98 Intruder 1400 has on cylinder getting much hotter than the other

[JOBA]

Just got done replacing the CDI and getting it back to running. The pipe coming off of the front is discolored for about the first foot off of the head. On first start that pipe will burn you finger after about a minute while the rear cylinder pipe is just warm. Is the front running too lean?

[WintrSol]

Before you jump into retuning the carbs, check the idle and throttle sync adjustments.

[hillsy]

Before you jump into retuning the carbs, check the idle and throttle sync adjustments.

And check whether the airbox is hooked up properly and there's a filter in there.

[JOBA]

It's got an air filter. The sync adjustments are a pull the gas tank off kind of job aren't they?

[navigator]

It's got an air filter. The sync adjustments are a pull the gas tank off kind of job aren't they?

YUP.

First, make sure you have 1/8" of freeplay at the throttle grip.
Second, adjust the sync cable so that both carbs butterfly plates start to open at exactly the same time.
Third, adjust your A/F screws.....instructions below.
Forth, you will need a manometer (sync tool) to perform the sync, either home made or bought.

A/F adjustment
1. Make sure you have about 1/8" of free play at the throttle grip.
2. Motor off,Gently seat each A/F screw and set both A/F screws 2-1/2 turns out
3. Engine running at operating temp, lower your idle to about 800 using the thumbscrew on the rear carb.
4. Engine running at operating temp, turn an A/F screw CCW until the motor starts to stumble, Then screw CW until the motor starts to stumble again, count the number of turns between, then screw CCW to achieve the best idle...about 1/2 way between stumble points.
5. Repeat on the other carb.

Now sync:
1. Remove screw near each manifold, install sync tool. (don't lose the fiber washers)
2. Raise idle to 1000 rpm with thumb screw.
3. Remove gas tank and hook up an aux. fuel source.
4. Engine running at operating temp, adjust the idle sync cable to balance carbs using sync tool. (rear cable on front carb)
5. Using the throttle grip, raise the rpms and hold them constant, any rpm will do between 2000 and 3000 rpm.
6.Adjust the throttle cable to balance carbs using sync tool. (front cable on front carb)

Presto!
7. Remove sync tool and replace screws and fiber washers.
8. install gas tank.
9. Test ride and smile.
You may want to blow a fan on the engine, it can get quite hot.
Make very small adjustments, and tighten each locknut when done.

[WintrSol]

Nav, doesn't the 1400 have a fixed vacuum port on the front carb for the boost sensor?

[JOBA]

Thanks for the detailed process. I've got the Carbtune from the UK and an alt fuel source from when I cleaned my carbs. I think I can do this. I just got worn out getting an electrical issue nailed down. How bad would it be to sneak it out for a ride or two before fixing it? The weather has just been bonkers gorgeous out this week.

[navigator]

Thanks for the detailed process. I've got the Carbtune from the UK and an alt fuel source from when I cleaned my carbs. I think I can do this. I just got worn out getting an electrical issue nailed down. How bad would it be to sneak it out for a ride or two before fixing it? The weather has just been bonkers gorgeous out this week.

If it runs, ride it.
Air should cool it.
You can also bring a wrench along and do a plug chop.

Nav, doesn't the 1400 have a fixed vacuum port on the front carb for the boost sensor?

Yup, you use that port

[Herb]

I had the rear plug go bad on my 87 on the way to work one morning when I was stationed at Camp Pendleton. I rode 35 miles on in to work on the front cylinder, and over 20 miles on the way home to an auto parts store. It would still do 70, with a completely dead cylinder. didn't seem to hurt anything, I rode the bike for over 70,000 miles after that.