[Reelimpatient]

I had some bogging in the low end RPM range between 2000-3000 RPMS. I decided to pull the carbs and clean and inspect them for trash and worn diaphrams. I cleaned them and put them back on and adjusted them per Mikuni's factory settings and still have low end bogging. It does scream above 4000 rpms and now runs up to 6000 rpms whereas before it would only turn 5500.

It has new plugs, runs premix and compression is @ 175 per cylinder.
All filters are clean and have been checked.

Any ideas from you Pro's out there? Thanks for any suggestions !

 

[Outlaw]

Try checking the reeds.

 

[Reelimpatient]

I checked the service manual and it said check the RAVE valve.

Any thoughts on that ????

 

[Outlaw]

yes if the rave valves are stuck open it would explain why you have a bog as well. They open up for WOT then are supposed to drop back down for low end power. If you are taking them off be careful not to lose anything i.e. spring, gasket.

 

[Reelimpatient]

ok, here's the latest:

Totally rebuilt carbs, replaced main jets and needles, springs, orings, check valves, rubber gaskets etc. Was real careful about it being clean and putting it back together correctly.

Replaced gray fuel lines with new.

Spent an hour or two on lake Saturday trying to dial it in, and now boggs badly at 3000-4000 rpms.
0-3000 rpms seems to run fine, beyond that, it will bog and die if I try to accelerate. I can sometimes feather the throttle and get it to jump past the bog to 4000 rpms and it will then take off like a rocket, and runs strong up to 6700 WOT.
What the heck can this be? This is driving me crazy and I want it fixed.
It does not have reeds, this model has the rotary valve. Runs premix and has great compression. Come on Pro's I know you guys have seen this before.

Thanks for any help !