dynojet slide drilling
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Squid
Joined: Oct 2007
Posts: 45
From: Newcastle, Australia
dynojet slide drilling
Hi guys,
In regards to drilling the slides for dynojet needles and springs. Do I drill the slide itself only or the piece supporting the top of the needle aswell. Effectively this will allow air in the spring area to equalize with the air stream through the carb body and allow the slides to rise faster(which is the whole point of it). I have only drilled the slide and I am guessing that I have to drill right through, just checking first!!!
In regards to drilling the slides for dynojet needles and springs. Do I drill the slide itself only or the piece supporting the top of the needle aswell. Effectively this will allow air in the spring area to equalize with the air stream through the carb body and allow the slides to rise faster(which is the whole point of it). I have only drilled the slide and I am guessing that I have to drill right through, just checking first!!!
Senior Member
SuperBike
Joined: Aug 2004
Posts: 1,806
From: Atlanta, GA
Did anyone notice much, if any, difference after drilling? I didn't notice much of anything.
The shorter Dynojet springs are a WHOLE BUNCH easier to put back in than the stockers. That's what I noticed.
The shorter Dynojet springs are a WHOLE BUNCH easier to put back in than the stockers. That's what I noticed.
Senior Member
Superstock
Joined: Jun 2006
Posts: 358
the person i got my bike from did a partial DJ kit and messed some stuff up while doing it, but didnt touch the drilling of the slides. i drilled my slides and added a long front intake runner and noticed better throttle response, but how much was from each mod i cant say. but then anything we can do to get thouse huge pieces of crap honda called carbs to respond better is worth the effort.
Thread Starter
Member
Squid
Joined: Oct 2007
Posts: 45
From: Newcastle, Australia
Thanks for the response. I will drill my slides tonight. The main reason why it needs to be done is the slides need to rise fast with the dynojet needles. The first part of the needle is quite lean and raising the needle is the only way to compensate for the lean part throttle surge that is common. I'd imagine by drilling the slide it allows air to equalize through both chambers so effectively it is working more like a flat slide by lifting so much quicker, and will allow the needles to get into a richer section of the needle of part throttle response.
I put 48 pilots in last night, feels great in part throttle but idles rough when hot. I will go back to the 45S pilots and drill them tonight. See the difference then.
cheers,
hymey
I put 48 pilots in last night, feels great in part throttle but idles rough when hot. I will go back to the 45S pilots and drill them tonight. See the difference then.
cheers,
hymey
Thread Starter
Member
Squid
Joined: Oct 2007
Posts: 45
From: Newcastle, Australia
I will try a set of them. I am actually going back to the stock needles. I have tried all different mainjets with the dynojet needles aswell as various needle heights and I have perservered with them for the past 12 months.
I dont read plugs I have a wideband afr meter and the bike has been pig rich in the topend. Going leaner creates low speed fueling.
I have spoken to Bill Finnegan from HPower in Australia. Bill is a VTR guru. He owned a VTR with 152 hp. He believes the best way to tune them is to block the air bleeds to the emulsion tubes. Then fit smaller mains, then it is like a conventional cv carb. And produces better results, easier to jet, but with only pipes and filter, stock needles combined with dyno jet springs produces better results.
He uses 45 pilots, 20thou shimmed needles, 178, 180 mains as a starting point. Initially when i had stock needles the bike was a little lean with the 20thou shim so I will go upto 40thou shim under the needls. Bill said they have no shims stock but i have read places they have a shim stock...mine did as the reason i am running an extra 20thou. I am starting at 175 178 mains and checking the topend afrs, if a little lean i will go up 1 size, if a little rich will keep them stock.
I dont read plugs I have a wideband afr meter and the bike has been pig rich in the topend. Going leaner creates low speed fueling.
I have spoken to Bill Finnegan from HPower in Australia. Bill is a VTR guru. He owned a VTR with 152 hp. He believes the best way to tune them is to block the air bleeds to the emulsion tubes. Then fit smaller mains, then it is like a conventional cv carb. And produces better results, easier to jet, but with only pipes and filter, stock needles combined with dyno jet springs produces better results.
He uses 45 pilots, 20thou shimmed needles, 178, 180 mains as a starting point. Initially when i had stock needles the bike was a little lean with the 20thou shim so I will go upto 40thou shim under the needls. Bill said they have no shims stock but i have read places they have a shim stock...mine did as the reason i am running an extra 20thou. I am starting at 175 178 mains and checking the topend afrs, if a little lean i will go up 1 size, if a little rich will keep them stock.
Senior Member
Superstock
Joined: Mar 2007
Posts: 268
From: San Diego
I put my DJ needles on 4th clip with one washer, it's too lean. 5th clip with one washer seems a bit rich, so I'm going to go 5th clip, no washer and completely drill the slides - previous owner didn't drill the supporting endpiece.
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