The man I was talking with came 4th in his class at first attempt.!!!!!
Thats 3 laps practice/qualifing plus 4 laps in race itself over a 37.5 mile circuit =260+ miles at race speeds.
I think he told me timing was 176mph on Sulby Straight and lap time was 97.??mph
How long do you think a race engine lasts before refresh???
This is not a piss about road bike but a built for purpose race machine.
To those that are not informed in these matters ;
A four stoke engine will require major engine refresh at anything near 20hrs running time to remain competitive at virtually any level today.
A two stroke will require a virtual engine replacement at about 8 hrs hard running at competitive level bar crankcases and some transmission components.
Yes, others will disagree with this !!!!
Let them tell you how much it costs when a rod lets go, caused by trying to save on refreshment of an engine. As an example:
At BSB level an engine will be refreshed daily if not per race,time permitting.
You get two sets of c/cases per rider per season=once you've destroyed one set even in a two man team your season is virtually over !!!!
The man in this topic wants a goal to aim at and that goal is horsepower and handling if as he says; he wants to race it .
It does not go hand in hand with reliability or longliverty.
I stated he could build a very competitive machine for about 2.5k Euro;this is not the same as running one .
Who today can afford the £700 required to enter even a club meeting at any circuit in UK and expect to run an entry on the cheap.You defeat the exercise and cost of entry and travel.
Fuel is £20 gallon (club level ) and you cannot just bring your own on most circuits
At BSB level fuel is now over £100 per UK gallon.
If you are prepared to build and race a motorcycle at even club level you MUST be prepared for maintaining it in top form and tuning to a competitive level -otherwise one would be better pottering about on a track day .
An example is :
At the start of last season a particular rider in my local club =NEMCRC, was entered in the first meeting of the season at Croft. After observing his progress in the first 3 laps the C.O.C had him black flagged and he reported to the race office. It was explained to him that both him and his machine were actually a danger to other riders and he would not be allowed to continue and his entry fees were refunded.
He was advised to go and spend time at a "race school" and have his machine attended to.
A local dealer who is very race orientated and also an official at the club took this man under his wing and also did some "work " on his bike,showing him what was neccessary.
That man returned this season and has just not only won the class championship he was entered in but by over 20 points .
The reason;He wanted to be competitive .!!!!

very well said, its an expensive game, but when do you stop !!!!!!! there is a tidy sp on the bay for 2k .

There was a semi s/fightered one up last week=spoke to kid about it=he got it off his mate who had butchered it=he was gutted as to what had been done to it. That made buttons and would have came here for a proper job on it but it was 300+ miles away & Ive got 9 in the garage now.
I take it you ride competitively!
You stop when you are able to and are slightly ahead of the competion .
Racing is like chasing rainbows.
I stopped when I spent two fortunes and could not raise another.

rrsp wrote:tts did the 440 kit, but you need the pistons milled out as the valves will touch the pistons, they are nice bit of kit but they are not a easy fit,not specified for a yamaha, they are just a 440 piston to fit any re bored 400 basically, they do look like yamaha kit pistons that i have in yzf 750. 1mm oversize is the way to go, skimmed head,gas flowed,flatslides, pressured air box,ram air,l&b crank, lightened fly wheel, remove alternator,zxr rad, you will be looking at 80+ hp

That sounds about right

Willandrip I concur with all.
Yes R6 engine cases get expensive.
I was a crew chief for a top SuperSport team here in Germany last year and I concur with prventative maintenance is the key to success for reliability. We would change engine before they failed (2-3 race weekends) . Cost for SS rider to join the team was 60k Euro and 120k Euro for Superbike riders. The rider basically shows up and rides.

Having a 2-stroke background taght me about watching the mileage fo sho!
The 2-strokes we would budget 500 Euros a weekend for parts. If we had extra at the end of the year, it was a bonus.

Back to the 400 build.
It the bike last 1 track day to get it sorted, 2 qualifying sessions, and a 14 laps race and the engine is still in 1 piece. I call that success, pull the engine and check all the parts and replace those that are worn and let the cycle start over again with just races. Take careful measurements and note the high wear items and work on reducing friction and see what items can be coated or replavced with better material.

Of course this is my personal project so I will probably go over the top.
22 years of marriage, no children, life is good!

You have exactly the correct outlook to be able to get an enjoyable and rewarding experience from this project,
A build of your anticapated quality has no place for shortcuts, it is most refreshing for me to be able to converse with one such as yourself who has a similar knowledge of racing 2 strokes and tuning machines for race use .
It is not often I come across men who realise the consequences of not replacing engine consumables .
I would also expect something very similar to your estimated engine lifespan. It will of course depend on how near to the ideal you can get it at the outset of testing.
As you will be aware the most wear of any component will always be in the initial period immediately after fitment.Lubricants and components have improved 10 fold since my competion days but a lot still depends on your engine builder/tuner and the mechanical sympathy abilities of the rider .
This will be a very exiting project; no "fly by wire " here; it will all be "seat of the pants" from the outset.

Gaffa tape and zip ties mate, that's all you need.

You'll be putting nikasil on the bores then

Hi Boris;
Can you expand on this piece please;

You'll be putting nikasil on the bores then

You've got your bore in one hand and nikasil in the other ... you interface them

Thundercat bores are nakasil'd (like 2 stroke bores) it reduces the friction and with a few other "tweaks" it gets an extra 10% power over the Foxeye. They didn't do it on the 400's, expensive though

I thought you needed ally liners to nikasil plate them?