The bike is FZR1000 1990 with Dynojet Stage 1 (Main Jet, needle)
After my latest cleaning and syncing the carbs the bike developed a strange problem. Before re-build the bike was running fine but had no idle so I took the carbs apart enough to be able to clean the jets and check the diaphragms/needles etc. Jets should now be clean and everything else seem to be ok.
Now when I set the idle in the correct area around 1000rpm:s and start riding, after a while the idle stays high, at about 2000 rpm. BUT, when I set the idle a bit too low, around 600-700 rpm (still idles well) then it returns always nicely to idle rpm:s after riding.
Any idea what could be causing this? My tech suspected the Dynojet kit (he's not a big fan of them) and also suggested turning out the the pilot air screw (have not done that yet).
The bike goes and pulls very well. Maybe when flipping the throttle when idling it does not response quite as well as it should but quite well anyway.[/i]
Idle problem
I've been going through this scenario after I did a carb service in March. I would get the engine hot in the garage and set the idle at 1200. I'd then go for a ride out and when I came to a stop it would be revving to high at 1500, after a blip on the throttle it would settle down eventually to 1200. Every time I came to a stop it would do it all over again. When I got back home while the engine was hot and revving to high again, I'd adjust the idle again. The next time I went out and came to a stop it would be revving to low at 800. This carry on went on since April. Last Friday after adjusting it one more time it seems to be behaving itself, well so far it is. I'm hoping to get out Saturday so I'll see what happens.
The carbs can be a pain in the are some times.
The carbs can be a pain in the are some times.
Bit of advice. Buy a good bed and a good pair of shoes, because if you aren't in one you'll be in the other.
Air leak was what I also suspected first but why it does not do it when I set the idle a bit too low?
I also replaced the inlet rubbers with new ones (OEM Yamaha) as well as the rubbers to air filter box. I guess the leak could happen also elsewhere but it did not have this feature before the carb re-build...
Maybe I'll ride it for a while and see what happens. Maybe it'll follow the Nuggit's bike's behavior...
I also replaced the inlet rubbers with new ones (OEM Yamaha) as well as the rubbers to air filter box. I guess the leak could happen also elsewhere but it did not have this feature before the carb re-build...
Maybe I'll ride it for a while and see what happens. Maybe it'll follow the Nuggit's bike's behavior...
I'm having to wait for Saturday to see how mine goes on.
I've checked it over for air leaks with spraying a little bit of easy start around the carb rubbers and there's no increase in revs. So that tells me everything is air tight in that area. Every time I went out for a ride after I'd adjusted it to either slow it down or speed it up, no matter which way I'd adjusted it, it went in the opposite direction. When I get home I have to lift the tank at one end and chock it up with a bit of timber so I can get my hand in to adjust it, because I have those carbon frame covers on which cover the hole for the idle adjuster so its a bit more of a pain in the butt. I'll report in on Saturday with good news I hope.
I've checked it over for air leaks with spraying a little bit of easy start around the carb rubbers and there's no increase in revs. So that tells me everything is air tight in that area. Every time I went out for a ride after I'd adjusted it to either slow it down or speed it up, no matter which way I'd adjusted it, it went in the opposite direction. When I get home I have to lift the tank at one end and chock it up with a bit of timber so I can get my hand in to adjust it, because I have those carbon frame covers on which cover the hole for the idle adjuster so its a bit more of a pain in the butt. I'll report in on Saturday with good news I hope.
Bit of advice. Buy a good bed and a good pair of shoes, because if you aren't in one you'll be in the other.
Some update to this topic:
I took the bike to a local tech for valve adjustment and after hearing the idle problems he offered to have a check on the carbs for a little extra money.
He did some further cleaning and tune-up, sync etc. and now the bike runs PERFECTLY!
He's opinion was that all the other parts in the carbs were original except the main jets. The guy who sold me the bike said it has a full Dynojet Stage 1 set inside. Well, that does not make me sad at all!
I took the bike to a local tech for valve adjustment and after hearing the idle problems he offered to have a check on the carbs for a little extra money.
He did some further cleaning and tune-up, sync etc. and now the bike runs PERFECTLY!
He's opinion was that all the other parts in the carbs were original except the main jets. The guy who sold me the bike said it has a full Dynojet Stage 1 set inside. Well, that does not make me sad at all!
I'm reporting back in with how my idle is going on. On some sections of the last ride out it was ticking over perfectly and then on the odd times it was a just little bit lower at 1,100. I'm not going to adjust anymore because if I do it will idle to fast.
Bit of advice. Buy a good bed and a good pair of shoes, because if you aren't in one you'll be in the other.