[Thrux-ton-up]

The latest on the project! Frame and about 10 other pieces due back from the powder coaters this week. Machine shop checked the cylinder bores and they are near perfect after 24,000 miles. Only .0001 wear in the center of the cylinders was measured. So the new custom forged 11-1 pistons will be dropped right in the existing bores and the existing rings from the original pistons will be fitted on the new pistons in the exact order and location. Not having to bore and re nikasil the cylinders is bonus dollars for me.

The heads were cut and 2mm bigger intake valves and 1 mm bigger exhaust valves have been installed and the valve guides honed to fit. I'm waiting on the arrival of the 42mm Mikuni's and billet intakes. The intakes will be sent off for port matching when the porting begins. The head will be resurfaced for a fresh start.

I also have access to a pro-com BC ignitor which I will test on the dyno before (or if) purchasing. To dertermine 2 things - first does the 3 degrees of ignition advance do any thing for performance and 2nd will the motor continue to build power to 9000 RPM or will it fall off on the way? More pics of the valve cutting process in the album.

Cams anybody? I have sent 2 detailed emails several weeks ago to Thunderbike relating the details of the engine build and asking if they thought their cams would be a good "fit" in the project. No response to date. I take that as a no??! Hmmm its looking like maybe stock cams will be used initialy, but they are an easy swap-out and if I find some good ones they can be added later.


After

and before

 

[Hozer]

Beautiful job!
Do you estimate being able to use pump gas even at 11:1? With a few more degrees of timing it might be close to detonation...
What a relief it must have been not to do a bore and re-nikasil!
The shop photos in your sub-folder are great too. I take it that place is local?
If you get 80rwhp, I promise you I'm pulling mine off and driving up to see you. I was going to wait to 10k miles to justify the expense but what the heck...

Will you have it complete by bike week?

Again, looking really great.

Don't know the specs but the BC cams might be promising...
http://www.british-customs.com/stor...customs-triumph-bonneville-thruxton-cams.html

Cheers, John


[ This message was edited by: Hozer on 2006-12-10 09:21 ]

 

[sweatmachine]

nice, I can't wait to get my valves in...

 

[SCCTrim]

You must be getting excited, very nice looking work on the head. Kinda wish I had went for bigger valve's when I had mine apart.

Rumor has it the best cam's for power are '03 and prior 790 cams, maybe you could score a set of them, and advance the exhaust 1 tooth for the best of both worlds.

:upthumb:

 

[sweatmachine]

John, what color did you go with on the frame?

 

[Mecchanica]

I'd be leery of refitting old rings. They NEVER get into exactly the same location and they may have lost some of their "spring" and exhibit reduced tension resulting in blowby, which will be amplified by the much increased cylinder pressures you will be generating. New rings and a light honing. Look into a set of Total Seal rings, if they are available for your pistons, that would be great, if not, you can have the top ring grooves machined to take them.
The new valves aren't machined to have the weight reducing cups in the heads, so will be more massive, expecially with the larger diameter....with the higher rpm you plan to operate at, you should consider new heavy springs, or new stock ones with some shimming to get the pack pressure up by maybe 30%. If you also fit faster opening higher lift cams, you will need to increase that figure.


[ This message was edited by: Mecchanica on 2006-12-10 13:11 ]

 

[bonnieblackinfl]

VERY NICE, but I agree w/mecch on the rings. You have it apart, replace them, besides, if the cylinders weren't worn, that means the rings were taking the blount of it.

Greg

 

[TBSstunta]

I can't remember, but have you/are you planning on having your black box hacked to raise the rev limit? Scott did that on his Bonnie and swears there's a ton of power hiding at the top even with just airbox and jetting mods.

 

[Thrux-ton-up]

On 2006-12-10 15:32, TBSstunta wrote:
I can't remember, but have you/are you planning on having your black box hacked to raise the rev limit? Scott did that on his Bonnie and swears there's a ton of power hiding at the top even with just airbox and jetting mods.

It's Scotts unit I will actually be using on the dyno runs to see whats up.

 

[Thrux-ton-up]

On 2006-12-10 11:07, SCCTrim wrote:

Rumor has it the best cam's for power are '03 and prior 790 cams, maybe you could score a set of them, and advance the exhaust 1 tooth for the best of both worlds.

The rumor I heard was the Thrux intake cam in the intake position and the 790 intake cam in the exhaust position advanced 15 degrees.

 

[Thrux-ton-up]

On 2006-12-10 11:23, sweatmachine wrote:
John, what color did you go with on the frame?

Jeff,

Frame is going to be black chrome powder coat. Base coat is chrome and 1 - 2 coats of black chrome. Kinda like painting candies - pick your base and then add candy coats until your happy. :-D

 

[caspianthruxton]

man, that frame is going to look nice!!!!!!!

 

[Thrux-ton-up]

On 2006-12-10 09:03, Hozer wrote:
Beautiful job!
Do you estimate being able to use pump gas even at 11:1? With a few more degrees of timing it might be close to detonation...
Cheers, John

John - 1st thing I thought of. We will see.

John

 

[sweatmachine]

Black Chrome...I can't picture what that looks like, but it sure sounds cool.

Decide on the color of the tank/fender yet?

That head looks suw-eeet! I won't get my valves until January sometime.

 

[caspianthruxton]

in my head i'm picturing a black anadized, a titanium look. Am i close?

 

[Thrux-ton-up]

On 2006-12-10 12:58, Mecchanica wrote:
I'd be leery of refitting old rings. They NEVER get into exactly the same location and they may have lost some of their "spring" and exhibit reduced tension resulting in blowby, which will be amplified by the much increased cylinder pressures you will be generating. New rings and a light honing. Look into a set of Total Seal rings, if they are available for your pistons, that would be great, if not, you can have the top ring grooves machined to take them.
The new valves aren't machined to have the weight reducing cups in the heads, so will be more massive, expecially with the larger diameter....with the higher rpm you plan to operate at, you should consider new heavy springs, or new stock ones with some shimming to get the pack pressure up by maybe 30%. If you also fit faster opening higher lift cams, you will need to increase that figure.

Mecchanica
Speed triple parts for the valve train - dual springs, titainium keepers, etc - stuff very similar to BC's shim under bucket kit is available to keep the valve train in order.

Piston rings - going with the experts opinions from the machine shop on this one. I thought the exact same thing as you - super light hone and new rings, but they said no - keep the rings in order and put em on the pistons. They are confident of no problems and so am I. Time will tell.

John

 

[Thrux-ton-up]

On 2006-12-10 21:11, caspianthruxton wrote:
in my head i'm picturing a black anadized, a titanium look. Am i close?

In sunlight it flips from bright silver to med grey depending on the light angle, with a pearl look to the powder coat.

 

[Thrux-ton-up]

On 2006-12-10 21:10, sweatmachine wrote:
Black Chrome...I can't picture what that looks like, but it sure sounds cool.

Decide on the color of the tank/fender yet?

Jeff
I'll get the frame back - put the chassis back together, and see where to go from there - kinda make it up as I go along. I have vision of about 15 other pieces to powder coat - some mirror black, some translucent red - then decide on the wheel color. Final paint is not even in my mind yet. The seat cowl I wanted to use did not work out so I'm on a quest for more body work.

John

 

[sweatmachine]

sounds cool, can't wait to see it.

 

[sweatmachine]

The new valves aren't machined to have the weight reducing cups in the heads, so will be more massive, expecially with the larger diameter....

I wonder if this will reduce the CC's of the combustion chamber slightly, and increase compression a bit more?