New 4to1 for gs750?

[trevor]

Hi guys I want to take my original Exhaust off my 1980 gs750e while they are still in pretty good shape and put them away. I would like to put on a 4to1 and have been looking at the Vance and Hines Street Megaphone System. gotta a price of around 328.00 plus shipping, tax and duties to me in Canada puts it at 418.00. I'm ok with that. Will I have to re-jet with this replacement?
Any other thoughts?
Thanks guys,
Trevor

[cr480]

Yes, you will have to rejet the carbs, if you don't the motor will run lean a condition that is detrimental to your engine. It will not run well at all. Jetting is a must.

[1_v8_merc]

Typically the rule of thumb is to bump up the Main Jets by 2 sizes, for 4-1 exhaust.

It's not like your bike WONT run with Stock Mains and 4-1 Pipes.
But you're probably going to have a Lean Spot around 5k-rpm's +.
(Lean = BAD = Potential Engine Damage)

My 78-750 was running with that for YEARS....and it's still alive!
(it wasn't in my possession during That time though...so it wasn't my fault)

Definitely upgrade those jets

[allojohn]

V&H recommend increasing the main jet to 130, the pilot fuel jet 42.5 and removing the stock airbox lid.
This information will be in the documents you receive when you buy the exhaust.

[mrbill5491]

4 into 1

When I installed my RC 4 into 1 ( looks just like the V&H pipe) I was using a K&N air filter as well ( not the pods) and did have to bump up the main jets, forgot what the number is since it was a long time ago. I also took into account the elevation I was at as well 3,800ft+. Pipes still blued some though not bad. I never changed the size of the fuel jets at all and never had a flat spot on the bike. Oh I do have ACCEL coils on too.

[trevor]

Thanks for the advice guys. I do have a K&N filter too. I will go by the specs I get with the pipe. Looks like I will get it from the motorcycle superstore about $430. at my door in Victoria.