OzVMX Forum
Marque Remarks => Suzuki => Topic started by: ninjamk on October 31, 2012, 01:59:58 pm
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Ok, so I am getting to the point where I am ready to start tuning my TS250. I am running a 73 TM250 top end and cdi with a TM34 carb and foam uni pod filter. Exhaust is a pro-form chamber with circle-f silencer. I am really paranoid about getting the jetting correct and not running lean. Is anyone running a similar configuration on their TM and if so what does your jetting look like. Also, what is the determining factor to switch to a leaner or richer needle rather than switching the emulsion tube or vice versa. Thanks
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Mikuni carburetor jetting.
Mikuni needle jet orifice diameter.
The chart below lists the inside diameter of the needle jet in millimetres, ie an N-6 is 2.580mm ID. This is true for every series of Mikuni needle jet, ie every N-6 is 2.580mm ID. Obviously the needle jet range is from N-0 as the leanest up to R-9 as the richest. Note that not every size is actually available in each and every series of needle jet -- this is just a size reference.
There are some other sizes and markings used, ie #224 series are numbered AA-0, BB-0 etc, and they are not shown here.
-0 -1 -2 -3 -4 -5 -6 -7 -8 -9
N 2.550 2.555 2.560 2.565 2.570 2.575 2.580 2.585 2.590 2.595
O 2.600 2.605 2.610 2.615 2.620 2.625 2.630 2.635 2.640 2.645
P 2.650 2.655 2.660 2.665 2.670 2.675 2.680 2.685 2.690 2.695
Q 2.700 2.705 2.710 2.715 2.720 2.725 2.730 2.735 2.740 2.745
R 2.750 2.755 2.760 2.765 2.770 2.775 2.780 2.785 2.790
http://cid-407d7ef0965d3991.skydrive.live.com/browse.aspx/Racing%20Model/RM%20Owners%20Manuals some carby tuning info in here
;D
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Thanks for the info. I have the Sudco Mikuni manual, but it wasnt really clear about that part of it. Both my TM34 and the stock VM32 have Q2 needle jets. Would you go up a size or two on the needle jet or just start with raising the needle a clip or two?
Thanks again
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#180 main and #30 pilot, it will be close as close and you can mess about from there.
apart from that call Ian williams tuning as he is the mukuni guru ( he is on the net)
he would still have my TM specs there as well.
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dont fork with the other stuff leave the Q's in there till you are really fine tuning if you have too.
Q2 will give you enough pipe to send it to the Main.
ONLy if its blubbering and you can fix it on the main then mess about coming down. but you wont need to go up unless your white lean and your out of supply to your main. Basically thats only the case if that nozzle has less internal diameter than the main your supplying and your Q will certainly not leave you short.
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Are you still running the slinger and oil pump ???? or have you done the case mod and removed the slinger.
I'm running a Circle F pipe and running a NEW 34mm carb with Std needle and have played with the jets along clip setting to suit my motor of which has had the oil pump removed.
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I am running the TM oil pump, not sure if it was any different than the TS but all the charts in the manuals made it look like it pumps a slightly larger volume.
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#180 main and #30 pilot, it will be close as close and you can mess about from there.
apart from that call Ian williams tuning as he is the mukuni guru ( he is on the net)
he would still have my TM specs there as well.
So I just checked the TM manual and apparently stock, the TM has a 260 main jet. I am going to assume that you meant to go with a 280?
Thanks
Oh, and I just got the pipe and everything fitted, here's some pics:
(http://i18.photobucket.com/albums/b111/mitchjagger/WP_000379.jpg)
(http://i18.photobucket.com/albums/b111/mitchjagger/WP_000380.jpg)
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nah im prity sure it was a #180 in there it was a 75 model TM 250 with a 34mm Round slide Mikuni carb. any more jet and it loaded up.
Just so you know also you cant run a flat slide in pre 75, before you get too carried away with jetting and stuff.
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are you talking round or hex jets? Also, I do not plan on competing on this bike, its just for fun.
My manual is showing stock TM250
Pre 74:
Main: 260
Pilot: 20
1974-1975
Main: 230
Pilot 40
So I am assuming that with the bigger carb and aftermarket pipe I need to be bigger than 20 and 260.
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Nice pipe champ ;D
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From the Suzuki parts catalogue..
TM250 hex main jet
72-73 .. # 230
74 .. # 200
75 .. # 210
pilot jet
72-73 .. # 40
74-75 .. # 35
My TM250 runs #35 pilot & # 190 main, anything big like # 260 & it runs like the choke on.
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By the looks you have a flat slide ???
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By the looks you have a flat slide ???
Yes I do, as I said in the first post. I am starting to get confused, I can accept that the bike runs best with a 180~190 main jet, but why are all the jet specs in the mid 200s?
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As we are all quoting figures from round slides....and your Tm manual would be refering to round slide also.
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Right, I understand that. I am just looking for a good place to start if someone is running something similar. I assume that I will need to be a few sizes richer than stock. Otherwise I will start way rich and work my way down.
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My manual is showing stock TM250
Pre 74:
Main: 260
Pilot: 20
1974-1975
Main: 230
Pilot 40
So I am assuming that with the bigger carb and aftermarket pipe I need to be bigger than 20 and 260.
Mate ;D im just telling you what i ran on a TM 250 1974/75 model and it worked and won more than a few titles and that's flat pinned. if as you say your just putting around for fun, you wont be lean unless you dont plan on changing gears. a quick look at the pipe tells me its set up for low revs, so it wont rev out anyway.
Forget what the Japanese book from 35yrs ago says your not in Japan and your not i assume 45 kg.
If you put a standard MUk 32-34mm carby on there which is what you will need to do to make the bike run properly and be legal then thats where i would start. Once you have done your first plug chop then you can take it from there. it will reveal all. it will take you 10 mins to find all this out.
2 of us are now telling you what the jetting is and its under #200. NO offence but Make it simple on yourself and just follow the advice, we are trying to help you. ;)
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Thanks,
I do appreciate the help. Just curious, how can you tell the pipe is set up for low revs? I have a basic understanding of how expansion chambers work but dont really know enough to tell what it is set up for. Also what did you mean by "so it wont read out anyway."
Thanks and sorry if these are stupid questions. ;D
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Think freaky is saying .... "Rev Out "
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yep rev out. stupid ipad shit. Im going back to the PC to compose emails or wording responses in forums least it my spelling that sux then and not being changed to other words entirely.
Yer its a long pipe in many sections specially that front cone and the tail, so it would be more a low down reving pipe. althogh the last cone is quite fat and visually short but because of the turn it would have a bit of volume in there.
you find the light switches are generally compressed fronts. NO big deal be good for what your doing as you say 'put puting' about and you WONT have to ring its nuts out just to get the clutch to take off.
But if its a bit soft you can easily cut an inch or so out the straight section with the springs either side and see if it brings the total tuned length into spec that suits that hybrid motor. because you working with so many strapped on parts its going to be a work in progress till you find how it all works best together.
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Well, I must say, you guys know your TMs. I just put in a 30 pilot and a 180 main. The needle still needs adjustment or a switch out because the mid range is way too rich, but once it gets on the main the thing takes off. I think the 30 pilot is a little lean, and 40 was too rich so I am going to pick up a 35 and see how that is. I am used to the riding the bike in stock TS configuration with slightly low compression, I was not expecting that big of kick when it took off ;D
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easy to ask, but some times you gotta have some faith and listen to the answers :)
drop the needle one and see how it goes, it might flatten the middle out for you.
good luck, its all sailing from here.......