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British Bikes / Re: Firing on one cylinder only
« Last post by Oggers on June 12, 2021, 08:42:24 PM »
Yes Boyer, and battery reads 12.5V when not running.

I can only think it is something I have done when either servicing the carbs or removing rocker covers. Would fitting the rocker covers upside down foul the tappets I wonder? I 'll take a look....

Swapped the HT leads - no difference.

Yet to try

Swap the coils - dont see why, but you never know
Run the bike with IN/EX oblong rocker box covers off - too see if valves are sticking. How do you unstick them!
Check O-ring on carb inlet manifold. I may have disturbed it when refitting.

Anything else?

Many thanks

 
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British Bikes / Re: Firing on one cylinder only
« Last post by Rex on June 12, 2021, 07:18:46 PM »
This may seem an off-the-wall question, but are you running a Boyer ignition unit and is the battery fully-charged? It's a well-known characteristic of Boyer-equipped bikes that with a low-ish battery voltage they'll only fire on one cylinder in use.
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British Bikes / Firing on one cylinder only
« Last post by Oggers on June 12, 2021, 12:56:04 PM »
Gents

Another  fault developed with 66 Triumph Bonneville Post the clutch issue - and thanks for all replies - I moved on to service the carbs (Amal 930s).  Just a visual of floats,main jets, slides etc to see if all was well. I removed the tank, removed the carbs, replaced everything as per. It's all pretty new, so didn't notice anything, and didn't really expect to as the bike was running fine. Another thing I did was simply to remove the rounded oblong rocker box covers - it has a later head - with the intention of checking the valve clearances. I didn't bother in the end as all seemed well. All reassembled as per manual and woe! Right hand cylinder is not firing - well mostly, it seems to now and then when testing on the road, but basically there is no power there. Left hand seems fine.

What I have done so far

Checked carb for float faults, needle, needle holder - all seems well. Bowl gasket fine. Carb seems to be delivering petrol to the engine and not flooding - I can see the spray through the inlet. All seems well here.

Checked for spark at plug. Fine. Good spark. Changed the plug just in case. No difference.

Checked the coil - all connections appear fine. No real reason to suspect this. Coils are pretty new.

Gave the exhaust valve several tap on the head- stuck valve perhaps. No change. Admittedly did not do inlet.

It's all very odd - it ran fine a day ago! I may have disturbed something, but no idea what.

All suggestions are most welcome
 
 
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Autojumble / Re: velocette gtp
« Last post by beardyimpman on June 11, 2021, 09:11:16 PM »
thanks for the reply ,will look at that type of wheel,
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Autojumble / Re: velocette gtp
« Last post by iansoady on June 11, 2021, 09:50:15 AM »
My post-war Francis Barnett cruiser has a 6" drum and a 1/2" spindle so might be worth looking for one of them. British Hub I imagine.
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British Bikes / Re: Notchy gearbox
« Last post by john.k on June 10, 2021, 02:28:01 AM »
If the clutch is actually dragging ,first thing to check is the pressure plate at full lift.....does it wobble as it turns.......may be that new springs in a matched set are needed,or just adjusting the spring nuts to level the plate at full lift...Another thing to check is primary chain tension.....check at the tightest spot in several rotations..........neutralizing or jumping out of top gear will quickly damage the whole box with steel chips ,not to mention the gears involved....Likely cause is excessive endfloat in the box somewhere,either selectors or even ball bearings.
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British Bikes / Re: Notchy gearbox
« Last post by Rex on June 09, 2021, 09:23:00 AM »
The length of the clutch push-rod has no bearing on the rear wheel rotating in neutral as the mainshaft (through which the push rod goes) is rotating too.
A quarter turn would be a miniscule dimension anyway.
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British Bikes / Re: Notchy gearbox
« Last post by Oggers on June 09, 2021, 08:16:04 AM »
Slight tweaking of the clutch actuating rod (winding it out @1/4 turn) and the rear wheel has almost stopped rotating when on the main stand. For sure there is no real drive there and it is easily be stopped by the rear brake. Chains - hadn't thought of that, will check. Many thanks
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British Bikes / Re: Notchy gearbox
« Last post by R on June 09, 2021, 05:22:06 AM »
You should be able to just tread on the brake pedal and the rear wheel will stop (in neutral).

I see you've done the fresh oil in the gearbox.
That has worked for me with other bikes.
You'd wonder why it should make any difference, but it certainly can.

After that, all I can suggest is you check that the primary chain is not too tight.
The final drive chain also, come to that.
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British Bikes / Re: Notchy gearbox
« Last post by Rex on June 08, 2021, 06:54:13 PM »
If it's in neutral clutch drag doesn't come into it. The rear wheel always rotates when on the stand because of oil drag between the main shaft and sleeve gear.
It's personal choice, but I've always rated the light and short Triumph gear lever action. Is this a recently-purchased bike?
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