Hi guys,
hurricane 1988 , I have done a lot of work on this bike and it it is good , the only issue I have is a lumpy tick over. The carbs have been ultrasonically cleaned and balanced. the bike runs beautifully with no flat spots and runs up to the red line. There are no apparent vacuum leaks. The only issue is on tick over the engine stumbles and appears to misfire and the rev counter drops and hunts, trying to stall. As soon as you blip the throttle, it runs cleanly with no misfire. I suspect the coils. Is this a trait of weak coil . I have tested the ohms across the primary and it is on spec but I cannot check the secondary coil as there is one coil for 2 spark plugs. Any help gratefully received.

My restored Hurricane. New alternator tensioner - cam chain - starter damper. Painted by myself, Nissan metallic grey.

 

idle should be set to 1,000 - 1,200 revs.
When were the valve clearances checked last?

 

The engine has been out for alternator chain tensioner and starter damper , cam chain etc so the valve clearances were set then- about 200 miles ago.

 

it will idle in the 1000 - 1100 range but it is lumpy and not steady.

 

How old is the gas?
Does it contain ethanol?
I have seen bikes with ethanol separate and run poorly in the lower revs.
Maybe replace the fuel and drain the bowls to see if that's the source of poor low end running.

 

Stick coil mod?

Won't say for sure if it'll help you, but, a cheap upgrade that solved some of my old hesitation problems. Besides, you're working with 31 year old coils and the associated HT leads. Cheap cure might be to build new spark plug wires.

Like TBT says. Idle speed is important

Odd note. I'm on my second Hurricane and have not been around another one to compare anything with. My old bike had some mileage on it. My new bike has next to nothing as far as mileage. Idling next to other more modern fours, both of my Hurricanes would/will pulse and burble and not sound as in tune as the newer bike next to me Nature of the beast?

 

gas is new - thank you

 

I'll second Woof's suggestion of stick coil mod. Eliminates 25 plus year old coils and delivers a fat, consistent spark.

Cheers, SB

 

Thanks for the input folks, I've bought a pair of used coils, however, my existing coils and these, have exactly the same ohm readings on primary and secondary windings ( with and without HT leads and caps) and are in spec., as per the manual, so I think my problem is elsewhere, however,I agree, the stick coil conversion is a good improvement.
I've removed the carbs and ordered new rubber manifold boots as mine were a bit chewed up from carbs being taken on and off a few times over the years ! I also noticed there was an o ring missing from one pilot airscrew, and the other 3 were not in good shape, so these have been replaced.
I am waiting for the manifold boots to be delivered from Germany, will report back when up and running again.

 

When you receive the boots, check the inside diameters. Some euro models have restricted power output. To reduce the power the boot I.D's were reduced.
You would need to open them up to gain the power back.