Power loss @ 3000 > rpm

Hello, new to forum

I have 90 FLHTCU tour bike. sbc - heads, cometic .030 head gaskets, bored .005 over, carb been rejetted/slide worked,hi-flow se a/c, ev27 cam, adjustable p-rods, se ignition module, v/h 2 into 1 pro pipe. less than 10,000 miles on build.

Problem : at 3000 rpm >< looses power. 60-70 tops in 5th gear. just bogs down and won't go.

I have checked :
1. carb has been taken apart and cleaned jets -- was ok--same power loss
2. checked for leaking intake --- was ok ---same power loss
3. replaced the ignition mod with the stock one. --- same power loss
4. checked all wires for raw places. --- none so far
5. cleaned the petcok filter and petcock. --- ok --same loss
6. checked voe switch for closing at 5-6 in vac. -- ok -- same loss
7. checked the pickup cup in nose cone for looseness. -- ok -- same loss
8. HAVE NOT replaced nose cone pick sensor -- today hopefully
9. checked brakes for dragging. not dragging
10. checked pushrods for proper adjustment. --ok
11. checked compression.--110 front. --115 rear
12. new plugs ---going for new plug wires today.
13. checked air filter, cleaned and replaced. -----same power loss


it acts like the timing is not advancing ??
I have no idea where to go from here. Any one got any ideas ??
Yes, I do have a service manual and parts manual and have been intimate with both......
Thanks for any help.

paco

Paco

Could the tank vent be pluged? Are you sure the tank is draining fast enough? Sure sounds like a gas problem.Just a thought.
Later Ole Ted

power l

Could there be any restrictions in your exhaust.....I had a problem like that when I put new exhaust on my sportty,the baffles were to restrictive,I couldn't get anything over 2000 rpm's....Hope you find your problem....

power loss at 3000 rpm

thanks for the replies.

I opened the tank cap last night and it didn't change anything. So , I don't think the line is plugged, I will check it again, when i get home from work.

I have a new pick up sensor coming today, i will check the exhaust when I put the sensor in, as i will have to pull the exhaust to install.

Again thanks for the replies.

paco

You might check for air restrictions in the air box/filter. I had a Honda once that did the same thing. A pack rat had taken up residence and had the filter clogged.

It seems to me if the ignition wasn't advancing you'd get some backfiring. I don't know though just a guess.

Not knowing how many miles you have on the build, what you described, going flat after a certian rpm, could also indicate that the valve springs are getting "tired" (valve float). My "built" car I change them out after 25,000 miles.

hey guys,

cleaned and checked air filter and all parts while had the carb off.


I did the build about one yr. ago. I also have a 1999 95 in. roadglide tc i ride, so the build has about 10,000 mi. could be the valves floating.....

thanks for the replies....
paco

Everything was done at the same time except the cam and pro pipe. The cam that I used with the build in the beginning was the ev46. I ran the ev 46 and the v/h pro pipe together about a month or so and had a base gasket leak. While i had the top end apart i replaced the base gasket with the Hayden oil fix and put the .030 head gaskets in. installed the ev 27 after talking to short block charlie. put it all back together w/the v/h pro pipe and it ran like a raped ape. Been running about 2 weeks great. it ran 122mph in the qrt mile Teresi dyno drags @ 75 hp at the local dealer.

paco

The plugs are running with a light tan apperance when i pulled them so I don't think it is getting to much gas, however I could be wrong. I will check again.

paco

Hi Paco

I have sean a case with a bad intake valve spring would alow you to see gass vapor blowing out the carburetor wile the motor is running. Another thing I've tryed. Take a business card and cover the exaust pipe with the motor running and the card will slap back on the pipe as the exaust is sucked back as the cylinder starting its intake stroke . Just food for thought.

Thanks for all replies. THE BIT*H IS BACK !!!!

Would have never thought that a hole that small in the carb diaphram would cause that type of problem. I was looking for the worse case senerio and i guess it was the simplest. there was a crack in the diaphram that was in the crease where the diaphram rolls into the groove in the top of the carb body. had another there on the self, dropped it in, put her back together and up the road like a raped ape, screaming at the top of my lungs. yeehaaa, i can do that here in Alabama!

Thanks to all again and especially kenfuzed for pointing at the carb. I am old and have always been a slow learner.....

later.......................paco

WOW! That is a slick demo, Ken. You couldn't have done more except go there and do the work yourself. I'm impressed.
Slim

power loss

Great you got the problem fixed....Now you can go out and catch some wind...I would go riding,but it's snowing out,michigan weather

Thanks All,

Snowing Whacker? Damnit boy, I'm glad I down here in Alabama. It's 54 and cloudy , but it ain't snowing! It's been in the 80's last weekend. I was in Sturgis, Michigan summer before last in late June, it was nice that time of yr.
Think we are headed to Key West at the first of next month, can't hardly wait to get in the road. Its always nice in the Keys! well, almost always....

later...........................paco