Ducati Monster Forum

Moto Board => Tech => Topic started by: Charlie98 on October 21, 2019, 03:43:50 PM

Title: Need help with Ohlins DU737 set up on the 796
Post by: Charlie98 on October 21, 2019, 03:43:50 PM
Jeepers... I must be doing something wrong.

I swapped in a used Ohlins DU737 on the 796 and I'm having a heck of a time getting it settled down, or maybe it's showing me how limited the front forks are?  The 737 has spring preload and rebound damping adjustments only.  Yes, I've read the generic owners manual, which, like all owners manuals, didn't help much.

I installed it with the factory base settings, and a guesstimate on the preload.  I've already had to take some of the preload out, which surprises me, because I'm probably 210# at rider weight, this on the stock spring.  Even now it feels pretty hard on the rear, and now the front feels sketchy.  I stupidly didn't measure ride height before I took the Sachs shock off, so I don't know if it's altered the ride height or what.

Anyone have one of these on their Monster and help a guy out?  I'd love to know what you came up with on settings...
Title: Re: Need help with Ohlins DU737 set up on the 796
Post by: koko64 on October 22, 2019, 04:19:18 AM
Cant help, but looking to get one sometime so I'll be watching. [thumbsup]
Title: Re: Need help with Ohlins DU737 set up on the 796
Post by: Howie on October 22, 2019, 04:41:37 AM
Just a thought.  Did you check the sag on the front?  Is the problem  comfort, handling or both?
Title: Re: Need help with Ohlins DU737 set up on the 796
Post by: Charlie98 on October 22, 2019, 07:08:34 AM
Howie... both.  Previously, with the stock setup, it felt very, very good... far better than my CBR1000F ever felt.  I slid the Ohlins in, thinking it was the Silver Bullet... and handling went to poo.

I was out in the garage fiddling with it last night... I decided to crank the rebound damping all the way out, and then all the way back in.  Here's where the lightbulb went off... even though Ohlins says the dial is only rebound damping... it does seriously change the compression damping, too.  Cranked all the way in, and using the very technical and exact 'bounce your butt off the seat' test, it was hard as a rock; conversely, turned out, it was a wet noodle... this with no preload change.  So... I may have answered my own question.  Previously I was only adjusting one click at a time... with very little effect.  Now I see I will have to dial out some of the damping, and maybe put some preload back in.  I guess I was just afraid to make drastic changes...
Title: Re: Need help with Ohlins DU737 set up on the 796
Post by: Speeddog on October 22, 2019, 07:39:25 AM
Yes, on the Ohlins the damping adjuster on the shaft changes both compression and rebound.

Handy, but it would be helpful if they did *not* call it a rebound adjuster.

Set your sag first, make sure you're in the ballpark on the rear spring.
Backing the damping off to full soft can make it easier to set the sag.

The shaft damping adjuster will let you find the compromise point between too much compression damping and not enough rebound damping.
Title: Re: Need help with Ohlins DU737 set up on the 796
Post by: stopintime on October 22, 2019, 09:10:01 AM
Fork internals next  [thumbsup]

IME, harmony between front and rear is almost/about as important as the quality level of each.
Title: Re: Need help with Ohlins DU737 set up on the 796
Post by: Charlie98 on October 22, 2019, 02:30:15 PM
Quote from: stopintime on October 22, 2019, 09:10:01 AM
Fork internals next  [thumbsup]

IME, harmony between front and rear is almost/about as important as the quality level of each.

Adrianni now makes cartridge conversions for the 796 Monster!

Quote from: Speeddog on October 22, 2019, 07:39:25 AM
Yes, on the Ohlins the damping adjuster on the shaft changes both compression and rebound.

Handy, but it would be helpful if they did *not* call it a rebound adjuster.

Yes, I went back and actually looked at the instructions to make sure I didn't miss anything.  I assumed spring rate and preload was the 'compression damping' settings, in lieu of a separate adjustment... but this makes more sense, and I can see where the correct spring would make a difference.  I just automatically assumed I would have to replace the spring... as I understand it, the stock Ohlins spring is adequate for a 170# rider, as I mentioned, I am about 210#... which was why I was so surprised at the harshness, initially.
Title: Re: Need help with Ohlins DU737 set up on the 796
Post by: ducpainter on October 22, 2019, 03:05:53 PM
In my experience too stiff a spring is way less harsh than too much compression damping.

The first gen monsters were under sprung, and over damped and rode like a hardtail, except at the front.
Title: Re: Need help with Ohlins DU737 set up on the 796
Post by: Charlie98 on October 24, 2019, 07:41:36 AM
As a follow up... I rode to bowling last night and it was much more well behaved.  Not perfect, mind you... I'll still need to make some adjustments, but I'll need to take it up north to my little 60 mile circuit that I ride sometimes... lots of bumpy curves and stuff like that, that will show me whether or not I have it dialed in.

[Dolph]
Title: Re: Need help with Ohlins DU737 set up on the 796
Post by: Curmudgeon on October 25, 2019, 09:53:51 AM
Not sure what is going on but my DU737 was ordered from Ohlins and fitted before delivery. I'm 175# and my dealer/Ohlins certified tech, Donnie Unger weighs 185. He set it up for himself. Needed to back off the preload a hair and off one click from stock. Yes, the adjuster does both compression and rebound. Shock performance is WAY better than the stock Sachs. Not as plush as a $$$ Ohlins but easily 90% there. Best I can see, my spring is 01092-41 / 115 L2110. If yours is different, you might want to call Ohlins in NC.

Never had a problem with the stock fork but Donnie changed the oil to Red Line at the last service. It's firmer now. Action is still smooth or smoother, but I'm guessing he reduced the air gap. Works OK but was plusher before.
Title: Re: Need help with Ohlins DU737 set up on the 796
Post by: Charlie98 on October 26, 2019, 07:41:11 AM
Quote from: Curmudgeon on October 25, 2019, 09:53:51 AM
Not sure what is going on but my DU737 was ordered from Ohlins and fitted before delivery. I'm 175# and my dealer/Ohlins certified tech, Donnie Unger weighs 185. He set it up for himself. Needed to back off the preload a hair and off one click from stock. Yes, the adjuster does both compression and rebound. Shock performance is WAY better than the stock Sachs. Not as plush as a $$$ Ohlins but easily 90% there. Best I can see, my spring is 01092-41 / 115 L2110. If yours is different, you might want to call Ohlins in NC.

Never had a problem with the stock fork but Donnie changed the oil to Red Line at the last service. It's firmer now. Action is still smooth or smoother, but I'm guessing he reduced the air gap. Works OK but was plusher before.

I was hoping you'd stick your nose in here...   [thumbsup]

I bought this shock used... so, taking the chance I would ultimately have to replace the base spring.  I weigh 185#, but my rider weight is closer to 200-210#... but I guess as long as you are consistent with what you are weighing, it doesn't matter.

My fronts are OK, they are a little harsh on the bottom, but they never bottom out... so there is that.  I don't know if AMS changed the fork oil last service, I'd have to go look at the service ticket.
Title: Re: Need help with Ohlins DU737 set up on the 796
Post by: Curmudgeon on October 26, 2019, 09:05:51 AM
Quote from: Charlie98 on October 26, 2019, 07:41:11 AM
I bought this shock used... so, taking the chance I would ultimately have to replace the base spring.  I weigh 185#, but my rider weight is closer to 200-210#... but I guess as long as you are consistent with what you are weighing, it doesn't matter.

Weights seem close enough. Can you read the number on your spring? If it's the same as mine, you're good.

Check your sag. Ohlins set everything up on the firm side from experience. Wish mine were slightly softer but Donnie is an ex-racer, so he leans toward firm. Works just fine. The Sachs wasn't rigid but decidedly numb/dead. Set you damping somewhere in the middle and back off or up from there in baby steps until you've mached the preload. Just my $0.02.  ;)