Proper Tuning Sequence

[jfmerk]

I want to check a few adjustments to my 78E which I've fully restored to stock, so a complete engine rebuild was done including the carbs which have all stock jets, float settings etc. I did remove the idle mixture screws during cleaning and put them back to what the manual stated: 1 1/4 turns out from lightly seated. Now this is preliminary tuning while it's still in the shop (my basement) as I have not had it out on the road yet... no gas tank yet, still getting prepped for paint.

Would the proper sequence of tuning be to:

1. Check and adjust timing if needed
2. Sync the carbs with carb stix, (I bench synced them using the bread tie wire method)
3. Adjust idle air mixture... HOW? Colortune?
4. Re-check timing
5. Road test

Thanks for the guidance!

[Larrym]

Eyes and Ears and Gauges, Oh My!!!

jfmerk,

"3. Adjust idle air mixture... HOW? Colortune?"

See this:

http://www.xs11.com/forum/showpost.p...60&postcount=1

Courtesy of Ken Talbot...

[3Phase]

Until the rings are seated, carb synch and idle mixture screw settings are going to be rough approximations at best. After the initial engine start and run-in take a test ride and seat the rings before you let the engine idle for a prolonged period of time.

After seating the rings and while the engine is still hot: check for leaks, synch the carbs and set the idle mixture screws.

Drain the engine oil into a pan, remove the oil filter and look for excessive amounts of shiny metal, bearing material and odd chunks. I took the oil pan off just to make sure nothing was lurking in the bottom of the engine but you don't have to do that if you don't want to.

If the oil looks good then refill the engine with fresh oil, start the engine and check for leaks.

Let the bike cool down overnight.

The next day when the engine is cold look again for leaks and recheck the valve clearance before you continue to break in the engine.

Have fun and enjoy your rebuilt engine!

Carburetor Maintenance Tech Tip: adjusting-pilot-screws-by-ear-vs-colortune

[natemoen]

Sometimes I will even redo the sync (not that it changes much when doing one idle screw, but it does change it) after each idle screw.

[CatatonicBug]

Sometimes I will even redo the sync (not that it changes much when doing one idle screw, but it does change it) after each idle screw.

I usually just keep the sync gauge on the carbs when colortuning. I'll sync, then colortune, then verify the sync again. It often requires a slight adjustment to the sync after the colortune.

[natemoen]

I usually just keep the sync gauge on the carbs when colortuning. I'll sync, then colortune, then verify the sync again. It often requires a slight adjustment to the sync after the colortune.

Well that how I do it as well (minus the colortune).

[79XS11F]

In this order ....

Valve clearance check & or adjustment
Cam chain tension adjustment
Ignition timing including Vacuum and centrifugal advance operation
Air filter check / replacement
Idle mixture adjustment
Sync


this is the order that the tasks are presented in the factory manual in the service and adjustments section. It goes without saying that valve clearance, cam chain operation and timing will all effect idle setup and carb sync results.

Rob

[3Phase]

Thanks, Rob, had a rough weekend and I knew I was forgetting something!

After seating the rings and heat cycling the engine the cylinder head bolts should be re-torqued while the engine is cold and the valve cover is off to check the valves and reset the cam chain tensioner.


Jf, did you rebuild the engine yourself or did someone else build it and you're doing the final assembly, fit and adjustments?

[jfmerk]

Thanks for all the input guys.
3Phase, I did the engine myself... That is I did a light deglaze hone, then brought the pistons and cylinders to a local engine builder so they could verify the pistons were OK to run in the cylinders which they were. I found them to be within spec but wanted an expert opinion. I also gave them the head to do a complete valve job. I installed new 1st oversize piston rings; at only .009" bigger diameter, I felt it would be OK and others here indicated they've done that without any problems. New main bearings as well.

So far I've run the engine 20-25 minutes at 2500 RPM per break-in oil instructions. (filter changed) I assume that is not enough time to achieve a full break-in period, although she smoked a fair amount and after 12-15 minutes the smoke was gone. Short restarts since then have been smoke free as well. My thoughts are to get my tank and side covers painted and finish up a couple odds and ends and get her out on the road several times before doing the post break-in adjustments you and others mentioned, checking valves, cam chain tension, head nut re-torque, carb stuff, etc. Sound good?

[XS1100_OEM4ME]

Heat

Thanks for all the input guys.
3Phase, I did the engine myself... That is I did a light deglaze hone, then brought the pistons and cylinders to a local engine builder so they could verify the pistons were OK to run in the cylinders which they were. I found them to be within spec but wanted an expert opinion. I also gave them the head to do a complete valve job. I installed new 1st oversize piston rings; at only .009" bigger diameter, I felt it would be OK and others here indicated they've done that without any problems. New main bearings as well.

So far I've run the engine 20-25 minutes at 2500 RPM per break-in oil instructions. (filter changed) I assume that is not enough time to achieve a full break-in period, although she smoked a fair amount and after 12-15 minutes the smoke was gone. Short restarts since then have been smoke free as well. My thoughts are to get my tank and side covers painted and finish up a couple odds and ends and get her out on the road several times before doing the post break-in adjustments you and others mentioned, checking valves, cam chain tension, head nut re-torque, carb stuff, etc. Sound good?

Sounds like you have done a good rebuild. I am guessing the 20 to 25 min break in run, you had some way to cool the motor? Be real sure you dont over heat all those new parts, good luck and keep us posted with your results!

[jfmerk]

Update

Sounds like you have done a good rebuild. I am guessing the 20 to 25 min break in run, you had some way to cool the motor? Be real sure you dont over heat all those new parts, good luck and keep us posted with your results!

Oh yeah, two fans keepin' it cool!

Tonight I thought I'd check compression just to see if it would indicate seated piston rings.. or not. I followed the manual's directions and my Penske compression gauge read 160 - 165 psi. (#1-160, 2,3,&4-165) Does being a bit higher than max pose any issues? Or are those typical readings of a fresh rebuild and they settle down a bit after more break in?

[3Phase]

Does being a bit higher than max pose any issues? Or are those typical readings of a fresh rebuild and they settle down a bit after more break in?

It looks like you've done fine so far, Jf!

I don't want to seem paranoid or anything but did you check the new piston ring end gaps before you put the engine together? If the end gaps are too close together you'll have really good compression but when the engine gets hot and the rings expand they can bind and, eventually, break.


Assuming the ring end gaps are okay: Just ride it! Do the checks and tuning and don't worry about it until you drain the oil at 500 miles. The rings haven't really begun to seat yet and you have to run the engine under load -- acceleration and deceleration -- at least a couple of times to begin the initial seating so try not to run the engine too much until you can actually ride the bike

If you run the engine at idle or unloaded for too long it can glaze the cylinder walls and the rings will never seat correctly. Once that happens you have hone the cylinders again and start the break-in process over again. Not that I know anyone that's ever done anything like that but I've heard that it's really annoying!

[jfmerk]

It looks like you've done fine so far, Jf!

I don't want to seem paranoid or anything but did you check the new piston ring end gaps before you put the engine together? If the end gaps are too close together you'll have really good compression but when the engine gets hot and the rings expand they can bind and, eventually, break.


Assuming the ring end gaps are okay: Just ride it! Do the checks and tuning and don't worry about it until you drain the oil at 500 miles. The rings haven't really begun to seat yet and you have to run the engine under load -- acceleration and deceleration -- at least a couple of times to begin the initial seating so try not to run the engine too much until you can actually ride the bike

If you run the engine at idle or unloaded for too long it can glaze the cylinder walls and the rings will never seat correctly. Once that happens you have hone the cylinders again and start the break-in process over again. Not that I know anyone that's ever done anything like that but I've heard that it's really annoying!

Yep, end gaps were adjusted to spec so I'll be doing as you mentioned, get the rest of the bike together and get it out on the road! The really frustrating thing about getting her out on the road is that our city just refinished our streets with the old fresh tar covered with crushed rock! I'm not going to ride on that just yet... all those little tar covered rocks stuck to the bottom of my restored bike is not gonna happen!

Thanks!