Rough Idle

red107

red107

Member
OK here's my next problem to solve.

The motor wont idle smoothly, also if held on a steady throttle position at any constant speed it wont run smooth.

It accelerates smoothly and better than I expected. Lots of power.

It does occasionally cough out of the Super G Shorty carb with tear drop cover. It also pops on decel.

There's new exhaust head gaskets on. Thanks to Oscar it's got 2-1 Big Dog pipes that look to be gutted with a tunable baffle (washer on a bolt just past it's 2-1 joint). Sound great by the way. Tightened up intake manifold. I've played around with the mixture screw. Didn't want to mess more with the carb in case I'm going in the wrong direction.

In case you need to know it's got a Crane ignition.

Al
 
Last edited:
Justintime

Justintime

Member
Check your jet sizes. Everyone might be a little different depending on where you live. I'm running a 32/76 combo with the Super G, Spike AC and V & H 2-2 pipes. The coughing out the carb. sounds like a lean condition. According to my local wrench the decel pop is being caused by the short pipes and isn't a problem.
 
red107

red107

Member
I Just took the jets out and they are 29 and 72.

That's in South Texas. 2-1 stock with the inners removed. Tear drop air cleaner with K&N
 
Last edited:
Oscar Maldonado

Oscar Maldonado

Guru
Calendar Participant
YEp, You might want to bump it up up a couple of sizes. I forget what I'm running. Sorry Al, I should've told you. I forgot.
 
red107

red107

Member
Oscar Maldonado said:
YEp, You might want to bump it up up a couple of sizes. I forget what I'm running. Sorry Al, I should've told you. I forgot.
Click to expand...
Hi Oscar, the bike was running just as bad before I put your pipes on. I'm going to try 32 76 from 29 72 what do you think

BTW love the pipes sound

Al
 
Justintime

Justintime

Member
red107 said:
Hi Oscar, the bike was running just as bad before I put your pipes on. I'm going to try 32 76 from 29 72 what do you think

BTW love the pipes sound

Al
Click to expand...
Red, go to the S & S website and download the tuning guide, it has some great information. I would go to the 31 intermediate jet first since the bike already is running. My bike wouldn't even start with the 29 and the 31 ran like crap but bumping to the 32 fixed my problem.

S&S Cycle | Carb Quick Guide

Also try removing the aux. bowl vent.
 
red107

red107

Member
OK got 32 76 in now.

It has improved the idle and steady throttle at a constant speed but it still could be smoother. Most of the popping has stopped.

Thing is do I go up one more from 32 to 33? on the intermediate. Is the main good at 76 up from 72. I've no previous experience with the S&S but from what I've read up the intermediate is the one causing the idle problem

Throttle response is terrific, bike takes off like a scalded cat

Looking at this chart I'm still at the low end @ 32 for for a 107 Super G

http://www.nightrider.com/biketech/hdcarb_S&S_jetting.htm
 
Last edited:
red107

red107

Member
Five Five said:
32 & 76 is a good starting point for the 107"
Click to expand...
Went to my local custom bike shop for a 33 intermediate but they were out of stock. The guy told me to remove the Aux bowl vent plug. He also said a 33 would be too big for my bike. Took the vent plug out and it made no difference.

Looking at all the charts I can find intermediates for a 107 start from 32.

I plan to still try a 33 and work up from there if need be.

Al
 
Little-Boo

Little-Boo

Well-Known Member
Troop Supporter
You should stay with a 32 / 76 and adjust you acel pump and air mixture. I run a 650 cam, ported and polished head with bigger valves, 2-1 pipes, S & S dual tune induction system and a XXX TAZ with two thunder jets and I run a 33/78 on a 117. :D . Your local bike shop is right the 33 is to big, but to each it's own. Good Luck with the 33

Carlos :whoop:
 
red107

red107

Member
Little-Boo said:
You should stay with a 32 / 76 and adjust you acel pump and air mixture. I run a 650 cam, ported and polished head with bigger valves, 2-1 pipes, S & S dual tune induction system and a XXX TAZ with two thunder jets and I run a 33/78 on a 117. :D . Your local bike shop is right the 33 is to big, but to each it's own. Good Luck with the 33

Carlos :whoop:
Click to expand...
Because I'm new to S&S I'm not sure if going from a 29 to a 32 was too big a move. The bike did run better with the 32 but not smooth enough. Maybe I went too big? Anyway I've ordered a 31 and 33. $16,65 Shipped from Lowbrow Customs

Taking out the bowl vent plug didn't help.

I did the carb adjustment as per S&S. Idle Mixture and accelerate pump. Thing is I can't really get past the mixture because it won't idle smoothly. Although I think I've got throttle response about right.

Al

Al
 
Dakotabos

Dakotabos

Well-Known Member
Calendar Participant
Troop Supporter
I know what works for me but i may be talking shit here but my 2 cents

Like I posted on a different thread for a rough running engine

check your Vacuum Caps



Should be two little caps on your manifold that need to be capped. Cap them if missing readjust the carb. Check your plugs or replace them.

Start bike take for test ride and dont "Open her up" keep the idle lower RPMs for a few blocks and then shut the bike off, pull your plugs and check the color Tan is good or a little black due to you dont want to run too lean in this heat

If plugs are good go for a fun run. Open that baby up Higher RPMs a few miles. get to a good spot and kill the bike dont let it Idle too long. Pull the plugs and check them again.
 
red107

red107

Member
Dakotabos said:
I know what works for me but i may be talking shit here but my 2 cents

Like I posted on a different thread for a rough running engine

check your Vacuum Caps



Should be two little caps on your manifold that need to be capped. Cap them if missing readjust the carb. Check your plugs or replace them.

Start bike take for test ride and dont "Open her up" keep the idle lower RPMs for a few blocks and then shut the bike off, pull your plugs and check the color Tan is good or a little black due to you dont want to run too lean in this heat

If plugs are good go for a fun run. Open that baby up Higher RPMs a few miles. get to a good spot and kill the bike dont let it Idle too long. Pull the plugs and check them again.
Click to expand...
Ok, New plugs in gap set, new vacuum caps, Changed intermediate jet from 32 to 31.

Tweaked the mixture screw. Idle set. Accelerator pump feels good.

Bike is very close to what I'd expect. Idles OK. Motor is smoother on a steady throttle/speed. Acceleration as good as ever.

I can enjoy the ride now.

It needs that little something doing to get it just right but I'm happy with what I got.

Being from England I've always had metric bikes, having you guys to point stuff out to me is much appreciated.
 
You must log in or register to reply here.
Top