The Mikuni's coming off, which Dellorto?

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Bufficus
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Mon May 18, 2009 1:59 pm

Having been unable to jet the Mikuni on my tuned TS1 satisfactorily I am toying with putting a Dellorto on.

I am unable to achieve clean jetting with the Mikuni at 1/4 throttle. It's too rich even with a 58 needle on the top clip.

I have even tried modifying a number 6 slide, but this has caused problems elsewhere in the range.

So, I'm thinking either a 34mm VHSB or a 30mm VHSH.

Any recommendations bearing in mind this particular engine likes it lean?

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mickeyb
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Mon May 18, 2009 2:22 pm

Never had any problem with mine....i took a delly off for a Mikuni,cudnt wait to get it off to be honest,luv my mikuni TMX 35 to bits!

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drunkmunkey6969
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Mon May 18, 2009 2:45 pm

Bufficus wrote:Having been unable to jet the Mikuni on my tuned TS1 satisfactorily
Just out of interest, what permiatations of jets/needles/clips have you tried, and what results/problems did you get?

(Post full engine spec also)

Bufficus
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Mon May 18, 2009 3:42 pm

drunkmunkey6969 wrote: Just out of interest, what permiatations of jets/needles/clips have you tried, and what results/problems did you get?
(Post full engine spec also)
Spec is:-
TS1 230
60mm Alpha
MB head
MB Racetour piston Wiseco rings
Exhaust widened to 70% of bore and raised 1mm
Boost opened out to 25mm
Transfer feeds opened and flowed to casing.
Exhaust 190
Transfers 135
V-Force reeds and MB inlet
Indian ignition, Augusto 7000 and lightened flywheel.
JL4
LI 150 box 16x47

I've tried various pilot and needle combos from 15 pilot upwards to 25, 57 and 58 needles.
I've tried it with a modified a No.6 slide to allow more air flow, which helped at 1/4 throttle but made it too even with a lean below.

The best compromise I have found is with a 58 needle top clip and 17.5 pilot, but it is too woolly for me at 1/4 throttle.

Good plug colour at this setting.

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corrado
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Tue May 19, 2009 2:36 am

What's 1/4 throttle Simon? :mrgreen:

Bufficus
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Tue May 19, 2009 9:49 am

corrado wrote:What's 1/4 throttle Simon? :mrgreen:
Ah, you racers are all the same. Point and squirt merchants. ;)

I/4 throttle is 65 mph cruising :)

Don't get me wrong I love the Mikuni. I have one on my RB which is a dream. And the TS1 used to run great with one as well when it was set up for touring with a Devtour and more modest port timing. But I just can't get it nice with the JL4.

Anyway I've picked up a VHSB for £72. All I need now is a fairly lean starting point for the jetting.

38 pilot, K21, DQ266 Is this anywhere near? I don't have much experience of these carbs :?

I understand I need a 350 float valve and to remove the filter in the carb.

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RinB
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Tue May 19, 2009 10:30 am

Bufficus wrote:
corrado wrote:What's 1/4 throttle Simon? :mrgreen:
Ah, you racers are all the same. Point and squirt merchants. ;)

I/4 throttle is 65 mph cruising :)

Don't get me wrong I love the Mikuni. I have one on my RB which is a dream. And the TS1 used to run great with one as well when it was set up for touring with a Devtour and more modest port timing. But I just can't get it nice with the JL4.

Anyway I've picked up a VHSB for £72. All I need now is a fairly lean starting point for the jetting.

38 pilot, K21, DQ266 Is this anywhere near? I don't have much experience of these carbs :?

I understand I need a 350 float valve and to remove the filter in the carb.
Good start point m8

may need to take some off slide to get progression right at bottom end. (50)

m8 of mine just done the same took Mikuni off as couldnt get bottom end tickover etc
same sort of symtoms as yours simular port timings.

I set up a Deli for him he put it on and straight away, instant bottom end 1/4 throttle
If its made of Metal Fettle it !!

Bufficus
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Tue May 19, 2009 11:04 am

I was hoping you'd come along. Thanks Smiffy.

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RinB
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Tue May 19, 2009 1:06 pm

Bufficus wrote:I was hoping you'd come along. Thanks Smiffy.
No Probs m8

Intresting though the problem area is same as m8 with the same set up
Something to ponder on :roll:
If its made of Metal Fettle it !!

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jason frost
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Tue May 19, 2009 2:54 pm

Had the samething last year, took the cable choke off and put the pull one on and it was fine so fitted a better spring in the cable choke and all was fine.

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