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Electronic ignition

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K2-K6:
Sounds like youv'e got a small improvement.

As an overview of this particular era it's probably fair to say that this is the start of running bike engines leaner to make them less poluting (particularly in USA) so where as previous models displayed more tolerance to precise jetting, ther is less room for margin on this model.

That doesn't mean it should run with faults, Honda did a good job of it and with it correct it will run very well so it has no inbuilt faults and you should be able to have it working perfectly well.

When you say it missfires on tickover is that without using the throttle at all? as that would suggest the idle jets are the first place to look if nothing else is obvious.

If it misses as you start to open the throttle it could be related to the accelerator pump (this sprays additional fuel into the carbs ONLY AS YOU TURN the twist grip) this is to overcome the weak running of the normal setup. It's a transition stage to make it accelerate cleanly without stuttering and if not working correctly would show as a slow or missfire response if not delivering enough fuel during that increased damand.

There are quite a few on here that have worked on this area of the F2 so would be confident of you getting it sorted, it's just a case of working through it logically.

p@ul:

--- Quote from: K2-K6 on November 21, 2012, 10:08:33 AM ---Sounds like youv'e got a small improvement.

As an overview of this particular era it's probably fair to say that this is the start of running bike engines leaner to make them less poluting (particularly in USA) so where as previous models displayed more tolerance to precise jetting, ther is less room for margin on this model.

If it misses as you start to open the throttle it could be related to the accelerator pump (this sprays additional fuel into the carbs ONLY AS YOU TURN the twist grip) this is to overcome the weak running of the normal setup. It's a transition stage to make it accelerate cleanly without stuttering and if not working correctly would show as a slow or missfire response if not delivering enough fuel during that increased damand.
--- End quote ---


Exactly that... The misfire is as i twist the throttle and clears after about 3000 rpm when all rattles and misfires disappear and the motor sounds sweat.... BTW the bike is a US model !!

You may just be onto something here K2, thank you. I've just got to find where the hell this accelerator pump in located now  :D

K2-K6:
Ah ha, could be getting somewhere......

The original set-up of this era acknolwledged that to lower emmisions you'd have to run the engine as lean as possible when now demand to pull the bike along was made. This ordinarily for any petrol engine is insufficient to get it to accelerate very easily at all......sooooo they specified an accelerator pump (fairly crude but easily effective) which sprays additional fuel straight into the carb venturi and bypasses all the other static jetting. This only happens as you are turning the twistgrip (this why I referred to giving a couple of twists before a cold start) The result being that the motor easily accelerates up into an area of carburation that is fully into running on the main jetting of the carbs then it would be away with no problems. All smoothness and light, but wthout this asistance it would be a bit of a pig.

UK Pete on here is one I've known to recently rebuild just this particular piece on his restored F2 so he may be the best to describe it for you. (he may have a bit on here already if you read his restore blog for the F2)

The USA model F2 and the one shipped here were all but identical so that's not a compromise as far as I know, The carburation strategy is common to both the F2 and the K7 which were sister bikes spec wise.

I hope you get it sorted out as they are really good to ride I think.

p@ul:
Thanks fella...... I've started the strip down now so when i do pull the engine out i'll be able to inspect it more closely and maybe replace parts that are suspect. That is a long way off yet though. In the mean time at least i know it starts and runs  ;)
Thank you all for your valued input.

There will be many more questions that pop up over time i'm sure, some will be silly due to my mechanical ineptitude  ;D

p@ul:

--- Quote from: SteveD CB500F on November 16, 2012, 02:19:26 PM ---If you want to look at the Dyna S system, go to www.z1enterprises.com

They're a good price and the exchange rate is good too.

Jeff Saunders (the proprietor) is a member on sohc4.net and is a very knowledable and helpful chap.

--- End quote ---

Hi Steve, that set up.might just be worth a punt but I just need to check the state of the accelerator pump before i proceed.... Thanks for the advise.

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