Timing problems on the 450 Bomber

[mo goldie]

Hi everyone

Well Just got one of the electronic Ign from the guy`s at Common Motors, i fitted it yesterday all fine till I come to try and Time it in, there are two lights one Blue ( left ) and a ( Green ) Right, on compression stroke and when you come round to the LF and LT marks the blue light is meant to go out when it hit the LF Mark, well it go`s way passed that mark by about 15 mm or more..... yes I have turned the cam plate to advance the timing but it still wont go anywhere near that LF mark.... do anyone know what could be wrong I have Noticed that on the rotor where the marks are that it is stamped CB450 K5 .......... i don`t know what the 1967 CB450 K0 rotor is meant to show on it .....as this is all New to me .... so just wondered if someone has fitted this rotor from a later Model if that is Possible and the marks are in a different place.... but asking you guys as you will know a lot more than I do.

Thanks in advance

MO
 

[mo goldie]

well found one more problem today when I tried to see if I had spark........... and Nope it has NOT 
so went through all my wiring to make sure I had done it right and I had ......... so why No spark ?

all seems to be right

as they say always something ha .............anyone got any Ideas ......about it all ? other than it might be the electronic Ign as i have emailed them ( Common Motors.com ) to say but ha ho its there Thanks given ............wondered why I got No reply ha 

[AshimotoK0]

The reason it will have a K5 rotor fitted is that the Bomber sprag clutch for the starter motor is notorious for failing with catastrophic results .. like chewed up rollers and the thin round plate which retains them. So its probably been replaced with a K5 , 5-speed rotor . As far as I know the timing marks will be the same as the K0 but need to check this. I think Roy Halliwell on here fitted a 5-speed rotor to his Bomber so he will probably know.

No real idea on the electronic ignition as I have never fitted one to a twin. For the relatively low miles these bikes do these days a lot of people just stick with points. However, not sure if you are going to do loads of miles on it.

[mo goldie]

are Ok Thanks Ash well at least that clears somethings up so it is ok then........... but as I say the timing marks don`t line up when you get the piston to TDC so makes me wonder what's going on with that, I have sent Roy a PM two days ago but Not had a reply yet....... so hope he can shed some light on the subject ?

Cheers Mo

[AshimotoK0]

are Ok Thanks Ash well at least that clears somethings up so it is ok then........... but as I say the timing marks don`t line up when you get the piston to TDC so makes me wonder what's going on with that, I have sent Roy a PM two days ago but Not had a reply yet....... so hope he can shed some light on the subject ?

Cheers Mo

I have a later 5-Speed rotor and an original K0 one to compare Mo but can't get to them until Tuesday to compare.

Count it as a plus point that somebody has fitted a rotor with the later starter clutch as the original K0 version was very problematic and often wrecked the alternator stator coil when it failed catastrophically. Plus a newer rotor may have  have more  magnetism left in it. A lot of original K0 rotors have weak magnets now.  Even a 5-speed rotor in decent nick is a £150-£200 asking price part. Roy and myself got ours from DK.

[royhall]

Now your asking a big question. From memory (it is quite a few years ago now) the K5 rotor and sprag clutch fits and the timing marks should be the same. That said, there are a few engines out there with a different crank configuration that were used mainly on the police specials. They are that rare I doubt you would have one of those.  So if the rotor is correct but still doesn't line up correctly something else is amiss. You didn't say what work has been carried out on the engine? Is it possible that the cam chain is maybe a tooth or two out that would put the cam out of sync with the crank. There are timing marks on the camshaft that need to line up, I would check that first. Also check that when the TDC mark on the rotor is set that the piston is actually at TDC.

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I used a "Charlies Place" electronic ignition, and to get the timing correct it was right at the end of it's adjustment. I never did get to the bottom of why that was as it ran well in that position. But there really was no adjustment left. Just a thought, is it possible to get back to the points setup and see if all is okay, or was it already running on points before you decided to fit the electronic. As I said, you didn't mention the bikes history before you attempted to fi the new unit.

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[McCabe-Thiele (Ted)]

I know nothing about black bombers but my casual observation is that in the first photo the two ignition sensors are in the lower quadrant, in Roys photo the sensors are in the upper quadrant - just looks so different even if neither is at TDC?

Could be different design of rotors - how do they compare to the original points base plate locations?

[royhall]

Yes I noticed that. I think it's just a different decision on how to best fit everything. Sensor position doesn't matter as long as the rotor is keyed correctly to accommodate that position. My biggest problem was getting both cylinders timed, as you can see the sensors are actually touching and there was no movement left. I had to half the difference and this left it very slightly out but it still runs well.

[McCabe-Thiele (Ted)]

Yes I noticed that. I think it's just a different decision on how to best fit everything. Sensor position doesn't matter as long as the rotor is keyed correctly to accommodate that position. My biggest problem was getting both cylinders timed, as you can see the sensors at actually touching and there was no movement left. I had to half the difference and his left it very slightly out but it still runs well.

Oddly enough it took me ages to get the timing marks correctly aligned for 1/4 and 2/3 on my 400 - it was fitted with the Dyna system.
Even though the individual sensors are slotted for adjustment getting it right between the baseplate & the individual sensors took me ages.
It was easy to get 1/4 right but 3/4 would run out of adjustment so then had to move the baseplate a bit, re adjust 1/4 then check 2/3 and repeat as nipping down the baseplate would change the settings slightly.
Definitely worth my effort as the engine sounded quiter & smoother when I finally got it right.
It actually took me attempts spanning several days as I would leave it saying thats close enough only to go back to make minor changes.

[royhall]

Yes that was my problem on the Bomber. Unfortunately I ran out of adjustment. I considered filing the sides of the sensor plates to get them closer together but it would have made little to no difference as it was so close anyway. Bit of a design and manufacturing problem I think.

[Bryanj]

Ifvthe marks dont line up at tdc nothing you adjust will be right

[K2-K6]

Worthwhile marking on the stator a true TDC mark as it's installed now...using marker pen / paint.

Then mark a F mark at static on the rotor to give (std setting, 14 btdc ? ) to be able to examine the trigger positions reference to this.

At least you'll see what you've got initially to then make decisions about what's wrong.

[mo goldie]

are thanks all.

Ash if you can look tues will be good thanks,

Hi Roy yours I see the adjustment is what I had a problem with as I see on your picture that the base plate run out when it hit the washer on the Exhaust adjuster which is where mine hit, but even then the timing mark was way past the LF mark.
I also see your pick ups seem to be all in one so do they go from the two triggers right to the coils ? as Mine have two pickp ups and then go to two Modules which mount behind the Ign switch with two light on one Blue for left cylinder and one Green for the right Cylinder you are meant to time them up where the blue on the comp stroke just go`s off when it hit the LF mark as i say it go`s off but well after the TDC mark By about 1/4" .... but one all saying that don't understand why I can get a spark at the plugs......... they did want me to Buy a set of coils two but Mine by the looks of them are not that old, Idid go check today on the resistance and they both near the same as each other Pri left was 0.41 sec was 11.27 right coil was Pri 0.40 and Sec 11.66 .... but as I sat they were both running the engine when I went and picked it up..... the guy`s at Common Motors also wanted me to buy there Coils, but at anther $120 I gave them a miss..... but they say that their units will work on standard coils fitted but need to be a resistance of 5.0 so do you think this to be true ?   

Hi K2

Yes I used a dial gauge and got top TDC and indeed it is past the LF by about 1/4" or so and I have put a marker pen make where TDC is..... still strange that I am Not getting a spark........ yes it was running on points before I put the E/I on and I No Nothing on how the engine was put together.


also one more thing if you look at my picture of the base plate you will see the dot on the cam is at the top should that be on the first blue pick up when its on ..or as mine is pasted the LF .... LT as mine it at the top when it near them.... so I tried to turn the advance unit round 180 to see if that made any differance but it did Not .... stummed       

[AshimotoK0]

Mo...your standard coils will be 4.5 to 5.0 Ohms, so should be fine.

[royhall]

Did you hear anything back from common motors? I think you need to chase down the no spark situation before anything else. If you can get it to run you can ignore the coloured timing lights and strobe it.

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