Are you sure the carb-cleaner you're using is flammable - there are a few non-flammable versions on the market. Check the can/research online to see if it's marketed as non-flammable. If you happen to be using non-flammable stuff, it make sense that the bike is cutting out and that may imply a vacuum leak indeed.

I would check the rubbers visually for cracks and splits before taking your carbs off(it's a pain to see anything with them on the bike though, so taking them off may allow you better visual access to the rubbers, so your call). Also may be worth checking that the little barb for carb synchronization is not missing the rubber cover on the front carb - mine split a while back causing a leak and it's close enough to the rubbers that you may well be spraying the carb cleaner up there. without knowing it - that would explain why it's shutting the engine down when spraying the front carb.

 

I would say any change indicates a leak.

 

Thanks for the replies. My carb cleaner is flammable... strange

Would you know the part numbers or the proper names of the rubbers that are air leaking? I was spraying the rubbers that connect carbs to the engine.

 

intake boots

or "pipe assembly" on a parts fiche
13101-20F00 PIPE ASSY, INTAKE FRONT
13102-20F00 PIPE ASSY, INTAKE REAR

 

To state the obvious, make sure your carbs and air box are seated properly before you go digging too much further.

 

Look at the little rubber caps on the unused vacuum taps...they tend to crack and leak but can look fine from a distance. Take them off and give em a squeeze...you'll see the cracks then if they're there.

 

If you take those rubber caps off, seriously think about replacing them with some lengths of vacuum hose.
It makes synchronizing so much easier when it comes time to do it, just plug the end of the hoses.

 

Cheers guys.

Glad I got so many replies.

I'm gonna take the carbs off and clean the boots first to make sure they are all seated correctly. They seem hard to get (specially in the EU region) so I will first try to fix the problem before buying new ones.

 

The actual rubber mounting boots don't normally crack...at least on the 1K's unless someone has been in there savaging it. But the vacuum hoses DO crack often, so they would be where I'd think your problems will be found. But certainly check the rubber mounting boots and be careful you don't hurt them taking things apart...the carbs can stick pretty tightly especially after the rubber has shrunk a bit with age and exposure to fuel. I've had to use a flat screwdriver to pry open the lip and dribble in some oil, then work it around the spigot to get them out before...so be patient and good luck.

 

So I took the carbs off yesterday and noticed that the front carb spring that is located on the top right side of the carb had the spring end side sitting in the rubber boot.

I twisted the spring upwards and put the carbs back in tightening it fully, sprayed some spray on the front boots while the bike was running and there was no more leak...

However, it started leaking on the rear boot now. I guess I might have put too much pressure on the front when I was fitting it resulting in back sticking out a bit.

Will play around more Today, hopefully I can get both ends fitted fully in

 

Hi guys,

So I took the tank off yesterday and tried to squeeze the rear carb into the cylinder further, it would not go any further in so I tighten the boot to the max and hoped for the best. While connecting hoses I noticed small tiny crack on the hose going from rear carb to tank, I replaced the little hose and put everything together.

Warmed the bike up and sprayed substance on the rubbers. Front was still perfect and no change in revs at all. Rear was a lot better, engine did not die any more and the revs went down by 200-300 so it stopped dropping at around 1000RPM.

IMPROVEMENT.

I went for a ride, success - many different high speeds, high accel and continuous 70-80MPH on highway for 25 miles - normally the cylinder would die already like 20 times but this time it was perfect all the way

Damn I thought I can trust that mechanic. After giving him the bike back 4 times cause he couldn't fix the problem, I had to correct his stupid mistakes.

Thanks for all your help guys!

 

Hi guys,


Damn I thought I can trust that mechanic. After giving him the bike back 4 times cause he couldn't fix the problem, I had to correct his stupid mistakes.

Thanks for all your help guys!

This seems to be a very common occurrence, well done for researching and fixing yourself.