First Generation Ascots > Tech Section

Performance problems

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triguyracer:
yes but there is still a butterfly in the carb that is attached to the throttle the air flow is still partly controlled with the butterfly,the slide can be wide open but you still have the restriction in the carb depending on how far open or closed it is.allowing the motor to only take as much air fuel that the motor can take,the only circuit that I can see that over rides this is the accelerator pump and that seems to be just of the bottom of the rev range,am I missing something

Lefty:
I'm running a #145 & a #58, as suggestef by J6 here ,I also got rid of the original paper filter & replaced with green a/f foam, so I'm running with the stock airbox, but a free-er flowing a/f.
The 1st season with all mods the bike ran out perfectly, i haven't clocked 200 miles since then, and now it's bogging in all gears if I really punch it.
So I'm guessin I should start by going down in size on the main jet? Also, where's a good site to order Jets?

J6G1Z:
If the bike ran fine in its current configuration last season & nothing has been changed, I'd try running a tank or two of Seafoam through it & see if it doesn't clear up. http://seafoamsales.com

After that, I'd try changing the spark plug for a fresh one.

Something else to consider... Possibly the rubber diaphragm in the carb has dried out & has a leak in it. Here is about the best FT Ascot carb rebuild kit out there. http://randakks.com/collections/honda-ft500-ascot-single/products/ft500-ascot-randakk-master-carb-overhaul-kit

Other than that, its trial & error time with the jetting. You might try SUDCO for jets & guidance. http://www.sudco.com

There are some jetting guidelines for Mikuni carbs stickied at the top of this section. Mikuni & Keihin use different jet sizing schemes so it would be a rough guide.

Good luck.
J.

triguyracer:
another thing to check is your spark plug cap almost all bikes from this era used a resistor spark plug cap,they do go bad and can be a very difficult to know they are bad and can cause many of the problems you have,spent many hours chasing down this problem on bikes when I worked in dealerships as a wrench,they don't go bad often but when they do they are a easy problem to overlook.cheap to fix though and a easy fix,it is one of those things that is just so easy to overlook and miss

Lefty:
Thanks for the advice guys, I will try Seafoam & have a look at the boot, I replaced the plug last year but I'll pull it & have a look. I'll also see if the intake is leaking.
I appreciate your input, Lefty

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