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PostPosted: Fri Sep 29, 2017 7:30 pm 
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Joined: Thu Sep 29, 2016 4:32 am
Posts: 226
Location: Indianapolis, IN
Jetting and fuel needed always follow the power made by the engine at that throttle setting. If I modify an engine, be it a two stroke with porting, squish and chambers, or a four stroke with cams and porting and headers, I know how well I did by how many jet sizes and needle steps more it needed from stock. The only way you will need idle jetting that rich would be lost fuel out the filters, a piston port two stroke with too much inlet timing will have large standoff at low rpms, and lose the extra fuel into the wind and low pressure behind the cylinders. The fix for that is a longer inlet tract, trumpet etc., and is a nice power gain usually. We raced Can Am small block engines with Mckay injection and long trumpets, and it always amazed me how you would see the standoff above the trumpets, that far from the injectors.

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PostPosted: Sat Sep 30, 2017 2:58 am 

Joined: Sat Jun 11, 2011 11:11 pm
Posts: 398
Location: New Zealand
DGA wrote:
Jetting and fuel needed always follow the power made by the engine at that throttle setting. If I modify an engine, be it a two stroke with porting, squish and chambers, or a four stroke with cams and porting and headers, I know how well I did by how many jet sizes and needle steps more it needed from stock. The only way you will need idle jetting that rich would be lost fuel out the filters, a piston port two stroke with too much inlet timing will have large standoff at low rpms, and lose the extra fuel into the wind and low pressure behind the cylinders. The fix for that is a longer inlet tract, trumpet etc., and is a nice power gain usually. We raced Can Am small block engines with Mckay injection and long trumpets, and it always amazed me how you would see the standoff above the trumpets, that far from the injectors.

Thanks for that, i will look into it when i have time. It might be rich on pilots because plugs are dark when removed after idling for five minits but if i open the air screw even 1/8 of a turn it starts hunting and takes a few seconds to come back to idle like its lean. and its less zippy. It is what it is for now. pulls great everywhere.
Having trouble doing plug chops. I am getting no reading at all. ive done them before (other bike) on pump gas and its as clear as a bell. single run.
And i am doing a double full throttle run, away from my trailer, then back to my trailer. done 230, 250 and 260s plugs show nothing.
Performance is the same for all sizes so far!! so i am just going to have to keep putting bigger jets in till power drops.
going to have to order some 270s and 280s :roll: does nice big wheelies though. even 3rd lifts the front :D


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PostPosted: Sat Sep 30, 2017 6:06 am 
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Joined: Wed Jun 08, 2011 10:04 pm
Posts: 2188
Location: Just north of Toronto, Ontario
I tend to just listen for detonation when selecting the main jet, I do realize this method isn't for everyone though.
3rd gear with the front wheel dancing is a hoot eh! 8-)

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PostPosted: Sat Sep 30, 2017 2:22 pm 

Joined: Sat Jun 11, 2011 11:11 pm
Posts: 398
Location: New Zealand
Walms wrote:
I tend to just listen for detonation when selecting the main jet, I do realize this method isn't for everyone though.
3rd gear with the front wheel dancing is a hoot eh! 8-)

Im not sure i know what detonation sounds like. Would it be obvious?


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PostPosted: Sun Oct 01, 2017 12:41 am 
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Joined: Thu Sep 29, 2016 4:32 am
Posts: 226
Location: Indianapolis, IN
Mostly sounds like marbles ratting around in a tin can. So you can imagine what a sound like that, what might be going on inside your motor, to your pistons, and in short time, if the motor is working hard, the detonation will burn a hole through the crown of a piston. Too lean of a main jet and too much spark timing will do it, but just lean is enough by itself.

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1974 Kawasaki H2B 750, 1981 Yamaha XV750 Cafe, 1983 Kawasaki KZ1100 Spectre, 1986 Kawasaki KDX200, 2003 Honda XR100, 2004 SDG140.


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PostPosted: Sun Oct 01, 2017 2:53 am 

Joined: Sat Jun 11, 2011 11:11 pm
Posts: 398
Location: New Zealand
Well there was no deto with the 230s so im good to go racing with the 260s in 8-)


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PostPosted: Sun Oct 01, 2017 8:38 am 
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Joined: Tue Jun 07, 2011 6:37 am
Posts: 9809
Location: Rio Rancho, New Mexico
Another thing when racing. IF the competition isn't that tight, and you have power to spare on them, you can go rich and save the motor.

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http://kawatriple.com/aylor


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PostPosted: Thu Oct 19, 2017 2:55 am 

Joined: Sat Jun 11, 2011 11:11 pm
Posts: 398
Location: New Zealand
Just an update. Tried the 280s just to experiment, still pulled well on the pipe but definately not as good as the 260s. so i am happy to race it the way its jetted now. Its pretty close, except on the pilots, but who cares. 5 Barnett springs was a bit much i recon, so i pulled the springs from my road H1 (locally wound, stiffness about half way between stock and Barnett) and installed them into the race bike along with barnett kevlar plates.
Had one practice day, then one race day last weekend and the bike went very well. A few things cracked and bent, but nothing serious.
The clutch is much better.
Most importantly, it seems to handle quite good, very good. I didnt push it that hard but no wobbles, very compliant. I think its capable of much more corner speed. ten times better than my stock H1. I wouldnt dare of taking a stock H1 on the track.
Braking is not great (have a triumph conical front hub) But still way better than a stock disc setup. Didnt scrape the pipes and i had it near the edge of the tyre. So very happy with my work. Missed a few gears though. The gearbox is my biggest worry. Gearbox is the only thing i havent had appart. :roll:
The bike is now on its way to the North island for a big classic race meet. I will follow it next week on the plane with fixed bits and spares.
Hope it stays together. Been a bit of a mission getting it ready for this meeting. Then the big South island meeting is a month later.
If the gearbox or engine doesnt explode................


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PostPosted: Thu Oct 19, 2017 7:58 am 
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Joined: Wed Jun 08, 2011 11:34 pm
Posts: 8004
Location: North Central NC
Good luck Coops!

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If it surges, that's normal, upshift.


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PostPosted: Thu Oct 19, 2017 8:44 am 
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Joined: Tue Jun 07, 2011 6:37 am
Posts: 9809
Location: Rio Rancho, New Mexico
Go get em Coops! Show em what a triple can do! :thumbup:

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I can teach your triple how to "reed"........
http://kawatriple.com/aylor


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