Running Flat.

[Yoshiboy]

Hello All, Im Ian from Preston in the UK. Just finished my GS750 rebuild after 1yr 11months. Proud of what i have achieved but tinged a little by poor running at low revs. With the help from a friend my carbs have been totally rebuilt and sonically cleaned. New Air Filter, Plugs and NGK caps. New genuine points and condensers.

So with all that in mind it just isnt crisp under the throttle and feels like it's running on 3 cylinders (but isnt). I thought about buying some Dynatech coils mainly because i haven't replaced the originals.

Im open to any suggestion or checks i could do to eliviate my problem.

Thanks in anticipation of any help. Ian

[tkent02]

Easy as pie to fix. The solultion to your problem is sure to be found on this page:

http://members.dslextreme.com/users/bikecliff/

[Steve]

Over the last few weeks, I have been noticing more people bragging about carbs that were ultrasonically cleaned.
I have also noticed that some of them have some running issues.
One of those posters took his carbs off last week and dipped them, which resoved his running issues.

I am not saying that ultrasonic cleaning is no good, but evidently it's not a cure-all, especially if you don't use the right solution for the right amount of time.

I have been interested in getting an ultrasonic cleaner, but now I'm not so sure.

.

[Agemax]

Over the last few weeks, I have been noticing more people bragging about carbs that were ultrasonically cleaned.
I have also noticed that some of them have some running issues.
One of those posters took his carbs off last week and dipped them, which resoved his running issues.

I am not saying that ultrasonic cleaning is no good, but evidently it's not a cure-all, especially if you don't use the right solution for the right amount of time.

I have been interested in getting an ultrasonic cleaner, but now I'm not so sure.

.

that is the main problem encountered with U/S cleaning carbs. if the right solution is used, it works just as well,if not better than dipping

[posplayr]

you might also check the voltage to the coils ; you should be running over 12V of no more than 1V down from the battery.

[Yoshiboy]

Many thanks to all who read and posted. I would say that i bought this bike 2 years ago. When i rode it for the first time it was flat at low speed and although ive done everything i listed its still the same issue.

Id like to think that changing the coils would cure this issue as its the ONLY thing i haven't done.

The other issue i have and it may be a contributing factor is the carb rubber trumpets from the air box are not in the best of condition and the airbox cover seals are missing. Can this have an effect on running as when i ride the bike i can hear an induction roar from the carbs too.

Cleaning the carbs seemed the right thing to do as part of the rebuild. Its a service offered by many people in the uk.

[koolaid_kid]

Yes, that is an issue that you absolutely must fix for it to function properly. The intake system is a sealed system and any leaks will render it inoperable.

[chuck hahn]

Steve, Seems to me that the ultra sonic vibes that are easily slammed against the outer and most accessable surfaces does a great job.

But, as you say ( and its been MY contention all along), the vibes just cant penetrate to the very inner smallest passages. That's why they had success with the dip...it chemically comes into contact with the crud and effectively dissolves it.

Much like ripples on a pond right next to a second pond. The ripples hit the shore of pond 1 and they cant travel thru solid ground and keep going to pond 2. So it is with the ultra"sonic" waves...useless once it hits the outer areas of a carb body.

[Yoshiboy]

On the subject of sonially cleaning carbs. If your doing a full resto job the carb bodies look like new once done, apart from the obvious internals being spotless too.

Glad someone mentioned the airbox sealing! I will replace all the trumpets and box seals next.

Many thanks for the comments ill let you know what happens.

Ta Ian

[sparki]

it is also worth noting that the small "home use" ultrasonic cleaners work on a different "frequency" to the industrial "professional" ultrasonic cleaners. not sure who did yours or if they were done yourself.... but getting them proffessionally cleaned will likely resolve if they were originally done "at home"... they also need to be blown out with an air hose once finished rather than simply rinsing and "air drying". coils.... the old suzuki ones are pretty sturdy but can easily be check with a meter before splashing out £100 odd on a set of dyna coils... which you won't notice any performance gain on anyway on a stock motor. cheaper to get other replacements imo or a used set off ebay