Losh's 1976 Yamaha RD 400

[losh1971]

Yeah Neville has to measure the squish and calculate the compression difference prior to reshaping and fitting the 250 heads. He want's to keep the compression similar to what it is now so as to reduce any likelihood of melting a piston. I currently have paper base gaskets 2 to help with getting the barrel heights right. Ideally it would have a third one but that runs the risk of it sucking in the middle one and it leaning out. I really need to one day get a pair of copper gaskets made and he may tell me I need to in Oct. That would mean the bike may not get dynoed though because it will take a few days to make them in Melb and I'm only in SA for 7-8 days. Heat is really only an issue if you running petrol or Av Gas, methanol runs way cooler, just never used to be allowed in Period 5, mainly I think because the TZ 750s make enough power now without going spastic and running meth.

As for oil I use Rockoil synthetic race oil at 33/1.

 

[losh1971]

Also it doesn't have a bridge and Neville never mentioned getting one. He hasn't gone spastic on the exhaust porting mainly because as you know it becomes harder to ride if you have nothing in the mid but mental power up top. When he built the motor I was given the option of going crazy with porting but then it becomes like a TZ and unless you're constantly sitting on 8k or above you don't have the mid range torque, like my 400 has. Some of the guys that race TZ 350s in Period 4 & 5 have two bikes something like an RD 350 which is fair bit lower power but just not as hard work when your in a race. If they want to win they pull out the TZ, depending who else is on the track and what the other really trick guys are riding.

 

[Deuce]

Loving this 2 stroke education lesson.
Would love a vid or sound clip of it winding out or passing by, or pulling out of a corner.
Keep up the good work mate.

 

[losh1971]

Booked my bike engine in for the first the first week of Oct. I have a set of 250 heads that Neville Lush is going to reshape the dishes to make the RD 400 go even better. I'd love to have it dynode while he is at it but it's gonna come down to finance. Heads alone will be 500 bucks, dyno would be another 250 or thereabouts. If I don't dyno tune it I'd have to wait and take it back to Neville to have it dynode before I bring it over to Tas. I have almost decided to flog the DT 175 air-cooled, which is how I plan to finance the upgrades on the RD. Kind of want to keep it because it is a great little trail bike. But I've ridden it no more than five times in four years for no more than 15mins at a time. I just haven't had time with building the house and also spending plenty of hours working on the ute. At least the house is now finished except for fences, and doors on the linen press & pantry. I want to keep the DT on one hand, because I doubt I will ever get another dirt-bike if I sell it. But then again it just sits in the shed not being used. Just can't decide.... I need the boss to take another two weeks leave before I head to SA for two weeks in Oct, if that happens I won't need to sell anything because I will get two weeks full-time hours.

 

[afstruct]

Once it's gone you'll suddenly get opportunities to use it.
I only used the Suzuki about the same in the last few years . Am loving using it again ( or after these few weeks not!!! , will again hopefully this coming week ).
Slip a flu virus in his coffee, ha ha ha .

 

[vc commodore]

Yeah Neville has to measure the squish and calculate the compression difference prior to reshaping and fitting the 250 heads. He want's to keep the compression similar to what it is now so as to reduce any likelihood of melting a piston. I currently have paper base gaskets 2 to help with getting the barrel heights right. Ideally it would have a third one but that runs the risk of it sucking in the middle one and it leaning out. I really need to one day get a pair of copper gaskets made and he may tell me I need to in Oct. That would mean the bike may not get dynoed though because it will take a few days to make them in Melb and I'm only in SA for 7-8 days. Heat is really only an issue if you running petrol or Av Gas, methanol runs way cooler, just never used to be allowed in Period 5, mainly I think because the TZ 750s make enough power now without going spastic and running meth.

As for oil I use Rockoil synthetic race oil at 33/1.

There is a place in Burton that makes copper gaskets....Can't remember the name of the place, but should be able to find it without too much drama if required

 

[losh1971]

Burton Adelaide? I wonder if Neville my mech knows about them. Copper would be ideal to set the barrell height to where it is perfect.

 

[vc commodore]

Burton Adelaide? I wonder if Neville my mech knows about them. Copper would be ideal to set the barrell height to where it is perfect.

Yep....Waterloo Corner Road past Burton Road intersection, heading towards Port Wakefield Road....Just can't remember the name nor the address of the place....But he is located in a group of sheds down that way

 

[losh1971]

Slip a flu virus in his coffee, ha ha ha .

Well things are pretty tight with all the coin needed to finish the house and then the ute, AKA money pit.... But some fortune this week. I get back from leave today and the boss goes home soon after 9am. This means I get to work until 3.30pm then I go up to my boss' boss to ask about doing a new time sheet and he says my boss is off sick until Thursday. That means an extra 9.5hrs. Answer to prayer that one, means I'm on track to putting some money aside for my RD as well as getting trans cooler fitted to the ute before I leave.

 

[afstruct]

Nice to know that little bit helps.
Well his few days of misery is your good fortune.
Not that I believe I predicted anything (it's that time of year) , I'd say it's time you had a good run with the ute. Unfortunately I don't believe I can predict anything , it I could surly I would have predicted a few reasonable lotto wins by now.