Author Topic: My LeMans IV restoration/engine build (Read 83537 times)

Chuck in Indiana · « **Reply #120 on:** July 03, 2016, 01:51:29 PM »

That first ride (or flight) on something you built is awesome, isn't it? Attaboy..

twowings · « **Reply #121 on:** July 03, 2016, 01:56:50 PM »

Your description of the first ride was SOOOO good I had to read it three times...great to hear your hard work and attention to detail is paying off! Time to clean up the wrenches and just ride....

pressureangle · « **Reply #122 on:** July 05, 2016, 12:21:51 PM »

Changed the needle jets from AB268 to AB265. Mistake, too lean. Back to 268.
Main jets from 130 to 140, huge improvement. Trying 150s today.
We'll see after a ride, but feels like I'll need to lean out the slides from 50/3. Anybody got a stock set lying around?

kevdog3019 · « **Reply #123 on:** July 05, 2016, 01:49:27 PM »

What makes you think slides? You are making rather large changes at one time. I went 265 to 264 and it was a whopping difference. Went from way rich to way lean. I'm not sure if there's a size between 268 and 265??

pressureangle · « **Reply #124 on:** July 05, 2016, 02:19:37 PM »

Yes, the initial changes are very large-but this is not the same engine that the carbs were on before. More compression, far better heads, big cam and open intakes.
Slides, because the just-off-idle is just rich enough to burble while easing around. With the 268's and the K19 needle in the leanest clip, the part throttle is lean enough to weaken if you open it too soon. I'll go to full rich on the needles and see what happens. Typically, I run my needles on the lean side for economy and tune the accel pumps to deal with whacking the throttle, which I'm not prone to doing anyway. So the seat of my pants says more main jet, more needle, and less slide.

So today's report is;
AB268/K19 lean; not too bad.
150 main jet; WOW. I found as much or more between the 140 and 150 as between the 130 and 140. In one short 1st gear crank the front got light over a little dip.

I have to check, I don't think I have any bigger mains than 150's. I'll do a proper plug chop in the future, and schedule some time at the local dyno for some real numbers. So far, it's stronger than I ever expected and smoother to boot.

kevdog3019 · « **Reply #125 on:** July 05, 2016, 07:03:08 PM »

I would agree to raise the needle if it's too lean just on throttle. I too had most of the same changes you did with my 650. Went from 30 to 36 carbs also. A 650 4-valve per. cyl. Lario (LM IV little bro). They like gas. Still getting 45 mpg mixed.

pressureangle · « **Reply #126 on:** July 07, 2016, 01:26:27 PM »

Went full rich on the needles, runs good-I'll have to drop them a clip at a time to find the sweet spot. Today I'll take out the 57 pilot jets and install 52's (because all I have are 55's and 52's) and see if the off-idle richness goes away.

kevdog3019 · « **Reply #127 on:** July 07, 2016, 06:57:10 PM »

Are you certain it's only rich just off throttle? Before you said it was too lean? Before you mess with jets try a middle notch on needle. One thing at a time. A hair rich is better than lean for temps.

pressureangle · « **Reply #128 on:** July 07, 2016, 07:18:04 PM »

Quote from: kevdog3019 on July 07, 2016, 06:57:10 PM

Are you certain it's only rich just off throttle? Before you said it was too lean? Before you mess with jets try a middle notch on needle. One thing at a time. A hair rich is better than lean for temps.

You're not following.

130 mains, 57 pilot, AB268 needle jet, k19 #1 groove lean. Burbles at barely open, weakens or quits when opening quickly. So-so top end.

140 mains, 57 pilot, AB265 needle jet, k19 #1 groove lean. Leaner and drivable at opening, very lean through the middle, better top end.

150 mains, 57 pilot, AB268 needle jet, k19 #4 groove rich. Burble is back at opening, good through middle, beastly on the main jet.

I've been doing this for 35 years, and on this particular motorcycle for 10. This is rough jetting, just getting it drivable in between too lean to run and too rich to keep plugs from fouling. It isn't rocket science to separate the basic fuel circuits at the same time when they are that far out. Of course, it's going to take 500 miles to get it perfect, and a dyno to get the mains there.

I'm not confused or confounded.

kevdog3019 · « **Reply #129 on:** July 07, 2016, 08:44:12 PM »

Quote from: pressureangle on July 07, 2016, 07:18:04 PM

You're not following.

130 mains, 57 pilot, AB268 needle jet, k19 #1 groove lean. Burbles at barely open, weakens or quits when opening quickly. So-so top end.

140 mains, 57 pilot, AB265 needle jet, k19 #1 groove lean. Leaner and drivable at opening, very lean through the middle, better top end.

150 mains, 57 pilot, AB268 needle jet, k19 #4 groove rich. Burble is back at opening, good through middle, beastly on the main jet.

I've been doing this for 35 years, and on this particular motorcycle for 10. This is rough jetting, just getting it drivable in between too lean to run and too rich to keep plugs from fouling. It isn't rocket science to separate the basic fuel circuits at the same time when they are that far out. Of course, it's going to take 500 miles to get it perfect, and a dyno to get the mains there.

I'm not confused or confounded.

As I understand it you went up 20 jet sizes and 3 clip notches with all else being equal (your #1 and #3 examples). Those are two major changes at one time. If you're close I'd do the simple change first by playing drop the needle, then try a little smaller jet if too rich. I'm not doubting your abilities but playing with one change at a time gives you more absolutes to go from. Mine ran great up top but way rich down low. Needle made little change. I changed atomizer one size smaller and moved up a size at a time on my mains until it ran best. Yahtzee!! Of course there's more than one way to skin a cat. It worked for me. Best with this.

pressureangle · « **Reply #130 on:** September 25, 2016, 04:39:05 PM »

Should be getting to the dyno next week for a final tune and recording. This thing is a beast.

Sorry no GoPro yet, I'll try to get to that next week as well. Haven't had enough time to ride to get 200 miles on it yet.

Rick4003 · « **Reply #131 on:** September 26, 2016, 12:30:49 AM »

Very nice report.

I especially like the jetting reports. Keep the updates coming!

-Ulrik

pressureangle · « **Reply #132 on:** October 19, 2016, 08:38:34 PM »

OK, got off to the dyno today. Made a couple passes, with the seat of the pants tuning. Was too rich everywhere, didn't have time to change anything and retest, so I'll go back next week.
Nearly 69hp, 55 lbs-ft of torque.
Not too bad, with a torque curve like a Caterpillar dozer. Good smooth top end, diving off about 7500 sounding like the valves didn't want to stay where they belonged. If final tuning shows it still going up at the same RPM, I'll revisit the valve springs down the road. I think 70rwhp is a given, and 75 not out of the realm of possibility. A truly roadworthy machine! I still have to get a GoPro video up sometime.

pressureangle · « **Reply #133 on:** December 11, 2016, 01:49:52 PM »

Final fitting and ready to ride.

A little more jetting yet, it appears that early on I'd been chasing the piston rings, which took surprisingly long to seat. I've been leaning it back up past where I began, I think. Back to the dyno after it has 500 miles.

Antietam Classic Cycle · « **Reply #134 on:** December 11, 2016, 02:01:36 PM »

Turin · « **Reply #135 on:** December 11, 2016, 05:21:34 PM »

I love the silver, she's a beaut!

pressureangle · « **Reply #136 on:** December 11, 2016, 05:35:32 PM »

Quote from: Turin on December 11, 2016, 05:21:34 PM

I love the silver, she's a beaut!

That's 1968 Dodge Silver. (leftover from my '68 Charger lol)

Chuck in Indiana · « **Reply #137 on:** December 11, 2016, 06:43:32 PM »

Purdy thang..

lazlokovacs · « **Reply #138 on:** December 12, 2016, 03:12:59 AM »

that bike looks really really good

well done!

Old Jock · « **Reply #139 on:** December 12, 2016, 03:53:06 AM »

Looks Fantastic

Groover · « **Reply #140 on:** December 12, 2016, 08:48:10 AM »

Very Nice!

ed@guzzipower.com · « **Reply #141 on:** December 12, 2016, 05:57:40 PM »

If you're jetting a LM1000 with 40 phm's, this will save you lots of time and work much better than any recipe with a K19 needle.

K4 needle, bottom clip
128 mains
68 idle
50/3 slide
265 atomizers

adjust mains + or - 1 size and needle up or down 1 position depending on your bike and altitude. midrange throttle will be night and day better. I post this recipe every few years.

And that huge lean section on your dyno result is a dynamic effect from vacuum drop when whacking open those huge carbs...dont get distracted by that- just look at steady state effects you can jack acc pumps way up to try to compensate but a little throttle control in real world riding is the best solution.

Chuck in Indiana · « **Reply #142 on:** December 12, 2016, 06:30:22 PM »

Hi, Ed..
The Kid's 1100 Spot had some ridiculous 168 or something like that when he got it. It wouldn't run at all at WFO. I mentioned you used a much smaller main. He's down to a 130, and it runs fine, now.

flapjack · « **Reply #143 on:** December 13, 2016, 02:18:35 PM »

Your bike looks great, better than new.

pressureangle · « **Reply #144 on:** January 06, 2017, 12:46:28 PM »

Ssoooo.... I finally got around to adding up the receipts for this thing. My guess was pretty accurate, fortunately.

Not including bodywork and paint (traded for labor)

$9891 and of course some consumables and pocket-washed local receipts from the hardware. So $10k.

Totally worth it.

canuck750 · « **Reply #145 on:** January 06, 2017, 01:01:27 PM »

WOW

It looks fantastic, and from your posts I see that a major increase in performance has been gained as well!

No easy task.

groundhog105 · « **Reply #146 on:** January 06, 2017, 03:48:43 PM »

What a fantastic result. I am interested in where your torque and HP curves and totals look like when you get the jetting right. These motors seem to always perform much better on the real world than the dyno shows.

Triple Jim · « **Reply #147 on:** January 06, 2017, 04:31:26 PM »

69 rwhp isn't a bad start at all. That's probably a good 80 at the engine.

pressureangle · « **Reply #148 on:** January 12, 2017, 05:56:40 PM »

One thing I forgot to update, that is important to me- the rear brakes. I de-linked my brakes, and since the stock rear master cylinder only runs half as many calipers, it was stiff and weak. I didn't care too much, since I'm a front brake kinda guy. But for the rebuild, I wanted them to work properly. The answer, it turned out, was pretty simple.
I did a lot of searching and researching, and almost by accident I discovered that a V50 front brake uses a cable to operate the front master via a lever. The master cylinder is the same physical dimensions as the rear on the LMIV, but has a smaller bore. All I did was find a good used V50 master on eBay and swap on my stock LM lever for the correct linkage. Bam. It's awesome.

Chuck in Indiana · « **Reply #149 on:** January 12, 2017, 06:05:56 PM »

Quote from: pressureangle on January 12, 2017, 05:56:40 PM

One thing I forgot to update, that is important to me- the rear brakes. I de-linked my brakes, and since the stock rear master cylinder only runs half as many calipers, it was stiff and weak. I didn't care too much, since I'm a front brake kinda guy. But for the rebuild, I wanted them to work properly. The answer, it turned out, was pretty simple.
I did a lot of searching and researching, and almost by accident I discovered that a V50 front brake uses a cable to operate the front master via a lever. The master cylinder is the same physical dimensions as the rear on the LMIV, but has a smaller bore. All I did was find a good used V50 master on eBay and swap on my stock LM lever for the correct linkage. Bam. It's awesome.

When the spineys came out, there was a hue and cry about using the small block caliper on the rear rotor..

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Author Topic: My LeMans IV restoration/engine build (Read 83537 times)

twowings

canuck750