Yamaha TRX850 Enthusiasts Forum

I've trawled/searched and hunted and can't find any reference to this here...

I've been told I need a new engine (as a more economical option than repairs) and I have found one that I'm interested in/willing to use... but it's the import japanese engine. All I've been able to find about these is that they're speed restricted, and that the carbs are pumper carbs (whatever that means... )

Since the one I've been quoted on doesn't come with carbs or electricals... can anyone tell me if the ones on my current (Australian delivered) engine can just be swapped on without problems? Are there any other issues that might crop up in the process of the changeover... i.e. electricals? speedo? etc?

I've spoken to a few mechanics and there don't seem to be too many that have any idea for that particular changeover, they just assume that it's all the same, or close enough anyway.

And cosmetically speaking... has anyone tried sandblasting the block, or repainting... I really don't like the black, but it seems to be the best option motor I can find.

Any help/experience would be fantastic... thanks guys.

Swap away to your hearts content. The speed restriction comes from the speedo and they all came with the same carbs. If you don't like the black just get some citric paint stripper. Bunnings sells it. You may want to do a engine clear coat once it's cleaned up to prevent corrosion on the bare aluminium though.

what sort of price are they asking for the engine..?

$2000 shipped... seems to be a fairly average price from what I can find... just a case of finding lower km's when it comes down to it.

What repairs are need to your existing one?

Apparently it "sounds like" it's done the big end bearing... it's in for diagnosis at the moment... hoping for a confirmation one way or the other tomorrow.
Since it's a low km motor, I'd like to keep it (if it does have to be replaced) with a mind to rebuild it in a few years time... not too sure on the practicalities of that... especially since I have next to zero mechanical knowledge!

Sell your bike with crook motor for 2000, add the 2000 you planned to spend on a replacement engine, and get yourself a good running bike for $4000

haha... Just bought it with a crook motor for 2 grand... and don't know about up there, but can't get one complete and running down here for under $5500 (and that's assuming that the ONE advertised is any good!)...

a few members around here have picked up a few bargains for around $3000. Gives you a lot more spares for an extra grand to either offload and make $ to recoup costs or keep for a rainy day when you fall off next time

There is one on ebay at the moment for ok money.

The engines are pretty straight forward for rebuilding. Only downside is availability fo aftermarket parts for the engine. You also may as well throw an 878 piston kit in it when you're doing your rebuild. There are acouple of 878 kits going on ebay at the moment as well. If it is just the big end bearings depending on what other damage it has caused you may not have to spend $2000. Fingers crossed for you.

A rebuild would certainly be a long-er term project... but honeslty I'm kinda just itching to get it on the road at the moment. And if I put in a new engine now, I have the option of taking as long as I like on doing a rebuild... which stricly speaking may be necessarry! lol

I've put the one on ebay on my watch list, it'll be interesting to see what it does go for, shipping can be a pain though, but I'd enjoy the ride ... there's a guy nearby selling a rolling frame for $800, so buying that and dropping in the "spare" motor may also be an option... I think I have too many options at the moment!!! and never enough money!

Couldn't find the rebore kit though... but as a long term project, from what I have found about them, I'm certainly interested. But at the moment, it's a case of cheapest option to get it running reliably.

Thanks for the help and suggestions guys.

Oh... and parts... I got a quote for all the parts needed to do a complete bottom end rebuild from BikeBiz... they recon 10 days to ship from Japan, but all the parts are still available brand new... came out to nearly $4000 for all the bits though!
Apparently any Yamaha dealer should be able to get them, but I found the guy I spoke to at BikeBiz (in Parramatta) put in the extra work (and more than made up for the slack left by me) by anticipating all possible parts that may be needed, rather than an endless list of emails exchanged asking part by part that no doubt would have resulted otherwise!

WOW! Did that include a new crank and rods etc.?

Here's the piston kit. I forgot to mention it was UK.

http://www.ebay.com.au/itm/330649526999 ... 1438.l2649

I've found as well that you'll have most luck with http://www.ebay.co.uk and I have had two lots of orders from http://www.kedo.com in Germany in the last 6 months. Valves, clutch springs etc. They have been really good actually.

Another option is to look at the TDM850 parts, alot are interchangeable also a TDM900 engine. It will go in with a couple of easy mods.

FYI, I swapped an engine on my last trx back in 03...$1200 for a lowish km Japanese motor crated to Canberra (the bike imploded south of Goulburn) and I think around $500 for the install...hassle-free swap. That was from Metropolitan Motorcycle wreckers in Silverwater. Whichever path you choose, best of luck

Yeah, that quote included the crank, connecting rods, pistons, all bearings and gaskets... just needed to confirm the size/colour of the bearings...

Thanks for that link... I thought I was searching worldwide, but nothing was coming up! Might have to go on the wish list for the eventual rebuild!!! Will be trying to manage that one myself in the back of the shed... as an extremely looooong term project! lol...

I think Metropolitan Motorcycle wreckers are the guys I'll be going through... but their prices have certainly gone up!!! Seems to be worth it though... he reckons it only got 16000kms on it... so fingers crossed this should see out the life of the bike!