Bought bike open pipes no jetting "HELP"

[Gsnoob]

Hi
I came across this form doing some searching, I recently picked up a 81 GS 650 GL for 500$ 24k miles on it bike is in beautiful shape however previous owner had some trouble with exhaust rust and holes and cut the baffels off just behind the rear hangers in other words it has open pipes , bike starts runs and accelerates fine aside form being a bit on the VERY LOUD side. However I know most the time you can not just cut the pipes like that on these old bikes witout jetting and have them run right. According to the previous owner its had no jetting done at all. The bikes been run less then 50 miles after being cut because he said it was just to loud for him to ride. Said he took it to town and back and put it up for sale. So my questions are, If I dont jet am I looking at engine damage even though bike seems to run okay plugs dont look like they are lean? Also why does it seem to run so well if it hasnt been jetted? IS it safe to run at all like this if its running smooth say the 8miles to my work and back or am i gonna blow it up? Also if i HAVE to jet it what are the recomendations for jetting I saw a dyno jet stage 3 for 100 bucks anyone have xp with them kits? Also after doing some looking on this site I can see there are plenty who are going to dog on the bike for being so loud thats fine I agree its to loud right now I will adress that later when i have the extra money for a nice 4-1 however right now my concern is the bike the way it is now and making sure im not damaging anything. Thank you!!!!

[Steve]

Yes, you will be damaging several things.

Besides the obvious things, like your hearing and your neighbor's feelings, running open pipes will lean out the mixture. A lean mixture runs hotter, which will soon damage the insides of the engine.

Why does it seem to work well now? Because you are just idling around. By the time you get out on the road, you will be getting into the ranges where the MAIN jet will be providing fuel to the mix and it's not nearly large enough.

If you insist on riding it like that, a Stage 3 kit is what you need.

XP is a computer operating system. What does that have to do with carbs?

.

[UncleBen]

You won't need to use a stage 3 kit unless you go with pod filters as well. for exhaust mod only, st 1 will be fine.

If it is too loud, you could get two of the Emgo universal 12" "shorty" mufflers and weld them on where the PO cut the pipes. They sound great and cost about $50 for the pair.

[Gsnoob]

I was saying it seems to run well caus ei took it out for test run when i bought it and seemed to accel smooth and run smooth at a full rpm range lol and ment xp as in experience. but thanks for info also yes i might look into the shorty mufflers thank you guys any other suggestions are welcome

Yes, you will be damaging several things.

Besides the obvious things, like your hearing and your neighbor's feelings, running open pipes will lean out the mixture. A lean mixture runs hotter, which will soon damage the insides of the engine.

Why does it seem to work well now? Because you are just idling around. By the time you get out on the road, you will be getting into the ranges where the MAIN jet will be providing fuel to the mix and it's not nearly large enough.

If you insist on riding it like that, a Stage 3 kit is what you need.

XP is a computer operating system. What does that have to do with carbs?

.

[Nessism]

Please don't run an open exhaust. The noise isn't good for either the public at large, and your bike won't like it either.

Harley mufflers are cast off by the thousands. Maybe drop by your local dealership and pick up some left overs. Several members around here have used them with excellent results.

[Rover]

JC Whitney carries some universal type exhaust pipes also; at reasonable cost...less than jet kit probably.
Good luck and let us know your progress.

[BassCliff]

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BassCliff

[1_v8_merc]

I personally love a loud jap bike, as long as it sounds solid and not obnoxious.

If you like em loud, just rejet and adjust the mixture accordingly.
If not, then patch up the holes on your exhaust or spend $350 on a new exhaust system.

[tom203]

I was saying it seems to run well caus ei took it out for test run when i bought it and seemed to accel smooth and run smooth at a full rpm range lol and ment xp as in experience. but thanks for info also yes i might look into the shorty mufflers thank you guys any other suggestions are welcome

My favorite thing about this bike is how smooth and quiet it is- I sneak up on dogs and people and enjoy their surprise! As Nessism said, harley cast-offs are everywhere and cheap-look on CL. A little back pressure helps the exhaust valves drop into their seats.

[UncleBen]

A little back pressure helps the exhaust valves drop into their seats.

How does that work?

[tom203]

How does that work?

It cushions the blow as they hit the seats-as back pressure adds a slight resistance to valve closure.

[UncleBen]

Learn something new every day!

[Steve]

Methinks it would have to be a LOT of backpressure to counteract valve spring pressure.

.

[tom203]

Methinks it would have to be a LOT of backpressure to counteract valve spring pressure.

.

Mehopes that cam lobe is restricting the bulk of spring pressure till it wanders off!

[Gsnoob]

Well ty for info, so just to be clear by all means if I put this jet kit in running these pipes open will not cause damage to my engine? CAuse the hole valves seating easier kinda threw some confusion in there lol. Since only maybe month or little longer of good riding left up here in MN going to finish out season with the pipes the way they are and save over winter for a good quality V&H 4-1 and pod filters for next spring. So im going to go with the Dynojet in prep for the V&H and Pods, I will not run it till i get the kit in if its not safe to run unjetted. I was hoping just the short runs to work and back would be okay but it sounds like even that maybe to much with out the jetting oh well a couple more days wont hurt im just dying to get the bike out.