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Old 04-03-2011, 11:13 PM   #1
CHRIS,T
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Default baffle removal

hey guys

i just bought a 1985 Honda magna 750 v45 and was wondering if i remove the baffles will it damage the bike? The reason i ask is the my buddy said the the back pressure would be too low and might affect the motor is this true?

thanks
Chris
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Old 04-04-2011, 09:01 AM   #2
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It is possible that removing the baffles will burn the valves, but it depends on the specifics of the engine and what's left of the exhaust system.
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Old 04-05-2011, 02:07 AM   #3
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If you remove the Baffles you will need to re-jet the carbs, that being said are you doing to gain performance or just to annoy the neighbors. On short rides it will be okay but on long hauls as wintrsol said you will probly torch your valves. Might i suggest getting removable baffles that way you can put them back in when you need to.
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Old 04-05-2011, 01:19 PM   #4
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Quote:
Originally Posted by rustrider View Post
If you remove the Baffles you will need to re-jet the carbs, that being said are you doing to gain performance or just to annoy the neighbors..
a bit of both
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Old 04-05-2011, 06:32 PM   #5
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yes removing the baffels will make the engines exhaust flow more and make the intake call for more air. So now you have more air demand and the not enough fuel so it will run lean. Rejetting the carb/carbs or remapping the EFI is needed!
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Old 04-05-2011, 06:52 PM   #6
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Quote:
Originally Posted by DoubleClutch View Post
yes removing the baffels will make the engines exhaust flow more and make the intake call for more air. So now you have more air demand and the not enough fuel so it will run lean.
DING DING DING DING!!!! We have a winner!!
Lean A/F mixtures run hotter. Thats what burns out the valves.
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Old 04-05-2011, 09:45 PM   #7
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That, and cold air can actually travel back up a short pipe and cause a hot valve to fracture, if the pipe is short enough.
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Old 04-06-2011, 01:12 PM   #8
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Magna's are very unforgiving on exhaust modifications. I suggest leaving it stock & selling it in order to buy a louder bike. Better that than risk damaging a good running motorcycle.
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Old 04-08-2011, 04:48 PM   #9
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Quote:
Originally Posted by Animedevildog View Post
DING DING DING DING!!!! We have a winner!!
Lean A/F mixtures run hotter. Thats what burns out the valves.

+100,
kind of a big problem with older airplane engines. there's always a lean one.


now if only we had those nifty mixture control knobs on our bikes too.....
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Old 04-09-2011, 08:24 PM   #10
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Quote:
Originally Posted by funderb View Post
+100,
kind of a big problem with older airplane engines. there's always a lean one.


now if only we had those nifty mixture control knobs on our bikes too.....
It's called swapping over to EFI lol
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Old 04-09-2011, 10:10 PM   #11
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^^
But that's not nearly as fun as sitting there with a fuel flow meter, and manifold press, and dialing in and out the fuel and throttle, all the while keeping a watchful eye on the number 6 cyl, waiting for the EGT to shoot through the roof just before you melt the cylinder head off and.....
maybe EFI does make life easy.
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Old 04-10-2011, 01:48 PM   #12
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well, swapping out the duel CV carbs for duel throttlebodies would have an added benefit of more airflow into the cylinders as well. The EFI I wanna use id from the NT-700. Would take some work though...

Having duel carbs instead of a single carb means I have two sets of jets to change, and I have to sync the carbs after. It can be a bit of a pain, but it's gotta be done if you do any extensive mods to the intake and exhaust.
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Old 04-10-2011, 05:43 PM   #13
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Quote:
Lean A/F mixtures run hotter. Thats what burns out the valves.
Holes in pistons actually.


Sky...
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Old 04-10-2011, 09:00 PM   #14
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Quote:
Originally Posted by Animedevildog View Post
well, swapping out the duel CV carbs for duel throttlebodies would have an added benefit of more airflow into the cylinders as well. The EFI I wanna use id from the NT-700. Would take some work though...

Having duel carbs instead of a single carb means I have two sets of jets to change, and I have to sync the carbs after. It can be a bit of a pain, but it's gotta be done if you do any extensive mods to the intake and exhaust.
To make things even more fun, the Magna has 4 carbs.
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Old 04-10-2011, 11:07 PM   #15
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Quote:
Originally Posted by 65sky View Post
Holes in pistons actually.


Sky...
Yes, it will do that as well if it gets bad enough... Also can lead to pre-ignition or detonation issues.

Quote:
Originally Posted by hijacker90 View Post
To make things even more fun, the Magna has 4 carbs.
So does a 1978 CB-750F. And the Datson 260Z I had came with three weber carbs.
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Old 04-11-2011, 06:53 PM   #16
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Quote:
Also can lead to pre-ignition or detonation issues.
yup.
- Overlean + Lugging/lowRPM > Preignition or Detonation > Burned valve seats or Blown pistons or head gaskets.

It also does wonderful things to rings, connecting rods, and a good list of other stuff.

I think the best way to stay safe, since its a bike, is to spend the extra pennies and keep a nice cooling Air/fuel mix, and run optimal RPM. Would you rather buy gas or a new engine?

The guys on the CPA forum seem to love this topic.
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Old 04-15-2011, 03:37 PM   #17
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well i decided to leave the baffles in the old pipes but here in Montreal we believe in the louder you are the safer it's to ride cus people are Fing stupid almost got hit. i was wondering what was a good pair of pipes for the magna or if i should make some of my own ?. also was curious is the magna considered a v-rod or metric ?
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Old 04-15-2011, 08:15 PM   #18
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V-rod = Harley Davidson
Magna = Honda

there IS a difference
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Old 04-15-2011, 08:39 PM   #19
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Quote:
Originally Posted by alalien View Post
Magna's are very unforgiving on exhaust modifications. I suggest leaving it stock & selling it in order to buy a louder bike. Better that than risk damaging a good running motorcycle.
It also should be mentioned that the Magna V-4 (with the 360 degree crank) has a flat crappy annoying drone when the pipes are opened up. The one negative about them. They sound best with stock pipes in my opinion. Now if it was the 1986 and on VFR700/750 V-4 (with the 180 degree crank) THAT is one fine sounding engine with a set of pipes. Sounds like a small block Chevy! Much like the VMax, which sounds like a big block Chevy.

If Honda had just put that 180 degree crank, which oddly enough gives stronger mid-range, in the Magnas we'd have sold them hand over fist. Put a set of pipes on it, then when the customer walks in and looks at one, roll it out and fire it up... sold!
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