2stroke top end & bottom end?

[69hondo]

Got a question for the experts. When you do the top end on your 2 stroke are you also doing rod bearing and main bearings?

I only ask as we are doing the top end on my daughters CR125 right now. The nickel/chorme needs to be replaced and it looks like it will be cheaper to just put a new cylinder on it. The shop is telling me I need to do the bottom end as well. The rod feels good and I dont see any signs of heat but he says it doesn't matter and I should do it. Now I know what will happen if the rod bearing comes apart but I just wanted to know if this is general practice.

Thanks Nick

 

[JUSTWANNARACE]

What year and how many hours? If it has a ton of hours I would suggest a crank rebuild. Or just buy a new one. If you have it rebuilt make sure it's by someone that knows what they are doing or you'll end up with a vibrating POS.

As for the nicasil, post a pic. If it needs to be replated call Millinium Technologies for a 125 it's like $100-$150 +shipping. Send the piston you are going to use with it so they can size the bore to the piston. Milliniums nicasil will be better than factory.

 

[69hondo]

What year and how many hours? If it has a ton of hours I would suggest a crank rebuild. Or just buy a new one. If you have it rebuilt make sure it's by someone that knows what they are doing or you'll end up with a vibrating POS.

As for the nicasil, post a pic. If it needs to be replated cal Millinium Technologies for a 125 it's like $100-$150 +shipping. Send the piston you are going to use with it so they can size the bore to the piston. Milliniums nicasil will be better than factory.

Its an 03 and I dont know the hours. We got it almost two years ago and was supposed to be fresh then.
So if I do the bottom end I should not try it myself?
Ok, I will give them a call. Thnakyou

 

[JUSTWANNARACE]

Its an 03 and I dont know the hours. We got it almost two years ago and was supposed to be fresh then.
So if I do the bottom end I should not try it myself?
Ok, I will give them a call. Thnakyou

To rebuild the crank you have to press out the lower rod pin. Then reassemble with new pin, rod, bearing and thrust washers and new outer bearings. Then you will need a truing stand to check the run-out on both ends and adjust them to make it true. I always tig weld the pin to the crank wheels once they are true.

I would look at the owners manual and check the crank tolerances. But in my experience the smaller cc bikes rarely need the cranks rebuilt unless it had the living piss ran out if it or if the bike has been ran lean for a significant amount of time.

 

[69hondo]

To rebuild the crank you have to press out the lower rod pin. Then reassemble with new pin, rod, bearing and thrust washers and new outer bearings. Then you will need a truing stand to check the run-out on both ends and adjust them to make it true. I always tig weld the pin to the crank wheels once they are true.

I would look at the owners manual and check the crank tolerances. But in my experience the smaller cc bikes rarely need the cranks rebuilt unless it had the living piss ran out if it or if the bike has been ran lean for a significant amount of time.

Ok wow that does sound like more than I want to handle. I will check the tolerances and go from there.

Just called Millenium. $310 to replate the cylinder. $511 for everything including piston, pin , bearing, inspect and assemble power valve plus gaskets.

 

[JUSTWANNARACE]

Ok wow that does sound like more than I want to handle. I will check the tolerances and go from there.

Just called Millenium. $310 to replate the cylinder. $511 for everything including piston, pin , bearing, inspect and assemble power valve plus gaskets.

Wow. Prices have went up in the last year. But I used to be a dealer for them so that's why my quote may have been lower as I wasnt thinking retail. But there work is 2nd to none and I guarantee you'll be happy with there work. $511 doesn't sound to bad for what you are getting though. And they will stand behind there work if anything was to happen, chipping, peeling, pour pockets ect..

If you feel you need the crank rebuild I would suggest not doing it yourself. I dont have any of my stuff set up right now to do it but. I would suggest Crankworks they are the best in the industry. My second would be Falicon

Premium Crankshaft Products & Services - Crank Works, Inc.

Crank Works offers billet crankshafts, connecting rods, and various services for dirt bike, ATV, UTV, PWC and snowmobile enthusiasts. Whether you need a new crank, a rod, or a transmission service, Crank Works can help you improve your performance and reliability.

www.crankworks.com

 

[69hondo]

Wow. Prices have went up in the last year. But I used to be a dealer for them so that's why my quote may have been lower as I wasnt thinking retail. But there work is 2nd to none and I guarantee you'll be happy with there work. $511 doesn't sound to bad for what you are getting though. And they will stand behind there work if anything was to happen, chipping, peeling, pour pockets ect..

If you feel you need the crank rebuild I would suggest not doing it yourself. I dont have any of my stuff set up right now to do it but. I would suggest Crankworks they are the best in the industry. My second would be Falicon

Premium Crankshaft Products & Services - Crank Works, Inc.

Crank Works offers billet crankshafts, connecting rods, and various services for dirt bike, ATV, UTV, PWC and snowmobile enthusiasts. Whether you need a new crank, a rod, or a transmission service, Crank Works can help you improve your performance and reliability.

www.crankworks.com

Yeah I am probably going to go with Millenium. Seems like the best deal for everything.

 

[poncho]

What year and how many hours? If it has a ton of hours I would suggest a crank rebuild. Or just buy a new one. If you have it rebuilt make sure it's by someone that knows what they are doing or you'll end up with a vibrating POS.

As for the nicasil, post a pic. If it needs to be replated call Millinium Technologies for a 125 it's like $100-$150 +shipping. Send the piston you are going to use with it so they can size the bore to the piston. Milliniums nicasil will be better than factory.

I was a hard chrome plater in my younger days and my ride of choice was a CR125. Thought I would plate and grind myself, found there is a whole bunch more than that to make it right, cross hatch for oil retention etc.

 

[69hondo]

 

[outboard_256]

on my 03 CR125 it says something like rings every 8 hours and piston 16 hours but that is under race conditions in the owners manual. I usually do a top end one a year and bottom end every 3 years when racing. When I use it for trail riding I just do a top end when compression starts to get low and bottom end if I hear/feel rattling. When trail riding usually isn't going to explode over one trip, you start to hear it before it becomes a problem. When I am racing I am on the pipe as much as possible so it can go if you aren't doing preventative maintenance.

 

[Duramax]

My race bikes were top ends every race and bottom every third race. As long as you are running good oil and keep the airfilter clean, you are fine. I'm sure your daughter is a fine rider, but she is not hard on it. For a piece of mind maybe, then you will be good for a long time.

 

[Drew]

Use good oil with a high flash point and bottom end will last a long time . When I raced i didn’t have a ( practice) bike so I would do top end every race. But that included 4 days practice. Bottom end when it started getting lose. Maybe once or twice a year. But I was just amateur rider. And low budget at the time.

 

[77charger]

I would just redo the top end.I have a cr500 i had a mainshaft beaing fail so obvious it all had to come apart i redid every bearing and seal plus top end.Think i spent about 720 bucks for everything ct racing did the crank and bore on cylinder.Service honda for the low end bearings and seals.

Lower end was 16 years old at the time I also like to run a 40-1 oil ratio to keep more oil in the crank bearings i was told by a couple of builders it takes 50-1 to reach the lower end bearings.Same ratio on my stand up skis too and i have been using 927 oil for about 35 years on all my 2 strokes.

 

[69hondo]

I would just redo the top end.I have a cr500 i had a mainshaft beaing fail so obvious it all had to come apart i redid every bearing and seal plus top end.Think i spent about 720 bucks for everything ct racing did the crank and bore on cylinder.Service honda for the low end bearings and seals.

Lower end was 16 years old at the time I also like to run a 40-1 oil ratio to keep more oil in the crank bearings i was told by a couple of builders it takes 50-1 to reach the lower end bearings.Same ratio on my stand up skis too and i have been using 927 oil for about 35 years on all my 2 strokes.

That's the oil I use as well. Only 2 stroke oil I have ever used. Thanks man

 

[69hondo]

Cylinder is on its way to MIllenium.

 

[Xring01]

My son and I ride KTM300 2 strokes. My son rides stupid fast and it one hell of a rider. I ride like an old man, cause I dont like pain anymore.

Why is this relevant? Well we have been running Saber 2 Stroke 100:1 Synthetic oil for about 5 years now.

I love this stuff. I highly recommend it for anyone with a 2 stroke.

Our bikes have very little carbon build up, and top ends have never been touched. Remember my son Rides his bike HARD.

 

[JUSTWANNARACE]

My son and I ride KTM300 2 strokes. My son rides stupid fast and it one hell of a rider. I ride like an old man, cause I dont like pain anymore.

Why is this relevant? Well we have been running Saber 2 Stroke 100:1 Synthetic oil for about 5 years now.

I love this stuff. I highly recommend it for anyone with a 2 stroke.

Our bikes have very little carbon build up, and top ends have never been touched. Remember my son Rides his bike HARD.

Amsoil saber is an extremely good premix. I run all my gas 2strokes at 125:1

 

[n2otoofast4u]

Wow. Prices have went up in the last year. But I used to be a dealer for them so that's why my quote may have been lower as I wasnt thinking retail. But there work is 2nd to none and I guarantee you'll be happy with there work. $511 doesn't sound to bad for what you are getting though. And they will stand behind there work if anything was to happen, chipping, peeling, pour pockets ect..

If you feel you need the crank rebuild I would suggest not doing it yourself. I dont have any of my stuff set up right now to do it but. I would suggest Crankworks they are the best in the industry. My second would be Falicon

Premium Crankshaft Products & Services - Crank Works, Inc.

Crank Works offers billet crankshafts, connecting rods, and various services for dirt bike, ATV, UTV, PWC and snowmobile enthusiasts. Whether you need a new crank, a rod, or a transmission service, Crank Works can help you improve your performance and reliability.

www.crankworks.com

Didn't Polaris buy Millennium?

 

[JUSTWANNARACE]

Didn't Polaris buy Millennium?

If they havent yet, it is in process but they are keeping the same management so I think it will work out ok. the only other choice is US Crome and they suck!! So I hope millennium keeps the quality they have built the name with!

 

[69hondo]

Update!
Cylinder has been with Millenium for over two months now. Pretty frustrated with them. Their communication sucks! Over the past 3 weeks I have emailed and called 3 times each. When I call I get the "oh yeah its basically done should ship out in the next few days" Last communication was last Tuesday. guy " its done man should ship out today if not tomorrow" Didnt here anything or get a shipping notification so I emailed Friday. Nothing so I just called. " its done man should ship today, oh wait we are waiting on an oil seal for the power valve and dont know when it will be in". FUCK! Why couldn't you tell me that before.

Anyway so we are just waiting. LOL

I have another cylinder to do but now I am wondering if I should use someone else. Its for a TRX250r so no coating on the cylinder. Any other suggestions.

 

[ArizonaKevin]

Update!
Cylinder has been with Millenium for over two months now. Pretty frustrated with them. Their communication sucks! Over the past 3 weeks I have emailed and called 3 times each. When I call I get the "oh yeah its basically done should ship out in the next few days" Last communication was last Tuesday. guy " its done man should ship out today if not tomorrow" Didnt here anything or get a shipping notification so I emailed Friday. Nothing so I just called. " its done man should ship today, oh wait we are waiting on an oil seal for the power valve and dont know when it will be in". FUCK! Why couldn't you tell me that before.

Anyway so we are just waiting. LOL

I have another cylinder to do but now I am wondering if I should use someone else. Its for a TRX250r so no coating on the cylinder. Any other suggestions.

I just had some motor work done and my engine builder said the long lead times with millenium has been normal for 2021, he still uses them because he feels they are the best in the business, just takes longer than it used to. Thankfully my cylinder only needed a hone.

 

[96motorhead]

Update!
Cylinder has been with Millenium for over two months now. Pretty frustrated with them. Their communication sucks! Over the past 3 weeks I have emailed and called 3 times each. When I call I get the "oh yeah its basically done should ship out in the next few days" Last communication was last Tuesday. guy " its done man should ship out today if not tomorrow" Didnt here anything or get a shipping notification so I emailed Friday. Nothing so I just called. " its done man should ship today, oh wait we are waiting on an oil seal for the power valve and dont know when it will be in". FUCK! Why couldn't you tell me that before.

Anyway so we are just waiting. LOL

I have another cylinder to do but now I am wondering if I should use someone else. Its for a TRX250r so no coating on the cylinder. Any other suggestions.

I use Duncan racing in Lakeside, California for machine work. They have a lot of experience with 250r's.

 

[69hondo]

Update, it finally arrived. No notice, no shipping information and it still says in process on their link but it's here so I will move one. Lol

 

[JUSTWANNARACE]

Update, it finally arrived. No notice, no shipping information and it still says in process on their link but it's here so I will move one. Lol View attachment 1067200 View attachment 1067201

Sometimes the left hand doesnt talk to the right hand but if you have it, and all looks good, time to put her back together!

 

[ArizonaKevin]

Update, it finally arrived. No notice, no shipping information and it still says in process on their link but it's here so I will move one. Lol View attachment 1067200 View attachment 1067201

Hard to tell from the pic, work look good?

 

[69hondo]

Hard to tell from the pic, work look good?

it looks good. I will try to remember to take a couple pics when I start putting it together.

 

[69hondo]

Well Millennium sent me the wrong wrist pin bearing. unbelievable

it looks good. I will try to remember to take a couple pics when I start putting it together.

 

[69hondo]

Local shop had a bearing. So she's getting it together. We leave Tuesday morning.

 

[ArizonaKevin]

Local shop had a bearing. So she's getting it together. We leave Tuesday morning.
View attachment 1068321

Glad I'm not the only one waiting till the last second before thanksgiving trip. One of the two is running perfectly, the other I put something back together wrong in the kick start assembly so tearing that back apart today.

 

[69hondo]

Glad I'm not the only one waiting till the last second before thanksgiving trip. One of the two is running perfectly, the other I put something back together wrong in the kick start assembly so tearing that back apart today.

Man it's always something it seems. Hope you get it figured out.

 

[ArizonaKevin]

engagement Man it's always something it seems. Hope you get it figured out.

Fixed it, there is a spring in the kick assembly that is designed to keep tension on the engagement teeth when being kicked, I had the spring on the wrong side of the assembly.

All is well now, gonna do another heat cycle tomorrow, another Wednesday, and have the wife take it easy Thursday

 

[Danger Dave]

Hondo where do you live?

 

[69hondo]

Hondo where do you live?

Hesperia

 

[Hammer]

I use Duncan racing in Lakeside, California for machine work. They have a lot of experience with 250r's.

Duncan told me 6 months out. I have a 1985 TRX 250r motor that needs to come back apart. I had someone replace all the case gaskets, now it won’t shift into neutral.

Anyone have any so cal connections to straighten me out?

 

[JUSTWANNARACE]

Duncan told me 6 months out. I have a 1985 TRX 250r motor that needs to come back apart. I had someone replace all the case gaskets, now it won’t shift into neutral.

Anyone have any so cal connections to straighten me out?

Will it shift into neutral when the bike isnt running?

 

[96motorhead]

Duncan told me 6 months out. I have a 1985 TRX 250r motor that needs to come back apart. I had someone replace all the case gaskets, now it won’t shift into neutral.

Anyone have any so cal connections to straighten me out?

For machine work, Racers Machine in Escondido is another place you can try, I haven't personally used them but some of my friends and family have with good results. They might do general motor repair work, I'm not sure.

If you are just looking for someone to split the case and diagnose your shifting issue you could try M&M Offroad in Lakeside, CA. I've never had them do engine work for me, but I've been going to them for suspension work for years. They built a wheel for my dirt bike about 2 weeks ago and they were pretty busy.

Two other places I have zero experience with but know they are into the 250r stuff are Eddie Sanders Racing and BDT Motorsports.

The only thing I don't do my self on my toys is machine work, I do all other engine work myself so my experience with shops is limited.

 

[Hammer]

Will it shift into neutral when the bike isnt running?

No.. I went to put the chain in and realized it won’t shift into neutral.

 

[Hammer]

For machine work, Racers Machine in Escondido is another place you can try, I haven't personally used them but some of my friends and family have with good results. They might do general motor repair work, I'm not sure.

If you are just looking for someone to split the case and diagnose your shifting issue you could try M&M Offroad in Lakeside, CA. I've never had them do engine work for me, but I've been going to them for suspension work for years. They built a wheel for my dirt bike about 2 weeks ago and they were pretty busy.

Two other places I have zero experience with but know they are into the 250r stuff are Eddie Sanders Racing and BDT Motorsports.

The only thing I don't do my self on my toys is machine work, I do all other engine work myself so my experience with shops is limited.

BDT didn’t answer there phone or call me back.
I’ll try ESR again. I’ve never had transmission issues with this bike and I’ve owned it 20 years. I’m not familiar with splitting cases. I can rebuild a top end no problem though.

Thank you for the shop names. I’ll try reaching out this week. I need to get this back running.. it’s ready to go with all new plastics.

 

[Danger Dave]

Hesperia

I would call Noleen and ask them who they'd recommend up in your area for engine work. Doc MX in Murrieta was my go to guy but he just closed his shop.

 

[Nanu/Nanu]

Try emailing bdt. Years ago I had him quote me for machine work on a case half and he was very prompt to respond. Things may have changed with him but may be very busy too.

 

[Nanu/Nanu]

The 250r is not very complicated depending on your tool set and comfort level. A service manual spells things out pretty much step by step if you get lost or out of order. There is also a check you can do to run through your tranny before finalizing your bottom end. If you have the time to do it yourself it's fairly easy. Id say a weekend would be fair estimate on the quick side. Saturday for teardown and Sunday for put together.

 

[JUSTWANNARACE]

No.. I went to put the chain in and realized it won’t shift into neutral.

So it will shift through the gears but wont find neutral?

 

[ArizonaKevin]

BDT didn’t answer there phone or call me back.
I’ll try ESR again. I’ve never had transmission issues with this bike and I’ve owned it 20 years. I’m not familiar with splitting cases. I can rebuild a top end no problem though.

Thank you for the shop names. I’ll try reaching out this week. I need to get this back running.. it’s ready to go with all new plastics.

Not sure exactly how the 250r is laid out but I would guess that not being able to find neutral has more to do with the shift mechanism than the trans itself. On most bikes, there is a good deal of shift mechanism that is under the clutch cover and does not require splitting cases to get to. I had similar issues with my wife's 125 not shifting correctly upon first reassembly, discovered I didn't have the shift cam stopper clocked correctly.

Worst case, if it is something deeper in the trans that isn't right, you can drop off just the cases with a mechanic and save some labor

 

[Hammer]

The 250r is not very complicated depending on your tool set and comfort level. A service manual spells things out pretty much step by step if you get lost or out of order. There is also a check you can do to run through your tranny before finalizing your bottom end. If you have the time to do it yourself it's fairly easy. Id say a weekend would be fair estimate on the quick side. Saturday for teardown and Sunday for put together.

I don't have time to mess with it. I'd rather drop it off and have it done.

 

[Hammer]

So it will shift through the gears but wont find neutral?

I cant tell if its shifting into the next gear or not. I just know it wont shift back into neutral. There appears to be play in the shift shaft in/out that I dont feel is normal, almost like the shift fork is sliding off the gear? I don't know enough about transmissions to diagnose it, nor do I care to figure it out. I just want a shop to fix it.

 

[Hammer]

Not sure exactly how the 250r is laid out but I would guess that not being able to find neutral has more to do with the shift mechanism than the trans itself. On most bikes, there is a good deal of shift mechanism that is under the clutch cover and does not require splitting cases to get to. I had similar issues with my wife's 125 not shifting correctly upon first reassembly, discovered I didn't have the shift cam stopper clocked correctly.

Worst case, if it is something deeper in the trans that isn't right, you can drop off just the cases with a mechanic and save some labor

I just want to drop it off on a counter and have someone tell me what's wrong and fix it. I lost any motivation to mess with a motorcycle engine beyond the typical maintenance stuff, light troubleshooting, cleaning out a carb and changing the spark plug.

 

[ArizonaKevin]

I just want to drop it off on a counter and have someone tell me what's wrong and fix it. I lost any motivation to mess with a motorcycle engine beyond the typical maintenance stuff, light troubleshooting, cleaning out a carb and changing the spark plug.

Nothing wrong with that. Where are you located? Some shops to recommend depending on location

 

[Hammer]

Nothing wrong with that. Where are you located? Some shops to recommend depending on location

Santa Clarita, Ca. I will take it almost anywhere in So Cal. The local guy wouldn't give me the time of day and I will never give him business again...

 

[ArizonaKevin]

Santa Clarita, Ca. I will take it almost anywhere in So Cal. The local guy wouldn't give me the time of day and I will never give him business again...

gotcha, it's a bit of a haul but the place I would look into is AHM Factory Services in Yorba Linda.

 

[Hammer]

BDT is 16-20 weeks out, responded quickly via Email I'll give AHM a call as well. Im not in a hurry but 16-20 weeks is crazy. I used to get stuff back in a few weeks.

LOL