraging development of aftermarket alternatives. It's the latter that I am interested in for much of what I'm changing on my machine...
 

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Hech all the gaskets are way over priced the wiesco base and head gaskets are over $100. for the big bore kits.That just 2 little gaskets.
As far a deck hieght change goes as little as .035 will throw the cam change marks off enough where it will look like 1/2 chain link.In other words depending what tooth your on you will ether be a 1/2 tooth adv or 1/2 tooth retarded when you got tdc mark lined up.Cam timing on a 4 valve head is alot more touchy then a 2 valve head because of the extra flow.If your off one way you have more top end power and less low end .If your off the other way you have less high end and more low end .dont ask me how I know this lol lets just say been done that.
 

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Discussion Starter #8
Hech all the gaskets are way over priced the wiesco base and head gaskets are over $100. for the big bore kits.That just 2 little gaskets.
As far a deck hieght change goes as little as .035 will throw the cam change marks off enough where it will look like 1/2 chain link.In other words depending what tooth your on you will ether be a 1/2 tooth adv or 1/2 tooth retarded when you got tdc mark lined up.Cam timing on a 4 valve head is alot more touchy then a 2 valve head because of the extra flow.If your off one way you have more top end power and less low end .If your off the other way you have less high end and more low end .dont ask me how I know this lol lets just say been done that.
Thanks Mike...most of my experience with boosting compression in this manner has been on my '71 bmw race bike - where changes in cam timing can be compensated for in the valve gear - and not on an OHC bike.

I've not pulled things down yet and was only going in as deep as the head...I've got a spare head I picked up from Baldwyn and was just starting to line things up for swapping it on. For the time being/coming riding season, I'll probably just put the '01 790 cams in and get the tuning right.

Cheers,

--Rich
 

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mike not if its right where you want it before the 1/2 tooth,then your a 1/2 tooth off ether way you put it.With good cams you dont want to move it around,they got it figured right .
 

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Discussion Starter #11
1/2 a link, that's 'bout 7.5°, sounds good to me either way. Higher CR and either more low end or more high end, sure beats going a whole tooth. :D
Okay, so say I boost compression by reducing the cylinder height/shaving the head and retard the bike 1/2 a tooth in the process...can the ignitor be reprogrammed to compensate for this much timing change?

On my bmw hotrod, the way this large of a timing change was achieved was by fitting an offset cam sprocket to shift the cam timing...anything like this exist yet for the NTB motors?

Remember, for every good, well-sorted system there is a problem waiting to be created... :)

Cheers,

--Rich
 

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No one makes anything to do that yet.I have been thinking on how one could do that .The chain sprokets on the crank is made on to the crank. The one on the head drives the cams by a gear that is made in one peace.Your best bet to get more power is a 904 kit.
 

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mike not if its right where you want it before the 1/2 tooth,then your a 1/2 tooth off ether way you put it.With good cams you dont want to move it around,they got it figured right .
Agreed Mike, if you're buying a ready developed set of cams, but if you're using stockers with forethought you could build it in to your tune and it's not as extreme as a whole tooth.
 

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Okay, so say I boost compression by reducing the cylinder height/shaving the head and retard the bike 1/2 a tooth in the process...can the ignitor be reprogrammed to compensate for this much timing change?

Cheers,

--Rich

The igniter can be reprogrammed to take in to account any engine performance changes.
 

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Discussion Starter #16 (Edited)
The igniter can be reprogrammed to take in to account any engine performance changes.
Well, well, well...I certainly can try a thing or two with the spare head I have laying about knowing the timing can be corrected at the ignitor.

That certainly is a better solution than paying major $$s for fabrication of a custom, offset cam idler gear...especially since I had designs on getting my ignitor reworked anyway. For schitz & giggles, I checked to see what the stock cam idler gear ran on Bike Bandit and it was a bit over $160!

While Mike in VA has a valid point that the simplist, most straight-forward approach is to fit the big bore kit, Wiseco's recent price increase to almost $800 has me looking at changes I can make that won't run me $1K, but will satiate the need for speed for a while...

Cheers,

--Rich
 
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