bogging down at speed

[Gregory]

I did ALL the things in BassCliffs tutorial. At first it was a little doggy like not running on all cylinders, but after I adjusted the points it fixed it....or so I thought.

I have been riding my 78 gs1000 around locally to the store and back for the past couple weeks and it seemed fine (strong running) until yesterday when I got out on the highway for a short trip. After I got up to highway speed for a while it started bogging down.

Although the tank was only half empty I stopped and refilled. It seemed to act a little better after that,for a while, but when I got down the road a ways the symptoms returned.

I am no mechanic so I am baffled. My first hunch is that the timing is retarded too much or something with the fuel vacuum not pulling fast enough. I will check the inline fuel filter first.

Oh and to top off my first shakedown cruise, the Tach stopped working. This 33 year old bike is gonna need some more attention.

My 78 has a V&H 4 in 1 with baffle. I have the standard airbox with a half assed home made top cover (but V&H recommends removing it anyway). My Jets are 105 mains and the others are 15's.

I have been doing all the work on this myself but am considering biting the bullet and taking it to a Dyno mechanic to fine tune it...

[tom203]

I'd lose the inline fuel filter and run petcock on prime spot as a simple test- sounds like fuel starvation.

[Gregory]

cool, good idea, that would be good news

[Maddevill]

You may want to pull the petcock and see if it is all crudded up. Sounds like it is slowly starving for fuel.

[chef1366]

Yup
Fuel starvation. Petcock and get a gravity fed lawn mower type fuel filter if you have to run one.

[Big T]

Bad points - did you replace the points and condensors?

[Gregory]

Bad points - did you replace the points and condensors?

Nope, points looked ok so I just regapped them. I rode it around town today and up to 50mph or so it runs like a champ.

I got the filter from a kawasaki shop near my house and they said it was the one they reccomend. I guess I can bypass it but still not sure about the cleanliness of the tank. I redid the petcock completely when I did all the other BassCliff recommendations.

Found out the Tach issue was that I hadnt screwed the cable back in tight enough and vibrated loose. That is about all the "wrenching" I'm up for today.

[Big T]

Nope, points looked ok so I just regapped them. I rode it around town today and up to 50mph or so it runs like a champ.

I got the filter from a kawasaki shop near my house and they said it was the one they reccomend. I guess I can bypass it but still not sure about the cleanliness of the tank. I redid the petcock completely when I did all the other BassCliff recommendations.

Found out the Tach issue was that I hadnt screwed the cable back in tight enough and vibrated loose. That is about all the "wrenching" I'm up for today.

Well, if your fuel flow is OK that's where you should look next

Condensors go bad with age

Is the problem relative to rpm or mph?

[Woodsy]

i'm thinking air leak on carb boots.. mine did a similar thing but only when at higher speeds.

[BassCliff]

Hi,

Also check to make sure the gas cap is venting properly and the little hole in the filler neck is clear.



Thank you for your indulgence,

BassCliff

[Gregory]

Thanks guy will check all this weekend and repost

[retcol]

Also check the o-rings behind the intake mainifolds. If they are cracked or broken, they can cause air leaks and a lean condition.

[Gregory]

Also check the o-rings behind the intake mainifolds. If they are cracked or broken, they can cause air leaks and a lean condition.

I replaced the ones on mine already, but maybe check to see if they are all tight

[Gregory]

OK here is the veridict. For those who guessed it a fuel issue YOU ARE CORRECT.

I went ahead and replaced the points and condensers, and put on a new in-line fuel filter. It was running like a scalded ape for about a week. I headed across town yesterday and it started running poor again and actually stopped altogether.

I was low on gas but not out. I ended up taking the tank off by the side of the road and looked at the filter which had rust sediment in it. I did not have an extra so I tapped it an blew out the sediment and it fired right back up and ran fine.

I bought a new filter and have a clean spare on on the bike for future clogs. I was really hoping not to have to POR the tank until I get around to repainting the outside of the tank as well.... it will depend on how fed up I get with the filters clogging.