ET: Engine (Twin) Rear 289 Float Bowl Top

bmetcalf

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The threads on the float bowl top seem to be worn out. When I tighten it up, it seems OK, but then when I tighten the banjo nut, it pops loose. Functionally that isn't too bad, but I would rather have it work as designed. The banjo just misses the tickler button, so that isn't the issue. My first reaction is to replace the float bowl and top, but that is a fair amount of money. How likely is it that just a new top and a PR6AQ washer would cure this ill? The threads all look fine now, so there isn't an obvious choice between a new bowl or top.
 

nigsey

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It’s obviously not gripping on the threads, so guess they are worn. Is it possible to use a thinner fibre washer on either side so the bolt/nut goes a little further in, thus gripping fresh thread lower down? If so, you need to make sure you you don’t over tighten, just nipped up. Alternatively, you could try packing out the thread on the bolt/nut with petrol/gas resistant tape. I’ve heard that plumber’s tape, known as PTFE tape here in the Uk is suitable for for fuel line threads.
 

Bill Thomas

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The threads on the float bowl top seem to be worn out. When I tighten it up, it seems OK, but then when I tighten the banjo nut, it pops loose. Functionally that isn't too bad, but I would rather have it work as designed. The banjo just misses the tickler button, so that isn't the issue. My first reaction is to replace the float bowl and top, but that is a fair amount of money. How likely is it that just a new top and a PR6AQ washer would cure this ill? The threads all look fine now, so there isn't an obvious choice between a new bowl or top.
Plumber's tape PTFE we call it in UK, Might be worth a try
 

Trickymicky

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You could try the top from the front carb in the rear float bowl and see if it tightens ok. If it does, a new top should cure it. Amal's idea of a replacement top feed float chamber top though, is actually a modified bottom feed (front carb) top, and they look different to the originals. You could also run in to problems with the float level, as i found out doing the reverse - fitting an original top feed top to new carbs.
 

bmetcalf

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I tried the front top on the rear bowl and it worked well, so I got a new top from the SparesCo and it is working as intended. Thanks for the advice!

I also got one of those top gaskets and put on and it put the tickler just under a fuel line, which made it piss petrol. Needless to say, the gasket is in my spares drawer now.
 

bmetcalf

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Turns out I was wrong about the reason it was pissing petrol. The tickler plunger on the new float bowl top is too long and doesn't allow the needle to seat at all. I am planning to shorten the plunger by the amount shown, plus a bit. I rarely use the rear tickler anyway. Has anyone else discovered this problem?

Float.jpg
 

bmetcalf

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Progress to report! My bike would start, but would barely run and I want to leave on Sunday morning for the North American Rally. All the above float bowl business is on the rear carb, so I thought that I would re-clean the front carb. Well, when I unscrewed the nut that holds the float bowl to the carb, the pilot jet/main jet were loose in the nut cavity. I tightened it back up, started the bike and rode up and down my street. Runs like it should! Idling fine, but not taking throttle was a big clue that the needle jet had a problem. Can't imagine how I didn't properly tighten the needle jet into the jet block.
 
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