67` Bomber running problems

[mo goldie]

HI

Well with the Help of the guy`s on here I have finally got the bike out for its first run today, first went to petrol station to get fuel only about a 1/4 of a mile from me it went fine, filled her up pulled away and it was good for about a mile and it went on one cylinder made it back home and it was the right spark plug and they are both New ( Now got two more cumming ) so I hope that was it....... but the thing that got me is the Gears it`s ok going up to top but when you come down the box it seems to go from fourth to third ok then seems to jump second and go right down into first gear ...it don`t do that all the time tho now and again......... I have Not touched the Engine well only to put a new clutch in but the bloke I got the bike off said it did Do that but I could not try it out at the time as it was Not running..... do anyone know what it could be ?............as don`t fancy taken the engine to bits after doing all what I have done to it ?

Cheers

Mo   

[AshimotoK0]

That's a bummer 'Mo. Always crap when a seller doesn't tell you the full story.

Worth somebody else chipping in here but you can check the shifter mechanism without separating the crank-cases (you  just have to take off clutch cover) See diagrams for things to check like the shifter shaft mechanism 1 and springs 2 &3 in top diagram attached.  ( and profiled shift plate and pins on the end of the shift drum plus the two spings 3 & 12  and associated roller mech 11. Also the spring loaded pin 9 that is mounted in the top crankcase and runs in the guides of the shifter drum. (possibly the 1st thing to check I guess before removing clutch cover etc) . Other than that you would have to check the shift forks and drum, which means removing the bottom crankcase. On the bomber the crank is totally different to most other Hondas of the period and later, in that the crank has pillar blocks mounted in the top case .... so splitting the cases (with top end undisturbed) is not too daunting ... albeit a pain in the ar*e seeing as you bought a supposedly restored bike. I feel you pain.

Perhaps someone else can chip in and confirm what I am saying ... Bryan/RoyHalliwell etc.

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[McCabe-Thiele (Ted)]

I've sent you a PM with a photo - I think diagnosing a gearbox fault is more difficult than distance diagnostics with electric niggles.

[K2-K6]

I'd agree with Ash in checking #9 item first to see if any problem there.

Seems to be a detent position hold (generally they are) to prevent the shift drum moving without command or instigated by lever.

Sounds like it's OK inside the main box, else you'd likely get conflicts between gear sets if there's variation within that part of operation.

Also as Ash notes, checking the drum etc with clutch cover removed to see if there's reasonably positive "stopping" of the drum itself ( shift exchange lever removed) would verify the positive operation of that #9 mech.

[McCabe-Thiele (Ted)]

On my 500 the bottom pawl type wheel on the shorter lever was badly worn - hole in the plate was oval - not visible until I took the plate off and cleaned it.
 
.gear shift levers etc by Macabe Thiele, on Flickr

[Bryanj]

OK , bit of an epistle here

I have never laid hands on a bomber, even at my advanced years before my time and not that common.

From your description i have a feeling the early 500 four used a similar mechanism and detent which was modified very early on due to 2nd gear problems, perhaps ( and this is a BIG jump) the later 500 change mechanism as shown in Teds picture could be adapted to fit the 450 without too much work, i do not know what would need to be done or even if its at all possible and may need a "hybrid" gear change shaft made from a 500 and a 450 combined.

If you look in Ash's dropbox or cave for all the bulletins there is one on there that shows you the modification "kit"
I have never done the bottom of a 500 either so dont know if those would fit either, a long and involved study of parts lists from cms may help but sorry i dont have the time at the present to do that for you.
There ought to be a lot of 500 twins hiding somewhere as they did sell but not in big quatities.

[mo goldie]

Are thanks everyone That's a bit to take in after all that I have done Thought I could just go out and ride Now Ha..... lol

I have looked on the D/S site ....... and they do have most like the Coller drum 24446-200-000 and the No 2 spring 24641-216-000 that they will have to order in....they have got No 12 spring No 24435-283-010 I have the No 3 spring already as that 24651-283-000.

If I unscrew that Detent 8-9 it wont drop anything inside will it Ash ? but I will take that out first to see if that is Ok and go from there.

[AshimotoK0]

Are thanks everyone That's a bit to take in after all that I have done Thought I could just go out and ride Now Ha..... lol

I have looked on the D/S site ....... and they do have most like the Coller drum 24446-200-000 and the No 2 spring 24641-216-000 that they will have to order in....they have got No 12 spring No 24435-283-010 I have the No 3 spring already as that 24651-283-000.

If I unscrew that Detent 8-9 it wont drop anything inside will it Ash ? but I will take that out first to see if that is Ok and go from there.

Pretty sure you can take 8-9 out Mo without it going inside but you may need a small magnet on the end of a rod to coax it out. Don't attempt to move the shift drum though with the gear lever. Before you do it I have some spare crankcases in my shed so I will look more closely at it. You may have to rock the drum a very small fraction either way to get the  the 'collar shift drum guide' Item#9  to release.

Also check arm #11 moves freely and has decent spring pressure from spring #12. Also that the screw #19 which holds the guide plate to the shift drum isn't loose.

I am pretty sure a 5-speed arrangement will not fit the Bomber K0 ... the bottom end of the 4-speed is totally different to the 5 speed .. the crank for instance bears no real resemblance to the 5-speed. I am told the 4-sp is more like a Honda race crank arrangement.

[mo goldie]

Great Thanks Ash for that.

I will have a look at it tomorrow and I have a small headed Magnet if needs to be to get down the bolt Hole, as I say I have the No 12 spring but will look at the 8-9 first before I go any were else...... as i have already last week took the casing off as I said before I put a new Clutch in with new springs which were EBC ones which they said were 15% stronger....... that when I got my cases back from spraying and fitted them in with the clutch new clutch plates and it so heavy, so last week as I say took the case back off and fitted the old springs and it is fine now...... just wish I had known More about the 2nd gear Problem while I had that to bits I could have checked that all out while that was off ha

Cheers Mo   

[AshimotoK0]

Here goes Mo. The hex head on the bit in the top crankcase was pretty tight but removed it and pictured parts in the images below. Also tried to photo inside the hole and you can see the channel groove in the shift drum directly below so pretty sure nothing can drop inside when you remove the 'bolt' thingy.
Cursing as the case wasn't on the shelf where I thought it was ... I had stored it away in the bowels of my shed. 

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[mo goldie]

Are ok thanks for that Ashley

Just took that out and yes it was very tight to get that undone Ash as you say....... must have used a road drill to put that in  but got it out and it don`t look to bad and not much of a bad fit on the end of the bolt but can`t get to see the other end but I have ordered the bits from the Pirates  but will take a couple of weeks to get to me as got to get some I think from the USA Branch. 

[AshimotoK0]

Updated my earlier post Mo .. check arm #11 moves freely and has decent spring pressure from spring #12. Also that the screw #19 which holds the guide plate to the shift drum isn't loose. But of course the shift shaft arrangement and it's spring needs to be looked at too.

I am also hoping that the little pins #4 which  run in the channels of the shift drum and retained by 'R' clips #5 are OK too but 1st you need to check the stuff outside the crankcases and hope that's the cause.

[Bryanj]

Looking at those pics disregard all the drivel i posted earlierthe system is totally different, as Ash said spring pressure is the only thing to check

[mo goldie]

Hi Ash

if you look at the picture I put on from the Pirates.... I have ordered all of the ones you have said about so will be looking at all of them when they do turn up oh the N0 5`s I did Not order as yes they are inside so hope I don`t have to go there  ...I am Not taken it apart till they get here as I want to use it to the little show if I can... but I will get on to it soon as ............ thanks Again as we all need help if we Not used to the bikes we have just got and all on the Honda site has been a real source of inspiration.

Keep up the great advice for us all.

Cheers Mo   

[mo goldie]

Hello

Just been out for a 30 mile ride and just to give an update of how it all went, it seems to be around the 4,000 Rev range to Not want to pick up and seem to be a bit lacking in power and seems a bit sort of Fluffy if you get my meaning, its Not until it hits the 5.500 ish range that it picks up a bit,  ( oh that's a rough revs as the rev counter is a bit over the place )  I did take it up to 70 mph seems more happy at about the 55 - 60 MPH..... it just seem that that 4,000 rev range is the problem and it just don`t want to accelerate anywhere up to and around them revs..... anyone else came across this and know what it might be....oh I did get my Carb kits the same ones as (Roy)  so should be all ok there ?

as other than that it went all ok..... even the gear problem was Not to bad it only done that a few times but when I get them parts as I said before I will sort that out too I hope.

do anyone have one of them as No wonder the tank move about ?
17614-283-000 FUEL TANK MTG. REAR RUBBER