problem in high rpm

[VMAX1260]

ok guys, i cant figure out what is happening. i solved the flame problem. the rear cylinders pipes where half unbolted and air was coming through the exhaust. but the other issue..... not solved i made a dyno, which you can see in my new post. over 6000 my engine makes a dive......

i will try cleaning them again and i will keep you posted. thank you for your help

 

[VMAX1260]

you can see the dyno here
http://www.vmaxforum.net/showthread.php?t=13559

 

[satariel666]

Firstble tell us what did you check/ done by this far.

Compression check? Coils check? Plugs check? Floats check? Boots leaks check? etc
Fuel filter my be little dirty and the carbs dont get enough gas flow at higher rpms.

I think it may be electrical too.
Maybe corrosion on the crimps from pickup coil. I've had one case someday with those green crimps.
It will not hurt to give a try.

Many options.

Update:
I just saw that You have old type TCI ignition box. They like to go bad somethimes, mostyl missing one cylinder.

 

[VMAX1260]

i have checked the plugs, the carbs, even changed the main jets float ok,i checked it today,no leak anywere, i have to check for corrusion though in the coils, it is a possibility,fuel filter ok

 

[davidon]

Did you try and swap the ignition control unit with another known good one?

 

[VMAX1260]

ok after all this time , with taking off putting on taking off putting on carbs. i think i found the solution. i switched today to 170 main jets and the problem dissapeared. i am telling i think because i think 170 main are way to big from the 152.5 factory jets? is this possible? i know my engine is 1300cc but i didnt think that i needed so big main jet. ??

 

[one2dmax]

Every engine is different.

 

[VMAX1260]

sean , i am anxious for my next dyno run , my bike with the problem i had made an 112 hp at about 6000. that i think was way to good. now that i can turn my thottle all the way. i am anxious what i wiil get. see the dyno run which my engine after 6000 is dead

 

[one2dmax]

Maybe they can get you an A/F reading at the same time.

 

[veebooster]

ok after all this time , with taking off putting on taking off putting on carbs. i think i found the solution. i switched today to 170 main jets and the problem dissapeared. i am telling i think because i think 170 main are way to big from the 152.5 factory jets? is this possible? i know my engine is 1300cc but i didnt think that i needed so big main jet. ??

Sean is right...every engine is different. I run 170's in my stock engine. It won't run at high RPM with anything less. HMF Headers and Morley jet kit. So...if it works, SMILE! :biglaugh:

Dale #2592

 

[VMAX1260]

Thank you all for your advices and yes my smile comes on my face when i twist the throttle bouxxaxaxax

 

[VMAX1260]

Ok the problem apeared again. Now that the weather got gold in high rpm i have again power loss in high rpm... In the summer when i installed 170 main jets seemed to be solved but now it came back at about 7500-8000 rpm only with full throttle. It feels like the engine tries to produce power but it cuts off , it gives again ..it cuts off again and show goes on. I dont think it has to do with the main jets. What should i do install 180 main's?????? I think it is very big. With 3rd gear and 4 gear it is very difficult to reach redline. My battery is 5 months old i did a check and i have 13.6 volts in 4000rpm as i rise the rpm nothing changes in the volt meter.

 

[mattness]

my friend had a blown reg in his bike and if you revd slowly it would reach high rpm, but if you tried to rev fast it just blugged out

 

[satariel666]

my friend had a blown reg in his bike and if you revd slowly it would reach high rpm, but if you tried to rev fast it just blugged out

this or too big MJ.

 

[VMAX1260]

what do you mean with blown reg. where i can find this reg??? to check it out.????satariel666 if my main jet is too big what would i see if the main jets where to small??? it never occured to me again i dont know the difference