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DRZ 462 39mm Slant FCR fueling help

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Hello, could I get a few opinions on fuelling suggestions to help smooth out the attached fuel curves for my bike, note the airbox is modified, E model slant FCR 39, MRD SSW pipe and 12.2:1 CR (estimated, 11.1 cr 434 kit with a 4mm crank), current jetting is 45 pilot, 150 mj, NCY - U needle clip 2, 2 turns FS, all other jets stock, removed coast thingy with the carb pipes linked, not blocked, I have an EMM needle which is ready to install, the fuel trace at half throttle shows the NCY needle at clip 4, pilot jet is close and this could be sorted by the fuel screw, and the main could be a touch leaner, maybe  a 148, the needle is way rich, does the needle affect the wide open fuelling at all? any suggestions would be appreciated (apart from buy a 41mm carb), note the throttle response is very good and the bike did improve a whole heap with the inlet cam being retarded a bit and the needle dropped 2 clips. Cheers in advance

DRZ 462 Dyno.JPG

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This bike is awesome, be great to have it perfected in terms of fueling and I haven't heard of any other 462cc DRZ'S in NZ, there was one Yoshi 450 and quite a few 434s but no +4+4 motors built, I think it surprised a few people on the rally with how fit it sounded and how fast it was, the fuel economy was excellent was well, used no more gas than when it was a std 400S, awesome and thanks for the tips.

DRZ 462.JPG

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I would suggest the EMR needle, clip 3 and run it with a 158 main jet...

Although the dyno is primarily a test of main jet , different needles will effect the WOT A/F ratio

Edited by Craigo 485sm
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Hello, could I get a few opinions on fuelling suggestions to help smooth out the attached fuel curves for my bike, note the airbox is modified, E model slant FCR 39, MRD SSW pipe and 12.2:1 CR (estimated, 11.1 cr 434 kit with a 4mm crank), current jetting is 45 pilot, 150 mj, NCY - U needle clip 2, 2 turns FS, all other jets stock, removed coast thingy with the carb pipes linked, not blocked, I have an EMM needle which is ready to install, the fuel trace at half throttle shows the NCY needle at clip 4, pilot jet is close and this could be sorted by the fuel screw, and the main could be a touch leaner, maybe  a 148, the needle is way rich, does the needle affect the wide open fuelling at all? any suggestions would be appreciated (apart from buy a 41mm carb), note the throttle response is very good and the bike did improve a whole heap with the inlet cam being retarded a bit and the needle dropped 2 clips. Cheers in advance

 

 

 

 

 

 

 

I have been trying to dial my 39fcr on my build as of late" doing lots of off road riding " and was wondering if you have +1 valves or 187 RHC cams? Im running pretty close to what craigo said but with a 156 main. Bike runs pretty strong  but I don't wind it out like I do on the street thats what the 41fcr is for. Don't have the time to bring or book my bike for a dyno day" test and tune"

 

pretty much a trail an error for me.

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I would suggest the EMR needle, clip 3 and run it with a 158 main jet...

Although the dyno is primarily a test of main jet , different needles will effect the WOT A/F ratio

Cheers, could only get the EMM needle in NZ, which is richer I think than an EMR?, obviously the NCY needle is way way too rich, dropping it to clip 2 improved things but comparing it to the original needle its mad rich, might have to order an EMR needle from overseas if its the only one which will sort the fueling long term, thanks for your assistance.

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I have been trying to dial my 39fcr on my build as of late" doing lots of off road riding " and was wondering if you have +1 valves or 187 RHC cams? Im running pretty close to what craigo said but with a 156 main. Bike runs pretty strong  but I don't wind it out like I do on the street thats what the 41fcr is for. Don't have the time to bring or book my bike for a dyno day" test and tune"

 

pretty much a trail an error for me.

 

 

You mean 155 mj..?

Edited by Craigo 485sm

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I have been trying to dial my 39fcr on my build as of late" doing lots of off road riding " and was wondering if you have +1 valves or 187 RHC cams? Im running pretty close to what craigo said but with a 156 main. Bike runs pretty strong  but I don't wind it out like I do on the street thats what the 41fcr is for. Don't have the time to bring or book my bike for a dyno day" test and tune"

 

pretty much a trail an error for me.

 

Hi, just standard size Vertex valves with new early E model genuine springs and collets, mildly clean up ports, relieved valve pockets, E model B camshafts, i.e. two exhaust cams with one modified to serve as an inlet cam, very close to the old stage 2 hotcams with a touch less lift but same duration (3.66" and 244 degrees), standard E model exhaust timing and 108 inlet. Already had 2 dyno sessions, the second was with this configuration wit a throttle that only opened to 4/5 and way too rich and made 42 hp at 7000 rpm, should be closer to 50 with the correct tuning, but that will cost a mint to do so I have to get some ideas and experiment, will let you know once its sorted. cheers

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 Yes, my bad 155.  that 5 and 6 are just so close to one another

Have you had yours anywhere near a dyno?

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No, closest one is 2 hrs away and is 2 weeks booking. With my line of work I never know when I'm home or when I'm home how long I'll be there. One of these days I'll get there but tell then ill b conservative n mine runs around 53-54hp

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You could go down on the main because on your wide open run it was still rich the whole way up the rpm scale. You do have to get a leaner needle. Have you tried raising the needle?

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I did a search on what Eddie S would have recommended....It's very close to what I posted...

http://www.thumpertalk.com/topic/568286-tt-39mm-fcr-jetting/

 

And about the needle effecting the AF ratio....http://www.thumpertalk.com/topic/859516-my-dyno-chart/?hl=%2Bair+%2Bfuel+%2Bchart#entry8955061

Edited by Craigo 485sm
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You could go down on the main because on your wide open run it was still rich the whole way up the rpm scale. You do have to get a leaner needle. Have you tried raising the needle?

Yep, I dropped the NCY needle to the second position from the top after this run, I failed to hook the cables up correctly before the dyno run, hence I was not getting full throttle, this was also sorted at the same time I retimed the inlet cam and I dropped the needle, the difference was pronounced, will try the EMM needle I have at clip 3, cheers for the advice

I did a search on what Eddie S would have recommended....It's very close to what I posted...

http://www.thumpertalk.com/topic/568286-tt-39mm-fcr-jetting/

 

And about the needle effecting the AF ratio....http://www.thumpertalk.com/topic/859516-my-dyno-chart/?hl=%2Bair+%2Bfuel+%2Bchart#entry8955061

This is gold, thanks for this

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Awesome, installed the EMM needle on clip three and all is well in the world, third gear wheelies no problem and bouncing off the limiter no issue, its the throttle response and part load throttle which is totally transformed, 1/4, half and 3/4 feel spot on, no hunting or cold bloodedness, I just thought it was the nature of the beast, but no it was and has always been that NCY-T needle all along, absolute waste of 40 odd bucks, the 20 buck EMM needle is the boss, it also doesn't seem to backfire as much and seems to be a little quieter, wow, the response is just as good, but the bike is so much nicer to ride now, interesting to dyno the bike again, I will do it again next month, keep you posted.

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