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Bogging down

macvette

Well Known and Active Forum Website User
Non-VOC Member
Series D Rapide, Monoblocs, 240 mains,30 idle jets, timed 34 degrees BTDC. The bike accelerates well but in top at 70, it bogs on acceleration. The rear plug looks like it is running hot. If I open the throttle cruising at 70 the bike accelerates slowly and hesitates if I roll off it smooths out. I've stripped the carbs and cleaned everything and blown through with compressed air. Any suggestions (printable that is)o_O
Mac
 

Howard

Well Known and Active Forum Website User
VOC Member
Retarded maybe? When I was sorting my new Pazon timing I was getting similar symptoms, but I could tell just by how hot the engine felt after a short run.
For better suggestions, the more enlightened ones here are going to ask for more details - carb size, compression, type of ignition fuel etc.
Good luck.
H
 

macvette

Well Known and Active Forum Website User
Non-VOC Member
Just started riding after winter, it was ok before. It has new fuel. Checked fuel flow from taps getting about 500cc per minute from the hoses at the carbs fuel level in carbs ok. I'm wondering if it's rich.
 

nkt267

Well Known and Active Forum Website User
VOC Member
What sort of throttle opening are you on at 70mph..Slide is from 1/4 t0 1/2 opening,1/2 to 3/4 neele jet amd full for main jet.( apologies if granny can already suck eggs)
I have had residues left in the bottom of the carb due to a long lay up and causing similar problems.. John
 

macvette

Well Known and Active Forum Website User
Non-VOC Member
I'm not sure, I would say 1/2 or thereabouts cruising but I will have to check
 

macvette

Well Known and Active Forum Website User
Non-VOC Member
Been on holiday so just got back to the bike. The symptoms appear at 1/4 to 3/4 throttle and if the throttle is eased back, the engine smooths out but will only accelerate slowly on very gradual throttle opening. I' be gone through valve clearance, carb set up ( including setting one cylinder at a time) and ignition timing, also checked tank cap vent. I' m stumped. There was a post on here about interference in the BTH cut out wire causing issues but I can't find it. anyone know where it is ?
Thanks Mac
 

Howard

Well Known and Active Forum Website User
VOC Member
1/4 - 3/4 throttle is usually needle position territory.
One of our section members had BT-H problems. He's rerouted the cutout wire away from the HT lead, and says everything is as it should be now.

H
 
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