Any body have an opinion on head pipe torque inserts?
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Anybody have an opinion on head pipe torque inserts?
- Thread starter 46th Georgia
- Start date
I have a set arriving today from yamahaxs650.com. I have read good reports on the quality of the part, but do not have any first hand reports on performance.
Everybody has an opinion
Mickster
XS650 Enthusiast
If you have larger diameter than stock headers on a basically stock motor like I have, then the reducers will make tuning easier and provide the low end torque that is lost by going with big pipes.
I bought some. Originally, they came from 3M at 650 Central. Mike had his own made. I got mine from yamahaxs650.com. My test fit into the head says these are first quality.
I’m running them on by 750 big bore - with larger open pipes and VM34s
I havnt run them without em so I don’t have a direct comparison, but what I can say is that the bike defiantly pull hard. Way harder than my stock bike. I also havnt flogged the motor yet as it’s a fresh build so I’m sure it’s still got more to give.
They are just a single machined piece that is of nice quality.
I havnt run them without em so I don’t have a direct comparison, but what I can say is that the bike defiantly pull hard. Way harder than my stock bike. I also havnt flogged the motor yet as it’s a fresh build so I’m sure it’s still got more to give.
They are just a single machined piece that is of nice quality.
My build plan is a 700 with a Shell #1 cam, welded crank, improved valve springs, 34MM Mikuni round slides and probably a Hoose 2-2 exhaust and clean up the head a little bit. I'm guessing that with the inserts, the i.d. of the headers will be irrelevant.
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46th, I'm running a very similar setup, as you kinow. MMM recommends exhaust port inserts for improved flow and outlet inserts to correct peak torque rpm for overly large ID of 1.75" pipes. I'm not arguing the point, but that combination works for me. MMM mentions welding the outlet inserts in place. I drilled and tapped for two 4 mm. screws with countersink heads in each pipe, countersunk the holes so the screw heads sit flush with the pipe, an installed with blue Loctite. Screws can't back out in any event because the mounting flanges of my 17" megaphones cover them. I'm very pleased with the performance.
Thanks, that's pretty much what I expected to hear. Hate to ask a dumb question, who/what are you referring to with MMM, and who sells the outlet inserts?
That's not a dumb question. The dumb guy is the one who made an assumption when he wrote. MMM=Michael "Mercury" Morse, owner of 650 Central.
I apologize for my part in that. Michael "Mercury" Morse is the XS650 guru among gurus. He ended up with the business 650 Central that Johnny Zelna (RIP) started before I knew anything about internet. I believe 650 Central predates Mike's XS.
I bought the EPO's from yamahaxs650.com and the TPO's from 3M.
So, run the epo's even with mufflers, correct? I'm thinking about buying them from Hoos, 1/2 mile set up. Also, you know there's always an "also" with me, now that I've scrapped the chinese POS flatslides, on the 34MM round slides, 650 Central offers 1 3/4 long manifolds, I'll have room, but if I remember right that will only be of benefit at higher RPM and will hurt bottom and mid range, at least it did on my 5.0 Ford. Am I thinking correct on that?
Exhaust tuning, cool. I have the same situation with a Ford Ranger, 2.3L, manual transmission. Cat has been removed, of course I'll put it back on, ha ha.
These trucks are underpowered to start with, so it is real easy to notice any changes in the way that the engine runs.
So, I have 2" exhaust now front to back with a 27" glasspack. I have lost some midrange power with this exhaust. I know I would gain some power with a big fat conventional muffler.
So, could I place restrictors like this into my system to get the same gain that I would get with a more restrictive muffler? If so, Where should they be placed?
kinda just using this example to understand the same situation on a bike, or, is it the same situation?
Wait a minute, is that flapper in the exhaust manifold doing the same thing but not effective enough?
These trucks are underpowered to start with, so it is real easy to notice any changes in the way that the engine runs.
So, I have 2" exhaust now front to back with a 27" glasspack. I have lost some midrange power with this exhaust. I know I would gain some power with a big fat conventional muffler.
So, could I place restrictors like this into my system to get the same gain that I would get with a more restrictive muffler? If so, Where should they be placed?
kinda just using this example to understand the same situation on a bike, or, is it the same situation?
Wait a minute, is that flapper in the exhaust manifold doing the same thing but not effective enough?
I've used extended mounts with VMs and presently run a pair of 33mm. Mikuni 4 stroke flat slide pumpers on Michael's extended mounts. Never noticed loss of power anywhere in the range. Re. EPOs from 650 Central, not throwing shade at anyone and especially not at good friend Marty, but if I have a choice between paying more to a man who developed a part or paying less to a pirate who copied the part, I'll pay more every time. And yes, run them with muffs.
How do I contact whoever it was who developed the originals? I, like you, would rather buy from the developer. Also, do you think it's worth the extra expense for the extended mounts with the round slides and what benefit would I get if I decided to go with flat slides?
As far as I know, these torque inserts replicate the exhaust port volume for a few extra inches. IF you consider distance as "time" in an exhaust cycle, these inserts keep flow speed high for a little extra time. That flow has mass and helps scavenge the combustion chamber as pressure goes down near, at or after TDC. Because they are the size of the exhaust port itself they do not ADD any appreciable restriction.
46th, that would be Michael Morse at 650 Central. There have been "torque cones" for the inlet around for a long time, but Michael's design has some unique features. Neither of Michael's inserts is a "restrictor." There is an unfortunate and prevalent confusion between restriction and back pressure, which properly refers to one part of the resonant pulse. Never attempt to tune by adding restriction. An exhaust system with a well chosen, free flowing muffler will yield good power over a larger rpm range than a straight pipe. I've used 17" Emgo short megaphones with good results for years. They have removable straight through smooth core baffles that flow very nicely. They're raucus as hell as delivered because Emgo puts only a little narrow ring of fibreglass on them that might as well not be there. If you give the baffles a full wrap with real exhaust glass like Helix brand, they'll give you good flow and a deep, mellow tone and the glass will last a long time. If you try to economize and use insulation glass, you'll be repacking often. Marty's cousin Jeff told me after one rally ride that he'd enjoyed riding behind me just to listen--high praise from a guy who knows a bit about tuning.
Gotta update some of the above. I opened a couple of untouched Emgo 17" megs that I've had on the shelf for awhile and found that the baffles were fully wrapped. The glass didn't look like very high end stuff, but it should be effective for awhile before enough blows out to require a rewrap.
I saw an article somewhere that a loose unpacked wrap is more effective in cutting down noise. I received a sheet of glass that is not loose and the rewrap is only a little quite now. My muff resemble Emgo 17 reverse cones.
G
I have seen some mufflers where the perforated baffle was first wrapped in fiberglass cloth (weave), then normal muffler packing outside that. Presumably to make the packing last longer.
