SuzukiSavage.com - Print Page

SuzukiSavage.com
/cgi-bin/YaBB.pl
General Category >> Rubber Side Down! >> New exhaust pipe issue
/cgi-bin/YaBB.pl?num=1489815187

Message started by Redryder652 on 03/17/17 at 22:33:07

Title: New exhaust pipe issue
Post by Redryder652 on 03/17/17 at 22:33:07

So I made a new pipe for my s40 and it is about 1 3/4 I.d. to about 4 inches past the axle. It is basically straight except for 2 washers inside to take a bit of bite off the tone.

I'm running a 155 main, 55 pilot, one metal washer on the needle, and probably 2 1/2 to 3 turns out on the screw.

Here's my issue, around town is fine, or slow speeds is fine, but at highway cruising if I give her a fair amount of throttle, she pulls good, I let off a little, give her gas again, and it's like a tiny bit of hesitation.
I understand a stock savage won't run good with a straight pipe, hence the washers inside. Should I put more baffling in there or play with the jets?

Title: Re: New exhaust pipe issue
Post by LANCER on 03/18/17 at 04:24:34

My suggestion is for you to put on a good muffler, the engine runs better with one.
I have only ridden one bike ever that had a straight pipe with baffle that ran well. The owner had designed his own baffle after weeks of testing different designs, along with a whole host of air filter designs. Diamond Jim was an engineer. I bought the bike and then later sold it to me son.
Anyway, point is if you really just want the straight pipe you will need to do your best to get a decent tune. If you get it running decently in the low and mid range then the high range will likely be a bit off.

Are you clear on the jetting/tuning procedures ?
There is a lot of help in the Tech Section.

Title: Re: New exhaust pipe issue
Post by SALB on 03/18/17 at 12:54:46

I believe that both Raask and BCB put the baffle right up front near the head pipe, if that helps. :-/ Lancer is right in that it will take some experimenting and fine tuning to get it right.

Title: Re: New exhaust pipe issue
Post by Kris01 on 03/19/17 at 08:15:26

Could the hesitation just be a quirk of the stock carburetor? It's not extremely responsive.

Title: Re: New exhaust pipe issue
Post by LANCER on 03/19/17 at 17:21:01

The stock carb is not a quick reacting type of carb. It naturally has a small built in delay from the Flick of the Wrist to the engine response. That can be improved just slightly but on a stock engine it is not worth the effort. The settings you have (jets), pilot screw setting and your needle setup seem to be to rich for your stock engine and a straight pipe with the little bit of baffling you have.
Did you try smaller jets ? If so what. We're the results ?
You definitely need to add another washer, one is not enough.
You said the pilot screw was 2.5-3 turns out...how did you end up with that setting ?

Title: Re: New exhaust pipe issue
Post by batman on 03/19/17 at 21:46:53

I think trying to tune the exhaust to the carb by adding washers is going to be ruff, I think you should make a reasonable exhaust ,and then tune the carb to it,this is the normal procedure .But what you've built for an exhaust is hardly reasonable,1 3/4 inches ID is much to large,we advised 1 1/2 inches as a max(use on modified motors) on your earlier post,you have little to no backpressure without a muffler which the motor needs,and therefore no pressure drop where the power pulse can reverse an to go back to the exhaust valve to aid extraction at the beginning of the next exhaust stroke.The stock header is 32inches long for that reason ,you have made one 5 or 6ft long with a couple of washers that may quiet the sound ,but little else .I fear trying to make it work will use up a big chunk of you future life.I'd advise using your stock header and a Dyna muffler if you want to ride anytime soon.Part of problem is that your jetting sounds rich ,which might be the cause of the motor bogging down.