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My first Yamaha IT 465

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Posted by: btarka---------------------

So I just bought my first 465 and I know absolutely nothing about it. I plan on doing a semi resto job on it. So if any of yall got some ideas, parts, or advice I'd really appreciate the input.


Posted by: 2 strokes for life---------------------

Well i just happen to have a 1983 IT465. It has been bored 4 times over and it melts a piston every time you open it up really good. Here are some of my links.
http://bikeboneyard.com/yamaha.html This guy is awsome and has almost every bike.
http://www.dgperf.com/vin/Vinproduc...asp?sidebarID=4 has good pipes.
http://autos.groups.yahoo.com/group/EnduroITseries/ Join them and never regret it.
http://www.yamaha-it.co.uk/ A UK based IT home.
http://www.vintageiron.com/ Has alot of parts for bike and good carbs.
http://www.x-tremevintageyz.com/product.html It is a YZ page but they did make a YZ465. Good luck. Tell me if you find any different and better sites for it. Fun bike but dont hammer the throttle too much or it will come up and bite you in the A S S.


Posted by: btarka---------------------

Thanks for all the info. I'm already a member of two of the groups. I'm really excited about doing a restore and get some local respect for the old school.


Posted by: 2 strokes for life---------------------

Well, mine dosent look good but it can fly when it wants to. Big ugle and white.


Posted by: btarka---------------------

Well, so far, in one week I've gotten another engine, a brand new carb and a complete dg exhaust for next to nothing. Things are starting to come together.


Posted by: KTM Mike---------------------

2 strokes - if your IT melts down anytime wide open, I would say you have a jetting issue - there is no inherent reason you should not be able to rip on that bike without worry, unless something (like jetting) is wrong. Go up a size or two on the main jet...see if that helps.


Posted by: 2 strokes for life---------------------

Alread tried that. This thing has paper thin walls and a huge piston. It is not the jetting at all. I had to go up a hole bunch on the main so it would bog the bike down at higher speeds.


Posted by: btarka---------------------

Just bought another 465, this one is an 81 white. Quick question, anyone know the seat/gas tank interchangability for the IT's? Say a 125 tank, will it fit the 465? Or 490 seat on 465? ECT...Thanks


Posted by: mtk---------------------

Quote:
Originally Posted by 2 strokes for life
Alread tried that. This thing has paper thin walls and a huge piston. It is not the jetting at all. I had to go up a hole bunch on the main so it would bog the bike down at higher speeds.


Then something is wrong with it, period.

There is no earthly reason for the behavior you describe and the idea that an air-cooled big bore automatically explodes at WOT is just wrong.

One possibility is a main bearing that is sketchy. At high RPM it lets the crank end move a bit, causing the seal to leak, resulting in a lean condition and consequently engine seizure.

Keep digging and you WILL find a problem.


Posted by: 2 strokes for life---------------------

I have done top end jobs and jetting but still nothing. It keeps mealting the piston ever time i really open it up.


Posted by: 76GMC1500---------------------

Well you havent' done enough jetting, then. Have you tried running a colder spark plug? What kind of ignition timing is the bike running? Has the head been milled in the past? Are you running enough octane? There are a lot of reasons a bike could be burning a piston.


Posted by: 2 strokes for life---------------------

Yes there are alot of reasons it is burrning the pistons. The owner befor me milled the head for way too much compression.


Posted by: mtk---------------------

Then run race fuel to solve the "excess compression" problem.

If what you say is true, detonation is blowing a hole in your piston. Stop the detonation and you'll stop the piston failures.


Posted by: 2 strokes for life---------------------

Is it really that simple. So i just put octain booster in my gas at the correct mixture and done. I will give it a try this spring when it has a new piston and rings.


Posted by: mxbundy---------------------

Try 2 base gaskets! Will lower the comp. ratio. Or you could have a new thicker head gasket made up to solve the problem also, but the best thing to do is to get a new head off of evil-bay and call it done!

bundy


Posted by: Britt Boyette---------------------

If race gas won't fix the problem, I would guess there is a carb issue that is wacky. Something like the slide having an odd cutaway or something. It could also be something as simple as a case that has a warped base for the base gasket or maybe a leak coming through the slip line of the case. Whatever it is, it's not normal. Find a carb that's known to be good to go for an IT465 and give it a try.


Posted by: 2 strokes for life---------------------

mxbundy, i shall try the double base gasket this spring.

Britt Boyette, the carb is fine. I think it is the high compression.


Posted by: btarka---------------------

Well I almost got my 82 together. Just waiting for some bolts from yamaha and the silencer should be in by tuesday. Still looking for misc. parts though. The guy who owned it before me painted it. I stripped it down but the tank has very bad discoloration so back to the hardware store and the plastics all got a fresh coat . It'll do for now. Hopefully by next weekend I'll be


Posted by: Britt Boyette---------------------

Quote:
Originally Posted by 2 strokes for life
mxbundy, i shall try the double base gasket this spring.

Britt Boyette, the carb is fine. I think it is the high compression.

Can't you just get another head for it? You see them for cheap all the time on a certain auction site.


Posted by: 2 strokes for life---------------------

Ys but i dont ride it alot to pay for it. But i might ride it more if the thing worked. But thats not going anywheres till the snow starts to mealt.


Posted by: btarka---------------------

Took my first ride on mine today and all I can say is WOW! This thing has incredible power and torque! Now I have to decide what I'm gonna do with my white 81. I got it running also and it sounds very good and the clutch feel good too. Decisions...Decisions...


Posted by: 2 strokes for life---------------------

The clutch is feeling good My clutch has to have a 20 or 30 pound pull to it.


Posted by: robbie_new---------------------

i have an it 175 i just restored and the seat maybe changable but i found that the tanks were different sizes


Posted by: btarka---------------------

I was actually able to get some decal/paint remover from the local autoparts store and it worked great. I then bought some plastice paint called fusion and about 4 coats later it looks really good to my suprise. It's not the original blue but it looks good. Still would like for find a new seat though.


Posted by: rd400pi---------------------

2 Strokes For Life,
Did they make an IT465 in 1983 for Canada? In the US, 1981 and 1982 were the only IT465 years. 1983 started the IT490 line. How is the toasting pistons coming?

Mike H.


Posted by: 2 strokes for life---------------------

rd400pi, i am almost sure they made a 83 IT465. I doubled up the base gasket and head gasket and it works. It also beats most 250 2 strokes or 450 thumpers on the strights.


Posted by: timmae 360---------------------

Quote:
Originally Posted by 2 strokes for life
rd400pi, i am almost sure they made a 83 IT465. I doubled up the base gasket and head gasket and it works. It also beats most 250 2 strokes or 450 thumpers on the strights.


More base gasket (thickness) has the effect of extending port timing and lowering comp, effectively raising the power band of the engine. IE less bottom end and ore top end. tune the rest of the induction and exhaust to suit. And machine the head to get your comp and squish back where it should be


Posted by: 2 strokes for life---------------------

timmae 360, if you have ever riden a 465 you would know that it dose not matter if some bottom or top end is gone becaues eaither way the bike flys.


Posted by: btarka---------------------

Well I now am at the task of jetting my carbie. I put the full DG exhaust on it and it's flat on the top end, like it's starving for fuel but it will foul the plug and run rich taking it easy. Ordered a crap load of jets this morning and I'm hoping to get them in before the weekend. 2 Strokes, do you get your gaskets from the dealer? I can't seem to find any aftermarket ones. I'm definately going to go through the bike this winter.


Posted by: 2 strokes for life---------------------

btarka, all my parts are from my local dealer because i like helping out the localy owned businesses. As far as jetting goes try a size smaller pilot jet and one size bigger main jet and put the clip in the middle postion.


Posted by: rang dagadang dang---------------------

I had the same problem years back. It turned out to be a sheared woodruff key on the magneto. The magneto spun right round on the shaft and ended up jammed against the broken piece of key. This allowed the bike to run but the timing was slightly out and this melted the piston. maybe it is this or maybe your timing is just out. - hope you get it sorted


Posted by: jsantapau---------------------

another possibility for the top end melting at wide open throttle is a too restrictive stinger or silencer


Posted by: JohnRichardson---------------------

Look at the logic of what is happening. Too much heat on the crown of the piston. I raced one for a long time in the heat of Australian summers while working for Yamaha with no problems although the usual ring change after 2 meets and normal servicing, air filter etc. There are many reasons for holing pistons and without an accurate record of the changed to the motor you will be battling to solve the problem successfully. My advice is to replace non standard back to standard and it will still have all the performance you can handle. I raced a a 490 both IT and YZ (very similar) after the 465 and prior to that a Yamaha SC500 now that was power to spare, a scary bike.



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