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 Post subject: Re: TM34 Jetting
PostPosted: Sat Jun 24, 2017 3:49 pm 
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Joined: Thu Jun 23, 2011 2:26 pm
Posts: 1805
Location: Running Springs Ca
Hawaii-Mike wrote:
soflah2b wrote:
FBG street pipes. You might want to ask the others what their plugs look like. Try the O-6's you said came with them, you will see your plug chop get lighter, then you will know you are going in the right direction. Different needle profiles will get you slightly leaner but it also changes where you come onto the taper and increase's or decreases fuel as you open the throttle. I have all needle jets O-0 through P-2 and some larger. O-0 is where its best. Yes it is very frustrating, time consuming and costly. I know I've been there and done that.

Upon closer inspection the needle jets are Q-6, not O-6 (too bad)! I have to use a magnifying glass with reading glasses to read the markings on the needle jets.

Soflah if you want to sell some needle jets let me know. I'm thinking of trying O-2 since you're on clip #4 (maybe O-2 will put me in the center clip).

Ron, do you have jetting specs from your prior H2 builds?


Not for TM34's, just VM34's with or without UFO's


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 Post subject: Re: TM34 Jetting
PostPosted: Sat Jun 24, 2017 6:49 pm 
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Joined: Thu Jun 16, 2011 10:19 am
Posts: 191
Location: Wellington, Fl
Needle position won't make the difference. Lower the needle, slower to come on to the taper, then you need more pilot to come off from idle, then your too rich at low end. FYI I am going to VM38's. TM springs are to stiff and available TM jets won't get to the ideal set up for our old 2 strokes. Only close. I would be happy to discuss my endeavors if you like. PM me and I can give you my number. Just trying to save you the time, money and frustration I went through.


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 Post subject: Re: TM34 Jetting
PostPosted: Sat Jun 24, 2017 7:58 pm 

Joined: Tue Jul 24, 2012 6:06 pm
Posts: 1135
Location: Honolulu
soflah2b wrote:
Needle position won't make the difference. Lower the needle, slower to come on to the taper, then you need more pilot to come off from idle, then your too rich at low end. FYI I am going to VM38's. TM springs are to stiff and available TM jets won't get to the ideal set up for our old 2 strokes. Only close. I would be happy to discuss my endeavors if you like. PM me and I can give you my number. Just trying to save you the time, money and frustration I went through.

Soflah,

PM on the way. I'm in Hawaii, you're in Florida I think - approximately a 5 hour time difference. I'll try not to call too late.

Tried out the 6FP55 needles, no luck. Went from the clip #1 to clip #4. Bike won't get off the line. At least with the 6DH3's I can ride it, just very rich from around half throttle to full throttle.


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 Post subject: Re: TM34 Jetting
PostPosted: Sun Jun 25, 2017 12:34 am 
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Joined: Thu Sep 29, 2016 4:32 am
Posts: 615
Location: Indianapolis, IN
My 2 cents on jetting for different load conditions. Slide type carbs are not load sensing, unlike diaphragm carbs that the slide will lift accordingly to load and throttle position. So in that respect, a pure slide carb will only truly be jetted correctly for one load range. If you accelerate lightly a lot, then the needle position and cutaway will need to be set lean. If you ride hard as a general rule, the needle and cutaway will need to be set richer. If, however, you do both, there will HAVE to be compromises; jet for high load, hard acceleration, then if you sometimes ride slower, the low end and midrange will be rich. Sadly, you can't have it both ways. The main jet is often ok because to get to that point on the throttle opening, there is usually a similar load regardless, from higher wind drag etc. The idle mixture screw and jet should just make a nice start without too much choke needed, and a nice idle, and carry smoothly into the cutaway and needle. If you try to use it to cover for other shortcomings it really isn't correct, and there will be more compromises.

_________________
1974 Kawasaki H2B 750, 1981 Yamaha XV750 Cafe, 1986 Kawasaki KDX200, 2003 Honda XR100, 2004 SDG140. 2006 Ninja 500R Turbo intercooled fuel injected.


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PostPosted: Sat Jul 01, 2017 11:23 pm 

Joined: Tue Jul 24, 2012 6:06 pm
Posts: 1135
Location: Honolulu
I want to thank Chris (Soflah) for his help. Last weekend we talked about jetting, what worked for him etc. Chris' bike is ported and his jetting is very different from what other guys are running, though there are just a handful of TM34 jetting examples posted. I think it shows every bike is different due to porting, ignition timing, pipes, filters etc.

Here's where I'm at today.

40 pilots, air screw 1/2 turn out.
O-2 needle jet
6DH3 needle, top clip (leanest)
230 mains

I lean the jetting out very gradually, you know why.

Started with the needle in the center clip. As I dropped it the bike started running better and when I got to the leanest clip it came alive. The mains might be a little rich but I'll leave them for now. Probably going to order a 6DH2 needle, which is leaner than 6DH3. And I'll change the pilots to 42.5 or 45, depending on what I've got on hand.

Regarding the throttle springs, I cut 2 windings off each spring. The slides still snap shut properly and it's easier to remove the needles to make adjustments.

It's an interesting feeling opening the throttle up at speed, the big carbs allow the bike to pull harder compared to VM30's with UFO's. Pretty soon I'm going to try out the TNT pipes.


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 Post subject: Re: TM34 Jetting
PostPosted: Sun Jul 02, 2017 8:02 am 
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Joined: Thu Jun 16, 2011 10:19 am
Posts: 191
Location: Wellington, Fl
I bought slightly softer springs for mine. A little better but still stiff. Your right to leave the main jets for last. This is how I hooked up my oil lines.

Attachment:
20170702_100746.jpg


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 Post subject: Re: TM34 Jetting
PostPosted: Sat Jul 15, 2017 10:06 pm 

Joined: Tue Jul 24, 2012 6:06 pm
Posts: 1135
Location: Honolulu
Fine tuning (maybe not final tuning).

- 42.5 pilots air screw half a turn.
- O-0 needle jets.
- 6DH3 needles, 2nd clip from the top.
- 230 mains.

Also installed a set of TNT pipes. The bike runs great now! It goes a little back and forth between lean and rich when on the needles, I'm not sure if I'll get it tuned better than this. Might try raising the needles half a notch or switch to 6DH2 needles.

FYI, the pipes took a lot of work to mount. They aren't a bolt on. The stock H2 kicker scrapes the right side pipe when I'm starting it up. The solution for me was to install a KZ1000 kicker, it clears the pipe with a few mm to spare.


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