top end and cylinder ?

[3Wheelermaniac3]

1985 350x. I have the cylinder and pistion. 12:1 wiseco. I need to know what to do to head ,cam,and valves for a reliable pump gas running trike? All bearings are good and new seals installed.

[3Wheelermaniac3]

Any info? I've looked into megacycle and powroll but unsure what exactly all needs to be done to head. I Don't want to spend unnecessary cash when I don't need to.

[chargercharlie]

First thing you should do is get a manual for your bike..if you havent done so already..its kind of one of those you've got it there might as well check all your valves and cam/rockers for wear and check everything else to manual specs as stated in said manual..2nd thing is your gonna be disappointed trying to run pump gas with a 12:1 piston..just my 2 cents

[DohcBikes]

I need to know what to do to head ,cam,and valves for a reliable pump gas running trike? If the parts are within spec, leave them alone. The most reliable bike is a stock bike. By far.

As charlie mentions, you're probably not going to be able to run pump gas with a 12:1 piston in a 350x. This is likely why you aren't getting replies.

[3Wheelermaniac3]

Thanks I figured pump gas was out of the ? . So I already have the .50 over piston can I turn it down. Also I've gone through the entire engine and everything checks out. Had to do cause I powder coated the case halves. And installed new seals on entire engine along with gaskets. Would it be better to bring it back to stock bore and go from there?

[DohcBikes]

So I already have the .50 over piston can I turn it down. Not sure what you mean, but if you mean can you machine it smaller, you could, but trust me, you dont want to. Give the piston to the machine shop with your jug.


Also I've gone through the entire engine and everything checks out. Then why are you messing with the internals? No offense but it doesn't sound like you have much experience with engines. What does your cylinder bore measure? You should know this before you buy a piston...


Would it be better to bring it back to stock bore and go from there?You mean buy a brand new cylinder? Because that is the only way to bring it back to a stock bore, if it has even been bored.

Post pics of your progress so far, so we know what you have going on here.

[ps2fixer]

You can find the 350x service manual on this site: http://www.oscarmayer.net/atc/manuals/

[3Wheelermaniac3]

Umm yea ( not being a di%& ) or anything but I've been doing this since I was 10. I am very competent on working on trikes just never did any performance mods to them. I took apart the case so I could powder coat them seeing as sand and extreme temp would kill any bearings in it. Also yes a machine shop would be the the only way to "shave" the dome on a piston seeing as I'm not ritch and don't have a lathe lying around. And I have a stock sleeve that I can swap out with my nice jug. Sorry for the antics but I don't like being looked down upon. And again not being a dick.

[3Wheelermaniac3]

And this is what I've gained so far
Megacycle can # 162-40 $144.00
Hard faced rockers $136.00
Valve springs up to .390 lift $159.00
Valve guides#6009 $77.00
CT 3 angle valve grind w\t port and polish $1144.00 not doing this.
CT head port $350.00
400EX cdi
1986 350x pick up
AMR revbox
400 EX carb.

[Dirtcrasher]

Umm yea ( not being a di%& ) or anything but I've been doing this since I was 10. I am very competent on working on trikes just never did any performance mods to them. I took apart the case so I could powder coat them seeing as sand and extreme temp would kill any bearings in it. Also yes a machine shop would be the the only way to "shave" the dome on a piston seeing as I'm not ritch and don't have a lathe lying around. And I have a stock sleeve that I can swap out with my nice jug. Sorry for the antics but I don't like being looked down upon. And again not being a dick.

If you did this since you were 10yo, then 12:1 shouldn't have been a question. Get down to 10.25:1 and a nice carb, midrange cam and springs/retainers etc.

[3Wheelermaniac3]

Thanks. So midrange cam,springs retainers, 10.25:1 piston (.50 over cylinder?) and 400ex carb. I also did a little porting to a spare head. I'm not sure how well I did but I guess will find out when I try it. Is there any bad ways to port a head? Obviously taking too much away is bad but is there any pointers to doing it?

[3Wheelermaniac3]

Also uploaded some pics of parts I powder coated in my 350x album. More to come tomorrow. I was really pleased with the fin layout. Coated the jug then went around the fins with a dremmel then polished the fin ends to a mirror finish with an arbour. Also polished the forks and am working on the triple but they are a pain in the butt cause of the tight spots.

[ps2fixer]

From what my dad has told me (relating to car engines), grind the ports smooth, and take out any lumps/restrictions. You can make the volume size of the port a tiny bit larger, but you don't need much to make a pretty large change. I'll admit, I have never ported a head or even watch the process, but my dad has worked on engines since he was a kid as well. I'm sure someone will chime in with better advice.

[3Wheelermaniac3]

Thanks pretty much just matched toe intake to the carb manifold ant took out the casting marks.

[DohcBikes]

I've been doing this since I was 10. Cool. I've been typing since I was about ten as well. Or did you mean building engines? or.. what? What did the bore measure? It'll be tough to help if you don't give us numbers, especially come assembly time.


I need to know what to do to head ,cam,and valves for a reliable pump gas running trike?Again, leave it stock.


unsure what exactly all needs to be done to head. Unsure exactly what are you asking? I'm not being a d$%k, i really can't make sense of this. If you have been doing 'this' since you were ten, I would think your questions would be a bit more pointed and technical. But what do I know about all this.



Thanks I figured pump gas was out of the ? .
I need to know what to do to head ,cam,and valves for a reliable pump gas running trike?So, you figured it was out of the question, but you need to know how to do it. :wondering


I already have the .50 over piston can I turn it down. What exactly are you asking here then?


Also I've gone through the entire engine and everything checks out. This is a great example of the lack of technical info that would be included if the inquiry had come from somebody that has been a mechanic since they were a young child. But what do I know about this stuff.


Would it be better to bring it back to stock bore and go from there?It depends on those bore measurements you took. What were they again? Let me get this right,, you want to build a reliable performance engine that runs on pump gas but you aren't going to measure things? Do you teach classes on how to accomplish this, I'm interested.


(.50 over cylinder?) Yes?, No. Maybe????!!!!


Is there any bad ways to port a head?Nope. Git you some of that.



Sorry Guys, you had to know it was coming:D


I don't mind helping people, but shoot I think you got a handle on this now that you have a parts list typed up. What do I know about all this. Good luck.:beer

[3Wheelermaniac3]

Cylinder bore is 82mm. I have a wiseco .50 over 12:1 comp piston that came with the bike. It was a spare that was given when I purchased the bike due to the previous owner did not make the necessary modifications to accommodate the larger displacement and dropped a valve. I am rebuilding this questionable set up and am unsure of the mods I need to do to run on pump gas. As I stated I have been " rebuilding " these engines since I was 10. And also stated that I never did performance mods to them. I should have said that I've always went to an over ring or next up bore. I've never messed with anything that has a .50 over piston. So yes I am kind of clueless on how to set up something with this size piston. Also the question on pistons is does wiseco make a .50 over 10.25:1 piston. And the port job I did is very light pretty much just took out what did not match to the intake flange. With an even transition.

[yaegerb]

A 12:1 compression piston ensures that you will run race gas or enjoy some pre detonation if you don't. Stock bore on the 350x is 81MM so you have gone up 1MM in actual bore diameter which has nothing to do with compression ratio. Maybe I am being thick here, but I don't understand how dropping a valve correlates to a larger displacement...I digress. My advice is to not worry about the piston that came with the bike, go to your local machine shop and have them mic the cylinder and tell you what size overbore piston you will need, then order the correct overbore size with 10.25 to 1 compression ratio (you won't be married to race gas). Get a nice middle of the road cam and have your rockers hard faced for extra life. It would also be a good idea to have a 3 angle valve grind (5 angle would be overkill for your application). Also might want to make sure your rod bearings are all good while you are in there.....my .02

[3Wheelermaniac3]

Thanks. I took it that the previous owner threw the larger 12:1 piston in it and ran it on pump gas. He didn't rejet it or anything. I take it that the valve that dropped was stressed or came in contact with the piston.

[DohcBikes]

Cylinder bore is 82mm. I have a wiseco .50 over 12:1 comp piston that came with the bike. It was a spare that was given when I purchased the bike due to the previous owner did not make the necessary modifications to accommodate the larger displacement and dropped a valve. I am rebuilding this questionable set up and am unsure of the mods I need to do to run on pump gas. As I stated I have been " rebuilding " these engines since I was 10. And also stated that I never did performance mods to them. I should have said that I've always went to an over ring or next up bore. I've never messed with anything that has a .50 over piston. So yes I am kind of clueless on how to set up something with this size piston. Also the question on pistons is does wiseco make a .50 over 10.25:1 piston. And the port job I did is very light pretty much just took out what did not match to the intake flange. With an even transition.Thank you!,,,, but there's still some confusing stuff here. As yaeger and DC have mentioned, 10.25:1 is your pump gas friendly choice.

Yes, they make it .50 over, but if you use a .50 over piston in an 82mm bore, she's gonna be a noisy smoker!!! The .50 means it is .50mm larger, but your bore is already a full 1mm larger than stock, a very sloppy fit!

Where yaeger isn't EXACTLY correct is that a larger than stock bore size actually does slightly increase the compression ratio, due to the increase in cylinder volume without increasing the combustion chamber volume. That's what compression ratio is, cv divided by ccv.

An engine is an engine. Stock or performance,, you need numbers, and a good understanding of how a four stroke works. All in all the work is the same, regardless of CR or cam size or bore. Btw, the correct term for the port work you did is "Port Matching", and if that's truly all you did, then you be aaiight.

Don't do anything till you get that cylinder mic'd. It is at the last bore size for the available Wiseco's, and if it is not in good shape (YOU CAN'T KNOW WITHOUT MEASURING,,,,) then you'll need a new one, or a sleeve, or you could save some money and just buy a whole trike at that point. Sad but true.

Measurements. In thousandths of mm, preferably.:beer

[jays375]

First things first.You will be very happy with the set up DC suggested.I basically have the same thing.The 350x seems prone to dropping valves.Not that it is a weak link.Just that the parts are old and tired.After being around for close to 30 years.After a lot of research I found out is the 350x seems to like stock bore.For relibilty and performance.I personally would try to find a way to achieve that.

[3Wheelermaniac3]

10-4 guys had a brain fart on the difference of piston and cylinder measurement I kept saying .50 over? My bad. Stock sleeve is going in, mid range cam, hard-faced rockers ,and new intake and exhaust valves. Along with CT performance 3 angle valve grind.

[jays375]

You won't be disappointed.Only thing is maybe a professional port job instead of the valves.a carb swap is something to look at in the future.For now ditch the lid.Don't forget to purchase new keepers for those valves.Kibble White makes some awesome valve seals.Either those or oem.A lot of the ones included in gasket kits aren't that great.Send me a pm if you like.I have found a guy to do port work.Does a awesome job on a flow bench,very reasonable.

[6speedthumper]

Don't forget to install heavy duty valve springs for the cam you are going to run. I think WEB is the only one that offers a "drop in" all around cam to work with the stock springs. Which I personally wouldn't trust with new, or old, stock springs.

[3Wheelermaniac3]

Will add to list for megacycle to do. Thanks guys for pointing me in the direction to go. All info is highly appreciated.