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Discussion Starter #21
Patoo
At that time MOSFET tech was very new to the motorcycle industries. It's a standard now in most all bikes
You are right Beestoys, new at the time.

Again to keep XX and other collectors alive, switch to MOSFET.
This is not a performance or customization mod but a bike healthy mod. Origin R/R failure could ruine the bike, the battery or the harness.
 

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Pattoo, are you saying this is a dirt cheap R/R from ali express that you show mounted on the blackbird?
If so, do not use. It will fail. It will leave you stranded and may take out other components at the same time, such as : battery, stator, wiring harness. Many members here including myself have already been thru this toothpaste tube. Replacing all the fried components will be more than buying than buying the genuine article in the first place. Check out this website for good info: roadstercycle.com
By the way, congratulations on bringing her back to life.
 

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Discussion Starter #23
Thanks Fizzy.
I understand your warning as I am newbie, I take in consideration the forumers experience.
The MOSFET mod remains the ultimate solution if R/R we all agree.
The ultimate installation would be:
  • Invest in top brand MOSFET
  • Modify the wire Harness from Stator and feed direct the battery.
My cheap Chinese MOSFET (temporary plug & Play mount) is not secure enough and will fail. I would say not more or less chance than Honda origianl R/R. Even with less consequences thanks to MOSFET techno (Tyristors fails in different pass or block the voltage).

I will chose this option untill next failure:
- install a volt meter to surveil the voltage permanence.
This will alert me in case of failure and avoid additional damage.
This is true for origin or adaptable R/R.

Thanks all for the advises.
 

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Discussion Starter #24
We can fine tune about R/R, I need to continue on my story of rebuild.

I said "Running 4 cylinders then suddendly becomes a 2 cylinders..." because this is what happened suddently.
The engine fired, the bike was naked but the engine ran smooth. So I decided to ride in a private parking.
I needed to check in field what are hidden points to focus on. I am in the very beginning of the rebuild.

So during the private parking run, I felt a sensation of bicylinders like the time I passed my bike licence on a GPZ500.
I drove back in the workshop, just time to park and the engine stopped again (no juice, I didn't received yet my second hand Origin R/R).

That was my tougher job to figure out what is going wrong to be 4 to 2 cylinders firering.
I guess you guys with experience knew what is wrong but me alone, in the room of the company, worikng on my bike after the job... I was alone...

Let play a little guys, forumers!
Tell me what is your scenario, what is wrong and what to check to prove it.

I can prove you I am a newbie as I will list all the step of check I did and all the mistakes I made as I am not a mechanics senior but to tell you the truth, it as much to find out than riding the bike... so much satisfaction, you understand?

So post your scenario at that stage... and why you think you are right.

I will then post step by step my check, find out, mistakes...

Go go go why goes from 4 to 2 cylinders firering???!!!
 

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Discussion Starter #25
What is wrong BB, tell me which cylinders failed to fire?

- check 1: which cylinders fire, which one not?
--> Touch the exhaust pipes
--> When engine running on 2 cylinders, unplug the wire going to High Tension Coils and see whic one affect the engine.

As a result, cylunders 1-4 fired, cylinders 2-3 not firering.
Both checks confirmed the situation.
Unplug left HT coil (cyl 2-3) feed doesn't affect the engine, unplug the right HT coil (cyl. 1-4) stoppes the engine running only on cyl 1&4.

Any idea/scenario from there?
 

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Could be trigger voltages for coils or coils. Blackbird uses a wasted spark system and fires 2 cylinders from one coil. In our case the cylinders are paired. 1 4 2 and 3. So first swap coils to see if you paired firing cylinders move. If so it's the coil if not it's the trigger voltages or supply voltages for that coil.
 

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Discussion Starter #27
Good point Beestoys.
Two HT coils with double departures for paired cylinders 1-4 ( right Coil) and 2-3 ( left Coil).

- Check #2 : Yes I checked this by swap left coil with right coil.
The goal was check if the High Tension coil failed.
--> Still running only on2 cylinders :1-4, not firering 2-3.
As a result, HT coil is not the problem.

Any other scenario?
Don't be shine, I tried many ways as I am newbie.

Post your suggestion, we are only at Check #2.

Come on, let's play!
 

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Discussion Starter #28
- Check #3 in line with the HT coils of Check #2, swap the cyl. 1-4 HT cables against cyl. 2-3.
The goal is to verify if the High Tension (voltage) cables and Plugs caps are OK.

--> After swap of the cables... still firering cylinders 1-4, not firering cylinders 2-3.

Any suggestion?
 

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If read right you swapped and the same 2 cylinders are still down. Verify plugs are not bad. Lay against ground on. Plug ground strap or use a spark gap tool. If it's still dead then I'd check supply voltages to that coil. Should be 12 vdc at one side and changing voltage at the other. If it is 12 vdc then your not getting your cdi trigger to the coil.
 

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Discussion Starter #30
Yes, Beestoys, here we are,
- Check #4, inline with previous checks for sparks... Plugs status and Electrods gaps.
All 4 plugs identified, gap checked / adjusted to 0.7-0.8mm, then reassembled (1-4) plugs into (2-3) cylinders. Basically swap again plugs from 1-4 with 2-3.

--> Guess what... still firering 1-4, not firering 2-3!

- Check #5 Can I witness all plugs sparkling?
Dismounted all plugs, attach then to the plug caps, touch the chassis for ground... Firering starter.

--> Yes I can witness all 4 plugs sparkling!!!

What else?
 

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Discussion Starter #31
Ok,
Backup...
Running normally on 4 cylinders, suddendly failed to 2 cylinders only, cylinders 1-4 only, cylinders 2-3 not firering.

Checked ignitions, plugs, sparks. All good.
Only timing of the spark can't be checked but no reason to have 2-3 disynchronized, impossible.

I considered the problem is not in the ignition section.

I went to check the fuel section.
 

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Either you have a bad FPR, or maybe a banana in the tailpipe*.

* Eddie Murphy, Beverly hills cop, 1984.
 

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Discussion Starter #33
Ok Fizzy, I was alone, newbie face to my problem, you need to tell me more.

- Check #6 How are the injectors?

I decided to swap injectors 1-4 over the 2-3.

--> Again and again, cylinders 1-4 firered but not cylinders 2-3.

Fizzy, please explain your hypothesis and how you get there.

I was looking for other checks... combustion chambers pressure...
 

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Well if you have fuel and fire then the next step would be a compression test as you begin to state. Suspect they now you have a open valve on those 2 cylinders. A leakdown test would tell you intake exhaust or rings. Or being its 2 cylinders side by side yuk a bad head gasket.
 

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If the FPR (fuel pressure regulator) goes bad, raw fuel can pass thru it and directly into the engine intake, overwhelming the ability to fire, maybe on a few cylinders, not all. Also, raw fuel can make its way into the oil, diluting it.
To test, pull the vacuum line off the FPR and check for fuel. It should be bone dry.
 

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Discussion Starter #36
Yeap Beestoys,
Ignition checked OK
Fuel Injection checked OK
No explosion in 2-3 maybe because head gasket communicates between cylnders 2-3.
I suspect this gasket because there is no reason to loose compression on 2 cylinders at same time nor piston rings at same time on 2 pistons.

- Check #7 Compression test with pressure gauge sealed on plugs threads.

HONDA specification for cylinder compression : 185 psi/ 12.8 bar

--> my mesurements on all 4 cylinders: 12.7bar!!!

Bad news : don't know where to research my problem after that.
Good news : My BB engine compression is nearly perfect!
20200831_021748.jpg
20200831_021620.jpg
 

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Discussion Starter #37
Fizzy, much respect, because you are 100% correct, you are expert!

I am newbie, I have no idea about the FPR face to my problem, so I made more mistakes...

Because I thought I checked all possible (all I know), I searched everywhere in forums... I was desesperated.

I then started to invent virtual failure (bet on possible failure).

I started to suspect the ECM... I remembered my battery failure to 0 volt, twice.
I suspect my ECM managing the injectors failed. Even invented a good injector command during starter on but not once engine started, for any reason, the ECM failed to keep the injection for cylinders 2-3.

See how much I was desesperated...

I started to search on ebay for a set of Key+ECM (model compatible only 99-00).

I found on for 349€ a complet set with fuel tank lock and seat lock.

I could not abandon now... I bought it.

Due to COVID-19 lock-done, took 3 months to get the ECM set, so much frustrations.

- Check #8 : Finally got it, install the ECM...

--> Still no fire ln cylinders 2-3!!!! Noooooooo!!!!

I was doubting... about this adventure of rebuid...

What now?
 

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Patoo
You say compression I'd good and you have verified fuel the the cylinders as in you have seen injectors firing into the ports.
There is another possibility you can develop compression if one of the valve sets isn't opening. You could either be not getting fuel into the cylinders or you could be dead heading because the exhaust isn't opening. Also have checked your injector connections and crossed 2 and 3
 

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Discussion Starter #39
Beestoys,
I couldn't accept the hypothesis of cameshaft / Valves failure suddently, without any signs of mechanics failure.

As I had no more idea, desesperated, my humain brain started to fail in logical analysis, my deep believes in mechanics started to leave me, I started to practice incoherents actions:

  • recheck the wires harness/plugs again or 3 times
  • recheck the HT coils
  • recheck the wirering, the voltage again and again
  • recheck and swap the ECM again
  • recheck the factory harness check plug (the big on under the battery).
  • And finally recheck again all 4 spark plugs unscrewed of the cylinder head, to push starter and check visually the sparks...
But this time my eyes and attention was attracted by 2 colums of "vapes" blowing out from the plugs threads of cylinders 2 and 3.

That was a huge difference between the visual gasoline vaporise flushing out from cylinders 1-4 (almost invisible vape) and cylinder 2-3 (as dense vape as my big electronic cigaret vape, 2 big colums about 25cm height each stroke of the cylinder 2-3).

My first thoughts were... Whaouh, there cyl 2-3 never firing accumulated so many gaspline in the inlet/exhaust due to my multiple attempt to start the engine...
I thought I just need to push the starter again and hold with no plugs threaded in, this will drain out all the gasoline because the vape colum are so dense, this will bndrain quick.
But after 30seconds (which is very long...) the vape never reduced.

My brain was slow but I started to realize, this is impossible situation:
  • The inlet pipe and cavity can not hold liquid gasoline
  • The exhost pipes (4 in 1 in 2) can not hold liquid gasoline as cyl 1-4 burned into the pipes.
  • if there were any liquid gasoline somewhere... after 60seconds of "pumping" I would drain all out, shouldn't have any vape anymore.
I realized I hold the final question of the problem: FROM WHERE THE HELL THIS GASOLINE CAME FROM???
(@fizzy At the time I had no idea what is a FPR even it does exist...).
It is clear in my head now about the problem:
  • too much gasoline : no firing cylinders concerned (2-3).
  • all checks I performed were OK just because it is OK.
So I started to imagine the injectors 2-3 failed to inject correct quantity of gasoline...
No impossible, because injectors swaped and worked fine. Injector pilitzd by ECM, ECM changed, can not be same failure to inject only cyl. 2-3.

So I disconnected the elect. feeding of injectors 2-3 and restart to run the starter to drain out the gasoline...
No way, same vape came out non stop each stroke from cyl 2-3!!!
Where the hell the gasoline came from???!!!

Then I started to look in detail all possibility to get gasoline from the tank to the cyl 2-3...
So many small rubber hoses...

This is a long post...
Next post, the final finding of this 3months and half blockage!
 

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Discussion Starter #40
Where the gasoline came from... what is the conexion to the tank despit the injecters disconnected I still have massive gasoline in my cylinders 2-3.
Detailed inspection of the gasoline flowlines:
Fi pump--> Fi rail left side.
Fi rail right side has a device --> back to tank.
I guessed this is the discharge device (overpressure/flow of the pump returning to the tank). In other words this is a safety valve or Fi pressure regulation valve or so called Fuel Pressure Regulator - FPR, a new vocabulary for me in the XX rebuild but very commun for my job as I am valve designer.

Still, nothing to expect from this fuel loop, no relation to the inlet pipes/cylinders 2-3.

Back again to inspect thoses small rubber hoses attached to the butterfly body.
All hoses are below (after or downstream) the butterfly level.
Easy to guess if butterfly (throttle) close, engine stroking, this will create vacuum.
Hiher rev, throttle close hiher vacuum.
Throttle opened, less vacuum.
OK git it, these are vacuum hoses.
Focusing on the one connected to injection pipes 2-3, they go to a tee, and goes to somewhere to the FPR, very end, oriented to the floor ( hidden I didn't see that during discovering the FPR first time).
Wait a minute... a relieve valve design coulb be stand alone or piloted.
Stand alone needs a poppet and a spring.
A pilote requirzs external power... VACUUM!
The small cap a right side of the FPR where the vacuum hose is connected is so tiny... no room to design there a piston+O'ring sealed slave receptor but can only be a membrane smave receptor.
GOT YOU, F.CKINK LEAK!!!!
No doubt about this the way this works:
The membrane receptor leaking, the main role of the FPR still work properlly but a fraction of the gasoline leak though the failed membrane, vacuumed to the cylinders pipe 2 and 3, givibg a massive flow of gasoline, annealing any chabge to have correct Air/Gas mixture to fire the cylinder 2-3.

Easy test: unplug the small hose from the tip of FPR, block the vacuum hole with a small screw or screw driver, plug a small external hose to the FPR drain to a container and fire the engine...
IMG-20200831-WA0000.jpg


I had gasoline only switiching on the key running the Fi pump and stated the engine all 4 cylinders running (YES!!!) And the leak flow getting worst.
I can even manage to have a test drive returning the leaking frain hose back to the opened tank cap.
WHAT A DELIVRANCE, I can dream again to finish this rebuild.

I straight away ordered a brand new FPR but... whuch one?
43 psi (1999-2000) or 50 psi 2001 and after.
After some benchmark, I decided to go 50 psi for better combustion (turned out to be a error, just ordered few days ago the 43 psi 2000 version for my 2000 XX for fuel economy as I do lot have PowerCommander to reduce injection timing.

Well well well
How the hell does work the vacuum pilot in the FPR?
What ever how the internal components are designed, the vacuum will pull in the direction of opening the poppet or in the direction of compression of the spring.
My guess of the function is:
  • or the membrane is "condom" shape keeping the spring at vacuum side, vacuum will compress the spring reducing the pressure on the poppet = reducing the Fi rail pressure, more return gasoline to the tank when throttle is off especially in high engine rev. When the throttle is open or high rev, the vacuum is less (butterfly opened), the FPR give the max pressure of the unpiloted spring.
  • or the membrane sits between the main spring wetted side and a vacuum side small spring (not necessary a coil style), the same function as above, vacuum will compress the vacuum spring, giving longer main spring stop... reducing its force applied to the poppet. Same as above, less Fi pressure when not needed (throttle off high rev).
If someone can confirm my guess (anyway sooner or later I will unswage the mistery failed FPR causong me so much problem, cost time and stupid purchase of complet ECM set (i have a spare 99-00 ECM set in case).

End of the 4 cylinders suddently becomes 2 cylinders firing problem.
I hope my story will help you one day because the FPR membrane IS NOT ETERNAL!!!

What is my next problem... need to read the summary ahahaha

Again fizzy, you got it from my check #5 I was still in the sparks section research... you are good Sir!
 
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