Looking for tips - GS1100E Emulators and Sonic springs way too firm

[oldGSfan]

I serviced my forks which had Race Tech gold valve emulators with a thorough cleaning, installed new bushings and fork seals, and put in .95 kg/mm Sonic springs. I used the Race Tech calculator at my weight and riding style:

230 lb
Street
Intermediate/B Class
Standard Stiffness
Not Lowered​

I filled the air holes with J-B weld, sanded them down flush and checked them out, all good. I bounced the forks with all except the top clamps tight to address binding. I initially filled them too high with 15w, to 120mm below the top, fully compressed with springs out, and set preload per the Sonic instructions. Oops on the level, they were terrible, like a rock. After realizing my mistake I took 30cc out, to be at 150mm, and they are better, but are still way too stiff. Impact compliance is terrible, a bone-shaking experience. I get only about 1.5" of travel out of them.

I checked the damper tubes and saw they were drilled out but didn't measure. Whoever the original owner was, he was pretty into the good mods and I don't think they were guesswork - but don't know and should have checked. There is adjustability in the emulators, maybe I should look into that (?)

I can dial back the preload, at max it's about 16mm which is Sonic's recommendation. I took them down 2 notches, maybe set at about 5mm now. and am only finding marginal improvements with that and the oil level correction.

Has anyone set these up with a similar spring rate and can advise me? Even less oil? Is the air space acting as spring pressure, the emulator set wrong, or did I get springs that are too stiff? I'm not confident about reducing preload as the instructions are clear to have 16mm so I'd like to have it at spec.

Thanks for any info and for reading my long post. Worst case I'll drill out the JB weld and go with air suspension and stock springs, but that would stink. I had high hopes.

 

[slayer61]

Have you considered that the emulators need some adjustment? IIRC, the old set that I had allowed you to separate compression damping from rebound damping... but It's been decades.

What are you using for a preload spacer?? I've only ever used PVC pipe. You shouldn't be afraid to cut down PVC pipe. It can be had anywhere & it's dirt cheap.

 

[oldGSfan]

Have you considered that the emulators need some adjustment? IIRC, the old set that I had allowed you to separate compression damping from rebound damping... but It's been decades.

What are you using for a preload spacer?? I've only ever used PVC pipe. You shouldn't be afraid to cut down PVC pipe. It can be had anywhere & it's dirt cheap.

Thanks, yeah I read that there is an adjustment possible. I will look at how it is done and give that a shot. I think the impact issue is worse than the overall stiffness. They also may loosen up with new bushings breaking in, that happened on my Norton recently that I rebuilt. Sonic included PVC and I cut that to the right length for preload.

 

[oldGSfan]

Took the springs and emulators out, which is easy with a magnet, and reduced the emulator spring pressure, that did the trick.

 

[Rob S.]

Hooray! More Norton pics, please. Maybe a start up video. I'm interested in that process.

I recall reading that late '70's Triumphs electric starters were not meant to start the engine on their own, but to 'assist' in getting it started.

 

[salty_monk]

Yeah, reduce spring pressure or lighter weight oil... 15w is actually pretty heavy. The spring adjusts the "blow off" so high speed compression. The oil weight adjust low speed compression but it will also affect high speed. That's to say is you use lighter oil you may need more tension on the spring and vice versa.

 

[oldGSfan]

Yeah, reduce spring pressure or lighter weight oil... 15w is actually pretty heavy. The spring adjusts the "blow off" so high speed compression. The oil weight adjust low speed compression but it will also affect high speed. That's to say is you use lighter oil you may need more tension on the spring and vice versa.

Yeah makes sense, I tested it by blowing through it and could tell the difference. Set on soft side and I think I'll use 10W next change and firm it up. I kept having to buy different grades of oil for different bikes and 15W was what I had on hand.

 

[oldGSfan]

Hooray! More Norton pics, please. Maybe a start up video. I'm interested in that process.

I recall reading that late '70's Triumphs electric starters were not meant to start the engine on their own, but to 'assist' in getting it started.

Rob, the Norton process is 1 kick when it's been running no matter what, two when cold. First kick I enrichen the Mikuni, and it fires for a sec then quits. Then turn enrichener off, crack throttle a bit and boom, it starts. My son can do it on about 15 kicks, if I don't stop him and do myself. It is only 7.5:1 compression so just get it to set midway where you feel compression and heave. I have read that if you put it on compression stroke sweet spot then wait 10s the compression will leak and it will be easier, but I haven't tried.

On the electric start, yeah I've heard that but many say this is just because the starter was weak. The Brit bike community is aging out and many bad knees, so aftermarket starters are a popular mod. Thankfully I'm not quite there yet. I have been too busy moving and working on the Suzuki to ride the Norton much, I intend to do a better video but all I have is a Rylo, not so great software but the quality of the video is very good. Oh, a belt drive would be nice on my bike but they all fit Commando and my primary is Matchless, too narrow. The most satisfying thing I think I did was put a disc brake on the front. It works beautifully but the K70 Dunlops rubber compound is crappy and there's little grip available, I can chirp or lock it up way too easily.