Surging at cruise

[GoSlow]

Hi Guys (and girls... gotta be pc ) I am aware that this subject is a slightly familiar one but even though I consider myself fairly handy with a spanner this is getting me a little wound up! So I thought I'd put it up for a second (or likely more!) opinion At any speed really at a steady cruise my storm surges... it's not a full on misfire, just a surge. Now that sounds to me like it's running weak? I have stripped the carbs and all looks spot on, 48 pilots, fuel screws make for a good sounding idle, 175 and 178 mains, standard needle, standard filter and standard trumpets. Inlet rubbers are in good condition and on the blip test revs return to bang on idle instantly. Now I haven't balanced the carbs due to lack of even an makeshift balancer but seeing as idle is so good (no misses or stalling ever when warm) then I can't really see it being that although I will do it when I get the chance. It's definitely weak as if i pull the choke at cruise it cleans up nicely but why when everything seemingly checks out? The only other thing I've noticed is that the temp gauge only goes up to a quarter at normal running, is this normal or is it possible that the engines running cold which may be contributing to the need for a richer mixture Please let me know any ideas folks before I pull my (remaining) hair out!

[popkat]

Is it an F2 ?. if it is it maybe to do with the pair valve system, but may also be nothing to do with it, just a possibility .? My last one which was an F2 did the same as you describe with yours for the first 5 miles or so of a ride, I got round it by having the choke slightly out then after those 5 miles or so pushed it in and all was ok, having the choke slightly out didn't effect the idle, just made the bike run smooth, bit of a pain but I was happy to live with it, I wondered whether it was due to the big bore Beawulf cans I had on but I don't have that bike now so don't know if that was the answer.

[lloydie]

Try turning out the mixtures 1/4 turn out,



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[GoSlow]

Mine's an early one so no pair system to interfere with things... The mixture screws are a good way out already, I overdid it a bit and set them at 2-3/4 and 3 turns as it idled better there than further in. I do have open cans on but I wouldn't expect this much of an issue . I'll balance the crbs this weekend and see how it is Anyone recall where their temp gauges run at normal running temp? Thanks for your opinions

[lloydie]

thats way too much for them to be turned out .
front 2 rear 2,1/4

with the engine running turn the front one in till the revs pick up then keep turning it in till the revs die down .
set it when the revs are at the highest then do the same with the rear .

[GoSlow]

thats way too much for them to be turned out .
front 2 rear 2,1/4

Yeah I know I overdid it but I kinda wanted to go too rich to prove the point if you get me? If it cured it then I could go back and wind them back in a bit as it happens even with them right out there it's still too weak so it kinda rules them out as the cause I'll pull the carbs again tomorrow, set the mixture screws to 2 and 2-1/4, have an even more in depth check for possible air leaks and check the carb balance... oh well as long as the suns shining and I'm playing with the bike I'm happy

[lloydie]

If you go to rich it will give rich surged as it bogs down and picks up


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[GoSlow]

Quick update for anyone interested... Even though the idle was perfect I balanced the carbs, only a fraction out so I headed off the MCN Live expecting no change at all and.... She's perfect! Happy days

[fabiostar]

temp wise mine barely reaches the the quarter mark unless i hit a traffic jam.

[VTRDark]

At any speed really at a steady cruise my storm surges... it's not a full on misfire, just a surge.

Adjusting the TPS will help with steady state cruise. And I agree with Lloydie that you mixture is too rich and you may be experiencing a rich bog down. What's she like when you go wide open throttle.

(:-})