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CRF230F Engine rebuild question/problem

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So I just bought this 2005 CRF230F after not having ridden a dirt bike in 20 years (street only). I got a good deal on the bike knowing it needed a few things, but once I got it home I realized the original owner whom i bought it from had done NO MAINTENANCE on the bike. ever. He might have changed the oil once, or maybe not. Original tires were bald, original chain/sprocket worn but not horrible. Clutch/brake levers bent but he just kept riding. So I'm riding it up and down the street here in the middle of Seattle (the neighbors LOVE this) and it doesn't seem to have much power, but I really don't know how much its supposed to have, I've never ridden one of these before. My friend Ben says these things are real dogs and just slow. I do a compression test and get 90psi. I check the valves to make sure they are not too tight. I do a compression test on my truck to make sure my gauge is not bad. I do 3 more tests all reading 80-100 psi. My service manual says it should be 180psi. So I decide to take the motor apart, do a top end. But today I got the motor apart, and everything looks GREAT. Shit. I was hoping to find worn piston/rings. Now I don't know what the problem is. Tomorrow I'll take some critical measurements from to service manual, and maybe there is a problem with the head I don;t see? I really don't want to just put it back together.  Any advise?

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You have a genuine Honda factory shop manual I'm hoping?

Compression test is super old fashioned, next time do a cylinder "leak down test"

Then you can pinpoint the exact problem before disassembly.

In my opinion:

If cylinder specs check out after honing with a rigid hone (Sunnen honeImageUploadedByThumper Talk1453268364.984550.jpg to square and true the bore) , then replace piston, rings, pin and clips with OEM parts.

Use a New OEM gasket set and valve stem seals, grind valves and seats.

If not within factory specs then an over bore is required. (Again Sunnen hone recommended) Use a "Pro X" piston kit for stock compression or a Wossner piston kit for higher than std compression (recommended)

Edited by adnohguy
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Like these guys said I was in your same situation a year ago. I rebuilt the 230 with a 11.1 Wossner piston and threw in a WEB cam and Kimble white valve springs and what a difference. This thing will haul @ss now and has tractor torque. I liked it so much I rebuilt a second 230 and added a BBR Big bore piston and web cam to it also. FUN FUN!!!!

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Like these guys said I was in your same situation a year ago. I rebuilt the 230 with a 11.1 Wossner piston and threw in a WEB cam and Kimble white valve springs and what a difference. This thing will haul @ss now and has tractor torque. I liked it so much I rebuilt a second 230 and added a BBR Big bore piston and web cam to it also. FUN FUN!!!!

I do like the the BBR 67mm piston kit, way lighter than a stock piston, + they are supplied with a base gasket and a solid copper head gasket!!

are they still available?

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I do like the the BBR 67mm piston kit, way lighter than a stock piston, + they are supplied with a base gasket and a solid copper head gasket!!

are they still available?

I'm not sure as the BBR kit came with the bike I purchased that was in boxes last year.

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I just took the parts to a machine shop on the corner to leak check the heads and check tolerances on piston/cylinder, should hear back soon. they can't do any work on the parts as they are too small for their equipment.

 

I'd really like the power of the big bore kit but need to keep the time and expenses down. I'm assuming you had to re-jet the carb with the big bore kit as well? If it really makes a noticeable improvement I'd consider it.

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I just took the parts to a machine shop on the corner to leak check the heads and check tolerances on piston/cylinder, should hear back soon. they can't do any work on the parts as they are too small for their equipment.

 

I'd really like the power of the big bore kit but need to keep the time and expenses down. I'm assuming you had to re-jet the carb with the big bore kit as well? If it really makes a noticeable improvement I'd consider it.

 

If I recall correctly BBR's Big Bore kit raises CR to 12:1.  Rick Ramsey had the BBR Big Bore kit for a while and had detonation issues.  If the CR is 12:1 a bigger/longer cam will help combat detonation issues.

 

If your bore is still within spec A Wiseco 11:1 piston can be had for under $90.

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My piston looks almost new, I was thinking of buying a set of OEM rings for $30 and a cylinder hone. Unless there is some other advantage to the Wiseco?

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My piston looks almost new, I was thinking of buying a set of OEM rings for $30 and a cylinder hone. Unless there is some other advantage to the Wiseco?

If you have to bore it and go with another piston get a Wossner or Wiesco to boost compression and then do the power up kit which is removing the air baffle in the air box and resetting the carb. You will be surprised at the gain the bike will have. Add a cam to the mix and the bike really wakes up. The stock piston is low on compression

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First thing I did was remove the exhaust baffle, intake restrictor, re-jetted the carb and added a K+N filter. It's a bit loud now but I still hadn't even had the bike in the dirt! My neighbors hate me 🙂

 

The extra power sounds great but I really need to watch how much I spend on this, at some point one should just sell this bike and buy a CRF250X for the power.

 

I think the stock piston is 10.5:1. I've seen pistons at 11:1 and 12:1 but the 12 sounds high, some guys had some trouble with pinging?

 

Also, how much is a cam?

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First thing I did was remove the exhaust baffle, intake restrictor, re-jetted the carb and added a K+N filter. It's a bit loud now but I still hadn't even had the bike in the dirt! My neighbors hate me 🙂

 

The extra power sounds great but I really need to watch how much I spend on this, at some point one should just sell this bike and buy a CRF250X for the power.

 

I think the stock piston is 10.5:1. I've seen pistons at 11:1 and 12:1 but the 12 sounds high, some guys had some trouble with pinging?

 

Also, how much is a cam?

Stock piston is more like 9:1 and I have built two 230's one with a 11:1 Wossner piston and the other with a BBR big bore kit and neither have detonation issues with 93 pump gas. IMO the 250X requires much more maintance over the 230f therefore put a little money in the bullet proof 230 and you will have a better bike. The 250X requires valve adjusting much more frequent than a 230. Both of my 230's will perform just as well as a 250X in the woods or track. The suspension is less desired but can be improved by sending the forks and rear shock to Bruce Triplett or John Helbo and for around $500 the ride will be totally different. Web cams offer several grinds which I chose the Coe special 89A grind which was $195 with a core $69. This a long with Kimmble White valve springs and the HC piston will give the 250X all she wants and maybe out do it. The reliability is what makes the 230f shine and its nimbleness in the woods. It all boils down to spend more money for a 250x or build the bike you have now to perform with the 250X and I suspect you will come out better in the pocket book building the 230 and you know what you have.
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First thing I did was remove the exhaust baffle, intake restrictor, re-jetted the carb and added a K+N filter. It's a bit loud now but I still hadn't even had the bike in the dirt! My neighbors hate me 🙂

 

The extra power sounds great but I really need to watch how much I spend on this, at some point one should just sell this bike and buy a CRF250X for the power.

 

I think the stock piston is 10.5:1. I've seen pistons at 11:1 and 12:1 but the 12 sounds high, some guys had some trouble with pinging?

 

Also, how much is a cam?

 

The CRF230F and CRF250X are two very different animals.  If you want some very good insight ask Chuck as he has a CRF250X and XR218.

 

The Wiseco "11:1" piston yields less than 11:1 CR and is just fine with pump gas, even when the engine is very hot.  Mine is fine with a Procom CDI, Web 40mc/402 cam, and Wiseco piston, all of which raise cylinder pressure very high at low engine speeds.

 

As a comparison the XR200 engine is 10.25:1 and has a cam that is +10i/+15e bigger/longer than the CRF230 cam.  These engines run forever and have zero detonation issues running on pump gas.  The CRF230F is so mildly "tuned" it is amazing it runs as good as it does.

 

New Wiseco piston for $88:  http://www.amazon.com/Wiseco-4816M06550-65-50mm-Compression-Motorcycle/dp/B000WJA6K8

Edited by VortecCPI

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Well, I think you guys have convinced me to get a new cam and piston. If I can get a Wiseco piston for $90 i'll get that one. The Wossner piston looks great but it's $100 more. I'll need a good torque and all-around cam. Web cam has their 280 that seems to be a good all arounder. I don't need anything custom. recommendations welcome! need springs too.

 

Do the new cams come with roller bearings or do you have to remove the old ones from my cam?

 

Got parts back from machine shop today and everything checks out. Cylinder is straight (mostly) and well within spec. Valves not leaking at all. The only thing I can figure was that I had the valves to tight doing the Compression test. I hear in these air cooled engines the valves actually loosen up as they warm up.

 

It does looklike there is some wear in the cam journals, although the cam bearings themselves look great. Also looks like a problem near the timing chain tensioner/sprocket area.


I'll check the ring gap tomorrow when I get home.

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IMHO:

The 280 is the worst cam that web sells for the 230, what made you decide on that one?

You say you want torque, correct? Then you want the 40mc/402 that web offers.

It's the best and most powerful torque cam that they offer for a 230f by a Hugh margin.

Terry Miller can, get you a Wossner piston kit with a solid copper head gasket for way less than $180.00, guaranteed

I recently purchased one myself.

A STD Wossner piston kit would use a STD Honda head gasket ( no copper gasket required)

Wossner has more compression than the Wiesco and that is a good thing!

Wiesco is way lower than advertised.

Those three photos are showing normal wear, what is your concern with them?

If you feel the cam chain is marginal, then replace it.

No matter what cam you choose, you should install new rocker arms also.

Also it would be a good idea to replace your valve stem seals, remove any carbon build up from your valves and seats, and at least lap your valves to the seats if your not going to "do it right" and grind the seats and reface the valves.

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I haven't decided on a cam yet, that was the first one i saw that looked popular. I'm doing cam research now but I don't want anything wild and crazy. I want a broad smooth powerband with more power than stock without compromising reliability. The 282 is the only cam I saw listed in their catalog for CRF230F. But based on what I want from my engine i would love to get more recommendations!!

 

 

As for the cam bearing wear, this is the first dirt bike motor I've pulled apart so I didn't know how much wear was normal and acceptable.

 

Also, the best gas we can get around here is 91 so I'm not sure the extra compression from the Wossner would be great. I did see that BBR has a big bore 67mm piston with base and head gaskets for $170 hmmm.. I should probably just stick with stock bore. 

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L

 

I haven't decided on a cam yet, that was the first one i saw that looked popular. I'm doing cam research now but I don't want anything wild and crazy. I want a broad smooth powerband with more power than stock without compromising reliability. The 282 is the only cam I saw listed in their catalog for CRF230F. But based on what I want from my engine i would love to get more recommendations!!

 

 

As for the cam bearing wear, this is the first dirt bike motor I've pulled apart so I didn't know how much wear was normal and acceptable.

 

Also, the best gas we can get around here is 91 so I'm not sure the extra compression from the Wossner would be great. I did see that BBR has a big bore 67mm piston with base and head gaskets for $170 hmmm.. I should probably just stick with stock bore. 

 

Look at cams for 2003-2005 CRF150F.  The 340/402 a.k.a 40mc/402 is what you want for slow short tight work.  The 389a a.k.a. 89a is what you want for  fast long open work..

 

The 304/402 is a true drop-in cam that works with stock springs.  The 389a requires new springs and clearance checks.

 

I highly recommend you buy a hybrid cam from Terry Miller.

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