MadManMarsbar

diaphrams have been checked , couldnt see any marks or holes at all

Yea its always something obvious , has happened a few times with other bikes next step is for the carbs to get ultra sonic'd and then see what happens i want to take the downpipes off and check the exhaust ports but the exhaust studs are about as half as thick as they should be lol

all of that was checked yesterday , all are working as the are , carbs are very clean inside , and bike is completely standard now , we had the original exhaust can fixed , so we could fix the problem without any doubt

carbs open fully , that was one of the things we checked , plugs are as they should be in a bike , no petrol left over at all so its burning it all , and yes tried with filter out but same problem

Hi Everyone So this problems has stumped alot of people in the past few weeks but if anyoine is gonna know it would be on here So here goes , bare with me on this So my dad has had his 4jh since about november , he swapped his triumph trophy 1200 for the FZR as the triumph was too heavy for him , obviously he didnt try to red line in straight away so we didnt find this problem until recently when the weather got nice and he got to know the bike so the Problem : it refuses to rev past 7000 rpm at all , when you get to 7k it will sit there as if it was on the red line , the weird this is tho , it will rev perfectly clean to the red line when its on the side stand the other thing is , when you get to 7k it will pull through it but it takes a very very time to do so wwe have changed the whole ignition system for new yamaha parts and my dad has checked the cards over for bad diaphrams or crap in the carbs but they were all fine an clean , he replaced the main and pilot jets for new ones too we has also checked for restrictors in the inlet ports , you can see straight onto the valves so thats not it , and from what i know the 4jh is 20 years old now and i believe they are too old to have an electronic restriction on them aswell one thing to not is we have change the exhaust for a stubby can my dad was given , but that isnt the issue as it does exactly the same thing with a standard can on it , its just alot quieter Anyone got any advice as to what we could check next ?