do I part it out?!

I've been reading some of your parting out stories for years and now I can't beleive it might be happening to me

in the past 3.5 years I put:
Dyna coils
wires
tires
rear shoes
front pads
front caliper rebuilds
SS lines
valve adjustment
petcock rebuild, you know many times
Complete carb rebuild(s)
carbs dipped in acid baths at local shop 3 times
signals
bars
controls
gauge maintenance
motor paint
the wrong air box
the right air box
the wrong foot peg
the right foot peg
the wrong starter button
the right starter button
tach cable oil seal
oil sensor oil seal
air filter
starter relay
sealed the tank
fork seals
manifold gaskets
flasher
bulbs
fuse box
mufflers
exhaust mid section


bought color tune, sync tool, IV bottle, I don't know how much oil from gas getting in, wrong plugs, right plugs, propane, RTV, tubing

Made my first 2 carb sync tool from baby bottles, had tons of good conversations with you guys, learned and immense amount of information here. I have seven hundred and twelve posts!

you wouldn't beleive me if I told you how many hours in the carbs

so now that it still doesn't run perfect I pulled the head. The valves are burnt, pitted, worn thin. Seats are shot, some loose guides, and my oil level gets low if I ride for more than an hour.


waiting on a top end rebuild parts price from Len but I'm not optimistic, at all. I'm in pain.

the new Dyna coils I bought over 3 years ago, one was bad, took me a year and half to find that, cause they ohm'd out perfect. during that I blamed the carbs, after that I blamed the carbs, then I blamed the valve clearance, then the carbs again. Does this mean we belong together or apart? someone tell me please!

 

my vote, keep it, your JUST now learning the bike and after you get her purring like a kitten ull enjoy riding it because you will respect the bad times you had with her.

 

What a terrible shame to let go of all that accumulated knowledge of a great bike ... I say keep it and get that top end sorted, you should be able to get it really humming.

 

you guys are right. More info, Len got back to me, he mentioned that the price would be astronomical for a Complete top end rebuild and recommends I look for a low mileage head.

HA! where the hell am I finding that (slight sarcasm), my seasons over I guess. There's a sweet maxim with 6300 miles up for sale in CT 3 hours away in the for sale section for $990, but it's a maxim, I have a seca

 

I would Keep it and continue to stick it out like you said you've learned alot and will keep on learning.. I'm in the same situation and its been a great learning experience so far..

 

Unless you are looking to do a true numbers matched full on restoration.

Grab yourself one of those more than plentiful 650 maxim engines that are for sale in the sale section, and swap it out for far less than the top end rebuild. Even a 750 swap is an easy modification.

Make sure you get a compression test done prior to laying out the green!

You have gone to far to give up and throw it all away now. That is just part the joy/frustration of working on a thirty year old bike.

Ghost

 

hmmmmmm, a 750 ey. is there a thread for the swap? my bike is a seca non yics

 

Its a straight bolt in swap, plenty of posts on it in the mods section. You will need to use the 650 oil sensor was the only limitation that I saw. Do a search for engine swap.

I have even heard of a couple 900's being swapped into the 650, but those are few and far between!

Ghost

 

If the motor only has 22K on it, the only reason the valves are cooked is from neglect. As long as the cylinders, pistons and rings are OK, a valve job isn't that big of a deal, or shouldn't be. Take it to a pro and get a second opinion.

The head from a NON-YICS Maxim will work fine.

Swapping a Maxim motor into a Seca involves some screwing about with shifter configuration; it can be done but some things will need to be "transplanted."

 

Intake and exhaust valves alone are 500 bucks!!!

 

Just buy a used motor and get riding. Nobody in their right mind here would pay 500 bucks for valves. If you want to take a quick vacation to upstate NY (WAAAAAAY upstate for you.....I'm about 10 mile from the geographical center of NY......Utica area) I have a 650 maxim engine and a 750 Maxim engine sitting the bench waiting for a new owner.

Dave Fox

 

Do a motor swap. Take your time and get a good 750 Seca motor, and you just gained 12 HP. Then your bike is special, which makes it all worth while. Save your bad motor for the "numbers matching" crowd when it comes time to sell. And show them your receipts - -sounds like your bike is worth $3,500 !!

 

http://cgi.ebay.com/ebaymotors/Yamaha-1 ... ccessories

just an option

 

Hog, tell me more about your 2 motorss please. They both road worthy? Yics?

 

so I purchased a used head, in the proccess of cleaning it now. it came off a bike with 18k miles and was said to be good. my plan is to clean it, paint it, lap the valves, put new valve guide seats. I do have a major concern about not getting in all the nooks for proper cleaning. So now I'm contemplating leaving it bare silver, but the motor is black. Here's the bike, what do ya'll think w/ a silver head? leave the valve cover black? either way I don't think it would look Too bad :?

 

I think with the black headers I'd leave it (the head) unpainted, although I am a Maxim owner lol.

If you had some chrome headers it would be like a silver line right through your bike, if you follow me

 

wow that's a really cool point. well i'm not gonna buy chrome headers just yet, maybe I'll leave the silver for now and see how she runs. The thing is, w/ the head gasket being pricey I can't get crazy. really hate air cooling fins :evil: . So after it's all back together I have to re-do valve clearances, fun :roll:

 

so after the cleaning, i can now see that there's two pefectly broken off intake bolts broken off in the holes. just perfect. I just read all the topics on this.

 

Well, with the head off, it's really easy to take to a machine shop and let someone else worry about those broken off studs.

I think I'd measure the play in the guides before necessarily replacing them. Definitely new valve stem seals, though.

I'm really surprised how expensive the valves came up. I replaced the four intake valves on my GPz last year and they were $24 a piece from the dealer.

 

Thanks. The broken studs are done. I drilled them out and tapped them to the original 6mm size, chased the rest, all good. Waiting for the spring comressor (C-clamp style) in the mail. This thing is clean but definitely gonna need paint. I do plan on sand blasting it on sunday. Plan to tape off the cam area.

 

Ok so I REALLY messed up a good thing. Sand blasted the head really nice, only the fins. Lapped the valves, they are really well seated. Shined the piston domes and took 3 hrs to clean the top of the cylinder heads for the new gasket. While wire wheeling the bottom of the head I used Silver bristles for #1 combustion chamber and it completely took metal away. So now I have to Hope the engine shop doesn't say I took too much off and it can be decked. Anyone know how much can be removed??? Almost had the cheapest head repair ever till this. The guides were perfect too and the stem seals came in the top end gasket kit. And I got the money refunded for the head cause it has two broken intake bolts and 1 bent stud! Leave it up to me to ruin a good thing.

edit: I didnt ask for the money back, I emailed the guy from ebay that the product didn´t match the description cause of the three things mentioned above, 5 minuets later I had an email from paypal saying I was issues a refund that was nice 8)

 

Well the head shop said the rule of thumb is max off a head deck is 10 thousanths. He guessed mine will need about 6 off. Followed by more compression and torque. 100 dollars, can't win them all, or maybe hardly any. He also mentioned that the black paint on my motor was from the factory, 2 main reasons, there's black in the valve area, just not where the cam sits/rotates and that he could tell it was backed and didn't look 'cheesey'. So I guess this motor is from a midnight maxim maybe? Non yics? I have some # checking to do later I guess

 

650 Seca engines had black painted jugs and cylinder heads (with bright fin edges).

Check the stamped serial number on the upper engine case, on the pad just by the clutch cover, and the first 3-positions are the frame code of the bike (5V2 or 5V3 for a Seca, 4W5 or 4W6 for a Mid Max) and tell you what model bike the engine came from.

 

I remeber for sure its 5V2

 

ok here's an update: I picked up the head today, the shop only needed to take 4 thousanths off. Took off the valve stem seals, what a bitch that was, thankfull I had those orange handle hook drivers from Harbor Freight, I don't think anything else would have got them off. put it in the sink, got a bucket of water w/ palmolive and a plastic bristle brush and went to town, that degreaser left white residue in many places, the cam journals too, got them smooth again though. dried with compressed air, taped it off meticulously, and put the first coat. MAN IT LOOKS AWESOME. so now I'm just trying to decide if I should bake it between coats or wait till I do three coats or so. Also wondering how long to keep it in the oven, I'm thinking 25 minuets is good. Oh, so this head didn't come with a cam or journal caps. So I'll be using my original cams and caps. I guess this is ok... pretty excited. Sucks that I'll be away tomorrow night for work, plan on riding this bitch this weekend! After the assembly, valve clearances (hopefully I have the shims I need), sync, colortune, sync. working on two other bikes too, splitting cases on my dirtbike to change internal seals, fork springs, shock springs, and the top end on another dirbike. would like all this done by sunday BUT, I might be enjoying my SECA

 

ok here's an update: I picked up the head today, the shop only needed to take 4 thousanths off. Took off the valve stem seals, what a bitch that was, thankfull I had those orange handle hook drivers from Harbor Freight, I don't think anything else would have got them off. put it in the sink, got a bucket of water w/ palmolive and a plastic bristle brush and went to town, that degreaser left white residue in many places, the cam journals too, got them smooth again though. dried with compressed air, taped it off meticulously, and put the first coat. MAN IT LOOKS AWESOME. so now I'm just trying to decide if I should bake it between coats or wait till I do three coats or so. Also wondering how long to keep it in the oven, I'm thinking 25 minuets is good. Oh, so this head didn't come with a cam or journal caps. So I'll be using my original cams and caps. I guess this is ok... pretty excited. Sucks that I'll be away tomorrow night for work, plan on riding this bitch this weekend! After the assembly, valve clearances (hopefully I have the shims I need), sync, colortune, sync. working on two other bikes too, splitting cases on my dirtbike to change internal seals, fork springs, shock springs, and the top end on another dirbike. would like all this done by sunday BUT, I might be enjoying my SECA

 

Paint: follow the recommended curing instructions on the can, or suffer the consequences!!

Cams: you MUST check the cam bearing journal clearances when swapping cams and/or bearing caps between different heads; typically you do this with a piece of "plastigauge" or similar:

Specified clearance: .020 - 054mm (0.0008 - 0.0021")
Maximum allowed: 0.160mm (0.006")

Install the cams, put a piece of plastigauge on the cam's bearing journal (all of them), and torque the caps in place (7.2 ft-lbs). Do not turn the cam while the plastigauge is in place! Then remove the caps and measure the plastigauge with their scale.


If the min or max. clearance is exceeded, well, then you have issues to attend to, and decisions to make.....

 

i have so many emotions reading that I don't even know where to start. well, first, thanks. what happens if you run the motor w/ bad journal gaps? well tight is obvious, metal shavings would get in the system, and if the gap is a little too big?

I have plastigauge, I don't know why I didn't do this test before I had 6-8 hours and a hundred bucks in machine work done to it. If it's out of tolerance, I don't even know, I might put this thing away till next summer, or whenever. If the ora of this bike stays true to form, the tolerances will be out. I guess I could go back to the original head and put new guides in it, that was the biggest problem, the valves wiggles pretty good. This other used head I bought are TIGHT, and the lapping shows really perfect seats.

just did second coat, I went from hating cooling fins to loving them

I WISH SOMEONE MENTIONED THE TOLERANCES EARLIER, this doesn't mean i'm not outrageously greatful for this site, I'm just pissed cause good things just don't happen with this bike, it makes me EARN. I just don't have the time to check them until I return from my buis trip Friday.

and oh, there was no mention of baking in the instructions on the can. I guess cause they bake themselves...

 

MOMENTUM, intake and exhaust are GOOD. Baked the head for 15 mins at 400F, cooled it, it feels Nice and hard, doesn't scratch off. got about 1.5 of cleaning left of random parts and it might be started by dark not going to get to ahead of myself though :wink:

pretty damn excited

oh hell here's some pics



I'll give updates tonight, pretty sure I won't be syncin or colortuning till tomorrow

 

and the valve clearances are:
OUT
.10 .12 .01 .16ok
IN
.229 .07 .17ok .03

shims I have:
260x2
265x2
270x3
275x2
280x2
285
290
295
27? (I guess either 270 or 275, I have to get batteries for my digital caliper)

now I have to find that handy shim chart. I guess I also have to remove the shims that are in there and see what they are. I guess it would have been a good idea to write them down before the installation. I thought it would be running by last night, what a joke!

 

ok, so 6 were out, need to order 2. As usual, I'll post updates with how she rus when the shims come this week. Was Really looking forward to riding my finaly hopefully mechanically perfect bike this weekend. oh well, I have springs front and back to change and split the cases on my race bike. My friend says I'm crazy with all the work/hours in this bike and that if i spent a quarter of the time on restoring the RD350 2 stroke in my shed it would be museum quality by now lol.

 

IT'S ALIVE. Still a work in progress. Oil coming out of the seam of the left muffler to header (I had the mufflers off and re-seated them late last night), stator pointy thingy is touching the coil pickup making a screetching sound, must have bumped it with the 21mm wrench when turning the motor to do the valve lash, and one of the bowl gaskets is leaking. BUT, without air box connected it idled and rev'd Mint. The new exhaust do-nuts are so thick I could barely get one thread on each nut, very annoying cause I feel like I'm going to break a stud or something and i'm only 1 to 1.5 turns in on each and every one. No oil leaks from the valve cover or cylinder head. The future looks good but I'm not getting ahead of myself just yet. This will play out the next few days.

 

well what I thought was the reluctor touching the pickup coil in fact wasn't even the sound of metal, it was a whistle coming from the head gasket right between holes 3 & 4 blowing towards the carbs. Torque spec for the head bolts is 26.1 ft lbs, I did it in small increments to 33 ft lbs and it's good - thank God, cause if it wasn't, I was putting the bike away for a very very long time, or parting it out. I went for a ride w/ the airbox connected of course and it doesn't rev to good under load (forgot to do a bench sync which I contemplated doing anyway), but the weather stopped me of doing a sync and colortune. I was kind of thinking if I should have came 3/4 out on all the mixture screws and a bench sync, kinda like starting from scratch. I wonder... what a pain in the ass. Oh, the carb gasket leak, ended up having a spare gasket that came off my '72 RD350 2 stroke!

 

running MINT. sync and 1 and a half out on the mixture screw across the rack. Colortune tomorrow. thanks for giving me the power guys. it really is running Perfect

 

This is turning out to be a nice story.

Congratulations!

 

Thanks. Ok so maybe its on the rich side, gonna try 'in' half turn now, but the hiway running is superb, 99.9% off the line

 

When you get the Pilot Mixture Screws "Close" to being Dialed-In ... don't think in terms of ...

"Fractions of a Turn"

A Half-turn could spoil everything you have gained.

When you are doing "Fine-Tuning"
Fine tune!

Move the Mixture Screw a few DEGREES.
The with of a DIME
The width of a NICKEL.

That's why the Pilot Mixture Screw has EXTRA FINE Threads.
So you can adjust it a "(My-nute)" amount.

 

Thanks. Ok so maybe its on the rich side, gonna try 'in' half turn now, but the hiway running is superb, 99.9% off the line

 

Rick, just so you know, I was typing my last response when you posted yours. I Absolutely remember that rule from when I started this project yrars ago lol but I was just messing around. So this morning I got down to it. After the colortune the screws are in fact all in different positions but it runs mint now, I did expect a little more power though. It idles extremely smooth at extremely low rpm, but my tach face is busted at the moment. The only 'thing' about the way it runs now is; it needs to be at operating temp to not stumble At All off the line, including sitting after 1 hour after a ride, but 20 minutes its still hot enough. But again, once the temp is up, no hesitation Anywhere, And the oil level doesn't change anymore either

 

it seems I have a road worthy bike that doesn't burn oil and runs pretty damn awesome. The Hot colortune proved 3&4 lean. Since that adjustment (and the crossthreaded sparkplug hole) the bike has more power, has that coasting factor - not much engine brake at all. And it doesn't stumble after warming it up for the first few miles off the line. I am a happy camper.

In hines sight, it was totally necessary to replace the head, after all the other work. It all would have been for Nothing. The carbs and coil issue took 100x longer than it did to do this head job.

Now I guess I can continue getting the bike complete.

Still need:
- both gauges
- left side foot peg rubber
- flasher (left signal blinks slowly and right stays solid)
- find out why my horn never worked
- find out why my new rear brake shoes are grinding/humming randomly with light braking applied
- reduce the handlebar vibration cause I had pins and needles in my right hand 30 miles into my 40 mile ride to work this morning.
- seat cover
- misc things painted

 

Good to hear that it is finally coming around for you. Hearing the motor purr always makes it worth it in the end.

Check with hogfiddles on that footpeg, and guages. He is parting out a 650 now, and has always done me good on the parts that I have gotten from him.

Ghost

 

I remember reading some other post recently that mentioned the same thing. I think it's a factor more related to the way XJ's like to be ridden. If you are chugging along at 45 mph in 5th gear, you won't feel engine braking when you downshift to 4th. But, if you run a gear or two lower at higher rpms, you WILL feel engine braking through the downshifts. (fun on twisty roads!)