Teething troubles with my new Kat?

[slartibartfast]

hi all

picked up my new bike yesterday, its a 98 600 (one of the curvy ones) with 17k on the clock, done maybe 5 or 6 k in the last 6 years, from blackpool and rode back up to bonny scotland

i noticed a couple of niggles with it on the way up, not even sure if they're related, but i've never experienced either on any other bike

1. at motorway speeds, if you indicate to change lane at 70-80mph, the bike sort of "hiccups" as if it momentarily loses spark. when i did it at 95 (on a track, officer) the bike cut out completely. couldnt make it stutter at speeds below 60.

2. when accelerating hard, as you get into the final third of the throttle before the stop, it doesnt really seem to do anything much other than make the bike feel as if its running rough. cant really notice this at lower speeds either, as the bike seems to pick up quicker anyway

any help would be greatly appreciated; felt really good to ride other than these i enjoyed a good 250 mile run yesterday and am looking forward to more!

tia

Jim

[steves]

#1 sounds like a fueling issue. Try running the bike on "PRI" or "PRIME" and see if the same thing happens.

#2 sounds like dirty carbs, or maybe badly adjusted cables. I'd spend some time resolving #1 first.

[slartibartfast]

thanks Steve

was wondering what the prime position did, never thought to ask the PO

i assume its okay to run the bike at speed with the tap to prime? just to see if it cures the problem?

sorry for all the questions but at the bottom of a learning curve here!!

cheers

Jim

[Free Coffee]

I have nothing to add, except that your username is awesome. Welcome aboard- and I hope you name your new baby "The Kat of Gold."

[Philskat]

I had the same problem as #1 on my old yamaha and it ended up being (only did it when i went left) the power wire for the rear left signal had gotten pinched between seat and fender and wore a spot in it and was grounding out to the fender. Probably not the same but worth mentioning i thought.

[Cheriff]

You say "you indicate to change lanes at 70-80mph" and it cuts out. Are you saying that if you don't indicate it doesn't cut out?? Or that if you stay straight it won't cut out? Is it happening as a function of RPM's and you only notice at those speeds because around town you shifting earlier?

Could also be a kinked fuel line that isn't flowing enough fuel when the bike's demand exceeds what fits through the reduced fuel line opening.

[slartibartfast]

You say "you indicate to change lanes at 70-80mph" and it cuts out. Are you saying that if you don't indicate it doesn't cut out?? Or that if you stay straight it won't cut out? Is it happening as a function of RPM's and you only notice at those speeds because around town you shifting earlier?

Could also be a kinked fuel line that isn't flowing enough fuel when the bike's demand exceeds what fits through the reduced fuel line opening.

thats correct. it only seems to do it at high speeds/revs at the moment you operate the indicator switch - also probably right about not noticing in town as the revs tend to be lower.

the bike seems to like being grabbed by the scruff of the neck and thrown around, no issues there

[bob393]

It's OK to run on prime. Pri bypasses the vacuum control and lets fuel flow freely. Just remember to turn it back when you stop as any leaks will continue to flow.

Roughens up when you turn the turn indicator switch on at speed. I have no idea on that one! The charging system is working? Right? How about switching from hi to low beam?

[steves]

Okay, I seem to have glazed over the fact it only happens with the indicator on. That is DEFINITELY an electrical problem.

[Cheriff]

If I am understanding correctly then it would almost have to be a short... or as bob393 suggested there could be something else (multiple things) wrong with the electrical system. I'm guessing it starts up just fine or you would have mentioned that. If the charging system was failing then your battery would be dead by now and it wouldn't start - so my money is on a short that seems to only be a problem when there is enough force pushing on something during higher speeds. That could be a tough one to find... What is the tach needle doing when this problem happens?

[slartibartfast]

the charging system appears to be ok, starts first time. just got to work (an 80 mile ride) and it only did it once - think i''ll live with it tbh, it will probably take far too long to find a short like that



the fuelling thing i do want to fix though; i ran it with the fuel tap to prime and it didnt feel any different.

is there an in-line fuel filter on the kat? i'm going to check the throttle cable is set up properly when i get time, but if there's a filter that might be worth checking too

i'm hoping to stay away from the carbs if possible!!!!


thanks again

Jim

[bob393]

My 750 pre has no filter just an internal screen. It's probably not the throttle cable, just as long as you have a bit of play in the grip.
I'm a big fan of throwing a bit, follow the directions and don't use to much, of SeaFoam, a carb/injector cleaner, in with the fuel. It won't clean really dirty carbs but I think it helps keep clean carbs clean.
I know it's a PITA because of the fairing but I might try and pull the hot wire off the effected turn signal on the front and the back, one at a time of course and see if you can isolate it to the front or rear indicator. From there it might be easier to diagnose.
If neither cause a change it's probably in the switch, flasher, or the indicator in the dash.