DT125R ARCHIVE

Calum122 · Guru

RE: 4DL TZR Engine Unmaintained!

AndyYam · Guru

Haha sounds good. Its a big distance for us to go but we may have to make the effort. My friend i ride with has bought a Brand new KTM150SX. Madman but he loves it. I'll have to convince him to make the trip up there. We usually use a trailer but i think a Van might be a better idea for that kinda distance. If we arrange a day ill give you a shout incase your free and fancy a ride!

Calum122 · Guru

Haha. Yeah it's always worth having a shout. From the sidelines it's an epic track. But way above my confidence level.

I haven't been to too many tracks. So i don't know how this scales up in comparison to others near you. But for me it's a very exciting track. Well worth the look if you're local. I'm not sure how much the bike will get used for the rest of the year. I don't own a van or a trailer and had to 'borrow' my brothers work van to get it there. Which was a massive pain emptying it.

You can sort of guage the scope of the track from the helmet cam. But believe me it doesn't do how steep those hills are any justice. They are steep to say the least.

slob · Guru

Great work, those crank nuts are insane how tight they get, I think the heating and cooling for years causes this to happen.

putting them back on is fine cause you just lock the crank and tighten them up to the tourque in the manual.

-- Edited by slob on Tuesday 22nd of October 2013 09:22:27 PM

Calum122 · Guru

OMFG! How hard is that flywheel to remove! Look at the bar extension I needed to turn it!

Can someone tell me how that is suppose to go back on....? PLEASE!

Ok so haven't been able to do much really. A combination of scared, busy and breaking more than I'm fixing!

I'm not worried so much about dissassembling. I'm using a bit of brute force to dismantle it. This is NOT! Something I want to do once I've spent hard hours on it when it comes to reassembling it. So tips and advice much appreciated!.

What have I done so far.

Well I've got LOTS of parts. Oil seals. Bearings. New con rod. Full gasket set. Lots of loctite. Lots of gasket tite. The engine has had a massive scrub down to remove all the surface oil. But it's absolutely engrained into the metal. Some emery paper and WD40 will sort that out. Got some heat resistant paint on the go for the cases. They were badly scratched and paint flaking. I'm pleased with the results. Fingers crossed it's durable.

Sprayed the generator cover too. No photo but similar job. No runs so i'm pleased.

Clutch dissassembled. Note the Minarelli Stamps

That fly wheel was solid to remove! Literally thought I was going to break it!

I get the impression this engine has been dissassembled before. Not many original bolts about. But I don't care what they've done. Full engine rebuild or whatever. They've done a SHOCKING job and I'm going to make sure a proper job is done on this. No time limit so who cares.

Sending the crank to Yamaha for a Rebuild with the Wossner con rod. Before you wise allects say it. I'm aware that the £30 one from PMJE would do exactly the same job. I'm aware that i'm paying over the odds for the name. It upsets me to pay so much for something that could be bought for £30. But on the same note this says High Performance on the box!!!! Lol. Sad I know.

Calum122 · Guru

Ah ryt. So the fly wheel goes back on. Then use the washer and nut and torque it and thats all you need to do. You don't need a fancy tool like the flywheel puller?

I'm going to rebuild the crank. Should i renove the woodruff key?

slob · Guru

Yeah the nut just pulls it back on, no fancy tools ect, the woodruff key will just come out of it's slot, watch yourself on the machined edges on the crank where it sits, I cut my finger badly lol they are like razor blades. It should pick out with a screwdriver.

Thinking of doing an engine myself, by sourcing lots of cheap parts on ebay for a frankinstein engine as a spare lol, looking at a trash bottom end for like £20. Good challenge to see how cheap it can be, some stuff on ebay does go for peanuts.

Calum122 · Guru

Well it's in pieces. Just need all those bearings ordered. Clean the shell like mad! Spray it. Rebuild it. Expect lots of updates in the next couple of months.

There are a million and one photos of engine rebuilds. But another one can't hurt. Purely for reference for myself and othres that want to rebuild a TZR 4DL motor!

So no more talking, here it is.

slob · Guru

Quite amazing how all those stamps are cast into the entire engine components.

Calum122 · Guru

I love all those Motoriminelli Stamps :D

Calum122 · Guru

Aww wow this is just absolutely joyous!

So went to yamaha to have the crank rebuilt. Gave him the crank and wossner con rod.

He was like. This is a belgarda crank isn't it?
I was like yeah how do you know that.
He said they've cast their mark on te crank and con rod. See. In order for them to get around import tax they cast their own crank and con rod. And if i remember correctly tzr and dt con rods won't fit between the crank. It's a smaller gap just because they wanted it to be different.

So basically that was a waste of money.
I said what are my options.

He said you can buy a 2rk crank. That will fit and then you can use this con rod.

So i went home. Put the 4dl crank on ebay. Looked for another one. I had a few interests. People messaging me. Then thought sod it. I'll cut my losses and just buy another con rod for the 4dl.

Went back to yamaha and said sod it just order a new rod and bearings and assemble it. He was like sure no problem. Make and model. I was like tzr125r 4dl belgarda. Ahh can't find. Grabs the engineer. He found it. Said it won't be cheap. Bout £100. But it's going to be OEM belgarda made. I was like cool i'll have it. Okay here we go. Ah. Discontinued.

I was like FFS! So what are my options. Can you not machine down the wossner rod to fit then shot peen it.

He said it's a possibility but thats about it.

So if this doesn't work i would have wasted £70 on a wossner con rod. Will need to spend another £100 on a decent crank. Then another £50 rebuilding it.

And if the initial one does work i'm paying yamaha prices for specialist machining work. On the other side of course i'm having a bespoke crank and con rod. Not that anyone but you guys are privilaged to know haha! I really hope it doesn't drain my bank acount lmao

slob · Guru

Hardlines mate, that's what happens when you are working on the exotic, think you will just have to buy the crank for it.

slob · Guru

Con rod I mean.

Calum122 · Guru

It's discontinued. They don't make them anymore. At the moment i've left it with him. He will try and machine down the con rod. Then put it in a special device to relieve it of any stress. Like shot peening but this is formula spec. Class! But by the sounds of things not cheap.

AndyYam · Guru

Is your conrod defo in need of replacing? Could you not just replace bearings? whats wrong with it?

Calum122 · Guru

No. It's probably fine. Probably. The crank is probably fine. Infact all the bearings inside the engine are probably fine. Thus the need for the engine rebuild is pointless. But it's a project. And i don't want any stone left unturned.

But also not a bad shout. If all else fails just replace the bearing.

AndyYam · Guru

Yeah as nice as it would be to replace. Unless the conrod is damaged or th surfaces the bearings run against are damaged i personally would just stick with it. I know what you mean about not wanting to leave anything unturned but sounds like more hassle that its worth to replace.

Calum122 · Guru

I think you may be right mate. It's such a ball ache. Replacing the bearings might just be the only way for it. We'll see how it goes though.

Calum122 · Guru

I got a phone call today from yamaha. They've rebuilt the crank. Thank god. Picking it up maybe tomorrow or later. Which is good.

Hopefully hasn't cost me an arm and a leg. But bespoke job done by yamaha so i won't hold my breath.

Calum122 · Guru

So picked it up to today. Extortionate prices from Yamaha it's unreal. A whole £20 to split the crank. File down the connecting rod and then to rebuild it. I mean what a joke!

Nah jokes I'm over the moon with the price, especially from a Yamaha dealer where the technician understands that it's a belgarda crank and is measuring tolerances to that specification is just really good.

Any who. More photos of the build.

Belgarda Rod (Can't get a hold of those any more :( )

The technician said that it wouldn't have lasted for very long without a rebuild. It's hard to see from the photos but you can just about to start see scoring along the big end eye where the bearings had begun to spun. So I'm pleased I did do it. Cracking bloke in there loves his two strokes and I get a real satisfaction from talking to another two stroke enthusiast who has a wealth of tuning knowledge.

The crankcases just need hardening in the over for 30 mins. Bit scared about putting it to 160 degrees though :/

-- Edited by Calum122 on Thursday 7th of November 2013 08:02:27 PM

Calum122 · Guru

A can of this has done plenty of layers of the whole bottom end.

bit.ly/16KlzJe

slob · Guru

Glad you got it sorted by someone who knew what they are doing and who actually cares, which is rare these days indeed.

What do you mean about putting the cases in the oven to harden them?

Calum122 · Guru

I know that was a poor sentence. The paint job on it. Needs to be hardened. The can says to 160 degrees but i'm not keen on that idea.

-- Edited by Calum122 on Friday 27th of December 2013 06:27:13 PM

slob · Guru

What kind of paint is it, deciding wether to powdercoat my spare engine I am building or save a bit of money and paint it.

Calum122 · Guru

Also slob. How did you get the crank back in the cases.

And how do i go about getting the bearings in the case.

slob · Guru

for the bearings I got them pressed in at the shop cost me £30 cause I didnt want to put the powdercoat in the oven, I would do it this time round as I reckon it would be fine as the powdercoat has not suffered at all even around my exhaust port.

You have the bearings in the freezer and the they just tap in, think you need the case at 200 degrees for this or maybe 180.

for the crank, you install the gearbox and apply the sealent, you then put the long bolts in and gently tighten them to pull the cases together, you hear the crank creaking as it is pulled into the main bearing I used two stroke oil to lub the crank where it inserts tightly into the bearing, then tourque them up to the proper spec and leave it for half an hour for the sealent to set.

Then dunt the crank ends with a rubber mallet to get the crank moving, it will feel pritty dam tight comparded to how it was but this is normal and will free up during the break in process.

DT-R_bradders · Guru

yo cal make sure u time up the balancing shaft when u throw it all together! gd job btw

NORFE · DTR Trusted Engine Builder

Calum122 wrote:
Also slob. How did you get the crank back in the cases.

And how do i go about getting the bearings in the case.

bearings in freezer over night

heat around the bearing recess with blow torch get it hot and the frozen bearings just drop straight in simples

Calum122 · Guru

Banged it in the oven lmao! Dropped right in.

Just need to put the seals in and then the put the crank back in.

Still concerned about the crank.

How do you do it NORFE?

NORFE · DTR Trusted Engine Builder

just put it in the case clutch side down and then put the mag side on and pull it down with the bolts it will creak and crack when the cases are together give the clutch side a good crack with a hammer loads of vids on ut to show u