high speed problems

[p_s]

I have an '85 GS550ES.
It used to get to 80 mph like a rocket and I would slide around on the seat a little bit. (Y'all with 1100s can laugh, but it felt very quick to me.) It was a little slower to 100, but pretty good.

Three weeks ago mistakes were made and I dropped it. It was not run since while I put:
-5 new double-sealed bearings front and back in a different "correct" pair of rims
-rebuilt front and back calipers with mostly new pots
-new stainless brake lines front and back
-cleaned all electrical connectors
-new Honda R/R
-new airbox to carb tubes
(I'm prepping it for a long trip.)

It starts far more quickly than it has in months, so that was good.

But now it is noticeably slower and I don't think it will hit 100. It took a long road to get to 95. 2nd takes longer to get to redline as well. Engine is completely stock.

I've had high rpm intermittent spark before, which felt like losing and gaining power very suddenly, and this doesn't feel like that. The front rim will spin maybe 2/3 of a turn--there is some drag. But there was about as much before my incident if not more and the bike was much faster. I noticed the right fork tube is sitting maybe 1 mm lower than the left--I will straighten that out, but I don't think that's the problem. After 5 miles of using only the rear brakes the front rotor are a bit warm but not hot--maybe 80 degrees F if I had to guess and it's 40 F out. The rear rim will spin about a turn. If I take the chain off, I think it spins several turns (although I can't remember if that was with the new rim and bearings or not--I will check again tonight).

If it were fuel would there be a small loss of power or would it feel like I've run out of gas? I'll try putting it on prime later and see if it makes a difference. Would sitting for 3 weeks do anything?

The carbs are fairly fresh, the valves adjusted a few hundred miles ago. I was going to do a sync this weekend, but I don't think that will help. The air filter has about 30 miles on it. New rubber in the intake everywhere.

???

 

[Big T]

The fresh airbox tubes may have sealed better, richening your mixture. (leaking air with the old ones.

Check your plugs and see if they're dark.

 

[earlfor]

If you installed an oiled foam type airfilter, putting too much oil on the foam will cause the problems you describe.

Earl

 

[p_s]

I put the old air filter back on and now it runs fast like it used to.
The old filter I believe is from Suzuki. The new one is an Emgo filter from Z1. They are both paper filters with foam around the lip. The Emgo has fewer folds in the paper filter and the foam is coarser. Also I think the foam on the original was oiled and I didn't oil the new filter. Is it possible the new filter is bad? I will try lightly oiling the foam and putting it in again and see what happens.

Everything in the engine is stock, and the problem was only at high RPMs WOT. Suggests the new filter is too restrictive? The plugs actually looked the same to me, light ashy gray, but I am not an expert. The CV carbs would compensate for less air, no?, so maybe that doesn't mean anything.

The old filter had some dust and such on the paper but wasn't that bad. I don't have an air compressor or I'd just reuse it. Maybe I'll take it to a friend who does and have the nasties blown out.

BTW, for the front brakes, after loosening and retightening the pinchbolts, axle nuts, and the lower nuts on the forks, the front wheel will spin 3-4 turns. I am very happy about that.