1981-82 GS650 HP rating/Muffler Question

[Anonymous]

I've been researching my new bike and so far for the 1981-82 GS650 I'm finding two ratings: 65hp and 73 hp... Which is it? Is one gross and the other net? What's up w/ this? LOL. Also...I'm looking into mods to my exhaust and stuff, found the MAC systems and others, however my brother suggested that I just drill out the five small holes around the baffle in the ends of the stock mufflers...is this a mistake or will it do something worthwhile? Thanks people.

[Dink]

65 hp sounds closer to the mark, although I dont have any figures to show you. Yes drilling the ends of your pipes will make a difference, they will be louder and will rust out sooner. MAC brand systems have areputation as a good stock replacememnt system and generally dont require rejetting, as they are fairly restrictive , so if you are after a performance increase it may be better to look at other systems.
Dink

[first timer]

the mac systems are fine, if you order the 4-1 system from the company directly you can order a competion baffel instead of the stock baffel this will give you all all the free flow you need. i also think they have 2 sizes of baffels a 1.5" and a 2". i have the 1.5" inch on my bike and it works fine and is loud but not to loud.

ryan

[Hotblack]

Considering a 550 is rated at 49 horsies and a 1,000 around 80, I would have guessed around 60 - 65 for a 650.

As for the 550 rating I've seen one or two things that state 54 for the E vs 49 for the L, but most give them both as 49. ????

Shark, I have a road test for a '81 or '82 650G from Cycle, if you're interested I can scan it in and e-mail it to you. Unfortunately no HP is listed, but it gives 1/4 mile times.

[brs127s]

When I replaced the rusted-out exhaust on my 77 GS550, I went with a set of Mac 4-to-2 flared slip-ons, and reused my stock headers(they were still in really good shape). I bought them from MAW. It was the best price I could find on the net. I really liked the Mac's. They were consideribly louder than stock, but were not too loud. They had a really nice tone. They were not as restrictive as the stock exhaust, and added a little performance without rejetting. I was very happy with them and would definitely buy them again if I needed to. I just picked up a pair of Jardine 4-to-2 slip-ons on ebay and will see how they compare to the Mac's. From the pictures I have seen, they look nearly the same.