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Discussion Starter #1
hey guys
ive had my 929 for a couple months now and i was wondering if you guys think its a good idea to remove the htev valve? it came with a two bros slipon and im thinking that if i remove that valve it would sound a lot better in the lower rpms:idunno: . i wasnt sure if that valve did anything for backpressure though? i was thinking i could have a buddy make me a cap out of metal and just bolt it up to the opening with some kind of a gasket to block any air. or maybe buy that $90 bit of pipe i saw on ebay to eliminate the valve (cant find the link now but when i do i'll update thread). any input will be appreciated
 

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wow... i was just about to start a new thread asking the same thing... thanks for saving me the time!! but yeah, any info on this will help out a lot!!
 

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You will lose some bottom end because it does cause back pressure till I think 8k rpm, then the valve rotates.
You can always disconnect the cable to the valve and place it in the straight through position to test it out. As long as you leave the servo connected you will not throw any codes.
 

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You will lose some bottom end because it does cause back pressure till I think 8k rpm, then the valve rotates.
You can always disconnect the cable to the valve and place it in the straight through position to test it out. As long as you leave the servo connected you will not throw any codes.
You will lose low end big time. I had mine wired in the 'midrange position' for 2 weeks and felt a huge loss.

Getting the eliminator isnt a bad idea but youll certainly need a map to correct the fueling down low.

Are you intending to remove it just for sound? I didnt notice a difference.
 

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Discussion Starter #6
my biggest reasons are to hopefully get a deeper sound out of the exhaust and prevent any problems that people seem to run into with that valve. the bike is fast enough so i dont care if it makes a couple more horses. im not really fond of dropping a couple hundred on a power commander either to re-map the thing, although i bet they run a lot smoother with one installed. i might just try taking that cone thingy off at the end of the pipe like fonzie said and see if that does anything
 

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I removed the core out of the HTEV and ran it today without. Removed the servo too. Im now installing them back. It ran like crap. Lost all midrange unless your highway droning and it didnt seem to matter.
 

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i removed the htev and removed the flapper door on the air filter and put a -1 front sprocket...huge diffrence now!!! from low to mid to high range
 

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i removed the htev and removed the flapper door on the air filter and put a -1 front sprocket...huge diffrence now!!! from low to mid to high range
The change in low/mid range is due to the front sprocket change, not at all from the HTEV/air flapper removal.
 

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The change in low/mid range is due to the front sprocket change, not at all from the HTEV/air flapper removal.
i did the flapper and htev mod before the sprocket and i lost low to mid power which i knew it was going to happen..then i ordered the sprocket and that took care of it
 

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Yeah, thats ideal! By removing or at least locking the HTEV in place, the servo is less likely to fail, simplifying the machine as a whole and by swapping the front sprocket to 15, you get your midrange back immediately and some more...
 

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I did the full exhaust with a PC3 on my first 929 and was disappointed in the mid range loss. Second bike added a slip-on and PC3 and happy with mid but disappointed with top end, just not as potent. I'll get it mapped with new cams and post results.
Bob
 

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I just disabled my htev the other day by unhooking cable and turning to valve open! But when i start up at idle it runs about 800-1000 rpms higher???
 

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i have the hass elimanator on my bike and i did the flapper mod with a bmc race filter. hass sends u a fuel map to go along with it if u have a pc3. i also cut the cone off the end of the pipe too. as for how it runs i think i did loose a lil bit of low end but anything over 3k and my bike pulls hard all the way to redline.
 

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I've recently removed the complete HTEV set up from my bike, installed and K&N air filter and had a PCIII mapped in on a dyno, the print out shows a dip in the bottom end but gains every where else.

To be fair my bike was running ridiculously rich when I got her and only putting out something like 123bhp at the back wheel, she's now pushing 137 at the rear with a baffle fitted in the exhaust (she was bought for track days). With the baffle removed I might see a further gain at bottom end, but for sake of keeping the noise down I won't be doing that..

I haven't changed the gearing on my bike as yet, does any one have the info on what tooth sprockets I should run front and rear..? The previous owner had recently replaced them but I believe they just mimic the standard set up..
 

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I've recently removed the complete HTEV set up from my bike, installed and K&N air filter and had a PCIII mapped in on a dyno, the print out shows a dip in the bottom end but gains every where else.

To be fair my bike was running ridiculously rich when I got her and only putting out something like 123bhp at the back wheel, she's now pushing 137 at the rear with a baffle fitted in the exhaust (she was bought for track days). With the baffle removed I might see a further gain at bottom end, but for sake of keeping the noise down I won't be doing that..

I haven't changed the gearing on my bike as yet, does any one have the info on what tooth sprockets I should run front and rear..? The previous owner had recently replaced them but I believe they just mimic the standard set up..

When you say you've "removed" the HTEV system, what did you replace it with?
Bhp is measured at the crank, hp is measured at the tyre.
I would expect to see gains in the topend and losses in the bottom when removing the baffle, but even some OEM mufflers don't pass noise restrictions at some UK circuits.
If you only do track days then you will be wanting to gear it to suit the circuit(s) you ride at. Are you getting into sixth gear on the fastest straights?
 

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Hi bladeracer,

Apologies, I should've put 'HP' and not 'BHP'....I think.! Either way the gains were good and she runs twenty times better, which is what I was really after.

I've not ridden her on track since the removel of the HTEV so will update you on that, but I'm pretty sure I'll be looking to go down on the front sprocket and up on the rear either way. The tracks I ride, or at least the ones that are more local to me, don't have sixth gear straights, so a gain in acceleration would be welcome. Any ideas on the ideal sprocket size..?

I've removed the HTEV system completley but left the servo plugged in, so I have no exhaust valve and no flapper in the air box, the PCIII is now doing the job on its behelf. Though I doubt I'll ever get back the bottom end loss, it's worth the sacrifice for track use.
 
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