Thundercat engine help

[jasonYZF]

Hi guys,

Firstly I'm new to the site so let me start by being polite and saying "Hello" . I have been meaning to join for ages but sods law the bikes gone wrong and I need help so as good a time as any.

In short, I need a decent 2nd hand Thundercat engine.

I've only had my Yamaha YZF-600R Thundercat for 3 and a bit months and the bloody things gone wrong. I'm pretty new to biking and didn't really know what to look out for as this is my first "biggish bike". Turns out after buying that I was getting an occasional neutral and having difficulty changing from 1st to 2nd on WOR.

Second gear has now started to slip and on research this is a sure sign the transmission is failing and is a very common issue. I'm pretty hands on , But doing the tranny myself is far too much work as you have to remove the engine, split the head and basically disassemble the whole engine to get to it . I'm therefore looking at just swapping the engine as this seems far easy.

Now the problem is where do I get one from?? I'm dubious about using E-bay for something so important. And the only breakers I've approached and researched turned out to be cowboys. I want to buy from someone or somewhere reliable so am turning to like minded people on the forum for help.

If anyone could offer me any help or advice please let me know as it would be a great help.

Wish me luck

Jason

[Blue_SV650S]

Are you sure you need to take the top half off??

The R6 (v-similar motor) you dont ... {click click click} ... here you go ... https://www.r6messagenet.com/forums/r6-how-guides/82595-how-2nd-gear-pop-out-fix.html

It IS a big job, but to be honest 80% of the work is the engine in and out ... that you would have to do even with a transplant motor
____________________
The purpose of life is to fight maturity.

[jasonYZF]

Hi CHR15,

I'm new to biking but I have a bit of savvy thank god. Although it didn't stop me buying a lemon.

I have checked and maintained the drive chain and the sprockets are in good order.

I have also considered the clutch but ruled that out. I get absolute no slip in 1st or 3rd. But I'm now getting pretty much no drive in second if more than a quarter throttle is used. Seems once the gear starts to slip the rate of failure is dramatic.

It's my only commuter and I'm a little stuffed to be honest. I'm skipping 2nd and going straight through to 3rd before applying any throttle, But obviously this is for from ideal and only a matter of time before the whole things Funked.

I'm planning to take a week of work to sort out from the 19th. hopefully it holds out and I have a new engine by then

[jasonYZF]

[Blue_SV650S]

[Kickstart]

Hi

R6 and Thundercat are not really related. Thundercat uses what is basically the mid 1980s FZR400 engine, stretched to 600 for the late 1980s FZR600.

However the normal problem with 2nd gear is that the dogs wear. When you accelerate hard it drops out of gear into a neutral, and unlikely you will get any drive at all after that until you knock it into gear again.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[jasonYZF]

[finpos]

You are stuck between a rock and a hard place. Once the dogs start to fail they get worse rapidly as the case hardening becomes increasingly damaged.

If you do a top-down to strip and rebuild on what I guess is an engine with a decent amount of miles on it, it will cost you a fortune as you find every part is worn to tolerance and needs replaced. If you put it back together with the worn parts, it's unlikely to last very long.

So you need a second hand engine. Except that any engine you buy is likely to have exactly the same basic fault; unless you can find a low mileage engine from somebody reputable, you are taking a huge risk. Even if you get your money back on what turns out to be a dud second hand engine, you've still wasted days of your life changing it out - twice.

Yes, these various scenarios have all happened to me!

f.

[Blue_SV650S]

[jasonYZF]