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oh400ex

350x Engine with Missing Parts

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Hello everyone!

 

I picked up a 350x engine for a great price.

 

The rebuild process looks like it is going to be a bit of a project. It is missing some components but is overall not too bad.

Main issues are the missing cam and piston. Piston kits are readily available. Unless I can get an OEM...

I'm going (with some trepidation) to take the recommendation and go with a Wiseco top-end kit.

 

The cam and gear are going to be a problem.

 

Starting with a look at a few friends house to see if they have a compatible year model.

Which years will have compatible top end parts? I'm getting a lot of conflicting information online.

 

I would assume (but do not know) that the 85 and 86 models of the 350x are compatible cam-wise.

Retro also mentioned the ability to interchange the 350A and 350D models from from 85 and 86 which is what I may have access to.

 

Anyone know exactly what models I can pull from and look for? Any place that I can find the concrete information would be greatly appreciated!

I will be looking for the parts here and other places online if I can't find them locally. Can get the timing chain NOS for a reasonable price.

 

Thank you for reading!

oh400ex

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The 86 & 87 TRX350A/TRX350D cam is the same (part # 14101-HA5-000) as the 85 & 86 ATC350X cam. You can find the specs for those cams listed in the TRX350 service manual and also on webcamshafts website.

 

All topend parts interchange within those models except for the carb (manual choke lever on the 350X vs a choke cable on TRX350s), the exhaust header pipes and the cable operated decompression release used on the early TRX350 models.

 

Any good used 86-87 TRX350A/350D cam and chain sprocket should be fine provided your rocker arms are not worn on the lobe heels.... they gotta break-in against replacement  cam lobes again, so assemble with a good looking set of rockers and don't allow the motor to idle very much (cam lobes breaking in need lots of oil) during the first 40 minutes of its new life.

 

A new D.I.D. cam chain is your best option for a cam chain, as DID supplied most of the OEM Honda 350X/TRX350 chains back then. Same chain as OEM but a cheaper price online...

 

https://www.partzilla.com/catalog/honda/atv/1986

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7 minutes ago, retro said:

The 86 & 87 TRX350A/TRX350D cam is the same (part # 14101-HA5-000) as the 85 & 86 ATC350X cam. You can find the specs for those cams listed in the TRX350 service manual and also on webcamshafts website.

 

All topend parts interchange within those models except for the carb (manual choke lever on the 350X vs a choke cable on TRX350s), the exhaust header pipes and the cable operated decompression release used on the early TRX350 models.

 

Any good used 86-87 TRX350A/350D cam and chain sprocket should be fine provided your rocker arms are not worn on the lobe heels.... they gotta break-in against replacement  cam lobes again, so assemble with a good looking set of rockers and don't allow the motor to idle very much (cam lobes breaking in need lots of oil) during the first 40 minutes of its new life.

 

A new D.I.D. cam chain is your best option for a cam chain, as DID supplied most of the OEM Honda 350X/TRX350 chains back then. Same chain as OEM but a cheaper price online...

 

https://www.partzilla.com/catalog/honda/atv/1986

 

Thank you very much for the info!

 

At this point, I hope that either my local guy, shade or someone else fairly close will have a cam and OEM piston they want to part with.

 

The cylinder appears to be within spec. I have a super old set of gauges and am not a machinist so I do not trust my measurements and will be getting a second opinion. I was afraid to hone as I only have a cheap one and am going to leave it to the professionals. My local machine shop is not too busy and treats me well.

 

Definitely going with the cam chain you suggested. Thank you for that!

 

Plan on splitting the cases and washing everything really well before it all goes back together.

I don't want to as I haven't seen any carnage but it is the right way to go. I used a flashlight and saw some non-metallic grit settled on the bottom.

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14 hours ago, oh400ex said:

Unless I can get an OEM...

I'm going (with some trepidation) to take the recommendation and go with a Wiseco top-end kit.

 

I take it you may have had problems in the past running Wiseco forged pistons? The Wiseco piston for early 350s is cast.... its coated cast in fact. Its not a forging like racing models get.... so ya got nothing to fear this time, as cast pistons like tight OEM spec'd clearances, unlike forged pistons which require a much looser fit in the bore. The Wiseco kit bumps the compression up to 10.25:1 too. OEM is unavailable so you're left with choosing between a Shindy kit or a Wiseco kit if you're looking for high quality.... both are very good.... stay away from all of the Taiwan offerings.

 

Definitely have an experienced shop hone your bore for ya using straight stones... ball hones should be avoided if possible.

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11 minutes ago, oh400ex said:

Plan on splitting the cases

 

Smart man! 😀

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2 minutes ago, retro said:

I take it you may have had problems in the past running Wiseco forged pistons? The Wiseco piston for early 350s is cast.... its coated cast in fact. Its not a forging like racing models get.... so ya got nothing to fear this time, as cast pistons like tight OEM spec'd clearances, unlike forged pistons which require a much looser fit in the bore. The Wiseco kit bumps the compression up to 10.25:1 too. OEM is unavailable so you're left with choosing between a Shindy kit or a Wiseco kit if you're looking for high quality.... both are very good.... stay away from all of the Taiwan offerings.

 

Definitely have an experienced shop hone your bore for ya using straight stones... ball hones should be avoided if possible.

 

Yep. That's almost certainly it.

 

I know that (is it ProX?) is basically Wiseco but cast pistons with the silicone coating so I at least knew this was a thing. 

Great to know the actual difference!

 

My bore and hone kit stops at anything that actually costs money. After all the times I've done it over the years which really isn't that many i'm still scared to use it on an old chainsaw and the replacement jug usually is around $50 😂 I can fix any lawnmower with it though.

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