Seca650 No spark

It's very possible that my incompetence is the culprit. I actually got the new shim and put it in . A 285 shim should have brought it down to .11mm, however, I couldn't even get a 10mm feeler gauge in there. So, I put back the 280 shim and it measured at .12mm which falls into spec. Why it initially measured at .16mm is beyond me. Nevertheless, I'm a happy man and the bike sounds AWESOME! thanks for your help.

 

could have been some oil under the shim

 

Do you stack feeler gauges to get the number? I have yet to find a set of metric gauges that doesn't require stacking to get some of the numbers. Therefore, I prefer to just use the SAE gauges that are easily obtained with the .001 increments.

 

I stack if needed, but I also wipe down each blade before stacking so there’s no false reading from dirt between the blades

 

Yes, I do stack the gauges. I try to wipe them down every time but maybe I missed something.

 

I'm working on replacing the fork seals. While I'm at it I thought I'd take a few measurements. According to the manual the spring length is suppose to be 23.86 inches. When I measured my springs they came out to just over 21 inches. Does this mean I need new springs? Would a heavier weight fork oil make up the difference in any way? Could I throw a spacer in there? I think I've seen them done with pvc pipe before.

 

I may be wrong about the length. According to Chacal's catalogue the springs are suppose to be 540.5mm which comes out to just over 21inches like mine so I guess I'm good and the manual is wrong?

 

21.28" straight from my 650 Seca manual

 

540.5mm 21.28 inches from manual 650 seca.

if it is to soft you can go up in oil wt.
or buy new springs

 

yes but only if you know whats in there to start with.

we have a member in recent post who is removing the added pipe because he feels the springs are to stiff. find thread and ask him how long his are

yes you can put a spacer in there.

 

It's interesting when we pick up these old bikes what kind of history it may have had before you bought it. The spring length that I mentioned in the above post were actually the springs of the forks that I purchased, NOT the ones that were currently on my bike. After taking apart MY forks (which I've done once before) to install new fork seals I measured the springs and they were barely 19 inches long!!! Why would someone put the wrong size springs in thier forks! I should've known something was off the first time I took them apart when I saw a pvc pipe as a spacer in there. I'll never learn. This explains why the handling was so poor on my Seca 650! Everyone raved about the handling and I just assumed this was good handling for 1982. It never occured to me that I had the wrong size springs in my forks. I obviously changed them and whoa! It's a whole new bike! I can lean easier in the corners. Oh man! I'm a happy guy. So all is good in my world. Thanks everyone. One more job before I start detailing the bike...new fuse box.

FYI, pvc spacers do NOT work.

 

Yes they do - they "space" don't they? They didn't work in your application, who knows why - what was the rate of this rogue spring? Exactly, who knows. Suspension design is a complicated subject, it ties in machine weight, rake, rider weight, damping oil viscosity, spring rate (as you've found), and damper technology.
This last one is a bit of a misnomer as applied to these ancient designs - it's a wonder they work at all considering what's inside them. So it should come as no surprise that changing one major item could upset this delicate ballance.

 

I just installed RaceTech springs in my Turbo (FZ600 forks) and they were considerably shorter than the OEM springs, necessitating a spacer.
Stiffer springs are a huge upgrade on these old forks. Don't throw out those springs, they are probably Progressive Suspension or RaceTech.

 

I wish I took a picture to compare the two different springs. All I can say is that the bike rides way better since changing back to the original springs. It also stopped tramlining which was a HUGE problem riding on the freeway. Every time I would hit a groove in the road while changing lanes I felt like a quick Hail Mary was in order. The bike would jostle all around like it got tank slapped. I also put 20w fork oil in there and the manual asks for 10w. It's what I happen to have lying around. Anyway, I have an extra pair of Seca 650 forks if anybody wants them.

 

the stiffer springs will certainly give you a more sporting ride, but as you say they will track road imperfections for sure.
Too often these old bikes with the original springs use up half their suspension travel just pulling them off the centre stand.
Personally I like going with the stiffer spring and 10W oil.

 

Because I had leaky fork seals for the past 9 months. Fork oil saturated my brake pads. Do I need new pads now? Is there a way I can salvage the pads I currently have on the bike?

 

Get new ones

 

no get new pads. oil does not work well with brake pads

 

Noted. thanks.

 

Never a dull moment on my Seca 650. My carbs are virgin carburetors. The welch plugs are still in them. Since I got the bike it's always been just slightly lean but not really a big deal. I decided to get the plugs out of there and turn the screws just a hair to get a little richer mixture. I have only done carbs 1 and 2 so far. The first carb came out to a little over 1 1/2 turns. Carb 2 was <1/2 a turn, I kid you not. Factory spec! 1/2 a turn. At first I was going to turn the screws out but I noticed there was a little dirt on the needle of the mixture screw so I'm thinking I should stay at spec and just clean everything up but I'm curious about Carb 2. Should I leave that at spec? only 1/2 a turn out?