Help with tuning....

[yama_rider]

First off I started out with a stock Rx1 that worked as it should be then I decided to install K&N filters for better performance and installed 165 mains at the same time. It never really worked the way it should have at WOT, it had a miss and was especially bad after the sled would sit by the trail for a while, then take off. I know a few different guys with good working RX1's (they have K&N's too) and told me that they ran a 170 main/20 pilots and Holtsman springs. So I ordered these parts a while back and finally got them this week and installed them today, except for the pilots because the ones they sent me did not match up. Anyways, the sled starts up fine and is now more responsive when I stab the throttle (from the springs I assume) and is pulling better than ever at WOT. But now I have a terrible hesitation from 1/4 to 3/4 throttle. I pulled the carbs again and couldn't find a thing. Any help would be great.

 

[tproteau]

is the hesitation a bog? you could probably mess around with the needle height to fix this issue.

 

[yama_rider]

Not a bog.....more of a bad misfire. Would the needle really have this much of an effect? You may be right tho. Can the needle be adjusted without removing the carbs? Thanks.

 

[tproteau]

You could take those black caps off the top of the carbs and pull the needles out there then adjust the clips higher or lower to adjust the needle have you checked your spark plugs for colour? Might shed some light on the conditions whether it be lean or rich

 

[yama_rider]

Plugs are prefect but I only ran it like this for a few minuits before bringing it back to the garage. I will play with the needles some time this week. Would you go richer or leaner with the needles?

 

[low flying missile]

Plugs are prefect but I only ran it like this for a few minuits before bringing it back to the garage. I will play with the needles some time this week. Would you go richer or leaner with the needles?

Richen it. I would set the pilot screws to 2.5 turns out and lower the needle clip one notch. I use hemostats to grab and pull the needles out of the slides. Needle nose pliers will work. I like to have carbs near room temperature so the plastic slide is more flexible. Pull straight up to remove the needle and push straight down to put it back in. I broke a slide years ago trying to force the needle back . Be sure to keep track of the little O rings.

 

[tproteau]

from the sounds of it I'm thinking you need to go richer with the needles because of those stiffer springs you put into the carbs. the needles aren't raising as quickly as they would with stock springs

 

[yama_rider]

The slide springs are not stiffer, they are weaker so that the slides can raise quicker. I had a friend of mine give me a hand with it last night and he said when I was plling it into his garage it sounded like it was dumping in way too much fuel. So we lowered the needle (all the way) and tried it. It helped but still had the hesitation from 1/2 to 3/4. This told us that the 170 was just too rich. Then we pulled the carbs and put the old 165 mains back in and presto....it was running fine again. But this is very puzzling to me as 2 other RX's I ride with have the 170's and they really haul the mail! Not sure why mine cannot handle it unless there was a mistake made with the jets somehow from the factory. I'm just happy it's running again. I may play a bit with my needle now to dial it in perfect. Needle is back in stock location again.