Too lean or too rich?

[dwaynemcfarlane]

what is your verdict?

This was after a long run. But last 20 min was through the city

 

[hovel]

Left to right, 1st plug too rich, second plug on the edge of too rich. Clean well or (preferably) replace and "Google" 'plug chop'.
Hint for the day: when installing plugs, always put a drop of oil (even off the dipstick) on the plug threads. You are installing steel threads into an al-u-minnium head, take care.

 

[dwaynemcfarlane]

Thx!!!

 

[bikefreakjon]

That is definitely rich, but where is it rich???

Idle, mid, main???

Reading plugs ant the best way to tune carbs.

 

[bikefreakjon]

Does it start easily? Does it need choke to start an a cool day? Does the idle go up or down as it warms up? Does it hesitate or big? Surge maybe at certain throttle openings? Are the tailpipes black with soot?

There are so many clues available without even pulling a plug.

 

[dwaynemcfarlane]

Thats the question. Any suggestions?

Sincerly D

 

[dwaynemcfarlane]

Does it start easily? Does it need choke to start an a cool day? Does the idle go up or down as it warms up? Does it hesitate or big? Surge maybe at certain throttle openings? Are the tailpipes black with soot?

There are so many clues available without even pulling a plug.

Yes it starts easy. I always start with choke. Idle goes up. Think i fixed the air problem. Explain hesitate or big (im a newbie ) i have to check the tailpipes asap.
Thx

 

[bikefreakjon]

Does it start easily? Does it need choke to start an a cool day? Does the idle go up or down as it warms up? Does it hesitate or big? Surge maybe at certain throttle openings? Are the tailpipes black with soot?

There are so many clues available without even pulling a plug.

 

[bikefreakjon]

Hesitate or bog. (Autocorrect)

Also double post! Lol

 

[bikefreakjon]

You say you fixed the air problem.

Did you have an obstruction in the air box?

 

[dwaynemcfarlane]

It hesitates but i think it might be a clutch problem. Concerning air and rise in rpm. I upgraded the pilot jets and bought some better straps. It worked is it maybe a mix screw problem?

 

[bikefreakjon]

So you replaced your pilot jets with a different size?

Set the mix screw when engine is warm for the highest idle. (This is a gross oversimplification)

Usually between 2 and 3 turns out.

If the idle goes way up, turn the idle screw down and keep adjusting the mix screw for higher idle. Also borrow or make a sync tool to equalize the vacuum.

 

[dwaynemcfarlane]

Yes im on 30s now. My bike is not stock.
Do you have a link explaining :

Set the mix screw when engine is warm for the highest idle. (This is a gross oversimplification)

Usually between 2 and 3 turns out.

If the idle goes way up, turn the idle screw down and keep adjusting the mix screw for higher idle.

Im gonna sync carbs next week

D

 

[bikefreakjon]

No link, sorry.

I've spent years just doing it and it has taken quite a while to develop a good ear for it.
There are just so many things to consider that it's difficult to write a quick post describing the best way to tune a carb.

 

[5twins]

To give you more and better advice, you need to give us more information. We need to know if your carbs are the stock '77 ones or some aftermarket carb, what mods you have (like exhaust and air filters), and if stock carbs, what jetting you've changed to.

If your carbs are stock, you may have over-jetted. It's easy to do on CV carbs because they're very forgiving. They'll still run, although maybe not very well, if the jetting is too big. Your #30 pilot jet for instance. The stock '77 size was a 25 so you're 2 sizes up on that. Normally folks go one size up (to a 27.5) so that 30 may be a bit much and contributing to your dark plugs.

 

[bikefreakjon]

And of course 5twins writes a quick post on carb tuning... Lol

 

[dwaynemcfarlane]

Ill try the 27,5 pilot jets again.
Those carbs are flying on and off these days .