Cam Shaft report - or HEY these do work!

ThruxTonUp

ThruxTonUp

TT Racer
Ok I put the South Bay 813 cams in my Thrux yesterday, Fred had a pair laying around in the shop and Carlos has been after me to try them for a year now. My bike mods - bigger valves, cleaned up and matched ports, Mikuni 42mm HSR's, forged pistons with a 2 point bump in compression. Still an 865 motor, Predators and K&N's. Cranking compression is 230 PSI inthe left and 225 PSI in the right - THANK YOU Keith for those outstanding numbers! I put the new forged pistons in the stock bore with new Triumph rings - no honing per the race shop experts advice after examining the bore (18,000 at that point, 33000 miles now). Many on another forum said the bike would not make compression, the rings would not seal, Nik a sil sucks, you need iron bores, etc. Even Fred the guy tuning my bike is on the iron bore kick - nik a sil is for water cooled, no good for air cooled, and so on - man was he surprised when we did the test yesterday. :D

I WILL have dyno sheets for this bike and Scott's later BUT the damn printer was out of ink yesterday. The Short story is this - installed the cams, checked the lash and put her on the dyno. We did a base line dyno run last week for our starting point. Engine has to be cold to lash the valves. First run we made 5 RWHP <increase>. Jetting we did last week is now ALL out of whack with the new cams. Short story again, changed to 32 pilots, 155 mains, changed the needle clip, NEED the accelerator pumps Installed - but did not have. Synced the carbs, set the idle - about 12 dyno runs later we had made 10 more RWHP and 4 foot pounds of torque. Thats a 17 % HP increase and 8 % torque increase. The good news is (and you will see this on the Dyno chart latter) the power was ALL the way across the board and not spikes or peaks in comparision to the stock 865 cams. Needless to say being a cam skeptic for so long this really surprised me - I had just not seen anything out there to verify cam performance. The number surprised Carlos even more, he gave me a 5 RWHP increase estimate on the phone Friday. I'll get numbers posted this week. On Scott's bike we made 102 RWHP with the D&D 2 into 1 - 69 foot pounds on the torque yesterday. Still with the FCR 39's and the 813 cams. Dyno sheet on that monster to be posted this week too.
 
mikenva

mikenva

Rocker
wonder how they compare with old 790 cams. What rpms did they pick it up at?
So would you say the 2 into d&d dont make the power the 2 into 2 will? I am a iron sleeve guy to but with stock bores i dont see why they wont work ok.What i am scared of is when you go to 988 or 904 bore dia there real thin .You wont see it on a regular dyno run but if you take both iron bore and the thin recoated and get them real hot like you do when you are running the bike hard i will all most bet the iron bore will get faster and the coated alum will slow down.i wouldnt try it on yours its running to good.
 
ThruxTonUp

ThruxTonUp

TT Racer
sweatmachine said:
so what are the new hp and tq numbers, if you don't mind me asking?
Click to expand...


See, they are the same as before ;) - My dyno runs on 2 other dynos showed what I have told you before, 68-69 RWHP and 52 Foot pounds of torque. On this Dyno the numbers are the same or close 69 RWHP and 54 Foot pounds of torque. The base line dyno run on this dyno though showed my bike at 59 RWHP and 49 foot pounds of torque, which compared to stock 08 865 motors which turn 48 RWHP on average on this dyno. So long story short this dyno reads much lower than your typical dyno, which makes the numbers Scott's bike is turning out that much more impressive at 102 RWHP. My next run should be over at MSP race shop and see if it's now cranking out 79 RWHP over there which would be consistant with the numbers over here at ATD.

I took the bike for a 140 mile ride up through the mountains today and the Grin factor is now huge, really a big difference. I like it a lot, Can't even image at this point, what Scott's bike will be like, last time I road it the power was less than my Thrux now. Jeff our bikes being so close other than the 904 kit on yours - you should see very similar gains on your bike with those cams.
 
ThruxTonUp

ThruxTonUp

TT Racer
mikenva said:
wonder how they compare with old 790 cams. What rpms did they pick it up at?
So would you say the 2 into d&d dont make the power the 2 into 2 will? I am a iron sleeve guy to but with stock bores i dont see why they wont work ok.What i am scared of is when you go to 988 or 904 bore dia there real thin .You wont see it on a regular dyno run but if you take both iron bore and the thin recoated and get them real hot like you do when you are running the bike hard i will all most bet the iron bore will get faster and the coated alum will slow down.i wouldnt try it on yours its running to good.
Click to expand...

According to our number the 2 into 1 are within a few hp of the dual setup, The 813 have both more lift and duration than 790 cams. The 2 into 1 will make more torque at the bottom end, the dual setup a little more top end power.
 
mikenva

mikenva

Rocker
oh john been meaning to ask you have you got the ballance shafts in your 988? I dont it made a big change on how fast it revs.
 
SCCTrim

SCCTrim

Banned
This is good news...finally something verifyable regarding cams. I too remember the iron bore nicasil junk wars. My nicasil barrels seem just fine after 15000 miles, and I'm glad I did it.
 
ThruxTonUp

ThruxTonUp

TT Racer
mikenva said:
oh john been meaning to ask you have you got the ballance shafts in your 988? I dont it made a big change on how fast it revs.
Click to expand...


Mike, Balance shafts are in which is a good thing, this bike revs amazingly quick now, and it has no rev limiter, we will also put the cam backlash gears back on it to quiet it down some, when we install and dyno the new cams for it.
 
sweatmachine

sweatmachine

moped
thanks for posting some good solid before/after results with the cams. Good info to have, and the first of its kind iirc.

Plus, as you said, our engines/mods are very similar, so the results are particularly interesting to me.
 
ThruxTonUp

ThruxTonUp

TT Racer
I'll get dyno sheets this week to post - what is really nice is the power gain for HP and Torque is all the way across the RPM range and not just in one portion. The torque curve on my bike is very flat coming on strong at 2500 and staying strong all the way to the limiter. Makes it very ridable on the street.
 
ThruxTonUp

ThruxTonUp

TT Racer
Here is the dyno graph - used a sharpy to color the yellow line which was so vague. Base run hp 59.51 torque 49.08 after cam change hp 69.03 and torque 53.14

CIMG1724.jpg
 
Bottle_Fed

Bottle_Fed

Two Stroke
I would still like to see a comparison between these and the 01 cams. Not that I'm being sceptical, but changing the thrux cams out for 01 cams would provide a gain also.

Greg
 
sweatmachine

sweatmachine

moped
Bottle_Fed said:
I would still like to see a comparison between these and the 01 cams. Not that I'm being sceptical, but changing the thrux cams out for 01 cams would provide a gain also.

Greg
Click to expand...

I think so too. The only comparison I've seen is when Peter Jenks put 790 cams in his thrux, but amazingly enough, Jenks doesn't understand rejetting :eek:, so I don't really consider his results valid.

But, to his credit, it seems that all 790 cams are not created equal.
 
ThruxTonUp

ThruxTonUp

TT Racer
Rumors I've heard is it's only very early production 01 cams. If the specs on them are what they claim then they would indeed provide a power gain over 865 cams. The 813 cam is at the limits for a shim over bucket set-up which is what my thrux is, I could put no more lift in it if I wanted without going to shim underbucket.
 
1087

1087

Vendor
Bottle_Fed said:
I would still like to see a comparison between these and the 01 cams. Not that I'm being sceptical, but changing the thrux cams out for 01 cams would provide a gain also.

Greg
Click to expand...

sweatmachine said:
I think so too. The only comparison I've seen is when Peter Jenks put 790 cams in his thrux, but amazingly enough, Jenks doesn't understand rejetting :eek:, so I don't really consider his results valid.

But, to his credit, it seems that all 790 cams are not created equal.
Click to expand...

Hey guys;
I really admire how persistent you are!
First the verifiable dyno's.
Second the lack of cam specs.
The correction factors
Then the 790 cams.
Now the 01 790 cams.
Also the 39's FCR's ( another thread)
I will enlighten you:
The 01 early Bonnies and the 02 up Bonnies had/has a better cam than any 865 stock motor.
Like John said and posted and since he and the dyno he use is verifiable ( Thanks God), the 813 or Street Plus, proved to be a far more superior cam than any early or latest 790 Bonnie cams for shim over bucket application.
I happen to have an original 790 Bonneville, and as you know I run and tested quite a few big bore kits, cams ,etc,etc, and the 813 is larger in lift, intake and exhaust duration and lobe separation than any of the aforementioned 790 cams.
Now if anybody likes a lopey cam, serious lift and duration, shim under bucket is the answer
I posted my dyno runs before and after 813 cams on such big bore kits.
Now that my 1087 is done, after break in, I will dyno the bike with 813 cams as a baseline and 39's.
Then I will swap for shim under bucket cams and re-dyno the bike, still with 39's on it.
May a ask, in your view, which will be the cams to compare after that?
As far as I know up to this days Triumph doesn't have any Bonnie/Thruxton with shim under bucket configuration, that you guys can rely on.
 
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