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1999 Yamaha TDM 850 engine replacement


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Hello,

Just wondering what options I have for engine replacement or repair for my 99 TDM 850?

As you can see from the photos attached, there is a crack in the engine.. It appears that it's only in the bottom block. I'm finding it hard to source a replacement engine. I'd much rather just bolt out, bolt in if possible, however it isn't looking likely. Is the TRX850 the same engine and interchangeable with the TDM850? If not, what are my options?

 

I bought this bike as a project with the intent to rebuild. I haven't had it started at this stage. After attempting to start it, the starter relay clicks, however the starter doesn't engage or turn over.

However the wiring in the bike is horrendous and will require a new loom, so I'm assuming this may be some of the issue.

 

Thank you, in advance

 

Andrew.

casing on.png

In this photo it shows the crack with the casing off, which goes right through. (in the red circle)

In the yellow circles, it appears that this is the separation point for the top and bottom of the block. Are there any suppliers that make this, or would it be easily accessable?

Is there anything I need to look out for especially for my 99 tdm 850?

 

Thankyou.

casing off 2.jpg

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I don't think the trx motor would fit straight in as it has almost dummy second cylinder which contains the airbox, also think the trx motor might be even harder to find. Your best option is probably a dona tdm, keep a look out for one on eBay you should pick up a project or winter hack really cheap this time of year

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First thing I would like to know is  why did it crack in the first place? Your going to have to fix that then I would look at getting the thing welded rather than replacing the whole engine. Yeah it looks horrible but are you positive it can't be repaired? Unlikely to be a stress crack it looks like something external hit it and that's what broke it in the first place, probably dropped on it's side so if that is the only damage it would be cheaper to repair it than hunt round for an engine that might be a dog as well. Look for an exploded diagram of your motor and see if the part that's broken is removable then decide where you want to go with it!

 

PS DON'T even think about starting it till you have replaced the damaged part, you have no idea what else is stressed out till you get it apart.

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The TRX850 motor does fit  - but they are rarer than 4TX engines.

it a difficult call, that's looks like a split crankcase job. I'd be inclined to try to find you local automotive engineer and ask their opinion - sometimes they have kit and techniques that allows them to perform repairs to cracks and breaks without tearing the engine down.

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I agree, also after being caught out buying both car and bike engines over the years, rebuilding that one is a better option.

There is no guarantee the replacement engine will be any good long term, it could come with hidden problems or god forbid be from a stolen machine. Stripping that one and fixing it will in the end be the best option, even if you end up needing a lower case that would be a better bet from a breakers than another motor.

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Is an option but he doesn't know the history of this motor either it could be goosed if its been run in that condition who knows what damage lies within

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He knows this one is goosed. So tear it down and see how badly then rebuild.

Twice in the past, one a v8rover and a 350 powervalve that were running sweetly etc. Heard both running. Neither lasted more than months because of deep down problems.

Working out the cost of pulling the motor again and then spending top dolla for gauranteed unit in the case of the v8 i would have been better off fixing what i had.

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Thanks for all of the help thusfar!

After a little bit of cleaning and investigating, I found another hole in the engine..

Please find attached photos.

enginecrack2.jpg

IMG_1840.jpg

Is this also the bottom end? or top end? It appears to be the top from what I can see.

Is this also able to be welded?

I've found a top and bottom end located in Germany, however I'm in Australia. Would it be worth the freight, or would welding be sufficient?

These are apparently for the 4TX.

bottomtopendnew.jpg


Thankyou for your help, its greatly appreciated :)

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That's what I would do if your able to find the part, anything can be welded but it does look like it's had a bit of a hammering. Work out the cost of welding against buying and shipping then make your decision. Don't go off half cocked and buy something then find out 3 weeks later that a repair is going to cost a third of the price. No engine is beyond repair it's just the cost that decides whether it's worth it or not. Don't forget with a new part your going to have to buy all new bearings seals and gaskets as well, it all adds up.

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Fingers crossed mate it will get worse before it get's better.

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So I've been informed that apparently a tdm900 engine will bolt straight in.. however I'm very sceptical about this. 

Can anybody please confirm or deny this?

there is a 2001 tdm 900 engine which has been rebuilt which the breakers seems to think it will go straight in..

thankyou!

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What about the electronics? Does he have the loom and all the kit that makes it run?

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1 hour ago, andrew_oc42 said:

So I've been informed that apparently a tdm900 engine will bolt straight in.. however I'm very sceptical about this. 

Can anybody please confirm or deny this?

there is a 2001 tdm 900 engine which has been rebuilt which the breakers seems to think it will go straight in..

thankyou!

the 9'ers are alloy frames,fuel injection, etc etc, i wouldn't bother. Are you sure its a 900? they came out in 2001

for info

http://www.jbx9.16mb.com/index.php?page=HST

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2 hours ago, andrew_oc42 said:

So I've been informed that apparently a tdm900 engine will bolt straight in.. however I'm very sceptical about this. 

Can anybody please confirm or deny this?

there is a 2001 tdm 900 engine which has been rebuilt which the breakers seems to think it will go straight in..

thankyou!

to my best knowledge it is not a straight swap: though the gearboxes are interchangeable.

you need to get over to carpe-tdm, the guys there will have definitive input - you name it jbx et all have done it.

 

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2 hours ago, drewpy said:

the 9'ers are alloy frames,fuel injection, etc etc, i wouldn't bother. Are you sure its a 900? they came out in 2001

for info

http://www.jbx9.16mb.com/index.php?page=HST

Great pickup!! The 900s came out in 02.. however apparently this was a 12-01 model. 

I can't tell from the picture supplied I've asked for the model number on he block. Are you able to tell if it's indeed a 900 or 850?

http://m.ebay.com/itm/B15-YAMAHA-TDM900-2001-BARE-ENGINE-MOTOR-/182058170504?hash=item2a63833888%3Ag%3AGtMAAOSw2ENW6z7d&_trkparms=pageci%3Aa86e4b95-9ab4-11e6-b650-74dbd1803c16%7Cparentrq%3Afbf857f11570a2af778512d2fffade95%7Ciid%3A1

Thank you :)

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looks like its a fuel injection model which the 900's had.

looks like the top will fit and put the gearbox inside the 850

http://www.justanswer.com/motorcycle/3qhvl-will-yamaha-tdm-900-engine-fit-tdm-850-frame.html

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