KDXRIDER.NET

I am somewhat new to this forum and a first time poster. I have been working on a rebuild through out the winter. Its a 1989 KDX200, and this has been an expensive project and has been kicking my ass over the last couple weeks. I have two different cylinders one is sleeved at 67mm and the other is an ebay 66mm cylinder from a 1991 that Power Seal welded and plated for me. After puting everything together bike seemed to run hot and overflow tank would bubble when opening the throttle (blown head gasket?) Tryed the other cylinder and different and same head, same ****. Not burning any coolant, but there is a little more than normal smoke that smells normal. So now I have been back pedaling and have now done an important test that I failed to do, a leak down test after resurfacing the head and cylinder again. I am getting a small leaks between the crankcase and the crank seals on both right and left sides. The seal lips are not leaking. In shop manual, I did not see anything about applying some type of sealant before driving in seals. I applied grease to help ease it in. They are not canted and are flush at the seal seat. Feels like it has really good compression and starts easy. I have done a compression test with a chinese testor (the testor came from China not being racist ) the testors shrader valve is at the gauge and is not at the end you would thread in to the spark plug hole. I have read these can give false readings. Has anyone else had these problems? This is only my second rebuild and would like to move on to my sons 2005 KX100. Would also like to mention i was using cheap head gaskets, this time I used a Wiseco and have not started it up yet. You guys on here are well experienced and have been getting alot of help by reading your post. I did not see anything mentioned about problems like i have. Thanks for reading!

Welcome to kdxrider.net. Sorry for the rebuild troubles. Hang in there. Hopefully, someone with some experience will chime in.

Definitely don't save your pennies on the gaskets, there are some out there that aren't worth the paper they are packaged in. The crank seals go in dry. What were your numbers for the leakdown? You should go to 5 psi then monitor, shouldn't lose more than 1 psi over 10 minutes or so, anything higher than that you should fix.

Thanks for the welcoming and I hope everyone is doing well through these tough times. I was going back at it again today and tested again. It was going back down down about 2 - 2 1/2 psi in 10 minutes. Actually it dropping slower than last night. After breaking into it further on the right side there are three grooves/slots that hold the crank bearing bearing seat. On the left side to, but there was more meat there and it didnt penetrate, so it wasnt leaking. I think its a design flaw? Also on the left side its just leaking aound the seal very, very little. and after applying a little heat seemed to go away. On the right side i plugged up with some permatex motoseal that I sealed the cases with. Letting sit for a day before i move on. What are your takes and have you seen this before?

Did you replace the crank bearings and seals with new ones? 2 psi is a lot of loss and needs to be properly addressed.

A lot of people see leaks around the reed cage/intake boot. You weren’t leaking there at all?

I have replaced every seal, every bearing and every gasket on the whole bike including the engine. There have been no leaks around the intake/reed cage. The main leak as of now is the right side. There are three grooves around the bearing that hold the steel crank bearing seat and where the steel is extruding is leaking. I dont know how to upload a pic yet.

Your right Bufftestor. I have learned my lesson on the cheap gaskets. I did buy wiseco this time and again because they were cheaper. They seem to be extremely well made compared to the other 2 sets I bought. If they for some reason they dont work i will order oem next time around.

Please look on page 2 of this pdf. Is that what is going on?

https://www.eric-gorr.com/files/pdfs/mo ... wasaki.pdf

Selectah wrote: 12:18 am May 07 2020 I have replaced every seal, every bearing and every gasket on the whole bike including the engine. There have been no leaks around the intake/reed cage. The main leak as of now is the right side. There are three grooves around the bearing that hold the steel crank bearing seat and where the steel is extruding is leaking. I dont know how to upload a pic yet.

Selectah, you have found the flaw on this series of motors, was a common problem where the bearing holders are cast into the case, the 3 slots you see take a screwdriver and scrape away the flashing-loose alloy in the slots, you most likely will see the steel holders, clean them very well with brake cleaner and fill the slots with JB weld.

Opps, KDXGarage you beat me to it and with a good link, my slow one finger typing ..

Selectah wrote: 12:30 am May 07 2020 Your right Bufftestor. I have learned my lesson on the cheap gaskets. I did buy wiseco this time and again because they were cheaper. They seem to be extremely well made compared to the other 2 sets I bought. If they for some reason they dont work i will order oem next time around.

I like cometic’s gaskets. They seem to be not as good as oem, but not garbage either.

KDXgarage and JimmyB you guys nailed it. That is a really nice right up and I will also apply this knowledge to my sons KX100. Next I will remove the crankcase sealer I put on and use some JB weld instead. Thanks for the help.

You're welcome. I think it was a dealer sheet info thing.

KDXGarage wrote: 10:24 am May 07 2020 Please look on page 2 of this pdf. Is that what is going on?

https://www.eric-gorr.com/files/pdfs/mo ... wasaki.pdf

I learned something new. Thanks for sharing that.