Breaking-up/sputtering revisited

Ernest Montague afm199 at
Wed Sep 3 10:50:31 PDT 2008

Pull the tank and remove the fuel outlet. The filter on it is probably 

On Sep 3, 2008, at 10:42 AM, Wayne Beaver wrote:

> Hi all,
> I have a very slight update to the below. Still grateful to hear an 
> ideas...
> Here's what I've done so far:
> Cleaned carbs, replaced air filter, replaced plugs (the color on the 
> old ones
> was fine, maybe a bit on the gray side of tan, but looked normal to 
> me...),
> visually inspecting wiring, checked fuel filter, verified fuel line
> routing/venting, visually inspected sure coil wires and spark plug 
> leads,
> verified that foam under tank was well glued, verified plug leads were 
> well
> attached to plugs with drain hole poining correct way, verified 
> against obvious,
> exhaust leaks, verified ground wire firmly attached to rear of engine, 
> verified
> negative battery lead OK.
> Here are results of my latest test ride:
> The first maybe mile was OK - accelerating
> powerfully through three or four gears with no sputters, no probs. 
> Then,
> suddenly, the tach stuck at 8K and the engine started sputtering again 
> - in
> seemingly all gears, all rpm ranges. I  *hobbled* home with severe 
> lack of power
> and inability to make the bike move forward. The Tach stayed stuck 
> unil I turned
> bike off.
> IIRC, the tach drives off a one coil, correct? So seems like problem 
> is either
> coil or upstream of coil? I had similar problem many years back with 
> an early
> 80's Honda Interceptor, - where an ignitor only shorted when bike was 
> hot, etc.,
> at which time tach danced, pulses to fuel pump stopped and I was left 
> stranded.
> Wondering if this could be similar?
> Unfortunately I don't have a peak voltage adapter for my voltmeter, 
> and not sure
> it would help anyway unless I could keep it attached while riding, 
> after bike is
> warmed up :-) Yes, I can start simple replacing all of the bits 
> one-by-one, as
> well, but just aksing again if anyone here has had similar experiences.
> wb
>> Quoting Wayne Beaver <wayne at>:
>> Did a track day at NJMP/Thunderbolt yesterday, which was great fun 
>> until the
>> bike started acting up (which, unfortuantely, was mid-way through 
>> second
>> session).
>> The bike feels like it's missing in various parts of the RPM range, 
>> which
>> changes slightly depending on which gear the bike is in. It often 
>> misses
>> between 5 and 6k, then again between 8 and 9k. Won't climb above 7k 
>> in top
>> gear. Seems to run fine at idle and through rev range when parked.
>> Only slight blip between 5-6k in first gear.
>> Has something similar happened before to anyone here? Any ideas where 
>> I
>> should start?

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