running rough

[Bkelley1975]

i have a 1987 gl1200 interstate, it runs rough and backfires through the carbs when it's cold and then smooths out when it warms up. The most puzzling to me is it starts running rough again after about 30 or so miles down into the ride. i have also noticed that there is a pinging noise in the left side that has been seeming to get a little louder. i have changed sparkplugs and ran sea foam through it and that seemed to help a little but after running the treatment is when i noticed the noise. i am fairly new to this, so if anyone has any syggestions i would appreciate it. thanks.

 

[joedrum]

welcome bkelly75 to CGW ...it sounds like a gas problem im delivery to the motor causing things to run crazy try adding 8oz of atf to the next tank of gas ....but it sounds lie the carbs might need tobe rebuilt but sometimes the atf dose a lot in cleaning things up ...the 1200 carbs have rubber diaphams that might be leaking im not sure on 1200 carbs buti to will be doing some soon for one of my bikes is going to have 1200 motor installed and carbs....

:mrgreen:

 

[dan filipi]

Backfires through the carbs,
try to figure out which cylinder is backfiring. Sounds to me like a possible leaking intake valve or valve timing is wrong.

What is the compression on all 4? Knowing this will help.

It's possible also the way the 1200 valve adjusters work that an adjuster could be hanging up allowing too much clearance, this could explain the lifter noise your hearing.

 

[slabghost]

Substitute half qt of atf in the oil. Helps clean up oil passages and hydraulic lifters.

 

[AApple]

A backfire can also happen if the fuel mixture in one(or more) cylinder is too lean, which could point to a carb problem.
Check plugs, and compression. Check compression both hot AND cold, and compare.
If the noise you hear actually a "ping", or could it be a valve/rocker(metallic tick) noise?

 

[54Greybeard]

The symptoms you describe when it's cold sounds like normal cold, carbureted engine operation. Is the noise a ping or more like a tick? When it runs rough when it's warm, do you smell fuel?

 

[rcmatt007]

1200 carbs are not the simplest in the world, I have just had a set off for cleaning. and then there are the hydralic lifters. certainly a qt of MMO into the oil can help loosen them up. other than that, sounds like a carb problem.

I am curious to know what your plugs look like. often that is a good indicator of how a jug is running... too rich, too lean etc.

 

[Bkelley1975]

i guess i would consider it more like a "tick" then a ping. i was riding it yesterday and after a few minutes the noise went away??? i will be curious to see if it comes back when the engine is cold. thanks for all the input!

 

[rcmatt007]

tick makes me think lifter

ping makes me think pre-ignition

 

[54Greybeard]

A tick that goes away after warm up is most likely in the valve train, a lifter as previously mentioned and really nothing to worry about.

 

[detdrbuzzard]

1200 wings are cold blooded, have you synced the carbs. 1200's have hyd lifters try flushing with trans fluid or mmo before pulling out and adjusting a lifter

 

[Bkelley1975]

Thanks so much for all the info! I'm trying the idea's and get back to you all! Thanks again!