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Discussion Starter · #1 · (Edited)
Running into a problem with my CB500T when I get up to around 60 - 65 mph.

The engine recently rebuilt with new rings and honed bores.
The carbs rebuilt and synchronized
Pamco ignition
New coils and plugs
K&N pod filters
Timing set perfect and verified advance

The bike runs great in any gear and at any speed below 50 mph. As soon as the bike is pushed to a higher speed, there is no more power. It feels like the air turbulence around the bike when at speed is causing the issue.

If you run the bike thru the gears to red-line, there is no problem. The problem always arises when you hit the magical speed.

Has anyone run into this problem before?

Any ideas on what to check?
 

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Discussion Starter · #3 ·
Not sure how putting points back on is going to solve the issue with getting air into the carbs at high MPH's.

The issue is not RPM related, it is more MPH related.

Trying to figure out how to insure the air is getting into the carbs at higher speeds.
 

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Do a plug chop - put in new plugs, take off hard and fast, reach the speed it glitches at.
Hold it there for a few miles. Kill switch, get off the road, pull the plugs and look at them.
 

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You have 2 things going against you here.

1. The pod filters
2. The shorty mufflers (which are probably straight through)

Neither of these will allow the bike to run properly.

Contrary to popular belief, pod filters actually restrict the airflow a lot more than the stock air filter. Often times running with pods will require rejetting the carbs.
Have you tried running with the stock air filters and see how the bike behaves?
 

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Discussion Starter · #7 ·
Thanks for the reply's.

The bike came incomplete when I got it so I don't know what it ran like nor did I have the airbox parts.

The rings were broken in both cylinders, the carbs weren't synch'd, the rear sets were cobbled together, there were no gauges, the wiring was a rats nest, it had crappy pod filters and the PO tried and failed to do a cafe conversion.

After rebuilding the engine, going through the carbs, painting the frame, sealing the tank, painting the tank, and upgrading the electronics, rewiring the bike, the bike looks good and rides great. Below 50 MPH!

For the carbs, my tuning led me to upping the jets from stock 150 to 160, and the K&N's helped over the crappy pods that were on there.

The bike starts and idles well, the timing is spot on and advances like it should, the carbs have good vacuum and both track together through the RPM range.

I'll do a plug chop and see what the results are.
 

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I would second pulling the pods too and see how the bike does.
 
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