At present I have no exhaust system whatsoever for my '72 A65T.
The proverbial blank canvas.
I'm thinking about factory shaped downpipes but the custom non header pipe version.
But looking at the design of the A65 head with it's splayed out push in exhaust ports, I'm thinking that the exhaust balence pipe is probably responsible for actually holding the header pipes into the head more than any flat steel brackets.
If I fit the non balence version am I going to struggle with headers that just won't stay put ?
I've only got riding experience of Triumphs with clamp on (push over) pipes.
Even the T140 I had was converted to push over stubs, so push in pipes are a new experience for me.
My unit single push in pipes work well, balanced however has other advantages with flow through 2 silencers reducing noise levels and reported mid range torque increases.
"but the custom non header pipe version. " Do you mean non balance pipe,, "headers", AKA down pipes , definitely need to be in there somewhere.
"If I fit the non balence version am I going to struggle with headers that just won't stay put ?"
In a word, yes. Unless you are willing to weld tabs to the frame, or tabs from front pipe to front motor mount
Tricky with the 71 , earlier dry frames pre 70 had tabs on the lower frame rails for the front pipes to locate, fitting this type of pipe will mean welding frame tabs to suit, relying on head and silencer to locate the pipe is a futile exercise in blind optimism,
The balance pipe does a good job helping to locate the pipes . Allows the motor to breath better as well.
Without a balance pipe you need some sort of tie bar to help keep the pipes braced.
Firebird type high level pipes , OIF type would bolt on , earlier dry frame types with a high RHS pipe will need some creative work with the clutch cable , and even more creativity with silencer mounts.
Theres a lot to be said for the stock low level system, the high pipe FS makes access to the LHS carb and air filter tricky.
If I had access to a custom pipe maker I would look at Dave Aldanas flat tracker pipe runs, LHS sweeping round to RHS , to staggered megas, keeps the primary side clear and makes rear set installation a bit easier.
I'm just in the process of fitting Siamese pipes to a 1970 (non OIF) Lighting. The old twin ballenced pipes were held rock solid by the ballence pipe and the Frame tab fixing bolts.
The Siamese pipes I bought have lugs welded near the head, that accept a tie bar (not surpplied). I expect the tie bar arrangement and the bolted frame tab will offer a similar stable fixing. I can't see free fitting pipes, until they meet the silencer, being as stable ?
A quick question...... should any exhaust jionting compound be used in the head ports, if so which type?
I have a 1971 Triumph TR6C with a very similar exhaust system to the '71 Firebird (except that it's in bright chrome)
It looks great and sounds even better.
Much better (IHMO) than the '71 low level pipes.
However I've picked up some really nasty burns from that stylish exhaust.
Proof that all that glitters isn't gold as they say.
I've always thought of the balence pipe assembly as an ugly rust trap, but it's got to be better than welding tabs onto a chromed pipe.
Has anyone been able to quantify any alleged performance gains over straight pipes ?
For my 750 the balance pipe works best, Ive tried OEM type siamese, and Dunstall type 2 into 1 passing beneath the motor, and a few silencer styles, short mega, Dunstall type mega, Goldie style, I get best sealing, security and performance from the stock 71 set up, I have never tried the FS type, mostly because i like my skin uncooked..
The balance pipe I have currently is no worse a rust trap than all the tight bends in a FS set up.
+1 for Gavins comments. PRT
Sealing the pipes in the head.
ordinary silicon bath sealer works, black stuff is less obvious, all mating parts should be cleaned to bare metal, , degreased , then given a final rub with vinegar and wipe dry with a towel before applying the goo ( acetic acid is the solvent in most Silicon sealers).
if all is clean it fills pretty grim amounts of wear, my 71 head is wallowed out and it works on that.
use a bit more vinegar to clean up excess squeeze out. It does not burn or melt. If you can be bothered some dangerously sharp beer can shims will help , I always cut myself on these and have since given them up, but they do seem to stick in very well when siliconed and shimmed.
Fitting pipes with a balancer , test fit , make sure everything lines up and you can slip the balancer around before getting goo anywhere,, push the balancer all the way to one side. Smear goo in the ports, a generous layer with a gloved finger, offer up the pipes and jiggle into place entering , shifting the balancer , repeat a bit at a time, wipe up the goo,
, slip the balancer around getting goo into the slip joint and tighten the clamps, after a heat cycle re tighten.
I sometimes use Exhaust putty for the balancer pipe, it comes apart pretty easily..
Theres at least two types of balancer clamps out there, some have tabs welded to the balancer , others have two splits and need two separate clamps, the clamps tends to bend and settle and need a retighten every now and again.
One other thing, According to the Umberslade hall book the exhaust port angles changed subtly for the OIF models, I had never noticed, but if your head is unworn it might make a difference when fitting earlier types. And might explain why the siamese set up was reluctant to stay in place when I tried it.
Silicon sealant is the last thing I would have tried.
I'd have thought that the heat would have killed it in no time.
Thanks for that, and the heads up about the change in port angle.
re Silicon sealer breakdown.
I am a habitual beach comber, I often find whats left of a silicon sealer cartridge after its been burned in a bonfire, the plastic cartridge disappears and the silicon is left as a perfect mold , with all its rubberiness still intact.
"Silicone rubbers are often one- or two-part polymers, and may contain fillers to improve properties or reduce cost. Silicone rubber is generally non-reactive, stable, and resistant to extreme environments and temperatures from -55 Â°C to+300 Â°C while still maintaining its useful properties."
In service as an exhaust port sealer it must be close to its upper temp limit , but Ive not had it fail , yet!.