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 Post subject: Re: Engine performance mods ?
PostPosted: Wed Dec 21, 2016 2:50 am 
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Joined: Tue Oct 08, 2013 6:31 pm
Posts: 42
Someone asked if there was a way to get good performance without the fabrication of a new muffler. I gave that some thought and posted on ADV Rider July 01, 2016 re drilling the existing muffler. No welding, and can be done on the bike without removing the exhaust system. Remember to do all three mods at the same time: airbox, carbs and muffler. I haven't heard any feedback on anyone trying this method, and I'm interested in how well it works.
http://advrider.com/index.php?threads/h ... 82/page-70


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 Post subject: Re: Engine performance mods ?
PostPosted: Wed Jan 04, 2017 3:38 pm 
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Joined: Tue Apr 22, 2014 12:58 pm
Posts: 40
Location: Ohio
My experience with this on other bikes is that it is very difficult and time consuming to get the carbs just right. Also I've always experienced a decrease in fuel economy when opening things up so the engine can breathe easier. I'd really advise against this unless you have countless spare hours to waste just trying to eek out a couple of extra ponys. Nope I've learned my lesson. I won't mess with my PC800 and just enjoy it.


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 Post subject: Re: Engine performance mods ?
PostPosted: Sun Jan 15, 2017 11:45 am 
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Joined: Tue Oct 08, 2013 6:31 pm
Posts: 42
Dear Offline
I'm sorry to hear that your experience with other bikes has been difficult. Thanks to the internet, I have been able to tell (and show) fellow owners exactly what to do to get major performance gains in an afternoon at little cost. I took the time and effort to assist fellow owners who may be inclined in the same direction by posting exact directions. I took the time, and saved you the work. As far as performance goes, the stock PC800 engine is very under-rated. The "extra ponies" are in the area of +20 hp at 7000rpm. If you don't feel comfortable with a screwdriver, don't touch anything. If you want some fun, look me up.
RS


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 Post subject: Re: Engine performance mods ?
PostPosted: Tue Mar 21, 2017 3:55 pm 
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Joined: Tue Jul 22, 2014 6:13 pm
Posts: 74
Location: Long Island, NY
Anyone else do these mods?

_________________
Brian
1997 Honda PC-800
1980 Honda CB750F
1982 Honda CB900F
1977 Honda GL 1000


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 Post subject: Re: Engine performance mods ?
PostPosted: Wed Mar 22, 2017 7:26 pm 
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Joined: Tue Oct 08, 2013 6:31 pm
Posts: 42
Blue Thunder
Look here. http://pc800.co.uk/cgi-bin/mwf/topic_show.pl?tid=1426
John used intake and carb mods. Different resonator and exhaust system. More power, but he does not say how much. For known reliable results, stay with my original recommendations. Tried and proven. Jetting and flow are intertwined.
I would like to hear from anyone who has tried the mods. BTW, I have never tried the changes to the existing muffler mods. See posts. That's unknown territory, Jetting is guess work with 0.090" under the needles, #40 pilots, and #54 mains.
Turning the PC800 into a true sports / touring bike is fun.


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 Post subject: Re: Engine performance mods ?
PostPosted: Fri Mar 24, 2017 11:08 am 
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Joined: Tue Jul 22, 2014 6:13 pm
Posts: 74
Location: Long Island, NY
IMaScot wrote:
Blue Thunder
Look here. http://pc800.co.uk/cgi-bin/mwf/topic_show.pl?tid=1426
John used intake and carb mods. Different resonator and exhaust system. More power, but he does not say how much. For known reliable results, stay with my original recommendations. Tried and proven. Jetting and flow are intertwined.
I would like to hear from anyone who has tried the mods. BTW, I have never tried the changes to the existing muffler mods. See posts. That's unknown territory, Jetting is guess work with 0.090" under the needles, #40 pilots, and #54 mains.
Turning the PC800 into a true sports / touring bike is fun.

The reason why I ask... I've been wrenching for 35+ years on many different makes and models. Many a person makes changes claiming that power is "fantastic". When the bike is placed onto a dyno, the results typically show that the bike makes less power. "Seat of the pants" method is very subjective and is not indicative whether a mod generates more torque or horsepower.

Note that I'm not disputing IMaScot statements, it just that I would like to see someone else confirm whether the mods really produce more power or just seems to.

_________________
Brian
1997 Honda PC-800
1980 Honda CB750F
1982 Honda CB900F
1977 Honda GL 1000


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 Post subject: Re: Engine performance mods ?
PostPosted: Fri Mar 24, 2017 11:09 am 
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Joined: Tue Jul 22, 2014 6:13 pm
Posts: 74
Location: Long Island, NY
IMaScot wrote:
Blue Thunder
Look here. http://pc800.co.uk/cgi-bin/mwf/topic_show.pl?tid=1426
John used intake and carb mods. Different resonator and exhaust system. More power, but he does not say how much. For known reliable results, stay with my original recommendations. Tried and proven. Jetting and flow are intertwined.
I would like to hear from anyone who has tried the mods. BTW, I have never tried the changes to the existing muffler mods. See posts. That's unknown territory, Jetting is guess work with 0.090" under the needles, #40 pilots, and #54 mains.
Turning the PC800 into a true sports / touring bike is fun.

The reason why I ask... I've been wrenching for 35+ years on many different makes and models. Many a person makes changes claiming that power is "fantastic". When the bike is placed onto a dyno, the results typically show that the bike makes less power. "Seat of the pants" method is very subjective and is not indicative whether a mod generates more torque or horsepower.

Note that I'm not disputing IMaScot statements, it just that I would like to see someone else confirm whether the mods really produce more power or just seems to.

_________________
Brian
1997 Honda PC-800
1980 Honda CB750F
1982 Honda CB900F
1977 Honda GL 1000


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 Post subject: Re: Engine performance mods ?
PostPosted: Sun Mar 26, 2017 6:34 pm 
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Joined: Tue Oct 08, 2013 6:31 pm
Posts: 42
BlueThunder
With your experience you would be an ideal candidate to make the modifications I'm suggesting. If you do, I recommend fabricating the custom muffler with the 32mm bore per my drawing. The good results and other changes required are known and posted if that particular piece is used. You won't be dissapointed. The power increase is big. The reason that the difference is so great is because the stock bike is so choked off. The next time you have a chance, have a look at the constrained intake path, starting where it enters the small round hole in the airbox entry. On the exhaust side, you have two exhaust pipes dumping into the resonator, and then you have a tiny 25mm exit. The whole setup shouts for improvement. The performance gains exceeded my expectations and made the bike far more fun to drive. And a big bonus is that the bike is still quiet and has that linear torque feel though the whole power band. It's not very often that we get to make significant gains without a penalty. I guess that's one reason I'm flogging the idea so hard. If Honda had marketed the bike with good performance, I'll bet that sales would have been much better. In any case, I hope you ( or anybody ) consider the project. I am willing to assist in any reasonable way.


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 Post subject: Re: Engine performance mods ?
PostPosted: Sun Apr 02, 2017 9:27 pm 
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Joined: Tue Oct 08, 2013 6:31 pm
Posts: 42
A fellow (Smitty Blackstone) from New York, U.S.A. says he is going to do BOTH the modifications. First, he is going to try drilling the muffler. After that, he is also going to fabricate a copy of the muffler I suggested. When he posts a completed project, I'll be back with the link(s).


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