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Bonneville Salt Flats Discussion => Build Diaries => Topic started by: lucasanderson00 on February 24, 2018, 01:39:48 AM

Title: Honda CX500 - EFI and boosted on a budget M-PBF 500
Post by: lucasanderson00 on February 24, 2018, 01:39:48 AM
Here is our CX build already in progress, more of an evolution than a build at this point but here it is anyway! It started as a lofty goal between myself (Luke) and long time friend Sean. We started out with a bone stock '79 CX500 that was traded for broken down '61 Rambler plus 600 bucks on their end. Great start, and it made up for its looks with how well it ran. We took it apart right away.

The first picture is in 2014, the bike already had its big 23" tire, chosen to get some more mph since the final drive gearing was fixed being a shaft drive and all. We also swapped a CX650 transmission and clutch/primary for even more gear. The BW K03 turbo was mocked up and I was stoked.

It took a couple years in our spare time to get the bike running again, fabricating the intake, exhaust and fuel tank. All the finish TIG welding was done by my friend Jerry Westhouse (and all the ugly MIG welds done by myself). We installed a Honda CBR954 front end and a Megasquirt II EFI system, initially controlling fuel only.

The second picture is at the Ohio Mile April 2016. We went to 2 OM events that year and set 2 records, 1 in an open class. Best speed of 123.8mph. We had clutch slip issues and ignition problems with our stock coils. Datalogging was also not working and we had no data to go off of, EFI had a steep learning curve to say the least.
Title: Re: Honda CX500 - EFI and boosted on a budget M-PBF 500
Post by: lucasanderson00 on February 24, 2018, 02:20:30 AM
After the 2016 season we fine tuned the bike, a lot was learned at Ohio Mile.
Post season changes:
-Charging system
-Coil near plug ignition
-AEM cam sensor driven off the old mechanical fan snout
-Barnett clutch
-Airtech seat cowl...that stock seat was so ugly and way too high up
-3D printed carbon composite turbo inlet elbow
-1600cc injectors for M1 methanol
-datalogging sorted out

The next goal of course was Bonneville
Title: Re: Honda CX500 - EFI and boosted on a budget M-PBF 500
Post by: thefrenchowl on February 24, 2018, 04:37:31 AM
Hi, Luke

That big rear wheel gives it an angry stance!!!

 :-o

Like it...

No intercooler plans?

Patrick
Title: Re: Honda CX500 - EFI and boosted on a budget M-PBF 500
Post by: lucasanderson00 on February 24, 2018, 11:51:05 AM
Yep that wheel certainly gives it a unique look! No intercooler plans on this one...unless it becomes absolutely necessary.
Title: Re: Honda CX500 - EFI and boosted on a budget M-PBF 500
Post by: lucasanderson00 on February 24, 2018, 12:11:26 PM
Spring of 2017 - we built a second engine with higher compression intended for methanol.
CP made the pistons, they have a 22 degree twist due to the head design on these engines. 11.5:1 compression
Flatout gaskets supplied us with custom headgaskets.
We now had 2 different setups-
Engine 1 - 10:1 compression with 550cc injectors for the gasoline class
Engine 2 - 11.5:1 compression with 1600cc injectors running alcohol in the fuel class
Title: Re: Honda CX500 - EFI and boosted on a budget M-PBF 500
Post by: Koncretekid on February 24, 2018, 05:08:10 PM
I'll be following your progress.  Fuel injection plus supercharging - - food for thought for my BSA.

Tom
Title: Re: Honda CX500 - EFI and boosted on a budget M-PBF 500
Post by: lucasanderson00 on February 25, 2018, 12:14:18 AM
We made it to Bonneville Speed Week in August 2017, very exciting, first time out on the salt. We roughed it in a tent at the KOA. Tech went well, no issues. Both Sean and I made our rookie runs and got our licenses, running in the 110-120 range. That course was very rough and was an eye opener to say the least. We moved over to the short course and I made several passes over the next couple days tuning and making an attempt at the M-PBF 500 record of 126.9mph. Monday the bike qualified and went to impound. Tuesday morning we experienced acute rod failure on the record attempt after I over-revved the engine at the top of 4th gear(oops). One rod cleanly separated itself at 10,500rpm and swung through the transmission (located in the crankcase). The countershaft sheared clean in half. We went back to the pits and swapped in the low compression engine and got back in line. We made the last pass of the day with Sean riding and requalified. The next day the bike ran 141mph and set the new record at 133.1mph. Good times!
Title: Re: Honda CX500 - EFI and boosted on a budget M-PBF 500
Post by: thefrenchowl on February 25, 2018, 06:41:27 AM
Quote
One rod cleanly separated itself at 10,500rpm and swung through the transmission (located in the crankcase).

Jeeees, this must have made the most horrific noise...  :-(

But you got a record 1st time out, so good preparation no doubts...

Felicitations...

Patrick
Title: Re: Honda CX500 - EFI and boosted on a budget M-PBF 500
Post by: fordboy628 on February 25, 2018, 08:34:43 PM

We made it to Bonneville Speed Week in August 2017, very exciting, first time out on the salt. We roughed it in a tent at the KOA. Tech went well, no issues. Both Sean and I made our rookie runs and got our licenses, running in the 110-120 range. That course was very rough and was an eye opener to say the least. We moved over to the short course and I made several passes over the next couple days tuning and making an attempt at the M-PBF 500 record of 126.9mph. Monday the bike qualified and went to impound. Tuesday morning we experienced acute rod failure on the record attempt after I over-revved the engine at the top of 4th gear(oops). One rod cleanly separated itself at 10,500rpm and swung through the transmission (located in the crankcase). The countershaft sheared clean in half. We went back to the pits and swapped in the low compression engine and got back in line. We made the last pass of the day with Sean riding and requalified. The next day the bike ran 141mph and set the new record at 133.1mph. Good times!


Unloaded "over-rev" connecting rod tension loads @ TDC overlap can be fearsome.   Use one of the engine analysis programs to calculate the load in G's.   The piston in the photo looks like it might be a bit on the heavy side, but it is hard to say for sure.   You are going to need very light, premium quality parts for reliability at high revs.

 :cheers:
Title: Re: Honda CX500 - EFI and boosted on a budget M-PBF 500
Post by: JimL on February 25, 2018, 09:55:16 PM
First off:  Good job!

I ran these CP pistons for years in my CX engines.  I often took them beyond 11,000 and never had a problem.  Take a good look at the wrist pin bores and the pins themselves.  I changed pins a number of times because they did not seem to oil well.  CP and I had a few brainstorming sessions about pin lube issues (on other engines as well).  I started putting the pins in with Lucas zinc-additive oil to buy a little more time.  I think it helped, but your mileage may vary.  I always wished for a row of parallel ridges across the bottom of the dome, but never got it (oil droppers for the top of the rod).

That said, look very carefully at the rod installation.  The oil hole orientation is easy to get wrong and that will reduce oiling into the wrist pin on an affected cylinder.  They run fine with a rod in backwards....until something goes wrong.  It is very easy to get these in wrong because the only rod big end access is through a pair of (rough, nasty) holes that are knocked through the inner crankcase during manufacture (absolutely bizarre manufacturing process).  As you already know, installation is done by feel through a sharp-edged hole and often includes some well-oiled blood (your own) inside the cases.

Pretty fast motors, all things considered, but really expensive to build heads that breath well.  If you are really careful, you can cut the 500 valve seats to take CX650 valves.  I had better luck with aftermarket valves and going down to 5.5mm stems (with appropriate bronze guides).  I also ran shorter springs with about .25" tall isolators under them to let the oil flow reduce the rate of exhaust heat getting into the bottom of the exhaust springs.  You may find your springs get too hot (and soft) at the end of a long pull.  The ports are too low and too sharp and so the top of the exhaust port gets smoked pretty quick.  

Watch for "pop out" pitting on the back slope of the cam lobes....that will tell you for sure if the exhaust valves are starting to float.  Those pits may be pretty small, but if you find them....you are in trouble.  The cams keep working fine, even after they pit, as long as you solve the float problem.

Like the previous post says, over-rev is ugly and uglier if you chop the throttle instead of powering into an upshift, or a brake, to pull the revs back.  With the throttle shut at high rpm, there is not enough intake air for the compression to help slow down those pistons.  I was taught to push into the rear brake (throttle still open) to capture an over-rev.  Easy to do on a bike.

JimL

PS....almost forgot to mention.  The shim stack behind the last gears on the shafts is a little tricky and can lead to missed shifts.  We also had a shaft slide in the clutch side shaft bearing, which makes the bike want to stay in 4th gear.  Just food for thought.  If you are ever putting one of these engines (with the home-brew trans work) together....and one day you pull the clutch lever and hear a little pop (and suddenly have a little extra slack in the cable) your shim stack is wrong and the input shaft has slipped in the clutch side of case bearing.
Title: Re: Honda CX500 - EFI and boosted on a budget M-PBF 500
Post by: Koncretekid on February 26, 2018, 07:49:53 AM


Unloaded "over-rev" connecting rod tension loads @ TDC overlap can be fearsome.   Use one of the engine analysis programs to calculate the load in G's.   The piston in the photo looks like it might be a bit on the heavy side, but it is hard to say for sure.   You are going to need very light, premium quality parts for reliability at high revs.

 :cheers:

Looks like the rod is the culprit, not the piston.  Can you get Carrillo or equal rods?

Tom
Title: Re: Honda CX500 - EFI and boosted on a budget M-PBF 500
Post by: lucasanderson00 on February 26, 2018, 10:32:37 PM
Thanks guys!

Jim, so much good information in just 1 post!. I have been following your builds and you have been an inspiration to us for years. The CP piston is slightly heavier than the stock piece, which I knew putting the engine together but ignored. This year the plan is to have CP/Carrillo make us rods as well. Lucky for me, they are located half a block from where I work now that I moved from Chicago to Southern California.

I am interested in spinning this engine to 11k if possible though, so I'm glad to hear you have done it with success. My options are becoming very limited to get this bike over 150 with its fixed final drive ratio. Now it looks like they eliminated the shaved v-rated tire exception for speeds over 150 for 2018. I'll have to go back to a smaller diameter z rated tire.
The best solutions I have so far are possibly retrofitting a CX650 Turbo clutch, primary, and front cover onto our 500 engine(very expensive/rare and maybe not even possible but has a much better ratio), or getting custom primary or transmission gears cut(probably equally expensive)
Title: Re: Honda CX500 - EFI and boosted on a budget M-PBF 500
Post by: wobblywalrus on February 26, 2018, 11:34:10 PM
Has anyone looked seriously at Honda's new 500 twin?  It looks like a good platform for an LSR build.
Title: Re: Honda CX500 - EFI and boosted on a budget M-PBF 500
Post by: edinlr on February 26, 2018, 11:44:36 PM
Wobbly, the new 500 is nice, but since it is OHC, it runs with the big boys in G, good try trying to get all of us CX guys out of the pushrod classes.

That is interesting that they took away the shaved V rated tire rule, can anyone shed light on this, was there a problem?  There are a lot of the smaller bikes that run narrow tires and the selections are very limited when you get narrower than a 160.
Title: Re: Honda CX500 - EFI and boosted on a budget M-PBF 500
Post by: JimL on February 27, 2018, 12:21:27 AM
This may seem counterintuitive....but:  if you want to spin fast you must cut the flywheel weight a LOT.  At high revs, the energy carried in a heavy flywheel adds to the stretch (and or) compression effect on the rod.  The rod is trying to hold opposing forces together.

Lighten the flywheel and save the rods (and a lot of other things).  If you don't believe it, look at the mini-flywheel used in modern F1 or Indy type engines.  Those folks know what they are doing.

Picture every part in the engine held together by rubber bands which always try to snap things back into place.  Big, heavy moving components don't like that kind of trouble.  Cut your flywheel down to just enough to hold the starter clutch.  And do not run an alternator.  It's just one more batch of pulsing forces tossed into the mix.  Two batteries is simpler and less stress on the engine.
Title: Re: Honda CX500 - EFI and boosted on a budget M-PBF 500
Post by: Koncretekid on February 27, 2018, 07:24:11 AM
11,000 rpm with a 2" (50mm) stroke only results in piston speeds of 3666 fps, which should not be an issue with good rods and pistons and that healthy looking crank.  Compare that to my B50 with 90mm stroke at 7200 rpm which equates to piston speed of 4248 fps with a crankshaft half the size of yours (maybe crank flex contributes to lower stresses on the rod and piston).  Also the B50 is a single while you have a V-twin with better balancing characteristics.
Tom 
Title: Re: Honda CX500 - EFI and boosted on a budget M-PBF 500
Post by: mtiberio on February 27, 2018, 07:35:37 AM
Wobbly, the new 500 is nice, but since it is OHC, it runs with the big boys in G, good try trying to get all of us CX guys out of the pushrod classes.

That is interesting that they took away the shaved V rated tire rule, can anyone shed light on this, was there a problem?  There are a lot of the smaller bikes that run narrow tires and the selections are very limited when you get narrower than a 160.

Having Nate Jones shave your tires, no problem. Letting Billy Bob hack at your tire back in the shed, not so good. With a rule stated like that, ANY shaving would comply with the rules, but only proper shaving actually increases speed rating.

I feel your pain, I have 2.15"x18" rims on my 1000cc Guzzi, and while I haven't busted 150, I could easily with a decent full fairing. I have some shaved V tires from Nate Jones (planned on it when I was going to run A with a +150 record, that was before they added all the low minimum M classes), but would be in a world of hurt if I had to run Z rated radials on those narrow rims. There is no narrow rim solution, no one makes W or Z rated narrow rim tires for bikes. All the radials require fat rims.
Title: Re: Honda CX500 - EFI and boosted on a budget M-PBF 500
Post by: Koncretekid on February 27, 2018, 07:41:55 AM
I'm curious about the shaft drive possibilities.  Are there other makes of shaft drive bikes that have a taller drive ratio, and if so, how difficult is it to transplant the entire rear drive assembly to the Honda?
Tom

P.S. In regards to narrow radial tires/wheels, I've gone to 17" cast wheels and have found some 2.5" wide rims on which I can run 110/70 ZR17 w rated tires for the front, and 3.5" rims on which I run 120/70 ZR17 W rated tires on the rear.
Title: Re: Honda CX500 - EFI and boosted on a budget M-PBF 500
Post by: mtiberio on February 27, 2018, 08:02:50 AM
I'm curious about the shaft drive possibilities.  Are there other makes of shaft drive bikes that have a taller drive ratio, and if so, how difficult is it to transplant the entire rear drive assembly to the Honda?
Tom

P.S. In regards to narrow radial tires/wheels, I've gone to 17" cast wheels and have found some 2.5" wide rims on which I can run 110/70 ZR17 w rated tires for the front, and 3.5" rims on which I run 120/70 ZR17 W rated tires on the rear.

I race a Guzzi with shaft drive, and I have 3 different rear ends, but there must be 6 or more out there. Most are too short. I have one that is so tall, that I only use 4th gear (out of 5). I also gave myself many more gearing options by bringing 3 rear wheels and 3 tires, a 100, a 110 and a 120 to Nate Jones, and having him shave the 100 to the minimum, skim the 120, and shave the 110 to be exactly in between the other two. He said he had never had anyone stagger their tires this way, but he liked it. They ended up being about 3.2% apart, the same as one tooth on a 33 tooth rear sprocket.  If I was you, if you need to go taller, I'd lace up a 19" rear rim, and runs a Z or (W) rated radial front tire on the back (SCTA, you see what you are driving us to? Does it appear safe?).
Title: Re: Honda CX500 - EFI and boosted on a budget M-PBF 500
Post by: edinlr on February 27, 2018, 11:45:59 AM
I have searched for info on using the front tire on the rear in the past and could not find any info about it.  The tire guys go into their dialogue about design, structure, load, etc., but never say it is unsafe to do.  Since none of us in the slow club will ever put huge loads on the tire, it is probably ok.  Now if a turbo Busa shows up with a 120/70-17 ZR front tire on the rear, then we are all in trouble.
Title: Re: Honda CX500 - EFI and boosted on a budget M-PBF 500
Post by: edinlr on February 27, 2018, 12:07:48 PM
The CX Hondas have lots of gearing possibilities even sticking with the shaft drive.  With the tallest gearing and that YUGE rear tire, if they spin this bike to 10,000 rpm it will run 190+!  Honda has five different primary gears, two rear drive ratios, and three or more 5th gear options.  Add in the variables with tire choices and Lucas can pretty much dial in the gearing he wants.  Or, with a little more degree of difficulty, just do a build like one of Jim L's and turn it sideways and convert to chain drive.
Title: Re: Honda CX500 - EFI and boosted on a budget M-PBF 500
Post by: wobblywalrus on February 27, 2018, 08:19:15 PM
There is a Bridgestone ZR rated Battleaxe 19-inch front tire and a matching 150x17 rear.  Both are radials and they work well together.
Title: Re: Honda CX500 - EFI and boosted on a budget M-PBF 500
Post by: hoffman900 on February 27, 2018, 08:52:17 PM
That seems counterintutive. The Harley guys have realized on the Spintron that a heavy flywheel helps dampen velocity changes at the camshaft. Some V8 builders are using steel timing sprocket or pulley with a high MOI to help with this as well.
Title: Re: Honda CX500 - EFI and boosted on a budget M-PBF 500
Post by: lucasanderson00 on February 27, 2018, 09:13:21 PM
Here's the part that makes this even tougher, I just had Nate Jones shave my 23" V rated tire 3 weeks ago before I saw any rule change, so now my tire is shorter and still not allowed over 150mph. There is a Guzzi final drive that exists with a better ratio - 2.91:1, my Honda has a 3.09:1 ratio. That would be great but now I must run a smaller diameter tire with a z rating, so I'm right back where I started.

Unfortunately the Factory CX650 Turbo primary gears that would solve the problem are unobtanium, I will probably have to end up buying a complete CX650T, take what I need, and part out the rest to recoup the 3-4 thousand it costs to buy one, which would be a shame and I would rather not do.

Open to any ideas on gearing, does anyone know of a machine shop that makes one off transmission or primary gears?

Title: Re: Honda CX500 - EFI and boosted on a budget M-PBF 500
Post by: JimL on February 27, 2018, 11:55:11 PM
Gearing up ahead of the trans makes the trans act like a wide ratio.  The 4-5 upshift will be tough.  

I ran CX500 primary drive even in my 680cc engine.  I shortened 5th gear by using the 5th gear from a 1978-79 CB 400 twin 5-speed trans.  You don't need both gears just the countershaft one....it mates to the existing 29 tooth input shaft 5th gear.  The part number I used was 23501-413-000 which is a 28 tooth gear (versus the 27 tooth part in a stock CX500 trans).  The result is a .965:1 5th gear which is the best you could ask for.  After my salt flats years were done, I discovered that the countershaft from that 400 twin will fit the CX with very little work, and so the chain drive job would have been much easier!  I was able to buy one of those shafts out of England (the 28T 5th gear that I used came from New Zealand through the good folks at Econo Honda).

The shafts and shift drum geometry (spacing) is the same as the later 6-speed 400 twins.  It should be possible to adapt to the 6-speed, but I think the slightly modified 5-speed will do the job.  That was the 5th gear that finally got me over the hump and saw a 163+ mph time slip from one of my 647cc destroked engines.

I guess that is about all I can suggest.  The final drive problem can only be solved by turning your engine sideways, building the chain drive setup, and then finding a suitable Honda product that has plenty of room in the stock frame so you can stay in M class.

That would be cheaper and simpler than the path you are on.  Daddy always said, "It takes a lazy man to invent a better way."  That was good advice.
Title: Re: Honda CX500 - EFI and boosted on a budget M-PBF 500
Post by: mtiberio on February 28, 2018, 09:03:49 AM
Here's the part that makes this even tougher, I just had Nate Jones shave my 23" V rated tire 3 weeks ago before I saw any rule change, so now my tire is shorter and still not allowed over 150mph. There is a Guzzi final drive that exists with a better ratio - 2.91:1, my Honda has a 3.09:1 ratio. That would be great but now I must run a smaller diameter tire with a z rating, so I'm right back where I started.

Unfortunately the Factory CX650 Turbo primary gears that would solve the problem are unobtanium, I will probably have to end up buying a complete CX650T, take what I need, and part out the rest to recoup the 3-4 thousand it costs to buy one, which would be a shame and I would rather not do.

Open to any ideas on gearing, does anyone know of a machine shop that makes one off transmission or primary gears?




Just re-read the new rules, and there is an out, although perhaps not in the 23" size. The new rule states:
151-200 MPH Production tires with speed rating of ZR or ZR-w or special tires for racing as designated by the manufacturer.

The 'or' clause is an out for me. I can get "racing" V rated bias-plys from Dunlop, Avon and Conti in 18" sizes. The Dunlops even say, not DOT approved, for racing only. They are also available in 19". I believe I could argue the 'or' clause makes them legal above 149...

Title: Re: Honda CX500 - EFI and boosted on a budget M-PBF 500
Post by: edinlr on February 28, 2018, 11:16:29 AM
I tried arguing with an official one time and he quickly pointed out that he wrote the rule, so he knew exactly the intent.  On the salt is not a place for clarification, get it in writing now.  I am guessing an e-mail from an official would be what I would want if I were going to try to use that loophole.  One would think that if you had a receipt that detailed the tire model, manufacturing date, etc., from a trusted shop, that they would accept that.
Title: Re: Honda CX500 - EFI and boosted on a budget M-PBF 500
Post by: Seldom Seen Slim on February 28, 2018, 11:33:53 AM
Who shaves the tires can be important.  The first time I went to tech with a shaved tire on the bike the inspector asked "Who shaved your tires?"  I said "Nate Jones" and the insp. responded "Right answer!"

On the other hand, you might get points for a good try if you said back to him
"I did, with my kid neighbor's mother's kitchen knife." :cheers: :cheers:
Title: Re: Honda CX500 - EFI and boosted on a budget M-PBF 500
Post by: lucasanderson00 on February 28, 2018, 09:52:01 PM
That's a good point on the jump from 4th to 5th gear, its a tough jump. I couldn't get the bike to pull in 5th gear until this year now that we are finally making hp. Very interesting that the 400 twin has the same transmission shaft spacing, I wonder what other Hondas also have transmission with a similar spacing? A taller 5th gear backed up with a taller 4th gear (maybe even an extended 3rd for the total package) could go a long way for top end mph on our setup.