Not reving above 2k when hot

rexeriot · Post by **rexeriot** » Sun Sep 01, 2019 11:31 am

Hi all. I've had my 89 Fzr1000 Exup for 4 years . I've been riding the bike with the Exup valve fully open for 2 years. The only issue I had was bogging down under 4k when hot and pulling away on a hill. This summer that has suddenly got a lot worse . Then one day is was so bad it wouldn't rev above 2k or idle . Once it cools down it's ok but as soon as it gets hot and you are below 4k the problems start again. I thought maybe the valve had moved but it hasn't. I'm baffled because the bike is becoming un ridable . Above 4 k and riding at speed is absolutely fine . Can anyone help ? Something has obviously happened but I cant figure out where. Thanks

Teego · Post by **Teego** » Sun Sep 01, 2019 12:25 pm

Toobs?

rexeriot · Post by **rexeriot** » Sun Sep 01, 2019 1:11 pm

Toobs ?? Not sure I understand .

Post by **Stig** » Sun Sep 01, 2019 2:10 pm

Worn emulsion Toobs in the carbs

http://www.exup1000.co.uk/tech_info_are ... ntoobs.htm

Or check coils aren't breaking down as they get hot

rexeriot · Post by **rexeriot** » Sun Sep 01, 2019 4:49 pm

Thanks for that. Coils are ok as the bike is always running on 4 when I have the problems. I guess the toobs start sticking when they get worn ?

Teego · Post by **Teego** » Sun Sep 01, 2019 7:14 pm

rexeriot wrote:Thanks for that. Coils are ok as the bike is always running on 4 when I have the problems. I guess the toobs start sticking when they get worn ?

Toobs start flooding the motor at lower revs when worn. It's an easy fix if you follow our how-to guide. Actually, take your time and it's very therapeutic.

pilninggas · Post by **pilninggas** » Sun Sep 01, 2019 7:50 pm

+1.

It gives you back the motor as it should be. Those jets dont half wear out and knacker the fuel.

Replace them toobs.

rexeriot · Post by **rexeriot** » Sun Sep 01, 2019 9:07 pm

Wheres the best place to buy them ? Thanks

YAMAEXUP · Post by **YAMAEXUP** » Tue Sep 03, 2019 10:50 am

I would've said...hold on a moment. I'd better not incriminate myself.... I wouldn't want anyone to end up in court

When were the valve clearances last checked?

YAMAEXUP · Post by **YAMAEXUP** » Tue Sep 03, 2019 10:54 am

Also, check the internal resistor elements inside of the plug caps. One of them went open circuit while on a rideout. Then 2 of the original plug caps split along the seam & the coil output jumped to the engine. New NGK plug caps resolved that situation, in my case

rexeriot · Post by **rexeriot** » Sat Sep 07, 2019 4:50 pm

Hi. I took the carbs off...... which , I believe , have never been removed. The inlet rubber clamps were in such a position that you could only reach one with a screw driver so the carbs had to have been fitted to the engine before it went into the frame . Every screw on the carbs were untouched and the only way of getting the bowl screws out was to drill.

Anyway I believe my problem is the carb tops . 3 are cracked and not sitting flush to the carb. Guess air is getting in ....would this cause my symptoms . The toobs look perfect .

rexeriot · Post by **rexeriot** » Sat Sep 07, 2019 6:33 pm

Hi . The bike had only done 25k miles . I will do that test and see. The cabs were very mucky inside and the inlet rubbers also had splits in them . The diaphragms were fine . Jets were clear. The tubes are out of stock at Allen's. Any idea where I can get carb tops from ? Thanks

two-stroke-brit · Post by **two-stroke-brit** » Wed Sep 11, 2019 6:31 pm

rexeriot wrote:Toobs ?? Not sure I understand .

is the bore dia known for a stock "tube "
thanks mark

Post by **Stig** » Wed Sep 11, 2019 9:24 pm

It's not the diameter that's the issue. A worn Toobs will wear oval

Teego · Post by **Teego** » Wed Sep 11, 2019 9:57 pm

Paul, some years ago we did a complete how to with pix for toobs. Can't find it now.