got some parts ordered but

[GAZ-V-21]

Alright I ordered stage 2 hotcam an 85mm weisco piston and a cam chain. Now I'm trying to find cam chain tensioner but can't find what I need tried eBay but didn't see it if you can point me in the right direction I'd appreciate it. Also is there any other little things I will be needing for this build? Or things you guys would recomend I get. With these upgrades will I need to re jet and do I adjust the valves the same as I do for stock? Hope I'm not asking to many questions lol.

[CJM]

OEM is the best tensioner. Local dealer, sponsored dealer on the forum or motosport/rocky mtn is where Id buy it.

Id also buy a cam chain and check the guides and buy them if need be.

Also it would be wise to have bought the next size piston b/c your bore might be worn and a new piston wont help. new rings might or might not.

[GAZ-V-21]

I thought that after I ordered the piston if it is needed after I get it apart and look I will sell mine and get my 400 bored let's hop its not needed lol. I also ordered 450r shocks who do you reccomend I send them to and get revalved sprung or whatever it is I need to do?

[GAZ-V-21]

Do they need to be bored more often than not? My 400 runs pretty good puffs a little blue smoke on start up and then sometimes when I get on it real hard but when just at idle or cruising around no smoke at all.

[CJM]

Smoke at idle is valve seals, smoke under acceleration/deceleration is rings. More often than not a bore needs to be done. 85.5mm woulda been abetter idea.

If the piston and the rings go into the cyl with ease then you know you need to bore. Should be somewhat hard to get in there.

[GAZ-V-21]

What bore would 85.5mm be 407? Just wondering so in case I need to do it I can get a price from machine shop? how much on average do you think I will be spending on boring. What should I order for the valves? Sorry for all the questions but I'm gonna be rebuilding at work on a weekend so I need to get everything at once so when Monday comes I don't have my quad apart in one of the mechanics areas. A Porsche technician I work with just bought a 400ex and is gonna help me with this project.

[CJM]

.20 is 85.5mm, .40 is 86mm

Valve seals are easy. Remove the valves using a compressor and they pop on and off. The valves probably could used to be reground (DIY using some grinding compound and a drill, youtube it) and the springs might be worn (check the tolerances using the manual) but otherwise its easy.

Boring is about 100 or less in most places. But they need the piston to do it as not all pistons are exactly .20 or whatever over stock.

[dxcody]

11:1?
Ill buy it from you if you decide to bore over!

And valves will need to be adjusted a little looser than stock, due to the higher lift of the cam.

I believe its .007 intake
.008 exhaust

but you might want to check it out.. There are a million threads on it, just search it and you can find it.

[GAZ-V-21]

Originally posted by CJM
.20 is 85.5mm, .40 is 86mm

Valve seals are easy. Remove the valves using a compressor and they pop on and off. The valves probably could used to be reground (DIY using some grinding compound and a drill, youtube it) and the springs might be worn (check the tolerances using the manual) but otherwise its easy.

Boring is about 100 or less in most places. But they need the piston to do it as not all pistons are exactly .20 or whatever over stock. does the head need to be removed to change valve seals.

[dxcody]

Originally posted by GAZ-V-21
does the head need to be removed to change valve seals.

Yes.

[400exmxracer]

For the tensioner I soups get a "cycles are us manual cam chain tensioner" if its not too late, you will be really happy with it. If the stock one goes bad (like they sometimes do...) you'll have a lot of problems that will cost you a lot of money. It costs like $49 and is worth every penny

[CJM]

Originally posted by 400exmxracer
For the tensioner I soups get a "cycles are us manual cam chain tensioner" if its not too late, you will be really happy with it. If the stock one goes bad (like they sometimes do...) you'll have a lot of problems that will cost you a lot of money. It costs like $49 and is worth every penny

Problem with one of those is you are responsible for adjusting it. You dont do it right your in a bad way.

I never had a tensioner go bad, I check it everytime I have a rebuild and its fine. I think its the original one too, I never replaced it. My friend had 2 go, but the timing chain was bad both times (dont buy peoples used parts!).

[jman7290]

You can get a tensioner for a Suzuki Z400, its heaver duty and fits with a little grinding on the head. The piston or whatever you want to call it that pushes on the guide is larger so you have to grind the hole bigger for it to fit through it. My cousin has his built to the hilt and that's the only thing he could do to get it to stop snapping timing chains.

[GAZ-V-21]

Is there any special tools needed to change valve seals like to pull head off? And from your experience how long would this maybe take adjusting valves and replacing valve seals

[CJM]

They snap right off, there just rubber.

Valve job shouldnt take more than a half hour or so.

[dxcody]

One thing i dont think that has been mentioned is lapping your valves.

Its always a good idea to do so.

[GAZ-V-21]

Lapping the valves?

[GAZ-V-21]

Originally posted by CJM
They snap right off, there just rubber.

Valve job shouldnt take more than a half hour or so. cool I think I'm gonna do that tomorrow night after work its an 07 and the valves have never been touched so they probably need some attention lol. I'm gonna wait until winter to put in all the other parts I ordered. What might I expect after a valve job any restored power maybe?

[GAZ-V-21]

Off the topic for a second has anyone used seafoam in atv? I did today and wow it is some good stuff I put some in my oil some in my fuel and sprayed some in carb And now the 400 seems to be much smoother.

[400exmxracer]

What do you mean smoother?

[GAZ-V-21]

Hard for me to explain just seems like it runs better maybe a very small amount of power has been restored. I put 3oz in oil 2oz in fuel and just sprayed about 5 sprays in the carb with it running if you never tried it I recomend it. I never use stuff that is an additive for fuel if oil but at the Porsche Mercedes BMW dealer I work at all the techs use it so I figured if they trust it enough to use in our trophy cup race cars then id give it a shot.

[CJM]

Yep, I used seafoam before and it works great. TBH I think its just some kinda heavily filtered kerosene-but it does clean out whatever you use it in.

Another old school trick is to spray a water mist inside an open carb on a car or bike-does the same thing seafoam does too.

[GAZ-V-21]

I like it. How often do you think it should be used? Guess since I'm doing rebuild this winter I won't need it for a while.

[CJM]

maybe every year at most. Throw some in your gas tank and go riding, should work that way just fine.

[GAZ-V-21]

That's what I was thinking once a year. Thanks for all the help cjm. I can't wait to get these parts in my 400 this winter I think I'm gonna go ahead and get the 85.5 weisco piston. I'm just curious after this rebuild piston stage 2 cam port polish how much difference can I expect compared to my mostly stock 400?

[CJM]

Originally posted by GAZ-V-21
That's what I was thinking once a year. Thanks for all the help cjm. I can't wait to get these parts in my 400 this winter I think I'm gonna go ahead and get the 85.5 weisco piston. I'm just curious after this rebuild piston stage 2 cam port polish how much difference can I expect compared to my mostly stock 400?

A stock 400 wont stand a chance. Buddy of mine raced me totally stock vs my old 416 with just an ex carb on it and couldnt keep up at all.

[GAZ-V-21]

Sweet I can't wait

[GAZ-V-21]

I love my 400 was gonna get a 450 but I think ill stick with this a few more years

[CJM]

Originally posted by GAZ-V-21
I love my 400 was gonna get a 450 but I think ill stick with this a few more years

They are no slouch if you build one up, but by now for me I need the power only a 450 can deliver.

[GAZ-V-21]

My nephew has a sweet 450 r but he won't be ridin for a while he wrecked on MOTO track a few weeks ago fractured his skull and had a seizure. He was riding without a helmet I don't know what he was thinkin.