Newbie 85 Tri-Z help

[Maxx]

Hi all, first time posting and have a couple of question on a barn find i got, 85 tri-z. This thing had been sitting under a lemon tree for 8yrs when it was given to me. Plastics really bad and would not start. Persistence on cleaning out carb, fixed the fuel pump and cleaned out the tank, finally got her to start but the bike filled the shed with smoke. After so long sitting the seals were shot. A complete teardown with 1st o/s piston and rings, internal seals and bearings im slowly putting her back together. Plastics have been scraped and wet sanding will follow with a fresh set of decals.

Question 1: fuel petcock under the pump leaks, whats the part number for the tap seals? I can get 'all balls' products here in new zealand but if there is another option I would love to hear. Its leaking from out of yhe tap itself and bowl underneath. Looks like the previous owner had done the wrench report mods but man butchered them, fingers crossed she will run sweet after all this effort. Stock carb tho running a 390 main, boysen reeds by the looks, not stock thats for sure, swiss cheese exhaust (i have a dg in transit) I will attempt to add some pics...any help would be very much appreciated 268049268050268051268052
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[El Camexican]

Hi and welcome to the site.

I’m not aware of any part numbers for the items your looking for. I’d suggest you carefully disassemble them and take whatever’s left of the seals, or o-rings to a seal wholesaler to see if the can match you up. Just make sure they know the dimensions are metric and that the material will be in contact with fuel.

That cylinder looks like it’s been welded on both sides of the intake. Is that correct, or am I seeing something else? If that’s weld I’d be hesitant about using it. That added boost port is horrific and work they did on the other side is almost as bad. Did they do any other grinding on the cylinder?

Great job on the plastic and the rest of it. You’re going to have a very nIce trike.

[ironchop]

Looks like some good progress

The plastics look 100x better after you rehabbed them



Sent from my motorola one 5G ace using Tapatalk

[Maxx]

Thanks guys...yeah i agree, horrific butcher job on the cylinder and yes been welded...i was told it's a runner but ive only been able to start it once after half an hour kicking just to fill the shed with smoke, before i did the dodgy main seals...no other signs of grinding or other head work tho...
Yes, i can take the rubber seals out of the petcock and i think I will take the pump assembly into the shop...tho the local yami dealer never herd of a tri-z...as rare as hens teeth here in NZ...

Thanks for the comments on the plastics...ive had a second thought on the rear one, found a brand new one at 'yamaha sports plaza.com' dam cheap...the old ones abit thin in places and white creases i think may be difficult to rectify...

Before i get too far ahead of myself...its becoming abit of a money pit... i really need to get her to run and break in the new piston... just to see if any other issue around those cylinder mods will cause me catastrophic problems

Will keep you'll posted with the progress and thanks again for your replies

Cheers ������

[El Camexican]

A trick to starting the Tri-Z after it been left to sit for awhile is to blow into the vent tube that runs from the tank to the steering head. Just pull it out of the stem and blow really hard for a few seconds to purge all the air out of the system and fill the float bowl with fuel. They usually fire after one or two kicks once the carb has fuel in it.

You don’t want to kick that engine over any more than you have to. The kick lever and clutch cover are both known to break if abused and they are expensive and difficult to come by.

Hard to believe they would do that to the boost ports and not make any other changes. I hope you can put more photos up. If you end up needing a cylinder let me know.

[Maxx]

Hey El Camexican, thats awesome thank you bro...ive been abit premature in getting her back together before really understanding these mods...u reakon i could slide the cylinder off, with the head on and it in the frame, then i could check correctly the distance between the top of the exhaust port and the head gasket...photos dont really show much
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[El Camexican]

Based on the photo I don’t think anyone has touched the exhaust port.

I saw what appears to be weld, or epoxy in the photo you posted of the intake and assumed that if anyone was willing to rape that cylinder with a drill bit as as it appears they did, then they would have likely gone on to abuse it in other areas. Hopefully for your sake the stupidity started and ended with the boost port modification and that the cylinder was properly welded and decked after it broke.

Please do a pressure test on the engine to check the seals and gaskets for leaks before you start riding it. You’ll save yourself a pile of money and time if there’s a leak to be found.

[El Camexican]

If you did want to take the cylinder off for any other reason I think it can come off with with the head on it, but if not, and you’re worried about removing the head and losing the gasket, you may be able to remove it and re use it by just adding one more pound of torque to the nuts than you did the first time you installed it. Not recommend, but as long as the gasket is new and hasn’t been run more than a few minutes you should be able to cheat a bit. Unfortunately those engines have a reputation of leaking at the head gasket even in the best of circumstances, so keep an eye on it.

[Maxx]

Thank you mate, yes i to think the cylinder may well come off with the head on...it has not been run since installing them. Weird of some people to do such a half ass job on the 2nd mod and not even complete the 1st lol
Shops are still shut here for walk-ins due to latest outbreak of covid but hopefully next week I can get the bits for a pressure test....i will definitely keep you posted with the results

Thanks again for your help m8

[El Camexican]

The exhaust port was probably spared because the only tool the guy had was a hand drill. If I had to bet he started off with a large bit and got in crooked. The correct way to do it unless you’re some sort of porting savant is to carefully drill a pilot hole with something no bigger than a 1/4” bit and then determine if you can open it straight through with a larger bit, or if you need to switch over to proper porting tools and correct any misalignment. I’ve done five of these and my arse still puckers up while drilling the pilot hole.

Not sure what your budget is for this, but if you do it right that trike should be worth a few bucks down the road.

If you didn’t already know, the single most valuable part on that trike is the clutch cover. Make sure all the dowels on the kick start assembly and clutch cover (2 for each) are installed and that there are no bolts missing. Nothing loose, but not over tightened either. There’s a spring clip on the starter worm gear that must be in good condition. They’re cheap, but if the wear and start to slip too easily your crack the clutch cover.

Search Tri-Z threads on this site if you have time, there’s lots of info on these trikes.

[Maxx]

Cool i will check that out tomorrow, i didnt dig in as far as the spring clip on the starter when i did the crank seal so i will double check that..had to also free up the clutch then too, as sitting in the elements for all those years seized the thrust arm needle bearing and needed replacing.

i got the cylinder off a yes as you suspected no work on the exhaust port, im tempted to give to my m8 who owns a motor machinist shop who honed the bore for me as i only own a dremel and dont think i can get the right angle on the port edge with that. Option 2 is to buy a right angle die grinder but it will have to be tiny to get in the bore...decision decisions lol.
Looking again at the cylinder does suggest that yes a drill bit too big, too soon and not incrementing slowly enough on both holes was attempted and no competence present lol

Cheers m8......I'll be back... lol

[Maxx]

It will probably cost $100+ bucks (and probably have it a month) for him to reshape the port and around $50 bucks for a die grinder for me to give it a go.... though not having done this before might just counter out the difference and i think being precise which im confident he will be, is a must imo

[El Camexican]

I’d suggest you leave that exhaust port alone for now, unless you’re planning on racing it. If you do decide to go it alone you’ll want to read up on shaping the top of the port and proper chamfering. If using a common 1/4” drive die grinder, you can raise that port from inside the cylinder, or by entering the exhaust port from the outside, but a typical 10,000 rpm grinder can be a handful and you could easily end up matching it to your boost ports.

[Maxx]

Roger that :cool:

[Maxx]

Kool, finally got a leak down tester and started the process but i cant for the life of me stop the reed valve from leaking. I've tried new gaskets and even smoothing all surfaces but dam thing refuses to seal. Maybe i will need to apply sum gasket goo or something similar?


268083

[cymbala23]

I solved this problem on an 1980 tri moto 125, by using an over sized o ring from a standard o ring set. It was very tight but it didn't leak. that is probably going to be your best option.

[El Camexican]

Kool, finally got a leak down tester and started the process but i cant for the life of me stop the reed valve from leaking. I've tried new gaskets and even smoothing all surfaces but dam thing refuses to seal. Maybe i will need to apply sum gasket goo or something similar?


268083

So assuming that you’re using soap and water to locate the leak, where exactly are you seeing bubbles? If they’re just in a few spots the surface of the intake runner may have warped when they were welding it, or there could be a hair line crack around one of the bolt holes.

You can check for and fix an uneven surface by stuffing the intake with a rag to keep crud out and running a large (1”), fine flat-bast*rd file across the mounting surface with event pressure in an x pattern. It may help to paint it up with a Sharpie first to contrast the low points. If it’s a crack, JB Weld should take care of it.

Using a thin smear of case sealer, Yamabond, or whatever you used on you cases on both sides of the gasket won’t hurt, but check for the warp first as sealers can only do so much.

Whatever you do, don’t run it with a leak.

[Maxx]

Awesome thanks guys, sorry i didnt realise we were on page two lol...yeah half my problem was a faulty regulator the other half was stupidity lol...i had too much pressure in the system. I block sanded the surfaces and applied a smear of some threebond sealer on the leaking seals and used a different guage and setting and hey presto success....so happy i didnt stuff more....onwards and upwards from here...last parts are almost here for final assembly ...ive binned the 390 main jet for a 480 for starters

My m8 who honed the jug suggested to also run the bike with water only, no antifreeze, the 1st time until up to normal temp, let it cool completely then re-torque the head and cylinder nuts before draining and refilling with antifreeze mixture...seems plausible to me

Any ideas on the oil ratio mix for the break in period?

Thanks again for all your help guys, its so valuable and hugely appreciated

[El Camexican]

Awesome thanks guys, sorry i didnt realise we were on page two lol...yeah half my problem was a faulty regulator the other half was stupidity lol...i had too much pressure in the system. I block sanded the surfaces and applied a smear of some threebond sealer on the leaking seals and used a different guage and setting and hey presto success....so happy i didnt stuff more....onwards and upwards from here...last parts are almost here for final assembly ...ive binned the 390 main jet for a 480 for starters

My m8 who honed the jug suggested to also run the bike with water only, no antifreeze, the 1st time until up to normal temp, let it cool completely then re-torque the head and cylinder nuts before draining and refilling with antifreeze mixture...seems plausible to me

Any ideas on the oil ratio mix for the break in period?

Thanks again for all your help guys, its so valuable and hugely appreciated

Can’t go wrong with anything between 20:1 and 32:1 for brake in. After that go with whatever the oil can says. 32:1 up to 50:1. Thinner than that is pushing it even on trails.

[Maxx]

Thanks bro...appreciate that (screenshot for future reference lol)...got another question though, looks like you guys have been thru this issue before, reading up on the posts here...the DG exhaust.


Mine arrived yesterday and looks mint, only issue i have is because this bike was past its use by date when i found it, it only had one exhaust spring.
I see by other posts i will need to fab atleast one (missing) maybe two tabs for the cylinder base nuts and get a decent exhaust gasket (not the thin one that came in the head gasket kit) but what length springs do you use. I cant be confident the one existing spring i have is correct. Currently the gap between the top two mounting rings is 90mm (with no gasket) so was thinking a 75mm spring...?

Also i see some rides have a rubber ring grooved into the exhaust snout or could this be introduced onto something like a sleeve? Was thinking ali tube 55mm i/d (snout size) with 58mm o/d (dg exhaust i/d size)? Just seems like alot of gap play in between the two...again it could be something else I've got missing here ...?

Where the expansion chamber mounts to the frame is slighty out but fabricating some sort of bracket there shouldn't be too difficult once i get these springs sorted.


Cheers guys
M

[El Camexican]

You’re going to need an exhaust collar. It’s basically a really thin metal shield that slips over top of the snout, or spigot of your cylinder and then your pipe slides over that compressing the little gasket you got, which should work just fine, but I like to smear a little bit of silicone around there anyway just to delay the inevitable seepage.

Yamaha stopped making those collars a long time ago, but there is a member on here who goes by muthey that makes a couple different styles including one that comes with an O-ring. They’re not cheap in terms of how many kilograms of steel you’re getting for your money, but they are well-made and you do need one and I’m sure they take a long time to make.

I suggest running two spring tabs on your cylinder base as well as the third one that’s cast into the cylinder above the exhaust. There’s a guy selling them for 15 bucks each here on the part store, but you can make them with a grinder snd a drill.

With respect to the springs, I’m not sure I can help you. I seem to have a lot of grief finding the correct springs for my Tri-Z as well as other bikes. The ones that you find on the Internet made by Raven don’t seem to fit anything I have very well. For some reason 50 mm, and 70 mm springs seem to be common, but 60 mm springs, which seem to fit a lot of my stuff, are something you have to search for on eBay and end up paying a pretty stiff price for and I doubt that all three of your springs are going to end up being the same length. I don’t have a DG pipe on my trike right now, so I can’t offer you any help, but maybe somebody else will chime in.

Worst case scenario, you order some Raven packages of 50, 70, 80 mm and then try to find yourself some 60 mm. If you can get your hands on three of each length you’ll probably be able to make something work and then have spares for the future.

As far as the fitment of the brackets goes, welcome to the wonderful world of mass produced 2 strokes exhaust pipes. There’s just too many variables in the fabrication process for them to get these perfect and still keep them at a reasonable price. Try to keep your adjustments limited to the brackets even if you have to do some grinding to open up the holes. The less stress you can put on the pipe and its connection to your cylinder when mounted the better.

[Maxx]

Thats excellent, thank you El Camexican, gives me heaps to go on. Having a butchered job to start with its like two step forward, one step back to get this thing sorted. Previous owner really did a job on this port not running a gasket at all with what looks like a homemade exhaust arch welded together (omg some people lol)

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The front edges of the port now are burred over abit, need to get my dremel in there to fix that. Making a couple of brackets for that cylinder bolts seems an easy enough task, cause the worst thing of being down here at the bottom of the world is the shipping cost and ofcourse customs want their cut of anything coming into the country. (Exhaust alone cost me $850 nz bucks to my door, :cry:)

As for the sleeve im grateful you have pointed me in the right direction, thanks, it didnt make alot of sense with that much play so i must have been missing something. I will try a few places around here for the right size pipe, might need it machined for that groove, worst case scenario a piece of 2mm steel rolled into the sleeve shape may well do the job (fingers crossed)

Local bike shop here has springs at different lenghts about $3 each so now knowing I can use a combination of different ones to get this right is invaluable.

Making up the mounting brackets for the rest of the exhaust will come down to trial and error. All of the original ones are long gone as well so making exactly what I need will another little challenge. I might try the local wreakers for maybe yz parts but then again fabrication looks like any easier option.

Thanks again my friend, i will keep you posted on the progress.

Maxx

[El Camexican]

Yeah, that’s what happens when people run the pipe without the collar, but I’ve seen worse. Muthey’s is really tight, so if you go that route and have an exterior burr it will need to come off.

2mm strap would be way too thick. Maybe some brass shim stock if that’s your only option. Using nothing will damage the cylinder even more and piss oil all over the place.

You paid how much for that pipe???

So the good news is that because you have no chrome to worry about, you can bolt that pipe on as stressed out as you want and then just take a torch and heat the pipe red hot all the way around in a few spots and all the stress will come out of the pipe. It will fit like a glove for the rest of its life. Just remember that you’ll probably need to heat it up somewhere around the head cone before it reaches the expansion chamber and then again somewhere between the mount on the expansion chamber and again near the stinger mount.

[Maxx]

Kool mate, that photo was the old piece of crap that was on it originally....(was just showing what this other guy ran with, swiss cheese) i got the DG extreme nickel plated one from dennis kirk.


I tried a few exhaust shops but no luck with the correct size pipe there so i had a chat to my mate who does sheetmetal work he said he could roll me a peice of 2mm steel, tig the seam then machine a groove it for a rubber ring for $40 (might be an option there). The snout measures 54.6mm and exhaust is 58.9mm giving me 4.3mm difference which im hoping with the rubber and exhaust sealent make up the difference...though 1.7mm or 1.8mm might be better...i will have to see what thickness he has available.

Still working on the springs but i will clean up the burring first to get a snug measurement and fitting.

Cheers

M