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Discussion Starter · #1 · (Edited)
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Hello, guys,


Let me start by saying I've only arrived at where I am because of both the tips and the knowledge of the folks in this forum.

I've been through many things with my bike, the latest being:
- brand new B8ES NGK plugs;
- adjusted the cam chain (spring was working fine);
- valve tappet clearance adjusted;
- rebuilt starter motor;
- cleaned carbs, piece by piece (needles, piston, bowls and floats, all screws) - straw test A-OK;
- adjusted carb floats (20mm);
- new fuel lines;
- synced carbs and went through the carb adjustment, as well as I could (Honda CB450K5 Owner’s Manual (1972))

Right after cleaning the carbs and reassembling them, the bike started fairly easily on the left cyl (had to go through the cold starting procedure, as per the manual - kickstarted it). I then swapped the plugs and it started with the starter motor on both cyls, strong both at idle or reving to much higher RPMs (not sure if the left plug, being hot, helped the right cyl ignition).

Some important data being:
- I have UNI foam filters;
- the main jets are #45;
- as stated, 3 weeks ago, the bike was running strong on both cyls;
- the garage it sits in is quite cold and humid;
- hadn't changed or done anything on the bike since it had been running 3 weeks ago;
- battery is Yuasa and seems to be topped or near - even if it wasn't, I should still be able to kickstart it.

This starting and right cyl not igniting issues have been a mistery to me, ever since I bought the bike.

Any ideas as to what it might be or things I should try?

Thank you very much for your input.
 

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starting fluid would tell you if it is a fuel issue or ignition issue.
 
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éter. fluido inicial. It is used for starting diesels in cold weather.

Just a light spray in the intake of the carbs, if it starts it is a fuel problem, if nothing happens it is an ignition problem.
 

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AIR, FUEL, SPARK... and of course let's not forget compression..
This is the BASICS of a internal combustion engine.. just a process of elimination ..
 

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Discussion Starter · #7 ·
éter. fluido inicial. It is used for starting diesels in cold weather.

Just a light spray in the intake of the carbs, if it starts it is a fuel problem, if nothing happens it is an ignition problem.
Ahahah, Jim! Thank you very much for the explanation and for the effort with the translation (though "fluido inicial" means "beggining fluid" :p)!! Man, people at this forum are just always helpful. I deeply appreciate all the tips and words of comforting everyone has lent me.

I will try that, Jim. Will check where I can get it, asap.
 

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Ahahah, Jim! Thank you very much for the explanation and for the effort with the translation (though "fluido inicial" means "beggining fluid" :p)!!
Damn google translate :p

In the US you can get it at any auto parts store, I don't know about Portugal.

It should only be used for troubleshooting. Don't try to run the engine with starting fluid for an extended time and only use a light spray, don't flood the carbs with it.
 
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Discussion Starter · #9 ·
AIR, FUEL, SPARK... and of course let's not forget compression..
This is the BASICS of a internal combustion engine.. just a process of elimination ..
Hey, Rob. Thank you for replying!

Fuel seems to get through, as the plugs are wet. Air (3 weeks ago) was going in fine, as the bike didn't sputter, didn't die idling and reved with power. The spark.. IDK - need to check if it sparks by getting the plug out by the engine metal and crancking the engine..

Just so damn frustrating that it was going fine just a while ago.
 

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Discussion Starter · #10 ·
Damn google translate :p

In the US you can get it at any auto parts store, I don't know about Portugal.

It should only be used for troubleshooting. Don't try to run the engine with starting fluid for an extended time and only use a light spray, don't flood the carbs with it.

Certainly! Will do! Thank you very much, once again! I'll let you know how it goes.
 

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Discussion Starter · #12 ·
If the plugs are wet it might have simply been flooded. I would dry the plugs and try it again.

the UNI foam filters, are these pod filters or did you take the original paper filter off and put uni foam in place? Like this thread, post #14 http://www.hondatwins.net/forums/49...n/36906-uni-foam-filters-who-uses-them-2.html

If pods, you might want to search for threads on rejetting the carbs.

Yeah, I thought that as well. Did clean the plugs dry several times and tried again. Then swapped them from one side to the other after drying again. No joy.

The filters are these ones. The paper ones were ruined and to get the paper out, I'd have to melt the (supposedly) toxic glue and I unfortunately had no proper conditions to do it in-house.
Yeah, read about rejetting, indeed. The thing is it ran just fine 3 weeks ago.. My God. I guess it will not run perfect with the UNIs and 145 main jets, etc. but I just wanted it to start and rev as it did... :sad:
 

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I haven't done any rejetting so I can't help there. I know there are several threads on adjusting and rejetting 450K's.

I cut the paper element out of my 450K6 and 500T and replaced with the green Uni foam, no burning required unless you want to. No rejetting since I am still using the factory filter frame.
 

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Discussion Starter · #14 ·
I haven't done any rejetting so I can't help there. I know there are several threads on adjusting and rejetting 450K's.

I cut the paper element out of my 450K6 and 500T and replaced with the green Uni foam, no burning required unless you want to. No rejetting since I am still using the factory filter frame.
That certainly gets better results. Will indeed give it a thought once I get the engine going with no further things to address.

Once again, thank you for everything, Jim!
 

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That certainly gets better results. Will indeed give it a thought once I get the engine going with no further things to address.

Once again, thank you for everything, Jim!
As Sonreir can attest, I am no expert but I can pass on my experiences, not like some members who worked on these bikes when they were new. One thing great about this forum is the majority are happy to help and we have members from all over the world.
 

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Discussion Starter · #16 ·
As Sonreir can attest, I am know expert but I can pass on my experiences, not like some members who worked on these bikes when they were new. One thing great about this forum is the majority are happy to help and we have members from all over the world.
No doubt about that! I am really thankfull for all the help and tips I've gotten from you guys. I will certainly not forget it!
 

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hi,

Welcome! 450 owners have had a lot of issues when using pods, so keep that in mind. For the battery, I strongly suggest throwing it on a charger/tender overnight and measuring the volts with a meter. Our bikes must have strong batteries or else you will experience all kinds of issues resulting in you chasing your tail thinking you're experiencing something worse.

Carefully go thru the proper ignition timing procedures; points gap etc. The timing must be done on the compression stroke, not intake. Your bike could start but it would require more effort and run incorrectly. This is time consuming but once you nail it in my experience, you won't have to do it more than twice during the riding season. Point can naturally wear out so inspect and make sure they operate properly. when in doubt, replace but please buy genuine HONDA OEM points because owners have posted all kinds of trouble resulting from crummy aftermarket brands.

Your spark plugs being wet indicates too much fuel and flooding so recheck your float heights; 20mm. this is critical. a pain? yeah, but the adjustment seems to stay almost all season for me. Search our forum for all proper setup techniques.

good luck! report back for help if needed.
 

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Discussion Starter · #18 · (Edited)
hi,

Welcome! 450 owners have had a lot of issues when using pods, so keep that in mind. For the battery, I strongly suggest throwing it on a charger/tender overnight and measuring the volts with a meter. Our bikes must have strong batteries or else you will experience all kinds of issues resulting in you chasing your tail thinking you're experiencing something worse.

Carefully go thru the proper ignition timing procedures; points gap etc. The timing must be done on the compression stroke, not intake. Your bike could start but it would require more effort and run incorrectly. This is time consuming but once you nail it in my experience, you won't have to do it more than twice during the riding season. Point can naturally wear out so inspect and make sure they operate properly. when in doubt, replace but please buy genuine HONDA OEM points because owners have posted all kinds of trouble resulting from crummy aftermarket brands.

Your spark plugs being wet indicates too much fuel and flooding so recheck your float heights; 20mm. this is critical. a pain? yeah, but the adjustment seems to stay almost all season for me. Search our forum for all proper setup techniques.

good luck! report back for help if needed.

Thank you very much for your tips, J!

My issue was sorted by a mechanic I found lived nearby.


The issue was simply two things: bad spark plugs and bad ground by the coils.
Really, really strange, but those were the third pair of NGK B8ES I had put onto the bike - I obviously had taken that out of the picture as a problem. The mechanic agreed it was really uncommon but he noticed that the spark was not happening by the plugs outer ring but on the inside. He recommended NGK BR8ES - it's just fine. He also grinded a bit of the bike's paint at the frame by the coils.

Idles high, so should be doing a carb sync by a pro whenever I get the time, but am really happy ATM.


Thank you very much all!!
 

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I had a set of NGKs bad out of the box...
needless to say I was chasing that gremlin for months..
 
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I would highly recommend using iridium NGK BR8E1X-S plugs. I used to have fouled plugs regularly when using the normal NGK B8ES but ever since switching to the iridium plugs a couple years ago, I have not had to replace plugs since.

The sparks are much stronger also.
You would need to replace the plug caps for non-resistored ones though since the iridium plugs are already resistored.

https://shop.advanceautoparts.com/p/ngk-iridium-ix-spark-plug-5044/15650072-P
https://www.amazon.com/NGK-BR8EIX-Iridium-Spark-Plug/dp/B000C5M2MW
 
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