Triumphrat

Thruxtonboy · 01-27-2008, 01:59 PM

Quote:

Originally Posted by Bottle_Fed

Nice indeedie! Did you coat your valves, or is that just the camera casting the colors? Also, is there anyway you can post the cam lift, intake and exhaust opening and closing events? Thunderbike has be tight lipped on thier cam specs. It seems you may have exactly what some of us have been looking for

Greg

Hi Greg, thanks for your reply. No, I did not coat the Valves, they came in this colour. These valves are universal, you have to cut them yourself on the right lenght. Problem is that the stockvalves of the Thruxton are very thin, (under 4,5 mm) and at the same time they are quitte long to, so that is why you can't buy anything on the market. The only thing we could do is buy these and cut them ourselfs. The TB cams seems to be really good, my tuner messured them out in relation to the stock cams en put this all on paper in a kind of schedule. (he's 60 years old and a little old fashioned, he is not used on working with a computer, so that's why) I can send you the pics I made of these. Later on I can give you the information about camlift, opening etc.

Bottle_Fed · 01-27-2008, 02:06 PM

Nice job man, I see you went with 34mm intake valves and 30mm exhaust? Could you take some pics of the head when you get it finished up? I would like to see the chamber after you are done with it. Yes, we have odd valves, but I've heard that honda civic valve blanks can be used for ours. The guides have to be honed a small amount and they can be used.

Greg

Thruxtonboy · 02-02-2008, 07:08 PM

Today we worked on the valves and the cilinderhead. The Wiseco kit is mounted in the engine, now we are working on the bigger valves.

Thruxtonboy · 02-02-2008, 07:12 PM

Just some more pics...

sweatmachine · 02-02-2008, 07:28 PM

great post! I've already done some of the same mods, I have the Wiseco 904 kit, bigger valves (+2mm intake, +1mm exhaust), ported/polished head and intake manifolds, and dual valve springs.

I can't wait to see some more info on the cams and how your bike runs after it's back together, should be a real screamer!

mikeinva · 02-02-2008, 08:05 PM

wow those are some wide seats in your pic .did you leave them like that or put a under cut angle on them .When i do over size valves i bore the inside of the seat out as much as i go over on the seat ,do a 3 angle valve job ,then blend the port dia. into it.
Once the valve is open the seat id. controls flow not the bigger valve.

Thruxtonboy · 02-03-2008, 01:09 PM

Quote:

Originally Posted by mikeinva

wow those are some wide seats in your pic .did you leave them like that or put a under cut angle on them .When i do over size valves i bore the inside of the seat out as much as i go over on the seat ,do a 3 angle valve job ,then blend the port dia. into it.
Once the valve is open the seat id. controls flow not the bigger valve.

Yes, you are right about the seats. They are not ready yet. We also do a 3 angle job, 15 degrees, 45 degrees and than 75 degrees, so this is not finished yet.

Thruxtonboy · 02-15-2008, 02:00 AM

Quote:

Originally Posted by Thruxtonboy

Yes, you are right about the seats. They are not ready yet. We also do a 3 angle job, 15 degrees, 45 degrees and than 75 degrees, so this is not finished yet.

Hi Guys,

Just some of the latest pics of the headwork, we're still going strong... I'm wondering what all this will bring, I also read the issue about the guy whit the 42 mm Mikunis on the Bonnie, he seemes to be very much impressed by the performance, what will I get....?

mikeinva · 02-15-2008, 01:10 PM

The highest hp i have seen so far with a 904 one guy got 87 i think with big valve head 42mm carbs and 2 into 1 pipes. looks like you built the intake port up what did you use?
What did you take the 70% angle all the way through the seat? That might work good.
i would love to see what would work better doing what you did and building port up to match or boreing the seat out thin and matching the port to that.Every motor takes alittle different port size so who knows.I have seen some that where to big to start with pick up by filling them and others that where to small that needed to be opened up.Ours are kind of strange any way most heads need more work on the short term rad. ours are screwd up on the long term rad.getting both as equal as posb. and getting the port the right size and shape is where its at.

Thruxtonboy · 04-14-2008, 12:16 PM

In the end of 2007 I posted my topic about the tuningproject of my Thruxton. After working very hard and solving lots of problems, the project is coming to a kind of final stadium. Last weekend we made a really good run on the Dyno. The bike produced a impressive 91,6 Bhp on the backwheel. Fact was that the clutch started to burn and smell nasty from around 85/86 Bhp, it seems to be a problem going over that kind of power with the stock clutch. So it was very slippery the last couple of 100 revs.... At the same time we did not have the good exhaust's on the bike and we improvised with two small racing exhausts.
Now we are waiting for the real exhaust system to arrive (home made) and we have to build in a stronger clutch. After that there is some more work to be done on the brakes and the suspension.

The things we changed on the engine so far are: Wiseco 904, FCR 39's, Bigger, homemade (Aart Nolen) intake- and outletvalves, Thunderbike cams (NZ), homemade (Aart Nolen) exhaustsystem, upgrade on the rev limiter with 1.150 Rpm plus (Aart Nolen), upgrade copmression to 10,4:1, very nice headjob by porting, flowing and build-up on the intake (Aart Nolen).

In a copple af days I will post some prictures...