2003 Honda Cr85 Nightmare..! help plz

I bought this bike about 2 weeks ago from some guy who said the bike runs great.. yeah right!! The bike started right up cause he had pre warmed it up right before I got there and it ran fine the short distance I had to ride in which was a short gravel alley about 1000 feet long. It'll bog when you first take off.. Low to mid range is very powerful but it'll bog write before the power band kicks in. If you're in the bog at WOT for 5 sec or more you can feel the power band kick in for a moment but not as it should. Sorry if this sounds stupid to you pro's out there.  

 

It's an all stock 2003 Honda CR85r other then a FMF silencer and here's what I did so far: 

 

Drained old gas and put fresh 40:1 Amsoil Dominator / 93% octane gas mix.. Installed new fuel line.

 

Disassemble/Cleaned entire carb with carb cleaner. Has stock 125/50 jets with the needle clipped in #2 stock position and A/F screw at 1 5/8 turn.. Floats are at 19mm.. I'm 692' above sea level. I tried leaning and richening the A/F with no luck getting all my power back.

 

New pre oiled No-Toil air filter 

 

There was some spooge coming out the silencer so I repacked the FMF silencer with the FMF (white) packing.. Packing isn't too tight but not loose at all.. The Old packing was burnt up and had lots of unburnt oil in it.

 

Compression is at 120 psi.. Is this low..?

 

New NGK Iridium BR10EIX plug.. Factory gap is .006-.007mm This Iridium is gapped at .028mm. I read somewhere that you don't gap Iridium plugs.. Is this true..? Or should I gap it to spec and try it anyway.. Also I know this isn't the proper way to do a plug chop but after about 5 mins of riding mostly at WOT the plug had brown tan looking color on the porcelain.

 

All frame grounds was cleaned to bare metal and used electrical grease on all connections.

 

New Boyesen super stock reeds. Strange thing is after installing the reed petals and on one side there was less than a mm of a gap. Could the reed cage be bad..? 

 

Drained trans oil which appeared to look normal and changed it with Amsoil 10w40 motorcycle oil..  

 

It does have an exhaust leak at the manifold but not really that bad. It seems to have good spark.. I wasn't able to do a leak down test cause I can't afford a kit right now but I did take starting fluid and while it was running I spray all around the carb and boot areas with no change in idle speed. So far this is everything I've done with no changes in performance. 

 

What do you think the problem is..? Or what other things should I try.. Thx in advance..!!!

 

 

 

 

 

 

 

 

 

 

 Should be upwards of 170-175

You did check compression while holding throttle wide open correct?

Edited by Blackwoodz

New NGK Iridium BR10EIX plug.. Factory gap is .006-.007mm This Iridium is gapped at .028mm. I read somewhere that you don't gap Iridium plugs.. Is this true..? Or should I gap it to spec and try it anyway..

Factory plug gap for the '03 CR85 is 0.6 – 0.7 mm (0.024 – 0.028 in).  You can leave the spark plug the way you have it since you are 'within spec'.

 

Your compression is on the low side (assuming you held the throttle wide open while doing the test). The 85cc engine with a fresh top end will see somewhere in the 155-165 psi range. Doing the compression check hot or cold with not influence the numbers much (maybe 3 ~ 5 psi lower on cold engine). A bike with 120psi compression is enough for the  bike to run and rev out normal, it will just be down on power.  If the bike is bogging when getting into the upper RPMs, something else is going on wether it is a spark issue, or an air/fuel ratio issue.

 

I see you are running 40:1 gas-  Im not familiar with the type of oil you are using for pre-mix but the stock carburetor settings on your bike are designed to run on a 32:1 mixture.  Using 40:1 is making your fuel mixture richer (less oil=more fuel), which causes the bike to make less HP, and not run as strong as it could.  All honda bikes run rich from the factory so you are potentially making it worse. The spooge coming out of your silencer is an indication of a rich A/F mixture-

 

These types of problems are pretty hard to pin-point over an internet forum. Ive seen people here post videos of them riding the bike which helps others to 'see' what is going on.

 

How many kicks does it take for the bike to start when it is completely cold?

Also, you never gap an iridium plug, you never even measure the gap, if you put a feeler guage in there it removes the iridium from the electrode and ruins the plug.  If you measured your plug with a feeler guage, that plug is ruined and will need to be replaced.

 Should be upwards of 170-175

You did check compression while holding throttle wide open correct?

 

Yes, I checked the compression with the throttle wide open.. I checked it again and it's still at 120psi.. 

 

Factory plug gap for the '03 CR85 is 0.6 – 0.7 mm (0.024 – 0.028 in).  You can leave the spark plug the way you have it since you are 'within spec'.

 

Your compression is on the low side (assuming you held the throttle wide open while doing the test). The 85cc engine with a fresh top end will see somewhere in the 155-165 psi range. Doing the compression check hot or cold with not influence the numbers much (maybe 3 ~ 5 psi lower on cold engine). A bike with 120psi compression is enough for the  bike to run and rev out normal, it will just be down on power.  If the bike is bogging when getting into the upper RPMs, something else is going on wether it is a spark issue, or an air/fuel ratio issue.

 

I see you are running 40:1 gas-  Im not familiar with the type of oil you are using for pre-mix but the stock carburetor settings on your bike are designed to run on a 32:1 mixture.  Using 40:1 is making your fuel mixture richer (less oil=more fuel), which causes the bike to make less HP, and not run as strong as it could.  All honda bikes run rich from the factory so you are potentially making it worse. The spooge coming out of your silencer is an indication of a rich A/F mixture-

 

These types of problems are pretty hard to pin-point over an internet forum. Ive seen people here post videos of them riding the bike which helps others to 'see' what is going on.

 

How many kicks does it take for the bike to start when it is completely cold?

 

Your right as far as the plug goes, I had my numbers mixed up..lol  

 

The 2 stroke Amsoil Dominator racing oil I use is an injector oil and is formulated to mix 50:1 to any spec.. Years ago an Amsoil rep said it's not necessary to richen it by adding more oil to make 40:1 and that it won't change the performance other than smoke more. Many will disagree with this but I've been using this same mix for years without any problems and use this same mix in my dirt bikes, atv's, outboards, chain saws, weed eaters, scooters and more.

 

Also, you never gap an iridium plug, you never even measure the gap, if you put a feeler guage in there it removes the iridium from the electrode and ruins the plug.  If you measured your plug with a feeler guage, that plug is ruined and will need to be replaced.

 

I called a NGK rep today and they said as long as you use the right tool, the iridium plug can be gapped. You just have to be careful not to damage or break the tip off. He also said so many people was gapping them wrong in the beginning and sent a note to all dealers to tell their customers "Don't gap Iridium plugs".. I've never gapped a iridium and never had a problem with one.

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I appreciate everybody's replies..!!! I'm going to guess I have bad rings or possible piston. I've never pull a jug or did a piston/ring job but have done a lot homework on how to do it and know a lot of people I can turn too if needed. I have a manual and to do it right I should just get a Wiseco piston and ring kit then after insulation see if I can borrow a leak down tester. Before I order I'll have to do some measuring..

 

If you think it could be something different then plz chime in and tell me what you think. Thx       

Update..!!! 

 

I fixed my problem.. Being that the compression was low I decided to order a OEM Honda top end rebuild kit $85.49.., 46-48mm flex hone $31.99.., 8oz of hone oil $9.50.. and a 2" (50.8mm) cylinder brush $17.53.. I also bought a rebuild carb kit $24.99 cause the float valve was bad and wanted to freshen it up anyways. Not bad for $169.50 and I did all the labor myself. BTW this is my first rebuild..

 

It wasn't a hard job to do.. Lots will tell you never to hone nikasil plated cylinders well I know many people that have without any issues. My cylinder wall wasn't scored at all, it was just glazed. I heavily oiled the flex hone with the hone oil then heavily oiled the cylinder wall. My 1/2" drill is rated @ 1200 rpm so I ran the drill just over half way at around 700-800 rpms moving the hone up and down the cylinder 1 second per stroke for 5 secs. then washed/dried cylinder and added more oil to cylinder and flex hone. I put the drill in reverse for another 5 secs and washed/brushed cylinder with dish soap and hot water. I dried it with a lint free towel and compressed air. The cylinder had no more glaze and had good looking cross thatching. I coated the cylinder wall with raw 2 stroke oil and install the ring down into to cylinder using the piston to center it about 10-15 mm in from the top. My ring gap was perfect at 0.011 in.. spec is 0.011-0.017 in.. I used raw oil on wrist pin and bearing and after installing the ring on the piston I made sure the "IN" mark on top of the piston was facing the intake side and squeezed the ring around the centering pin as I was lowing the jug down. I used a mallet to tap into place then torqued to spec @ 20 ft lbs. I then installed the cylinder head and torqued to spec @ 20 ft lbs. I added antifreeze and leaned the bike down to help with air pockets and topped it off. I also installed a new NGK BR10EIX iridium plug. After I completely rebuilt the carb, adjusted it to stock settings and installed it I moved on to installing the expansion chamber. My exhaust gasket was on back order so I decided to clean the outside of the exhaust manifold and the inside of the chamber with carb cleaner and a rag. I put a bead of high temp (red) Permatex on the exhaust manifold and a thin coat on the inside of the chamber. I wiggled the chamber on, bolted it on, installed spring and wiped off the excess for a clean look. I allowed it to dry for more than 24hrs.   

 

I know there's many ways and theories on how to break in a top end and this is how I did it..

 

I use the gas mix I regularly use which is Amsoil Dominator 2 stroke racing oil. It's an injector oil and is formulated to run 50:1 regardless of spec. I run it at 40:1 cause I like a little more oil in my gas. I started it up with the radiator cap off until I seen the coolant flowing then put the cap on and let it idle on its own for 5 mins then turn it off. About 30 mins later it was completely cooled down so I started it up and let idle for 7 mins giving it light-med throttle every 10 secs. I turned it off and allowed it to completely cool. I started it up for about 1 min and took off to the trails.. After about 5 mins of half to 3/4 throttle I noticed a slight bog so I turned in the A/F in 1/8 turn in, adjusted the idle and no more bog. Now was the big test.. It was strong off the line and strong threw the power band with no bog..!!! On the last stretch to the house I opened it up and it wanted to wheelie every gear.!! I wasn't geared to run like a fool or it would of wheelie every gear.  After about 15-20 mins of having fun I parked it and and let it cool. I took a compression test and it was at 155 lbs. I was told in time as everything seats in, the compression will increase.

   

 

I know there's many way's to rebuild and many ways to break in top ends. I might have left some things out but I did it this way to see if it works for me and if this fails I'll let you guys know.. Thx for all the replies..!!!

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