Yamaha TRX850 Enthusiasts Forum

Due to the fact that
No 1 I've done my ticket for 12 months
No 2 The bike has now got about 95000 kilometres on the clock
No 3 I'm getting pissed off with any bike useing more than 2 spark plugs belting me down the straights
I think I will get the head flowed and a general motor up lift so any Aust rider's who have had head work etc , can you recommend a shop

Unless the head / top end actually needs work doing (eg regrinding valve seats) I would be inclined to leave the head alone unless you are talking about throwing in some new cams as well.

The effect of flowing / porting / skimming on a completely stock engine is not going to reap the rewards that you want and if you put it into a shop it is gonna cost you.

Much as it pains me to say it (as I was always a bit of a sceptic) the best value pounds (or dollars) per bhp is in flatslides.

To put it into context, FCR41 made nearly as much difference to the power as the combined effect of a big bore kit, flowed/ported/skimmed head and cams.

As an added bonus, you should be able to put the FCRs on yourself.

ps presume you already have free flowing exhausts?

phuk72 wrote:
Much as it pains me to say it (as I was always a bit of a sceptic) the best value pounds (or dollars) per bhp is in flatslides.

Can I insert my "told ya" line here?

I was waiting for that

I aim to please!

Thanks phuk72 , I priced new 41's today from a shop (Show and Go South Australia ) $ 1600.00 new with bell mouths . just need to confirm cable lengths and TPS with shop and will probably go that way. Max whats the set up for your filter , will it go onto the bell mouth and your breather hose.

If they are TRX specific FCR41 then the TPS just plugs straight in and works fine.

As for filters, you can use either a Ramair sock filter (like Max) or K&N pod filters (like me).

Also, buy yourself a cheap engine breather filter from somewhere like ebay to use on the crank case breather.

Yes, the RamAir filter fits over the bell-mouths. Before I added my oil catch tank, I poked a hole through the filter between the intakes and stuck the breather in there. Helps get rid of a bit of oil stink in the process.

Dunno if anyone had spotted these...

http://cgi.ebay.co.uk/Keihin-FCR41-Verg ... dZViewItem

Here's mine: Ramair foam pod filters on Keihin FRC41's.



Crank breather hose just openended and secured between the filters to suck anything back in through the carbs.

Dave.

Dave

I would seriously recommend putting a filter on the end of the breather. If something goes wrong with the motor, oil will come out of the breather like a hose and straight over the back wheel - at least a breather filter will give you a chance.

Here's my single RamAir pod with the hose poked between.




And with the oil catch I made up for the race.




I now have a filter sock from a 50cc scooter on the breather end just to keep dust out.

There's plenty of room under the tank once the airbox is gone, you can easily make something up. For race regs, mine had to be at least 1 litre.

Max , Trxynut and pluk72 a few question , Looked at your pics of the filter,do you have a part number? I assume you placed it straight over the trumpet ( velocity stacks ). The FCR's I ordered for a trx don't come with TPS so I should do the wiring fix,yes ? Whats the go with the heater tubes ,do I block'm off or bridge'm out to bi-pass the carby . Thank fu-k it's XMASS I'm like a kid wait'n for SANTA for the carbs to arrive , thinking next time at the track them bloody 4 spark plug bastards will be in for a shock

I can't remember the part number off hand, I may have the package out in the garage (I'll try to find it tomorrow)... I sent one to someone on this forum, HansJ maybe? Can't remember...

Yes, it's a stretch over the stacks job, fits great and lasts a long time. They also breath much better than paper filters and are washable.

Yes, you should do the TPS mod or I think your tach will bounce around like a drunk on Saturday night. Someone else here would know better about that as I run the OVER box that has no TPS circuit.

You can just loop the carb heater hoses together with a small piece of metal tubing (I wouldn't recommend plastic, unless it's very strong) and maybe a bit of safety wire. I think phuk72 got a bit of a leak on his that he thought was coming from a head gasket. I have plugged mine off at the source by pinching and welding the nipples (did that for the race, can't be too careful) and I NEVER plan on putting the stock carbs back on.

Don't expect to be blasting 4cyl bikes away down the straights, but you will make their necks shrink when you get behind them in the corners. Lots of sound comes from these bad boyz and people start running wide when the hear you coming! When you get them on and set, you'll think the bike lost 30kgs of weight and wonder why Yamaha ever put those stock lumps of garbage on there in the first place.

Just went out to the garage and luckily it was within reach!

MS-H09 is the part number on my single pod (fits over both stacks).