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Old 12-31-2012, 08:30 PM   #391
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Not the best pics, but here to attempt to show it was nice and clean inside. Not bad at all for almost 2 years and 40 k. Filters must be working OK. Although I did have to drain the float bowel of water a while back, so maybe something was flushed out then.




With the carb out, it was time to fit the Merge Racing adjustable leak jet seen in the pic above along with the dangling R&D fuel screw thats been there since I fitted the FCR. I got the adjustable leak jet a while back when they were on sale for about $50 or so, figuring I'd use it on something. With the Bergs already having either a Taff or BK mod that enables adjustment, it would inevitably end up on the DR.

http://www.mergeracing.com/products/...bleLeakJet.php




If your carb does have the boss, its easy enough to fit the BK mod for almost no cost. The one above is the FCR 41 on my FE650. Drill and tap a hole in the boss and fit a bolt. The way I set mine up, the amount of thread showing between the locknut and bolt head is the same as the gap from the end of the bolt to the black AP lever. It can be easily adjusted with the carb on the bike with 2 spanners.

The FCR MKII that I have on the DR doesn't have a boss in the carb to enable the fitting of a BK mod like I did to the FE650's, so to change the AP behaviour, the leak jet needs swapping. The MXRob spec #35 fitted does actually work OK, ie no bog detected, but. DR Steve has a #45, and this might be partly because of the leaner NCVT needle.

Another possible complication for some is that not all FCRs have leak jets. My Bergs are a case in point.




If you have a MKI FCR, then the Taff mod is needed. It uses what is referred to as a block connector. Dunno quite why its called that, but its the round collar in the lower right of the above pic. Its secured with the grub screw to the AP shaft and should go under the dust cover. Slide it up and down to adjust. Available at hobby model shops.




Above is the 39 FCR fitted to my FE501 with the Block Connector fitted to the AP shaft under the dust cover, so not really visible at all.

So, back to the DR. In the pic above you might notice that the Merge bit is shiny on the bottom and not blue anodized. I sanded off about 0.3 mm to make bit more space to clear the power connection to the starter.

Which leads me to an admission. Another reason for fitting the Merge thingy was because its anodized blue. All the bling on my DR is also blue............... so it matches my eyes




Here's a tip. Spray some silicone on the airbox boot and inlet rubber to make fitting the carb easy. Also remove the hose clamp from the airbox boot otherwise it gets in the way. Nice and slippery and slides right in. Use it on all the hoses too and they'll come off easy next time.

So a new NCVT needle on the middle clip, an adjustable leak jet backed right off and a 40 pilot fitted for the first run. And with the lug on the starter shortened and only one nut securing the power cable, and the ground down pump, heaps of clearance.




Note the short range tank fitted for testing. Available for not too many $ from your local power equipment service centre. I think this one cost about $5 years ago.

Now to ride it. Maybe tomorrow
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Old 12-31-2012, 09:31 PM   #392
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Sooner or later you're going to get an offer of employment from Suzuki to help them design their DRZ650.
What years is the MKI FCR-MX carb from? Everything I've seen about the merge racing ALJ says that they fit all FCR carbs (i assume they mean the ones with an AP but do the non AP fcr carbs have leak jets too?).
Who had the ALJ for $50? I remember Ballards having them on sale a while ago but not that low, an extremely good price you got it for.

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Old 12-31-2012, 09:48 PM   #393
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Steve,

You sound like you need one of these..
http://www.bmotorsports.com/shop/pro...roducts_id/357

I bought one a few years ago and it's been one of the best $250 I've spent on any type of tool - and I have lots of them.
I've also could have bought lots of them for the money spent on dyno sessions over the years (all cars).

I find the best way to compare needles is find out where the problem area is, say 1/4 throttle, and mark that position on the needle while in the carb, even if it's not the exact point that's doing the metering it gets you in the ball park. I then set the verniers to suit that diameter and while the needle is sitting in the verniers you can drop your other needles in beside it to see how they compare. It's easy to see the relative clip positions from one to the next this way. You can work your way right down the taper doing the same thing. You will find that the NCVT starts it's first taper probably 1/8" before the EMP does.
Not sure if that makes sense - I'll post a pic later.

Pics of what I was trying to describe..



Needles left to right - NCYS (same taper and L1 as NCVT), JD red, EMP. Pics progressing down the needle taper.

Clip for clip on the taper the Honda needle is richer everywhere compared to the EMP. The big difference is that it's quite a few steps leaner on the staright diameter and the much earlier starting taper already mentioned.




Cheers,
Steve
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Old 01-01-2013, 01:14 PM   #394
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Quote:
Originally Posted by BergDonk View Post
..................... The MXRob spec #35 fitted does actually work OK, ie no bog detected, but. DR Steve has a #45, and this might be partly because of the leaner NCVT needle.

..........................So a new NCVT needle on the middle clip, an adjustable leak jet backed right off and a 40 pilot fitted for the first run. ....................
So who picked up my flawed logic above?

At odds with what fuel control jets normally do, ie flow more fuel and make for a richer mixture as the hole gets bigger, a bigger leak jet allows more fuel to return to the float bowel instead of being injected into the intake air flow, so not only is DR Steve's needle leaner, so is the net effect his #45 leak jet.

By backing out the Merge ALJ it simplifies testing steady state and roll on responses. Unwinding it opens the needle valve more, allowing more fuel to leak back, leaning it off. If its wound in, or the AP is just doing its thing, it can complicate the process. Get the normal jets and needle right, and then dial the AP afterwards.
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Old 01-01-2013, 01:21 PM   #395
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Originally Posted by Kernel View Post
Sooner or later you're going to get an offer of employment from Suzuki to help them design their DRZ650.
What years is the MKI FCR-MX carb from? Everything I've seen about the merge racing ALJ says that they fit all FCR carbs (i assume they mean the ones with an AP but do the non AP fcr carbs have leak jets too?).
Who had the ALJ for $50? I remember Ballards having them on sale a while ago but not that low, an extremely good price you got it for.
I doubt Suzuki pays any attention to forums such as these. Testing job would be interesting though.

I'm not sure of the FCR MX history, but the MKI was fitted to the 98+ WR400s and YZs and the early RFS KTM Berg clones AFAIK. Mine supposedly came off a WR400. Internally they are much the same as the MKII, but not so tidy with the AP implementation. Some jets are different too, like the pilots. At the right price, they do the job. When I fitted the MKI to the 501 way back when the MKIIs had not long come on stream and were insanely priced, and the MKI wasn't given away either.
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Old 01-01-2013, 01:24 PM   #396
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Quote:
Originally Posted by DR Steve View Post
Steve,

You sound like you need one of these..
http://www.bmotorsports.com/shop/pro...roducts_id/357

I bought one a few years ago and it's been one of the best $250 I've spent on any type of tool - and I have lots of them.
I've also could have bought lots of them for the money spent on dyno sessions over the years (all cars)............................................. .....
You might be right again

Perhaps later after the seasonal hump


Quote:
Originally Posted by DR Steve View Post
.............................
I find the best way to compare needles is find out where the problem area is, say 1/4 throttle, and mark that position on the needle while in the carb, even if it's not the exact point that's doing the metering it gets you in the ball park. I then set the verniers to suit that diameter and while the needle is sitting in the verniers you can drop your other needles in beside it to see how they compare. It's easy to see the relative clip positions from one to the next this way. You can work your way right down the taper doing the same thing. You will find that the NCVT starts it's first taper probably 1/8" before the EMP does.
Not sure if that makes sense - I'll post a pic later.

........................

Clip for clip on the taper the Honda needle is richer everywhere compared to the EMP. The big difference is that it's quite a few steps leaner on the staright diameter and the much earlier starting taper already mentioned.

Cheers,
Steve
Description make perfect sense. I'll take some more measurements and graph it up so we all get a visual.

Thanks
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Old 01-01-2013, 09:34 PM   #397
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Quote:
Originally Posted by BergDonk View Post
So who picked up my flawed logic above?

At odds with what fuel control jets normally do, ie flow more fuel and make for a richer mixture as the hole gets bigger, a bigger leak jet allows more fuel to return to the float bowel instead of being injected into the intake air flow, so not only is DR Steve's needle leaner, so is the net effect his #45 leak jet.

By backing out the Merge ALJ it simplifies testing steady state and roll on responses. Unwinding it opens the needle valve more, allowing more fuel to leak back, leaning it off. If its wound in, or the AP is just doing its thing, it can complicate the process. Get the normal jets and needle right, and then dial the AP afterwards.

I did notice that, but didn't bother to point it out.
The above therory is still not really whats happening, which becomes obvious with the wideband hooked up and some needle measuring. The main difference between the popular EMP and and the Honda NCVT is the root diameter. The NCVT is richer more or less everywhere from about 1/8 throttle up.

What I got with the EMP was way too rich around 1/8, too lean at 1/4, a bit lean at 1/2, and ok at 3/4. I found the 1/8 richness could only be cured with a much leaner root diameter and the E taper would not cater for the other throttle positions...

Through the transition from idle/cruise (around 1/4) into the power the NCVT is a fair bit richer than the EMP, meaning it doesn't need as much acc pump assistance. I tried a 60 leak jet, which I couldn't get to bog, but the wideband showed it wasn't really small enough even though there was no bogging. I had a #35, #45, and #60 to choose from - I'd say a #50 or #55 would be ok. I now have both, but haven't bothered to pull the carb to change the leak jet.
With the acc pump rod removed, I could easily ride the bike without any bogging - you really need to wack the throttle open fast to get a bog.

Based on my set up, your jetting would be giving you a case of too rich - too lean - ok at the top end, so the overall fuel economy change from what you have now might not be much. For the last 10K since getting the FCR dialled in, I get on average 22klm/ltr with a variation of 21-23.5. To give that some context, I only have a tail bag for luggage, and I can't seem to get any rear tyre to last more than about 3K - so I'm not riding to save fuel !
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Old 01-02-2013, 05:15 PM   #398
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Hi Steve, I guess my point was that its better to dial the jets and needle without the addition of the AP in the first instance, then dial it in after the rest is working.

Your descriptions are really helpful too as usual, thanks.

I did get to do a small test ride yesterday and first impressions are positive for sure. Started straight up with choke and happy to idle without after 15-20 secs as usual. A couple of gentle kms to test the knee and let the bike warm a bit and get a feel for steady 1/8 - 1/4 throttle and then gentle rollons to 1/2 - 3/4. Its definitely crisper off the bottom, so the leaner root dia is the go for sure.

Once I got back home after about 20 kms I dialled the idle and the FS is at a neat 1.5 turns, so right on the money there with the #40 pilot it seems. Still with a #70 PAJ too. There was no apparent bog or hesitation when rolling on, or snapping on from anywhere in the rpm range. Nice.




So I let it cool for a few minutes and then loosened the hose clamps on the carb and the fuel screw where its attached to the stator cover, full left lock to get some slack in the throttle cables, and twist the carb. Off with the top and its time for a clip experiment and to do some better measurements of the needle. 5 mins max to do a needle change, so no excuses not to fiddle.

I had started with the needle on the middle clip and decided to raise the clip to position 2 from the top, so 2 clips up and leaner. A short ride, about 2 kms up the hill and I ran out of fuel. I forgot to top it up in all the excitement, doh! Fortunately I'd gone up hill from my gate so was able to coast into a U turn and roll all the way back down the hill, through my gate down the driveway and into the shed without any pushing, about 2.5 kms. My knee was pleased.

So refill, and back up the hill and it feels like the clip is now about as lean as it'll go, but I'll go to the top clip next to be sure. And I'm at 800 m and want it to work at sea level, so thinking clip 3 will be where it ends up. I then decided to play a bit with the ALJ. With the test tank on, I can access it with a screw driver whilst sitting on the bike, so I screwed it in a couple of times and the snap gets better for sure, until it was indicating a bit of bog at 1/2 turn, but nice at 3/4 turn. Dunno what leak jet that equates too, and I haven't found any info that maps the ALJ turns to jet size. Its definitely more responsive as the ALJ is screwed in, but not unresponsive when its backed off at 3 turns which is the limit according the install guide and where I started. I'm thinking as its so easy to adjust, rich for trail riding and lean for touring if I could be bothered. More testing to come in the mean time.

Which brings me to a discussion led by Dale Lineaweaver years ago over on UHE. He was, and maybe still is, of the opinion that the AP isn't needed on big bore bikes if all the rest of the jetting is right, all it it does is mask poor jetting. The eventual conclusion, I think, was that some small AP is good for some snap and its in enduro/trail riding where its noticeable. His thinking was that the FCR carbs originated in road racing for 4 cyl bikes of 750-1000 cc, so cylinder capacities up to 250 cc. The big thumpers that we use the MX versions on have more vacuum than the smaller cylinders and therefore suck harder and need less AP assistance. My Berg testing seemed to validate that. It actually became almost unrideable with the original AP settings after the dyno time, and its now set at OTTMH, 0.2 mm stroke. Its responsive to 0.1 mm changes too.




While the needle was out for a clip change, I took some better measurements. I aligned the needle with the steel rule and marked them both at 5 mm increments with a fine tip marker. Then measured the diameters at those marks. Not super accurate, but indicative for sure.




The results are in the above tables and graphs which are hopefully mostly self explanatory. The last graph is the one that is perhaps the most useful, and the leaner and richer parts of the needle can be seen.

Quote:
Originally Posted by DR Steve View Post
.................
Through the transition from idle/cruise (around 1/4) into the power the NCVT is a fair bit richer than the EMP, meaning it doesn't need as much acc pump assistance. ............
I believe what Steve is saying above is visible in the bottom graph above where the red line, the NCVT, dips below zero and goes richer from the leaner part above zero before.

What's also in the graphs is an attempt to calculate and plot a theoretical EMP versus what I measured mine at and the NCVT now fitted. Its the green line. When I calculated the 1 deg taper it has to start at about 65 mm and not the 79.15 L1 that the tables suggest. If I start the taper at about 79 mm, ignoring the transition curve, which isn't much anyway, I think, it looks nothing like the EMP I have. By propogating the 1 deg taper back from the tip diameter of 2.09, I get the above. I must be interpreting the diagram wrong or something. But when I do it my way, the measurements of my EMP aren't too far off, about 1% richer at <> 1/2 throttle and 1% leaner at 3/4 throttle, so dunno.

More needle positions and ALJ testing to do. I'll back the ALJ off again and lean the needle for the next phase.

Not withstanding fine tuning, the NCVT is the go for sure right now for me. Thanks to DR Steve for his hard work getting there and allowing us all to take a short cut and the reap the benefits

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Old 01-02-2013, 08:39 PM   #399
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Hi Steve,

Glad the needle is working out for you.

What size main are you at ?

I'd agree with the statement about acc pump requirements on these big bore bikes, as mentioned previously, I really have to wack open the throttle to get a bog with the acc pump rod removed. The DR is not that sort of a ride anyway.
With your ALJ, is less squirt screwed in or out ?

It sounds like you will end up at a similar clip to where I am. FWIW, i tested from sea level up to 1000M in temps from 10 - 30 degrees, and found clip #2.5 to be ok to cover all those conditions. Clip #2 was too lean and #3 was too rich.

Our bikes differ a little in that your running the bigger header and different muffler, and I assume you don't have the velocity improver at the carb entrance ?

btw I'm going to port the head next, as the pictures I've seen indicate some free economy and performance should be available. After all, it's only going to coast a head gasket !

Cheers,
Steve
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Old 01-02-2013, 09:33 PM   #400
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I didn't change the main. Right now its at:
Main 150
Needle NCVT
clip from Top 1
PAJ 70
Leak 3 turns
Pilot 40
Fuel Screw 1.5
Float 9
Start 85

As you might note, I have tested the top, leanest clip, this afternoon. My bum can't tell the difference between clip 1 and 2 right now.

The Merge ALJ is a needle valve like the fuel screw, so unwinding increases the leak. All that seems to happen as I screw it in is that the 'snap' gets stronger until past 3/4 turn when it starts to bog. Not a big difference as it gets snappier, but nice all the same.

I might go back to clip 2 and try it on a proper ride and test the ALJ some more too. I'll either find one setting for everything, or just tweak it on the day to suit the terrain if I could be bothered, it only takes seconds with the right screwdriver.

Its pretty warm here again today so the air density isn't that great, maybe I'll just copy your clip 2.5 and try that for awhile. Plenty of time to contemplate anyway.

I have an intake sleeve loctited on the carb from MXRob, so arguably it could flow better. I recall MXRob reckons his testing couldn't pick a difference worth mentioning, or something. When it arrived, I thought then that I should have made my own, but at the time I thought it was the real thing, until it arrived. I did make a nice tapered bellmouth for the 501 when I did that years ago. I guess its still on the to do list, just not at the top right now. When I got the FCR for the DR it was just on 2 years ago, and the great Oz Christmas shutdown was in place. I had no suitable bar in stock, and none available for a while. I had MXRob's bellmouth here because it was cheap and I expected it to be a bellmouth, and everything thing else, so put it on. As I don't know any better, its still the best I know excuses, excuses.................

Head porting, nice. A mate down here had to pull the head off his FE650 after a minor catastrophy of his own doing. Part of the fix involved an extrusion port job. We set it all up much like my FE650 and it goes nice. Of course without the dyno, if he has 1 or 2 hp more than me we'll never know. Different mufflers too, he's got an Akro and mines the stocker bored out. He's probably lurking and might want to comment on his head. No doubt something along the lines of all these great bikes he has and never rides them.............
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Old 01-02-2013, 09:54 PM   #401
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And I just noticed this thread will likely soon have had 50,000 views, so we must be keeping a few inmates entertained.
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Old 01-02-2013, 10:10 PM   #402
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Old 01-02-2013, 10:59 PM   #403
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I'm not sure that the bellmouth would make any noticeable difference, but it seemed silly not to include it given I was machining my own. In the past these type of mods seem to have had more effect on response, part throttle driveabilty/rideability, than they do on outright performance and as such rarely show on a dyno run. You could probably machine up an insert to glue into your current sleeve.

The other area mine will differ to yours, is the slide cut-away. I did raise that in an unsuccessful attempt to cure the incorect needle root diameter.
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Old 01-02-2013, 11:11 PM   #404
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I'm not sure that the bellmouth would make any noticeable difference, but it seemed silly not to include it given I was machining my own. In the past these type of mods seem to have had more effect on response, part throttle driveabilty/rideability, than they do on outright performance and as such rarely show on a dyno run. You could probably machine up an insert to glue into your current sleeve.

The other area mine will differ to yours, is the slide cut-away. I did raise that in an unsuccessful attempt to cure the incorect needle root diameter.
I recall you mentioned the slide cutaway mod. I was reluctant to go there because the only way back is a new slide, and you did also mention it was a bit of a dead end and that the NCVT was the go.

If I get bored in the weeks to come I may just make up an intake bushing/bellmouth. I do have some Delrin in the shed and that'll probably do the job I suspect. I like your thinking Steve

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Old 01-02-2013, 11:17 PM   #405
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Yeah, changing the slide cut-away didn't really make much difference mixture wise - just thought I'd mention it as it may change things a little.

Delrin should be fine for that and a bit easier to shape too !
You can then tell me if it makes a difference. I wanted to try it both ways but was too impatient, so went the bellmouth straight up.
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