Need help identifying piston size

[Orville538 10]

9 hours ago, F250 guy said:

Lot of work to do there. 

Yeah Im just gonna do this...I really don't care for the BBK this atv my son is gonna ride it anyway,I'm building me a 01 Raptor660r with all Hotcams Top end stuff,Hinson clutch basket and pressure plate,gytr clutch,and so on.... but back to the Honda subject I'll just get this 300cc kit,I ordered the rocker arms last night "Honda brand" not cheap crap...but I want to THANK YOU SLAMMED & FISH for you dedicated help...you guys are awesome!!!! All this is for my boy.... Isee that any 330cc kit  cases need machining....

[SlammedRanger 1,556]

Your very welcome bud! Glad to help! Make sure you keep us posted. And maybe a picture of your son enjoying it when its all said and done. Thats what makes this all worth while!

[Fishfiles 20,145]

Orv' , I was over at the other  site where you posted about your piston ID , there are 2 post and one was yours ----- hope you stick around and take up thru the rebuild process and the final outcome 

[F250 guy 107]

Keep posting as your doing the top end, I never seen a sport ATV before. 

[Orville538 10]

On 1/16/2020 at 8:47 AM, Fishfiles said:

Orv' , I was over at the other  site where you posted about your piston ID , there are 2 post and one was yours ----- hope you stick around and take up thru the rebuild process and the final outcome 

Hey Fish and Slammed I didn't notice some I should have,the piston only had 4 rings it was missing the darker color ring that does in the center of the piston you know in between the top and the 3 bottom ones (the 2 skinny ones and the wavy one that goes in the center of the skinny ones) well that one was missing for sure because I didn't take it out at all.... Now  How was that even working/running? Thats obviously not good? What a hack that guy!!!! 

[Orville538 10]

Just now, Orville538 said:

Hey Fish and Slammed I didn't notice some I should have,the piston only had 4 rings it was missing the darker color ring that does in the center of the piston you know in between the top and the 3 bottom ones (the 2 skinny ones and the wavy one that goes in the center of the skinny ones) well that one was missing for sure because I didn't take it out at all.... Now  How was that even working/running? Thats obviously not good? What a hack that guy!!!! 

I will post all the pictures of all the work I do to the TXR EX300,bare with me because I'm buying parts little by little,next I'm buying the 300cc head kit wiseco piston,the Hotcams stage 1 with new sprocket,already bought rocker arms waiting on delivery....

[SlammedRanger 1,556]

Well yeah it would have been down on compression a good bit. It was missing one of the compression rings entirely. Not to mention it would have smoked pretty good also. Hack is putting it nicely.

[SlammedRanger 1,556]

Just a heads up also bud. Its a trx300ex. That is the proper name for it. Or a fourtrax 300ex.  Not to be confused with the trx300. Or fourtrax300 which are utility quads. The best way to tell the difference is sport quad 300ex is manual clutch drive. The 300 utility quads are semi auto.

[Fishfiles 20,145]

Wow, Orv , you did get redneck hacked .... Slammed is the man when it comes to EX engine builds so you are in good hands with him ------- be careful when ordering parts as like Slammed mentioned , there is the TRX300EX ( sport ) and then the TRX300FW ( 4wd )  or TRX300A ( 2wd )  ( both considered utility )  and they are different , and I would stay away from anything made in China  

[Orville538 10]

13 hours ago, SlammedRanger said:

Just a heads up also bud. Its a trx300ex. That is the proper name for it. Or a fourtrax 300ex.  Not to be confused with the trx300. Or fourtrax300 which are utility quads. The best way to tell the difference is sport quad 300ex is manual clutch drive. The 300 utility quads are semi auto.

You say this correct? TRX EX300  I look at everything and ask questions to the sellers before purchasing parts,Thank you very much Slammed & Fish again!!! Fish you reminded me of someone who I grew up with and he is like my brother but from another mother,he called me Orv' for shorts all the time... Many blessings to you both and your families!!!! Pictures will be posted as soon as I can gather the parts...I'm not buying nothing Chinese either knock off's crap!!

[SlammedRanger 1,556]

Can you take a picture of the whole quad? We want to be 100% sure you have a 300ex. Im not sure where you are getting trx ex300 from? That isnt anywhere or on anything. From the pictures you had posted before im almost positive its a 300ex sport quad. If it is we can leave your thread in the sport quad section. If not it should be in the utility section. Just to keep things in order.

[Orville538 10]

11 minutes ago, SlammedRanger said:

Can you take a picture of the whole quad? We want to be 100% sure you have a 300ex. Im not sure where you are getting trx ex300 from? That isnt anywhere or on anything. From the pictures you had posted before im almost positive its a 300ex sport quad. If it is we can leave your thread in the sport quad section. If not it should be in the utility section. Just to keep things in order.

Also I'm gonna get new plastics from someone  for a decent price,or I might just get the front plastics and gas tank cover.... but Sir this is where I'm getting this Trx EX300 from... its an 04 TRX EX300 

[SlammedRanger 1,556]

Ok so its a 300ex sport quad for sure. And that sticker reads trx300ex to me? Either way saying it that way is gunna confuse alot of people.

[shadetree 5,880]

for the record OP, all atvs from honda use the letters and numbers like this -> trx300ex, they never have ex in front of trx :-).

[jeepwm69 7,600]

I don't know squat about the sport machines, but supposedly the 520CC top ends will fit on the 420 ranchers and 12-up 500 Foremans if you grind the cylinder down to fit in the cases.

 

After looking at what had to be done to get that one to fit, don't think that's something I want to do!  LOL

 

I'm going to follow this one.  Post lots of pics while you put it back together please!

[Orville538 10]

3 hours ago, jeepwm69 said:

I don't know squat about the sport machines, but supposedly the 520CC top ends will fit on the 420 ranchers and 12-up 500 Foremans if you grind the cylinder down to fit in the cases.

 

After looking at what had to be done to get that one to fit, don't think that's something I want to do!  LOL

 

I'm going to follow this one.  Post lots of pics while you put it back together please!

Jeepwm69 yeah I guess someone tried that grinding thing you're describing,but this 300ex had the loudest knock ever....and I thought that the cases were machined to fit that bbk but when I had difficulties pulling up the cylinder I knew something was wrong,then I noticed the grinding and was like wow...No F'ing wonder this thing is knocking...but anyway I'm buying parts as I can,but everything I'm buying is Wiseco,Hotcams stage 1,Kibblewhite racing spring kit and kibblewhite black diamond valves(something like this),Honda rocker arms,Wiseco Timing chain ,and debating on the exhaust.... FMF or DG

[Orville538 10]

1 minute ago, Orville538 said:

Jeepwm69 yeah I guess someone tried that grinding thing you're describing,but this 300ex had the loudest knock ever....and I thought that the cases were machined to fit that bbk but when I had difficulties pulling up the cylinder I knew something was wrong,then I noticed the grinding and was like wow...No F'ing wonder this thing is knocking...but anyway I'm buying parts as I can,but everything I'm buying is Wiseco,Hotcams stage 1,Kibblewhite racing spring kit and kibblewhite black diamond valves(something like this),Honda rocker arms,Wiseco Timing chain ,and debating on the exhaust.... FMF or DG? ,I will post pictures when I start to rebuild it again!!! Then I have to finish my other one... Raptor660r but that's gonna be a BEAST!!! 

 

[SlammedRanger 1,556]

29 minutes ago, Orville538 said:

debating on the exhaust.... FMF or DG

Go fmf. Or hmf. DG is cheap but you get what you pay for. DG always sounds raspy and doesnt really gain anything but sound really.

[Orville538 10]

On 1/24/2020 at 6:06 PM, SlammedRanger said:

Go fmf. Or hmf. DG is cheap but you get what you pay for. DG always sounds raspy and doesnt really gain anything but sound really.

Ok...thank you very much Slammed....you've been a great help and  Fish as well.... so far I have new Rocker arms (Honda) New Camshaft sprocket (Honda) and Hotcams stage 👈this I have  and next Im ordering the Valve spring kit with KibbleWhite Black Diamond valves,Cylinder kit with Wiseco piston and the FMF exhaust and Id like to grab a Dyno jet kit too!!!! Thanks 

[SlammedRanger 1,556]

19 minutes ago, Orville538 said:

Ok...thank you very much Slammed....you've been a great help and  Fish as well.... so far I have new Rocker arms (Honda) New Camshaft sprocket (Honda) and Hotcams stage 👈this I have  and next Im ordering the Valve spring kit with KibbleWhite Black Diamond valves,Cylinder kit with Wiseco piston and the FMF exhaust and Id like to grab a Dyno jet kit too!!!! Thanks 

No problem! Always glad to help! Sounds like you got a good start for a happy son riding a quad around! Keep us posted if you need any help and keep the pictures coming! We all like pics!

[retro 4,048]

@Orville538, have you checked the top of the rod for wear yet? Is the crankshaft and rod in good condition, bottom end in good shape?

[Orville538 10]

1 hour ago, retro said:

@Orville538, have you checked the top of the rod for wear yet? Is the crankshaft and rod in good condition, bottom end in good shape?

R

@retro honestly no I have not checked the top of the rod,what would I be checking for? The inside where the piston pin inserts through?  Because like I had previously asked Slammed or Fish I believe that the rod has a little play from side to side but no play up and down,but I will double check again just to be sure since all this is exposed now,because once this is all put back together it would suck opening up all of it again...thanks for the letting me know retro!!!!

[SlammedRanger 1,556]

1 hour ago, Orville538 said:

R

@retro honestly no I have not checked the top of the rod,what would I be checking for? The inside where the piston pin inserts through?  Because like I had previously asked Slammed or Fish I believe that the rod has a little play from side to side but no play up and down,but I will double check again just to be sure since all this is exposed now,because once this is all put back together it would suck opening up all of it again...thanks for the letting me know retro!!!!

Good call retro. I think i was just going with he checked the lower rod with the piston still on the rod. You will want to check visually for wear. It will have scores or will look like a copper color. You will also want to measure it with your caliper in multiple places to be sure its not ovaled. The factory service manual will have a spec for the measurement you are looking for. Generally speaking though if you have the piston on you shouldnt feel any slop up and down at all. Just like the test for the lower bearing. Side to said as long as it isnt excessive is normal. Usually around an 1/8 inch of movement at the very top of the rod.

[retro 4,048]

If the wrist pin bore looks good, no galling, you can slide a wrist pin into the top of the rod just far enough that the pin is barely sticking out of the opposite side of the rod. Then lift straight up and down holding the long end of the wrist pin in your hand. Any play there should be barely perceptible, or none at all. The wrist pin should fit the rod bore perfectly and rotate freely inside the bore.

 

You can check the big end rod bearing using the wrist pin to lift and drop vertically as well. There should be no perceptible play on the big end. End play on the big end might measure between .016" to .025" which is probably within spec. You can look in the manual to find the service limit spec for rod end play.

 

Since this motor was such an amateur hack job (cylinder wedged into the cases) when you got it you may want to try to verify that the rod did not get bent due to the cylinder being wedged into the crankcase off-center, or unsquare with the block. You can get a pretty good idea whether the rod is bent or not by putting the new piston and wrist pin on the rod without the piston rings installed. Just slide the wrist pin in (don't put circlips in yet), center it in the piston then drop the new cylinder (lightly oiled) over the piston onto the base gasket.squarely. Then rotate the crank by hand until the piston is near TDC and rock the piston in the bore by pressing down on the piston over top of each end of the wrist pin. The piston should be free inside the cylinder while rocking it.

[Orville538 10]

On 1/26/2020 at 5:35 PM, retro said:

If the wrist pin bore looks good, no galling, you can slide a wrist pin into the top of the rod just far enough that the pin is barely sticking out of the opposite side of the rod. Then lift straight up and down holding the long end of the wrist pin in your hand. Any play there should be barely perceptible, or none at all. The wrist pin should fit the rod bore perfectly and rotate freely inside the bore.

 

You can check the big end rod bearing using the wrist pin to lift and drop vertically as well. There should be no perceptible play on the big end. End play on the big end might measure between .016" to .025" which is probably within spec. You can look in the manual to find the service limit spec for rod end play.

 

Since this motor was such an amateur hack job (cylinder wedged into the cases) when you got it you may want to try to verify that the rod did not get bent due to the cylinder being wedged into the crankcase off-center, or unsquare with the block. You can get a pretty good idea whether the rod is bent or not by putting the new piston and wrist pin on the rod without the piston rings installed. Just slide the wrist pin in (don't put circlips in yet), center it in the piston then drop the new cylinder (lightly oiled) over the piston onto the base gasket.squarely. Then rotate the crank by hand until the piston is near TDC and rock the piston in the bore by pressing down on the piston over top of each end of the wrist pin. The piston should be free inside the cylinder while rocking it.

I will check on all this tomorrow,take some pictures and let you guys know the scoop,so far on parts,I've bought new Valves Kibblewhite Black Diamonds,Hotcams Stage 1,Rockers arms,Camshaft sprocket,74mm Cylinder  and FMF 4.1 exhaust,.....Now  next week I'm planning on getting the Kibblewhite Spring Valve kit, New Timing chain and 74mm Wiseco piston kit,what are the best Gaskets and Head gasket to use?  Thanks all you guys for taking a little bit of YOUR time to help me out get this atv right for my son....