KDXRIDER.NET

I just did a top end rebuild on my 97 220 this winter. New wiseco piston, boyseen reeds, all new gaskets, and I also had Ron mod my carb and head. Right now I'm running a 40 pilot, 150 main, needle clip 4th from the top, air screw 7/8 turn out. Bike will start on the first or 2nd kick, no choke needed. Idles great. However when blipping the throttle it seems to take a bit too long to settle back down. Its not excessive but it does take longer than it did before. I have double checked everything was tight around the head and intake. I don't believe I have an air leak anywhere. Am I reading too much into this or should I keep digging? Not sure where I should look next. I also did a plug chop test last night and the plug was still pretty white, so I'm thinking I need to go up a size on the main. Any thoughts appreciated. Thanks.

I did the same thing last year and had the same problem! It was a air leak for me, one of the bolts on the reed block was not tight.

Ron's normally pretty good about getting the jetting real close for you. I would suspect a leak as well.

check the crank seals for a leak

Jaguar wrote:check the crank seals for a leak

I would like to think that this is not a strong possibility as I did not have this problem prior to my rebuild. I will triple check all the gaskets and bolts though.

Mnmonster wrote:I just did a top end rebuild on my 97 220 this winter. New wiseco piston, boyseen reeds, all new gaskets, and I also had Ron mod my carb and head. Right now I'm running a 40 pilot, 150 main, needle clip 4th from the top, air screw 7/8 turn out. Bike will start on the first or 2nd kick, no choke needed. Idles great. However when blipping the throttle it seems to take a bit too long to settle back down. Its not excessive but it does take longer than it did before. I have double checked everything was tight around the head and intake. I don't believe I have an air leak anywhere. Am I reading too much into this or should I keep digging? Not sure where I should look next. I also did a plug chop test last night and the plug was still pretty white, so I'm thinking I need to go up a size on the main. Any thoughts appreciated. Thanks.

the mixture and clip position say your pilot is too lean. richen up the pilot a few measures, retune the clip and mixture, i bet it doesn't hang anymore.

I disagree since he can start it without the choke

Jaguar wrote:I disagree since he can start it without the choke

This is where I get a bit confused as well. Starting without choke would lead me to believe I am rich...however the hanging idle would point to being lean...kind of contradicting.

Ok I tried swapping in a 42 and a 152 and then also a 38. No change as far as the idle goes. Same slight hang. See video below.



Am I making too much of this? Right now I have the 38 with the 152 main. I've got some spooge with the bigger main but the bike just rips from 1/8 throttle on up. Slight bog from idle to 1/4 when accelerating hard.

Jaguar wrote:I disagree since he can start it without the choke

i think you're right, too.

meaning.... there is weird stuff happening that should not happen. he's rich when first started (start without choke) and lean once running (idle hanging).

i bet there is a air leak and jet block / fueling issue happening.

I tried tightening everything again, reed block, cylinder, and head nuts. No change. I had Ron replaced all the gaskets in the carb, including the jet block.

Does the slide "snap" shut when you blip it?

jjavaman wrote:Does the slide "snap" shut when you blip it?

Yes it opens and closes smoothly and doesn't hang up.

I would lube the cable just for giggles. It's quick and easy. Other than that I would say rich on the pilot or leaking fuel passed somewhere.

Still chasing this. I am not loosing any transmission oil or coolant. No visible leaks of any kind. I've tried spraying wd-40 and carb cleaner all round the intake, base and head gaskets with no change in idle.

Yesterday I took the reed block off to inspect the brand new reeds I installed when I did the rebuild. Here's a pic. You can see a bit of light in the corner. Is this enough to cause an issue? And if so, I believe this would show up as a rich condition, not lean that I am experiencing, right?



Also I snapped a pic down into the piston to find some real nice gouges on my ~5 hour piston.



Starting to lose interest in chasing this stuff.

Wow on the piston picture. What is your warm up procedure? Is this the first time with a forged piston?

I only see two if the four corners . . . . but I havent seen gouges that deep or narrow with a 4 corner siezure.

Yes first forged piston. Had the stocker in it when I took it apart.

Warm up, I just let it idle for about 5 minutes then ride easy for a minute or two. Then ride as normal.

Can anybody tell me the inner diameter of the exhaust and intake? I'm going to make a leak down tester and need to order some plugs.

Built myself a leak down tester. I did have some small leaks at the reef block but got those sorted. However I have a pretty significant leak still. Lose about 1 psi per minute. Can't seem to locate anything around the intake, spark plug, head, or base gaskets...this would lead me to my crank seals I suppose

I have not lost any tranny oil, so I assume my problem lies with the left (flywheel side) seal. Is there any way to verify before diving in? I know the bearings and seals are relatively cheap, but what would I be looking at for labor if I brought just my motor in to get split and seals and bearings replaced?

Starting tearing everything down. My piston is in way better shape than I thought. The previous picture had me worried. Here are some pics.





Those gouges in the earlier pictures aren't gouges at all. Can't even feel them with my fingernail.





Thoughts?