Anyone out there had good performance from fitting a 2.5 cut-away slide (3.0 being the standard) into their standard DT400 twin shock carb?

2.5 being richer. Interested to know the reason behind the possible change. Thanks.

There have been a few posts where members have recommended this slide change to help with the "surging". 

(I could be wrong but I think the first time I read about using a 2.5 on the 400 was from DEET on the old forum...  had to be more than 10 years ago now.)

The tall slide the DT400 used is not easy to find in a 2.5 though.  I think someone here said they used a new short slide with a homemade spacer on top?  Oh wait, Jammyyammy said he tried the spacer on top of a standard 2.5 slide that Pedalcrazy posted about doing.  Post #15 here:

yamaha-enduros.com/index.php/forums/74-7...date?start=10#149872

RT325, I'm not sure what the purpose of this question is since it came from someone who said a few months ago that they had tried the 2.5 and even (tentatively) recommended it to others?

 

Yes I posted several times on replacing the 3.0 with a 2.5 as the DT400C needs help not being so lean and surging. I bought mine from Summit Racing and yes it is not as tall so I cut an old slide to make up the difference and it rides on top of the 2.5 to keep the 2.5 from letting the needle come clear up out of the carb body sticking the bike on full throttle. The spacer is a must for that reason.

Pedalcrazy- apologies for my post being misleading about the slide and spacer idea. I'll try to re-word it.

Apart from me!, has anyone out there had good performance from fitting a 2.5 cut-away slide (3.0 being the standard) into their standard DT400 twin shock carb?
My fuel tank is at the fixers at the moment, so I’m not able to do any test runs, but was wanting to see how common this mod is (obviously not very common!), and have discussions (recommendations) about tuning from members who have performed the mod.

I changed my 3.0 to a 2.5 probably 4 years ago by now. I was in search of eliminating the dreaded surging and bucking. I recorded all my mods that summer but I eliminated about 90% of the surging. Here is how I ended up (from memory): Timing 2.9, 2.5 slide, main jet standard, pilot jet up several sizes, air screw 1 1/4 turns out, standard spark plug and gap, engine on 3rd oversize bore (fresh), all Yamaha parts including 6Volt magneto and coils. Premium non-ethanol gas. I’ve put about 1500 miles on it now since rebuild. Fun to ride now especially with a sleeper pipe by Meis. Hope this helps.

Edit…Important to keep the idle down as low as you can…1300-1400 if you can…