79 GS425E lacking previous power

[Guest]

This is my first post, so let's hope I do it correctly.

My GS425E had the rectifier go last year and sent a power surge through the bike, cause my season to end early. This year, I have been able to get it running relatively well, with a little help.
What's been done:
Carbs have been cleaned, rectifier replaced, points adjusted, all of the lights that blew have been replaced as well.

Here is my problem: I can't get the bike to go over about 50mph. I don't have any backfiring, but even with the throttle wide open my bike seems to be lacking and will even lose speed significantly on any decent incline, never mind a hill.

I'm not sure where to go from here, I thought carbs would be the answer but that wasn't the case. If anyone can send some hard earned wisdom my way I would be grateful to be able to finally take a ride.

[Anthony]

Did your cleaning of the carbs consist of dipping them in carb cleaner overnight and also cleaning out all the jets and screws? You may also have a vacuum leak, as that can cause power issues. So can not properly adjusted idling.

[TheKevin]

I sprayed them with carb cleaner really well and blew out all jets with compressed air. A Vacuum issue was suggested to me, but I don't know where to start looking for one.

[MunkyMastr]

Any gurus have another option? I've checked the carbs, the only thing that seems potentially suspect is the diaphragms, but I didn't see and tears or holes in them. The bike just feel choked out. It Revs up high, but takes longer than I feel like it should, and the RPMs don't drop as quickly as they should. I'm going to adjust the valves with him when a new gasket comes in, but I was wondering if anyone had any other ideas?

[78550GS]

Pull the carbs back off and dip them correctly.

FULL teardown and replace ALL orings. including the orings on the intake pipes.

[tom203]

Munkymastr...

Are you and the original poster working as team on different bikes??? Or his bike?
One or both of you need to clean carbs properly,not hope or spray cleaner at them!
While you're at it, check petcock for correct operation, so you can eliminate it as problem.
Since bike had electrical surge,be suspicious of contact points/ condensers.

[TheKevin]

Update

I've, in my mind, eliminated any vacuum leaks around the carb area.

I did however discover that my left exhaust pipe was pushing out cold air while the right was pushing out warm.

What I've done now:
Took the left spark plug cap off bike runs as it does, took the right one off and she won't start at all.

Swapped the coils and now she doesn't seem to want to start.
Notes: the vacuum line between my carb and fuel selector(can't think of real name) blew off while trying to start with a small puff of smoke.
Also, right exhaust has slight smoke trails after a loud "puff" sound when trying to start. Left has none.

[tkent02]

You have found the problem. Running on only one cylinder will definitely make it not want to go very fast.

Now do all of the neglected maintenance.
Running on two cylinders is better than running on one, but running on two working perfectly is sooooo much better.

[tom203]

"Notes: the vacuum line between my carb and fuel selector(can't think of real name) blew off while trying to start with a small puff of smoke."

Vacuum line from carb to petcock blew off? Hmm,make sure you put valve clearance check on your to do list.

[TheKevin]

Well, it would appear that OEM coils run about $230.

I am thinking about getting these instead because of low funds:

http://www.jpcycles.com/product/380-506

Here is my new question, is 3.0 ohm correct for a GS425? I can't seem to find what the the stock coil ohm is anywhere.

A big thank you to all who posted with helpful ideas and advise. I feel a working motorcycle is in the near future!

[Griffin]

Why not get a used coil off ebay? They rarely fail, and you have a 99%+ chance of it being good, for cheap.

Like this one:

http://www.ebay.com/itm/1981-Suzuki-GS450T-GS-450-Twin-S398-ignition-coil-B-with-wire-/351103793668?pt=Motorcycles_Parts_Accessories&hash=item51bf6aba04&vxp=mtr

or even this one:

http://www.ebay.com/itm/B-SUZUKI-GS-500-E-1999-OEM-COIL-1-/111300782763?pt=Motorcycles_Parts_Accessories&hash=item19ea0b2aab&vxp=mtr

A gs500 coil will work fine on your bike, and they are extremely common. You might have to slightly alter the mounting, but it will work fine.

[hjfisk]

Before you go spending money on coils why don't you take the FREE advise and do the maintenance work that you inevitably will have to do to make the bike run properly. Spray cleaning carbs DON'T work you need to do a complete strip and dip with O-Rings, and then do the valve adjustment. There are so many of these old bikes parked for lack of maintenance it is unbelievable .

[Nessism]

You have found the problem. Running on only one cylinder will definitely make it not want to go very fast.

Now do all of the neglected maintenance.
Running on two cylinders is better than running on one, but running on two working perfectly is sooooo much better.

This^^^^

Newbie mistakes thread link in my signature.