Topic: Who's running a Delkovic exhaust?

[Scott S]

 Curious about your set up with the Delkovic. Their website says no jetting is required. True?

 I picked up a used full system with the smaller straight-style muffler. I have a stock CB550 with a UNI filter in the stock air box. I will be running PD carbs. I though about going up on the mains from 90 to 95 and adjusting the mixture screws.

 What's everyone's experience with the Delkovic system?

[slikwilli420]

My brother has one on his '77 750K and he loves it. Easy install and quality piece. Typically, unless you push more are in (intake) you won't need to rejet. The exhaust only helps move out what the engine burns and if you arent sucking more air in you don't need more gas.

[Scott S]

 Does the '77 750 have the "lean" carbs, too? That's the only reason I'm thinking about going up on the mains.... the PD carbs.

[Bankerdanny]

I just put a Delkevic on my 750-F1, but haven't had a chance to ride it yet.

The PD carbs on the 550 are set up leaner than the prior carbs so I don't think that bumping the mains up 5 would be a problem, especially given that the 77 550F with the factory 4-1 and non-PD carbs ran a bigger main jet than what you are talking about here.

[lafindufondu]

I had the delkevic 4 into 1 on my 74' cb550 and on my 75' cb750, I didn't rejet and the bikes ran great.  I went with the small straight muffler on the second set I ordered.  The system installs easily and sounds great.  Can't beat the price.

[beemerbum]

I installed a Delkevic on my K7. I never touched the jets and the bike runs great. The entire Delkevic system weighs just a hair more than just one of the stock pipes. I did like the 4 into 4 look but my stock system was patched with beer cans and duct tape. This looks so much better and sounds great

[Stev-o]

Stock jetting in my Mikuni's!

[RustyF]

I have a Delkovic 4 into 1 on my 78 550.  Running stock air box & paper filter, I cleaned the carbs and re-jetted up 1 size on pilots and mains...the bike ran very rich with an inconsistent idle, then changed back to stock pilots, cleaned up the idle and slow-mid range but over 5000 was still rich...jetted back to stock mains and 2.5 turns out on the pilots and the bike runs great.  Hope this helps

[Scott S]

Hmm.... so the stock 90 mains on the PD carbs might be fine?

[slikwilli420]

Does the '77 750 have the "lean" carbs, too? That's the only reason I'm thinking about going up on the mains.... the PD carbs.

Yes, PD carbs, and he did not rejet or make any adjustments to the carbs.

[BenelliSEI]

Mine works great, “as is”!

[754]

 I put a Hooker 4 into 1 on my 750 in 1975..
 And K&N pods, except they were not called pods and had rubber ends.,.. the first ones..
Stock jets and it ran great, but my buddy was always just a bit quicker on his K3, with a Jardine.  He weighed about 75 lbs less than I.
 Everybody always talked about running bigger jets., so after running it about 4 months like that, I put 120,s in
Oh my Lord, it was a real difference, and now  I could beat my buddy..

And then a few days later, we had a bad mishap, he ran into me, me  turning, him closing up at 95 mph.. total both bikes, broke the cases on both of them..

 But back to the pipes.. what do you want... a pretty lighter pipe ? Or Performance ?
 To me it's a waste if it does not make more power. If it breathes better, it should handle  more jetting,
 I can't see a power increase without it.

 At any rate, always check your jetting with a pipe  or other major change..

[BomberMann650]

98's would be great 

[slikwilli420]

I put a Booker 4 into 1 on my 750 in 1975..
 And K&N pods, except they were not called pods and had rubber ends.,.. the first ones..
Stock jets and it ran great, but my buddy was always just a bit quicker on his K3, with a Jardine.  He weighed about 75 lbs less than I.
 Everybody always talked about running bigger jets., so after running it about 4 months like that, I put 120,s in
Oh my Lord, it was a real difference, and now  I could beat my buddy..

And then a few days later, we had a bad mishap, he ran into me, me  turning, him closing up at 95 mph.. total both bikes, broke the cases on both of them..

 But back to the pipes.. what do you want... a pretty lighter pipe ? Or Performance ?
 To me it's a waste if it does not make more power. If it breathes better, it should handle  more jetting,
 I can't see a power increase without it.

 At any rate, always check your jetting with a pipe  or other major change..

Frank, a pipe can only put out what gets put in, though more efficiently. If it is restricted to stock intake, I don't see why jetting would do anything.

[754]

 If a pipe is left restrictive  it can produce more power.
 Are you only running a 4 into 1 on Superbikes go save weight.
 Pipes either work or don't some good some bad..
I have one set of pipes  with smaller primaries that greatly changes the way the motor runs.

[Gene]

just bookmarking this thread. this is something I may be looking at in coming years. Not for the weight, not for the power, but for the stainless steel.

[754]

 Fwiw
Glencoe dragstrip Sturgis SD.. me on a 80 R 100 RT.

Make  baseline run. Then pull airfilter .. 3/10 difference in 1/8 mile.. that is about 1/2 second in the 1/4 mile
 A lot really for a 0 dollar change.
 Then I pulled  the mufflers, but I have no jets with me. BTW mufflers are pretty quiet, so i imagine that is a result of being restrictive.  I make a few more runs, the time  stays about the same, but its louder now, and the crowd likes it, you can hear it now and it sounds good. And getting the wheel up into second, and a bit into third, they like that stuff.. but it feels lean  like it needs more fuel.
 So I think, maybe a burnout is in order, after all we are at the drags.  And I do it,  knowing full well that I cannot  drop the clutch as it will head skyward..... it's all part of the show..

 But unfortunately that wounded my clutch... not can't ride it home wounded  but give it thru a few hard shifts and it slips.

 Can't help but think I would have picked up some time  with one or two sizes up on the mains..