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new setup, cpi's and 28's mikunis with 4mill


extreem9

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Thats what I always thought too. Check out this link. Right under the pics it says what jets they use, under the 175 is says it takes a round jet. Wierd huh?

mukuni parts

 

 

No it doesn't, all the carb models listed on that are vm's and ym's. not tm's.

 

Sredish, although I admire your optimism on how well you think your single carb performs, I have put in the time already, and its just simply not the way to go on a dune bike, period. Especially with the pipes he is running. I also saw what you listed in your setup, and I am pretty sure your sacrificing power with running that big single with all the other parts you have bolted on. Only gains to be had with the proper sized single are a very small amount of power at the very beginning of the power range. You put an oversized carb on like that 38mm with stock cylinders, top end pipes, top end reeds, your holding back your power potential on the top still, and your hurting that low-mid gain you would intially be looking for with running the single setup because of the intake velocity your now achieving. I am one of the god fathers of that single carb setup, I ran one for a few years, I dyno tested different setups with it.I am telling you and all the other guys on here, it does not make sense to run it, its not worth it, steer clear of it. It is just simply a mediocre part thats a waste of money.

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I was waiting for your response..... :evil:

 

i hear you and I could be wrong on some levels but dynos don't show the whole truth, just part. on our hondas, when we first started setting up dune/drag setups.... we went from the stock POS to the FCR carbs... on a dyno, there weren't any gains and after modding them some still wasn't much if any gains, showed to be not worth the cost and effort on the dyno. but, on the sand/dirt/wherever, they were faster and the response was highly noticeable. that's just one example and there are many. dynos are great tools but you can only take them so far then you have to go with real world experiences. I've done the duals, the singles and all of them back and forth and the single works for me. i used to live and die by the dyno and i rarely get on anymore, just for some prelim tuning and that's it.

 

taking my real world experience, my single carbed stock bore/stroke bike was more than holding it's own against several higher modified banshees, and they all probably made more hp than mine but they were looking at my tail lights; that's good enough for me.

 

 

Edited by sredish
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wouldn't let me edit again:

 

this is purely civil and a sort of fun discussion and may not belong in this thread; i don't want to turn this into i've been doing this longer than you or not, because i'm sure we've both been running them forever and I agree with you on some level with the low/mid velocity issue but I also believe it can be tuned to over come with proper porting, jetting and pipes, which all have to do with the velocities and matching of the engine's dynamics.

 

if you're running CPIs, Shearers and so on building a true drag specific stretched bike, then i agree that duals are the way to go and the carb could hold your top end back but the top end limit is lower with a Toomey/PT High type of non-drag top end pipe and I don't believe it holds you back and my bike was revving very well with the 38mm.

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i hear you and I could be wrong on some levels but dynos don't show the whole truth, just part. on our hondas, when we first started setting up dune/drag setups.... we went from the stock POS to the FCR carbs... on a dyno, there weren't any gains and after modding them some still wasn't much if any gains, showed to be not worth the cost and effort on the dyno. but, on the sand/dirt/wherever, they were faster and the response was highly noticeable.

 

do you think that could be due to using a dyno-jet or similar, which being intertia dynos, can only measure a full throttle run, and not actually test engines under load over all rpms, like the way a dyno dynamics dyno can?

 

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do you think that could be due to using a dyno-jet or similar, which being intertia dynos, can only measure a full throttle run, and not actually test engines under load over all rpms, like the way a dyno dynamics dyno can?

 

yea, that's mostly what it is. you can only do so much with inertia dynos. i've spent many hours on them and they're great tools for certain things but no alternative for the real thing.

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I have put in the time already, and its just simply not the way to go on a dune bike, period. I ran one for a few years, I dyno tested different setups with it.

 

Like I said, I ran the setup, and I have tried everything I ran on the dyno on the bike riding it as well. Not worth it. Something as simple as jetting cause cause a slow bike to run a lot better than a supposed "fast bike". So I wouldn't base real world comparison tests against other bikes unless you know they are tuned correctly.

 

An example is this. I ride with a guy that I warned not to buy a stage IV trinity 350 bike. He bought it and brought it to the dunes. He literally has receipts from the guy he bought it from for $4500 in motor work and parts from trinity. I have around $2,000 into motor work and parts. He has ridiculous shit like 38mm pwk carbs on it, and those god damn stage IV pipes. He races me and beats my by 1/2 bike length in a drag race. He can't take in the holes I go in cause his setup is all wrong. After looking at his receipts I figure out it has a 4 mill long rod crank in it too. He feels real dumb after I almost beat it and brings it to me to tune. I change some stuff with the timing, gearing, tires, and work on a few other small problems it has. Next time out he beats my bike by 3 bike lengths. So moral of thew story is, anyone can put go fast parts on and spend a bunch of money. Once they learn how to tune the bike, then it becomes fast. When we test parts and setups we ride the bike in the holes, drag race it against another bike we have thats always tuned well, and we even go as far as running the stop watch on it or test it with the radar gun.

 

If I dont recommend something that I once stood behind, then its because I have thoroughly tested it and dont believe it warrants enough gain per the cost or performance it provides. In the case of the single carb setup with what your running for other parts, I definitely would recommend a set of mid sized duals. You are killing your top end with the single intake, and your carb is too big to provide the low rpm gains they are only known for providing. Besides, pwk's on single intakes are old news. Lectrons are the way to run them. They provide about 15% more low end power than a keihin or mikuni flatslide on the bottom end. They run about the same everywhere else. My bike hauls way more as with the twins on it, and it pulls hard on acceleration. I like it way more now than when I had the single carb. Maybe your bike runs good, but it probably doesn't run as good as it could if you matched up your parts and setup better.

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anyone can put go fast parts on and spend a bunch of money. Once they learn how to tune the bike, then it becomes fast.

 

we both agree on this one and i do intend on trying a set of duals at some point for the shit of it but i've been there before. as for lectrons, i like them a lot but they come on a little too quick for my taste, meaning 0 to WOT.

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OP.....i went race my bike this weekend and it was fine cept for 3/4-WOT. It seems the 158 mains are too rich. I ordered some leaner jets. But i will go do a plug chop very soon to confirm. I could be lean too but im just not sure. But it did the same thing with 162 mains and it seemed to get better with 160 then 158's. It's taking longer to bog. My jets should be in friday.

 

The pilot and needle clip position was easy as cake to adjust. This main always gives me trouble though but i will get it.

Edited by RagunCajun
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it does not make sense to run it, its not worth it, steer clear of it. It is just simply a mediocre part thats a waste of money.

 

 

agreed ,choking cfm down is no way to make power .if you want strong lowend response and torque there are better ways such as ignition timing ,compression, and correct porting

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id like to give props to sredish and snops for having a civilized conversation. they didnt bash each other, make fun of each other or anything bad. they exchanged information in a nice way and we are all alittle smarter for it. well, maybe not me. im still a savage neanderthal. i dont think that will ever change :)

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we both agree on this one and i do intend on trying a set of duals at some point for the shit of it but i've been there before. as for lectrons, i like them a lot but they come on a little too quick for my taste, meaning 0 to WOT.

 

Dude I love that angry baby pic, that is funny as hell. Makes me smile every time I see it! :biggrin:

Edited by extreem9
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when you're done playing with the duals, grab a single 38mm PWK... good duner setup.

 

Hey do you still have your old carb, it was a 35pwk right. I want to get a secong 35 pwk so i can see the difference between all 3 setups ( single 35, dual 28's, and dual 35's)

 

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