JET KIT AIN'T JETTIN

[BIGKAT1100]

I Recently had a Dyno-Jet stage one jet kit installed into my 1988 Katana 1100 and now I have a couple of issues occuring during riding.

1) If I hold steady at any RPM under 4000 and try to accelerate, I get a stumble before it catches and accelerates.

2) Surges when cruising at highway speeds (top gear - 5000 and higher rpms) then stumbles when trying to accelerate from that point.

(note/question) The problem initially was item one, then progressed into the second item. Is it possible that whatever was causing item one also fouled out the plugs, thus producing item two?

The mechanic that installed the kit seems to think the K&N air filter has the wrong air inlet in it (K&N filters come with 2 fittings: one for stock jetting, the other for modified). On the other hand, after reading the instructions that came with the kit, I get the idea that raising the needles may solve the problem. In the mean time, I gotta use the cage.

SAD AND SO DISTRACTED UNTIL WE RIDE AGAIN

P.S.
Is the power gain noticable once the kit is installed correctly ? That may sound like a stupid question but I have little experience with mods. Other bikes that I have owned already had the mods done so there was no way to gauge improved performance unless I rode the stock versions. Plus, I was happy with the performance.

Let me know what y'all think ...

[GregS]

Stumbling is more often associated with lean mixture. What happens if you raise the needles? What position do you have the needles on? What happens if you lower the needles?

[BIGKAT1100]

My carb experiences are very limited. The kit was supposedly professionally installed by a mechanic. The reason I said raise the needles is because that's the conclusion I came to after reading the attached literature. He may have other ideas. I just want it running right.

(God, that last statement sounded squidly)

[bubba]

My bike has a jet kit as well and it does the same thing BigKat. It seems that the JetKit likes higher RPMs, so anytime I want to goose it I downshift a gear so that my RPMs are higher, then punch it and shift back up. Also, my bike is set to run pretty rich.

[The CyberPoet]

Stumbling on added throttle between idle and 5k means that the diaphrams aren't raising fast enough. Replacing the DynoJet diaphram springs with the OEM diaphram springs will probably resolve the issue.

Cheers,
=-= The CyberPoet

[md86]

May have been "professionally installed" , but that don't mean he tuned it right , or even took the TIME to do so . First , do some reading and try to gain a better understanding here .....

http://www.factorypro.com/tech/carbtune,CV,high_rpm_engines.html

Next , my initial thought is this ..... check plugs . But do so in a specific manner , as I believe the problem may become more apparent . Firts just have a look and see what they say . Next , try what I've dubbed and "idle chop" . Similar to a plug chop , but at idle instead of while in motion . Ride for a bit (while thinking about what you read in the link) , then when you get home let it idle for a couple minutes before shutting it off . No blipping . Recheck plugs once it cools and see what they look like . After messing with mine more and trying this way , I found a couple cylinders were a tad lean on idle , and after adjusting it feels stronger at part throttle now .

[BIGKAT1100]

I put a fresh set of plugs in when the jet kit was installed. The concern was that the initial condition described in item one caused plugs to foul. I'm sure that Dyno-Jet would not produce a product that would not provide smooth acceleration bottom to top. the mechanic tried to hint around that if you install the kit, it could change the performance dynamics (making excuses for the hiccup). I knew that was a load of crap.

Thanks for the link. I will look into into that for more info. I started this topic to just get some ideas. As far as the repairs, he got good money to perform a task so he needs to complete his end. The bike was running fine before the jet kit. I just want to enhance performance a little.

I appreciate this site, it's charactors (could not think of a better way to state that), and the input.

Thanx all y'all