Author Topic: Starting issues  (Read 4360 times)

Offline tosh

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Starting issues
« on: February 24, 2016, 11:31:07 AM »
Hi guys, I'm having major problems getting the bike to fire up, it spins up fine on the starter and try's to fire but just won't catch. Bit of history: when I bought the bike it was starting and running to a point, was leaking fuel from overflow on Carb #3 and it was struggling on any more than 1/4 throttle. the guy I got it from had put pod filters on but not done anything else to the carbs.
What I've done: removed carbs, upped main jets from stock 92's to 120's, given them a bit of a clean (although they were fairly clean inside) sorted stuck float valve on #3, checked float heights which were all over the place so set them to the stock 12.5 mm across the board. The pilot screws were all over the place to ranging from 3 turns to almost all the way out so these were set to the stock 1.5 turns.
I have spark, I'm getting some fuel through, the boots look good, the only thing I can see is a small weep from #4 float bowl which shouldn't stop it starting at least?? Anybody able to share some wisdom  :-\

Offline paul G

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Re: Starting issues
« Reply #1 on: February 24, 2016, 12:55:32 PM »
Tosh,
                  Stupid question but is it fresh fuel !!
Timing and point set.
I normally give it a quick try on easy start to eliminate everything else if it runs fuel problem.
Don't go mad with the easy start !!

Regards,
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Offline tosh

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Re: Starting issues
« Reply #2 on: February 24, 2016, 01:05:57 PM »
Hi Paul, yea fuel fresh, electronic ign so no points, new spark units put on by previous owner but have had a look at timing and looks ok as per book. Looking at plugs 1&4 they only just look damp after turning it over. I'll have to go and get some easy start and try that, was (probably wrongly) assuming that as it was only 3 months since it was last started carbs would be clear still :-\

Offline mike the bike

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Re: Starting issues
« Reply #3 on: February 24, 2016, 06:34:28 PM »
Make sure the choke machanism is all ok
Where's that 10mm socket got to?

Offline K2-K6

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Re: Starting issues
« Reply #4 on: February 24, 2016, 07:24:32 PM »
Rap a rag, something like a towel over the pods to make it suck harder which if it's not pulling petrol in may just make the difference. Take it off if it fires.

I'd start with the pilots at  2 to 2.5 turns out to give you a base start set and trim them when warm.

Offline Bryanj

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Re: Starting issues
« Reply #5 on: February 25, 2016, 05:52:25 AM »
If the carbs have been set up with the tickover either fully closed OR too far open it will be a bitch to start

Offline tosh

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Re: Starting issues
« Reply #6 on: February 25, 2016, 04:45:21 PM »
Thanks for the advice suggestions guys, I will try/check these and post results up here. Fingers crossed

Offline tosh

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Re: Starting issues
« Reply #7 on: March 11, 2016, 04:14:00 PM »
Well finally found the time to try the advice given, mixture adjustments and filter restrictions had no effect but it does fires up on easy start so I'm guessing it's a carb problem, so back to the kitchen table they go, any thoughts?

Offline Bryanj

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Re: Starting issues
« Reply #8 on: March 11, 2016, 04:21:59 PM »
If it fires on easy how old is the petrol you are using, anything over 7 days on those extra lean carbs and starting is a beatch

Offline tosh

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Re: Starting issues
« Reply #9 on: March 12, 2016, 02:55:36 PM »
Yea fuel isn't that fresh so went and got some fresh this morning, drained tank and refuelled, put carbs back on "again" after checking mains and pilots clear ect and it still won't go, gonna try putting the 92 mains back in just in case the 120's are just to bigger step up, beginig to run out of ideas now .....frustrating because I know it runs

Offline tosh

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Re: Starting issues
« Reply #10 on: March 13, 2016, 11:24:56 AM »
Update- got it up under its own steam, mixture of plug gap and choke butterfly's on carb 1&2 not closing fully, only running on 3 pots but think it's plug on no2 as couldn't get socket in to get it out, runs rough and only on full choke bet hey it's a start

Offline Krzychu

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Re: Starting issues
« Reply #11 on: April 03, 2016, 12:11:19 PM »
Hi Tosh, what year exactly is Your bike or what model of carbs do You have in there ?
I have a Haynes book for my wee girl and yes it says to set the pilot screws at 1.5 for the start and then work on them, but then when I go to the last pages it gives separate settings for different models ( US, UK ) and years. There is quite a big difference between them as its 1.5 turn out for one and 2.5 turn out for the other.
Good luck with it anyway  ;)
LwG✋

Offline tosh

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Re: Starting issues
« Reply #12 on: April 11, 2016, 06:24:46 AM »
Hi krzychu, it's a RC03 1979 with PD51A carbs so uk spec. After new plugs leads and caps it's now running ok on the stand (front calipers in bits at moment so unable to see how it behaves under load, with the 120 mains stock pilots and pods) seems to rev freely through the range although running leaner on No 1 than the other 3 pots. I think a lot of the problem was that I hadn't noticed that the PO hadn't reconnected the choke spring on the carbs properly so although 1&2 were functioning properly 3&4 were always a good 1/4 " off closing fully  ::)

 

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