Author Topic: Changing back to 4 into 4 from 4 into 1  (Read 651 times)

Offline AndyH

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Changing back to 4 into 4 from 4 into 1
« on: October 15, 2017, 11:25:58 AM »
I'm pondering whether I should sell my left kidney and invest in a set of 4 into 4 exhausts for my "almost" stock resto.

The bike currently has a 4 into 1 (I think it's a Delkevic) and after refurbing the carbs to stock (#40 slow, #100 main, jet needle clip position #3, IMS 1.5 turns out) the motor is still a little "rough" on idle and up to around 3k RPM with no load, a bit "unsmooth".  (Struggling to describe here).

Out on the road the bike pulls nicely over a large rev range (2000rpm up) but still sounds a little bit rough at idle.

I guess my question is: what are the tuning differences between 4 into 1 as compared to "stock" i.e. 4 into 4 which is basically what I've set everything to?  Do I need to do anything?

Cheers
Andy

« Last Edit: October 16, 2017, 07:16:08 AM by AndyH »
Andy

1971 CB750K1
1972 CB500 Four K1 (SOLD)
1978 Suzuki GS750E
Previously....
1967 Honda Sports 90
1971 Yamaha CT2 175
1973 Yamaha RD250
1975 Kawasaki KX125
1979 Yamaha XT250T
BMW R65
BMW R80
BMW R100LT

Offline Seabeowner

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Re: Changing back to 4 into 4 from 4 into 1
« Reply #1 on: October 15, 2017, 01:07:15 PM »
This year I have changed my Motad 4/1 system for a set of DS 4/4 exhausts. The decision was made almost entirely on the fact that it returned the bike to its original look and the exhausts are as pointed out elsewhere great quality and brilliant chrome (hope they last). I already had the brackets and the connecting pieces but still a big expense. And I bought them last year before they went up here.
I haven't noticed any change in performance and haven't changed the jetting. I think the sound is a bit better and the looks far better, but that's it.
Phil
1971  CB500K0  Candy Jade Green or Candy Gold
1973  CB500K1  Candy Ruby Red
1975  CB550F1   Shiny Orange
1978  CB550K     Excel Black

Offline hairygit

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Re: Changing back to 4 into 4 from 4 into 1
« Reply #2 on: October 15, 2017, 01:24:48 PM »
One of Motads main selling points was "No re jetting required" along with easy oil filter access and centre stand retention. Don't know whether Delkevics  needed rejetting or not, if they do, and you're running std jetting, that could be part of your running issues.

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Offline Johnwebley

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Re: Changing back to 4 into 4 from 4 into 1
« Reply #3 on: October 15, 2017, 03:06:48 PM »
This year I have changed my Motad 4/1 system for a set of DS 4/4 exhausts. The decision was made almost entirely on the fact that it returned the bike to its original look and the exhausts are as pointed out elsewhere great quality and brilliant chrome (hope they last). I already had the brackets and the connecting pieces but still a big expense. And I bought them last year before they went up here.
I haven't noticed any change in performance and haven't changed the jetting. I think the sound is a bit better and the looks far better, but that's it.

  my set of 4-4 pipes are about 26 yr old,a little surface exterior corrosion 9,treated with zinc paint)

  To help them last,NO short journeys ,ALWAYS ride to get them HOT !,

 and they will last ages !!
lifelong motorcycle rider,and fan

Offline deltarider

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Re: Changing back to 4 into 4 from 4 into 1
« Reply #4 on: October 17, 2017, 07:32:07 AM »
Quote
To help them last,NO short journeys ,ALWAYS ride to get them HOT !,

 and they will last ages !!
+1 My first set lasted some 75.000 kms. My second set  has now done 60.000 kms and although in there something maybe loose (which doen't affect performance btw), the outside is still as new.

 

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