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Jetting!


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Hi,

 

My name is Nick and I am new to this site but not new to riding. I recently had my bike built by Duncan racing and I have a few concerns regarding thier tuning. Well to begin I have just about every single mod to a 350 without stroking the motor. I have thier pyramid reed vavles, port and polish, welded crank, power head with 18cc domes, 34mm Kehins, intake manifold with boost bottle and T6 Pipes and k$n. Also, its 20 over so the displacement is a little bigger. From the get go, Lauren from Duncan didn't like the fact that I had T6 pipes and thats totally understandable. My bike is fast but I dont think its anything it should be. My friend who weighs 260 pounds on a bike with mild head, T6 pipes and k&n is giving me a run for my money. I only weigh 170 with all those mods and I cant seem to walk him. I knew our other friend who had a shee with pipes and he weighed about 115 pounds and he would stick with me the whole time up the hill. the funny thing is I asked Duncan and they said they were willing to let me try out their pipes to see how I like them. I think that they purposly set my bike up like that so that I would get their pipes. I am not accusing anyone but I bet if I let them tune my bike with thier pipes it would run like a bat out of hell. I am not that great with jetting but it seems a little rich. What size jets would you guys run?

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I ran the bike hard threw a few gears and when I check the plugs they seem to be a blackish color. I am riding at gordon Wells with temp ranging anywhere from 80-90. the current needle position is in the 3rd position(from the bottom) and they are cg-j needles. The jetting on the carbs is 165 main and 58. Is that about right? I dont think my bike is running at its best.

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Im don't know much about Kehins. There a some other fellow HQ'rs on here that run them and will pitch in. But you are saying that your plugs are black after the first few girls. So far you sound too rich, get somewhere where you can get into high 5th, or even 6th, then shut it off(no coasting, etc) Make sure they are new plugs and then check them after that run.

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A few things...

You sound like you're jetted too rich.

 

Duncan's banshee tuning skills don't impress me much...I'd find another builder.

They build a killer 4 stroke, though...

 

T6 pipes do not respond to very aggressive porting or port timings. I'd see about some T5 or Trinity pipes...

 

I'd be surprised if Duncan's shop doesn't have a dyno... I'd ask them to put it on an air/fuel meter with the T6's on it...and see how far it is off...correct it..and make a few pulls.

Then, let them put their pipe on...jet it...and make a few more pulls on the dyno...

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Yeah I am never taking my bike to them again. I for the most part can perform any mechanical work on my bike but I lack a little knowledge when it comes to jetting. I have not had the time to actually get on a dyno and make changes accordingly. You know your one of several people that I have heard the T6's dont compare to the older model T5. As far as I know, Duncan does not have a dyno but dont quote me on it. As a matter of fact I dont think they do. How about thier pyramids? Are they decent vavles? My porting is high on the exhaust side so I am loosing bottom end but it tends to make up for it on the top. I am seriously considering redoing my bike completly.

 

Should guys with pipes, k$n keep up with me? I know I wont beat them by 15 bikes but I was expecting my bike to run alot faster than that?

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A properly tuned banshee with good porting should be pulling on a piped only shee with air filters pretty good... There's something not right with your setup.

 

Don't get me wrong, T6's are great pipes...if you leave your bike fairly stock, or use very, very conservative porting and port timings....

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See thats the thing. I had a guy do some porting on the cylinders before and I think he had it set up for top end because he ported reall high on the exhaust side. Then when Duncan got a hold of it he had told me that whoever ported this engine before went to high on the exhaust side and he said he would do his best to fix it. I think its mostly set up for top end but even then, I dont hink the bike is running as good as it should be.

 

I dont know if I am allowed to post this but does anyone know anyone with some stock cylinders for cheap? That way I can just start all over!

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well you gave the answer yourself. you mean youre willing to just toss all this stuff because you cant jet? if your plugs are black then its way too rich, you need to be cardboard colored.. go down a few sizes on the main and see what happens. you are blaming a builder for this but you need to get it jetted right. take a minute and at least get your plugs looking like they should before you start talkin shit on a builder.

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How am I talking shit about him??? He told me himself that this is the best it would run unless I used thier pipes. I am trying to get other people's opinion as far as jetting goes. I think he set it up rich so it wouldn't be at its best. I think he wants me to buy his pipes so that he can get the thing runnin how it should be. Also, I am not giving up on it, I just wish I didnt make the mistake the first time around. You live and learn.

 

As far as taking it to a shop I will to have the porting and machining done but when it comes to reassembling I think I will do that myself. I just need a manuel and I am set!

Edited by onefastbanshee
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Am I not being clear or something?????? I specifically stated that I was lacking knowledge when it comes to jetting a bike properly. I simply asked for peoples opinion. What arent you understanding?? I paid to have them port and polish and freshin up the top end. Thier job is to jet it right so that its running its best. What arent you understanding?????????????????????????

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