A forum for owners of Yamaha TTR250 trail and enduro bikes!

Forgorin · Senior Member

My 350 project.

ttboof · Super Guru

You should get a few tips

I haven't had trouble but will recomend good quality Allen headed sockets. Really don't want to damage the heads

-- Edited by ttboof on Thursday 20th of February 2020 07:53:51 AM

TTRfan · Super Guru

Good to see you have made a start without Steve and I Michael biggrin biggrin

If the head hasn't been off for a while those head bolts are really hard to move. I use a 14mm long socket on a T-bar and then slip an old pair of handlebars over the T bar to get sufficient leverage to break them undone.

I try and get these loose when the engine is still in the bike as, on my own, it is difficult to hold the engine whilst applying full force in undoing the bolts.

I hope it will be easier than I make out wink

Brian

PS I have a travel bag packed, with an old pair of handlebars thrown in, just in case......

Forgorin · Senior Member

Hehe. I guess I'll have to get someone over to hold the engine for me... That's for the offer of handlebars but I've got a couple of extra!

ttr steve · Super Guru

Just make sure that the your allen keys fit really well, you don't want to round the heads of They will come undone though

I can come and hold the engine for you, but may take a while to get there

mossproof · Super Guru

As Brian suggests, a 14mm socket is best. Preferably 6 sided rather than 12 to avoid rounding the edges off the bolt.

tripodtiger · Senior Member

Impact driver probably wont help much. Impact wrench may be the ticket. I nearly went and bought one yesterday, getting the clutch centre bolt free. The opposition leader came out and gave me a hand. Saved $200. Beaudy!

You could also try heating the bolt heads with a hot air gun for a few minutes, spray some 'Freeze & Release' onto the bolt, give it 30 seconds or so and then insert the allen key and add a bit of impact to the end of the lever.

Forgorin · Senior Member

Thanks guys. No free time this weekend. Ended up spending three day helping a friend pack up his house...

Forgorin · Senior Member

Well, spend the morning working on the engine. Managed to get everything off and apart. My new impact driver did the trick!! Hehe.
I'm now stuck. The crankshaft needs a special tool to push it out. I thought hitting it with a wooden hammer would be ok. It's moving but slowly. Any ideas besides to keep smacking it?

Also, this thing is full of carbon. Is this normal? I thought it was burning rich. The spark plug was dirty too.

dlee22 · Senior Member

Do you mean the gudgeon pin? If so have you made sure you removed the retaining clips before pushing it out?

Good luck!

TTRfan · Super Guru

Hi Michael - good to see the progress!

You are right. It can be tricky to remove the crankshaft which is an interference fit in the LH main bearing.

If you have access to a hot air gun then maybe heating up the bearing and surrounding area before hammering might help?

Supporting the crankcase firmly is essential so that the mallet can have the best effect.

I have seen a few crankshafts which needed to be repaired after their tapered end and threads had been damaged by a previous owner having been a bit heavy handed or used an inappropriate hammer to get the crankshaft out.

Also make sure that the conrod is wedged or held firmly in the crankshaft as repeated sharp bangs might possibly damage the big end which isn't really designed to take sideways forces.

I have looked back through some of my engine rebuild threads and can't see that I ever made up a special extractor.

Good luck!

Brian

Forgorin · Senior Member

Thanks a few more taps and it all came out.

Not the grudgen pin. I'll have a go at that stuff tomorrow.

There seems to be some heat damage to the crankshaft. What do you guys think?

TTRfan · Super Guru

Well done! Glad it wasn't a problem.

Don't worry about the "blueing" as most TTR crankshafts have it - something to do with the factory's build process I guess.

Forgorin · Senior Member

Great. Thanks. I'll take it to the shop tomorrow and hopefully have it back in a week or two.

Time to go bearing shopping and get my rear shocks rebuilt... That is gonna be expensive...

TTRfan · Super Guru

If you are getting your shock rebuilt, can you ask the shop exactly what seal head they use please?

Your bearings should be cheap as all the best makes are from Japan wink

Forgorin · Senior Member

Will do!

I saw your post about bearings. Gonna try and follow that and get them cheaper than from Yamaha.

Forgorin · Senior Member

Wow, looks like about $300 to get the rear shock rebuilt...

Well, I am also looking at getting the steering head bearing and the swing arm bearing replaced. Anyone have luck with non yamaha bearings? Got any part numbers youre willing to share!!??

ttboof · Super Guru

On face book

Forgorin · Senior Member

Hummmm... Maybe I'll look around and see what i can find used here...

tripodtiger · Senior Member

Simplest bearing replacement are the kits that come from All Balls.

I've heard some criticism from various sources but I've never had an issue. Good luck and enjoy the process.

Forgorin · Senior Member

Thanks. I'll.get the engine case back tomorrow. It took three weeks. I'll start putting things together in the next few weeks when I have time...

Forgorin · Senior Member

So, got the engine case back today. Cleaned out all the swarf. I'm thinking to only replace the main bearings. What do you guys think. They all seem mint!

mossproof · Super Guru

You need to be absolutely meticulous in getting all the swarf out. It can get trapped behind bearings if they were not masked off, and blow through all the oil passageways with high pressure air. I use aerosol brake cleaner to wash out as it removes oil that swarf can stick to, then blow out with airline several times.
No reason to change bearings if they are not worn or notchy, but replacing the mains is probably sensible just as a precaution.

tripodtiger · Senior Member

How old is the engine? Do you intend to keep it 'forever'? How much to replace, or have replaced, the big end bearings?

You've got it in pieces now and
the bangs are going to be bigger.

Regarding All Balls kits - only problem I had was with their carb maintenance kit - quite a few bits were wrong. As has been shown by TotallyTTRs extra bits in their version of that kit.
One god thing about their bearing its is that the external seals are included.

Hope this goes well for you.

Forgorin · Senior Member

Thanks guys. The engine has about 10,000 I'm on it. Basically new!

Forgorin · Senior Member

Is there anyway to tester the odometer?

TTRfan · Super Guru

Forgorin wrote:
Is there anyway to tester the odometer?

Do you mean its accuracy? If so, you need to get a GPS or a GPS app on your phone and fix it safely to the TTR so you can compare.

Or do you mean its not working and you need to find out why?

Forgorin · Senior Member

Ah. I really should proofread before I post. I meant to ask if there is anyway to reset to odometer. Once I get the 350 in it would be nice... Mostly just curious.

mossproof · Super Guru

Um, that would be illegal, at least over here!
There may be a way by disconnecting an internal battery, but it is a record of the vehicle's history, not the engine's alone, hence "clocking" is regarded as fraud. Only the trip meter is resetable.

Forgorin · Senior Member

Alright. Thanks. Just thought it would be easier to keep track of the I'm in the new engine. I guess I'll just have to remember!

tripodtiger · Senior Member

Take a photo of the odo. File under 'TTR350'

Forgorin · Senior Member

Ya. I have a file for it already.

Question. I know that for the front forks there needs to be 555 ml of oil. Let it settle then measure. It should be 130cm from the top. My question is what to do if your are just replacing the oil. I havent take the internals out. Just drained out the old oil. How would i measure it?

This weekend I should have all the bearings replaced. They were full of swarf. I tried to clean them out but was unable to get them satisfactorily clean so went ahead and ordered all new bearings.

The top two piston rings slip on alright but the bottom ones don't. The three rings do no want to all fit in. Any ideas?

Also, I am sure i have asked this somewhere before but forgot the answer. What kind of gas mileage are you guys getting? I get around 25-26kmper liter. I wonder just how much that would go down with the 350. As it is I get almost 400km to a tank!

mossproof · Super Guru

Good decision on the bearings - not worth the risk. Little needle rollers too?

Regarding the piston rings. The bottom oil control ringset - put the corrugated one in first. The ends should butt against each other, NOT OVERLAP. The thin flat rings then fit either side of it like a sandwich. Try to keep the 3 gaps away from each other. Doesn't matter which way up, but the upper 2 rings have marks on to show which side should be uppermost.
Lubricate with a bit of clean oil before you fit . Take note of Brian's hints - rag over the hole when fitting the gugeon pin clips so they don't disappear into the cases when you drop them!

I measured 65 imperial mpg during the first 350 miles of use (somewhere down page 3 of the 350 thread) which I reckon to be 23ishkm/l. Not as frugal as a 250, but more fun/km!

Forgorin · Senior Member

Thanks Moss. Well, I was putting everything back together this morning. Getting the gears all aligned was a bit of a b*&^%. Now I am sitting here looking at it and am terrified that I didn't do it correctly. I am thinking to take it all down to my motorcycle mechanic and have him put it all back together! Ah. Wish Steve and Brian were here...

ttboof · Super Guru

It can look complicated. Mine went from a mess on the bench to running in under two hours

mossproof · Super Guru

Hang in there!
There are not many ways the gears/drum can go together. If they're in place without the use of a hammer it's probably ok! Check the intermediate selector shaft is aligned (the one in the crankcase that links the external shift lever to the starwheel - 3 teeth on one and 2 on the other - you can see it with a torch through the hole from the clutch housing side) and that the dot marks line up on the rh end of this shaft line up. Without oil, changing the gears will be difficult, even when turning the countershaft by hand, but if you can go up one and down one, 6 are probably all in there

Good luck!
Simon.

ttr steve · Super Guru

Hi Michael

Sorry to hear you are struggling a little putting it back together, but Simon and Brian are on hand to help you out with the tech stuff ( and loads of other forum members)and I can give a bit of moral support! So come on deep breath and keep at it, ask away, everyone on here is supportive.

That's a team work Emoji apparently wink

Forgorin · Senior Member

Well, I almost had it all done. Was just about to work on the top end when I found this in my parts bin. I am 95% sure it's from inside the engine. I've looked at the parts catalog and the manual but I can't figure out where the bigger goes!! Any ideas?!

TTRfan · Super Guru

Oh dear! If it has some serration marks on its inside then it might be the one that fits under the gear change mechanism. I didn't find the washer until I had buttoned everything up disbelief

Engine assembly8.jpg

Forgorin · Senior Member

Ah. I think this is where it goes....well, I hope so!

Forgorin · Senior Member

Brian. Just saw your post!! Ahhhh. That's a relief!!!!

Forgorin · Senior Member

Well, I was putting the head? on. The bottom gasket is quite small. the barrel wants to catch it and slide inside. Should I just go ahead and trim it to make the hole a bit bigger? Or am I missing something?

mossproof · Super Guru

Yes. Put the gasket on the case with the dowels holding it in position and use a sharp craft knife blade to trim it to size.
I would recommend a VERY thin smear of gasket sealer both sides to help it seal, particularly at the joint in the cases, 'cause it is much narrower than the original - just gives it a bit of help! I deliberately avoided the O ring because machining a chamfer for that would make the sealing surface of the gasket even skinnier.

-- Edited by mossproof on Sunday 26th of April 2020 10:09:38 AM

Forgorin · Senior Member

Mos, thanks. Well, I dont know how anyone could get this done if just a few hours! It's taken me days of work... Well, just need to get the right shims for the valves. they are all out.

mossproof · Super Guru

After about the 5th or 6th time you get faster at it

-- Edited by mossproof on Tuesday 2nd of June 2020 10:02:18 PM

mossproof · Super Guru

You've gone quiet Michael. Everything ok?

Forgorin · Senior Member

Hey guys, just got everything back together and on the bike. now, the starter spins but nothing else. I tried to bump start it but no go. The odd things was if it was going backwards it seemed to want to turn over the engine...

Sigh. Not to sure what to do. Ive checked all the starter gears and they seem to be all lined up properly. Not to sure what to do next. I was hoping to do it this weekend. I need that bike for work...

ttr steve · Super Guru

Morning Michael.

Sorry to hear of your troubles cry

First check the obvious, fuel, spark etc, sounds more like that sort of problem to me. Is there compression? Did you check the cam sprockets for alignment in TDC when putting it all back together?

ttr steve · Super Guru

Sorry reading your post again, the sprag is not engaging when you try to turn the bike over? Or are you saying that even when you bump start the engine isn't engaging? like a clutch problem?

-- Edited by ttr steve on Sunday 7th of June 2020 07:54:24 AM

TTRfan · Super Guru

Sorry to hear of the problem Michael.

Either the starter is spinning the wrong way or the sprag isn't engaging for some reason.

Take the starter cover off and push the gear both ways to check that the sprag is free in one direction and engaging in the other.

If it is free both ways then either the intermediate starter gear has been left out (unlikely I know!!) or there is an issue with the sprag not engaging with the boss on Gear 3.

If it is engaging in one direction (good name for a band eh?) then check the starter motor is spinning in that direction.

The remedy will be determined by what you find.

Brian