Getting tuned in on a GS450

[JRHemmen]

Hi all, firstly thanks to everyone for all the help you've been on the forum. I've finally got the rusted out bike I bought for $200 running. I'm hoping for some help on getting the carbs just right. I have the Mac 2-1 exhaust, and currently have the no-name EMGO lookalike filters that the PO included with the bike. I currently have 137.5 mains and 40 pilot jets in. I haven't done anything to the needles yet. The bike is still giving the real occasional backfire (through carbs), but its pretty uncommon now, maybe once on my two mile ride. On a straightaway, I opened the throttle up a bit, and the bike kindof studdered and rocked a bit while slowly accelerating. Also, when I pulled in the driveway, I shut the bike off, and when I turned it back on, there was a massive backfire out of the exhaust, then it started, idled, and ran just fine. The carb boots and O rings are all new, the carb bowl gaskets and O rings are all new as well. I set the float height, though I can't remember what it was set to off the top of my head.

How do I go about syncing the carbs and deciding what to do to the needles?
Would K&N filters greatly outperform the no names? If so, I want to buy and swap before I spent a lot of time getting the carbs set properly.

Thanks in advance.

 

[tkent02]

Step one for tuning anything is to lose those crappy Emgo Sand Sifters. They don't filter much at all, don't flow much air, and have a terrible shape inside which makes tuning difficult or impossible, the air has to go around a square corner to make it into the carb. Air doesn't like going around square corners. If you're going to use pads use K&N or Ape pods, they work well.

 

[JRHemmen]

Step one for tuning anything is to lose those crappy Emgo Sand Sifters. They don't filter much at all, don't flow much air, and have a terrible shape inside which makes tuning difficult or impossible, the air has to go around a square corner to make it into the carb. Air doesn't like going around square corners. If you're going to use pads use K&N or Ape pods, they work well.

Okay, I figured those filters weren't any good but I wanted a second opinion before I dropped ~$90 on new ones. The K&N rc-1822 are the ones I was looking at, and those appear to have a hard corner for the air to navigate as well. Is there a better K&N pod that members here prefer?

Link to aforementioned filters:

http://www.amazon.com/dp/B000E7DN44...TF8&colid=3LGPMXK5JDGW2&coliid=I2FDX30U3BZT2U

 

[Thumper88]

Yes, RC-1822 is what I used on my GS450--work great.

If you want to save a little money you can go with the RU-1822 (doesn't have the chrome end caps):
http://www.amazon.com/RU-1822-Universal-Rubber-Filter/dp/B000E7DMZE/

 

[Guest]

I'm thinking you might need mains at 145, pilot at 45 to start
I bought the Emgo 2 gage vacuum set and I've used it to balance the carbs on my 400 and 550 so far. I'll set the 450 tomorrow if I can get the old girl to fire (it's been at least 11 years). Easy to use/set. Hard to get to the adjusters !
Balance has made a huge difference in performance, especially starting, low and mid rpm.

 

[JRHemmen]

I'm thinking you might need mains at 145, pilot at 45 to start
I bought the Emgo 2 gage vacuum set and I've used it to balance the carbs on my 400 and 550 so far. I'll set the 450 tomorrow if I can get the old girl to fire (it's been at least 11 years). Easy to use/set. Hard to get to the adjusters !
Balance has made a huge difference in performance, especially starting, low and mid rpm.

Sounds good. Is this with K&N filters, or EMGO?

 

[JRHemmen]

K&N's will be here tomorrow

 

[tkent02]

Excellent, the difference is inside, good pods have a velocity stack shape inside, crappy ones don't. On twins you can get close on the synch by disconnecting one spark plug at a time and adjusting the throttles so they drop about the same RPM. Do it at a few different idle RPMs.

Probably not as exact as using the proper tools but you can get it close enough to run pretty well.

 

[JRHemmen]

Went for a ride with the new pods, it certainly feels better. It still surges a bit when i give it throttle, and it still tends to rev up on its own when I pull the clutch in, but those conditions are a hell of a lot better than they were with the Moxi's. Also, there's both a whistling and a clicking sound coming from the engine. I'm thinking exhaust leak and chain or valve clatter?