What did you do today? Cobba's rebuild

[Con Rod]

....
Single compound before the ct2's but a good cheap all rounder I found especially if you purchase 3 pair from the US. .....

ah this makes sense, sorry I assumed Pilot Power 3s.

Yes I found the same with the original Powers, they were great for about 3000km but needed to be changed at 5000.

So far so good for me on the Power 3s I am getting good even wear, no squaring

[rbaron25]

Very impressive mate, talk to you in a bit...
And yes Tarj he can talk that much in person if not more

[cobbadiggabuddyblooo]

May have found the culprit why the back tyre was feeling a little squirmy the other day... I may have sprung a leak from the rear shock... it was only referbished and just over 12mths ago and only 3000km on it...
All nice and clean again so we'll see if there's oil there after the next fang.

[Rod.s]

May have found the culprit why the back tyre was feeling a little squirmy the other day... I may have sprung a leak from the rear shock... it was only referbished and just over 12mths ago and only 3000km on it...
All nice and clean again so we'll see if there's oil there after the next fang.

[cobbadiggabuddyblooo]

Some info to keep for the records on the std TRX pistons

STD TRX850 piston weight

piston weight 315.1 grams
rings weight 18.5 grams total
pin weight 72.1 grams
pin clip weight 0.6 grams x2

[cobbadiggabuddyblooo]

Ok next thing on the list for modification is the rear disc/calliper set up.
A little fishing around I found the DT230 uses a rear disc with the same bolt pattern,hole size and I.D.
The bonus is the disc is 4.5mm so 0.5mm thinner and 0nly 220mm not 245mm like the std TRX disc.
You can see the disc comparison on this photo.


The calliper itself is smaller and the calliper holder uses a 20mm axle and is exactly the same width as the TRX at the axle point.
So two ways around it to either make up a bracket to sling it under the wheel like the std rear calliper, but I'm just going to get a little tongue welded on the rear swing arm and mount it on top and get rid of the brace underneath altogether.



I'm sure I could do a little weight saving on the bracket too and the whole thing will weight as much as the std TRX calliper alone plus the weight saving on the disc will again help no doubt in rotating mass.


With the rear wheel weight at 11.2KG with the 245mm disc , 180/55 Michelin pilot power but no 520 rear sprocket and spider, I'll weigh it again with the DT230 disc in place and I'm sure I'll be down to 11 Kg neat for a complete back wheel.




Tyre weights from different manufacturers can be easily over 1/2 Kg and the same with discs so potentually adding another Kg so just something to be mindful of.

The front Dymag comes in at 7.5KG with the Michelin pilot power and disc bolts and discs weighed in at 2.5kg so 10kg neat
22.1kg complete for the front and rear wheels including discs and sprocket/carrier

So off to Dave Kellett Engineering once again and I'll get him to space up the front dymag at the same time.
I'll keep an eye out for the Honda Accord thermo fan switch to try that in the mean time too to regulate the water temp a little better with the fan kicking in earlier at 92*c./cut off 87*c

[cobbadiggabuddyblooo]

After dusting off the plastic wrap containing the crankcases and started to sort through the boxes of parts to initiate putting the motor together.
I've passed on putting in the YZF 750 SP 6 speed as it would just take too much time and money to get it to a working stage.
First off I had all of the 27 engine case bolts bagged and numbered from the dismantle and after one bolt sheered earlier I went and purchased all new genuine bolts,washers and copper washers to go into the case threads which have all been tapped clean.
Then gathering all the tools to start and placed within reach plus all those secret ingredients to get the job done right.
Torque wrenches and sockets plus assembly grease and loctite.


So the original gearbox is back into the cases and smeared with a liberal amount of the assembly grease and checked the gears selected with no issues.
Next up was to coat the crank bearings and torque the conrods onto the crank and sit it in place into the top half besides the gearbox.




Next job is to coat the face of the cases with the loctite 515 and replacing the seal on the drive shaft that lives behind the front sprocket.
Gently locate the opposing case and begin the tightening sequence on the 27 bolts till all is locked into place.

18mths after dismantling the cases I now have the something that is taking shape.

[Con Rod]

good stuff Cobba. Great to see more progress on this.

No need to go nuts with the moly, a little is all you need. It is really only there so as the engine doesn't start dry. Once you have warmed up the engine the engine oil will take over.

Nice stuff though.

[Rod.s]

good stuff Cobba. Great to see more progress on this.

No need to go nuts with the moly, a little is all you need. It is really only there so as the engine doesn't start dry. Once you have warmed up the engine the engine oil will take over.

Nice stuff though.

You can never have to much protection

[cobbadiggabuddyblooo]

Cheers Paul,
I'm sure it won't take long to get in the rhythm of things again.
A little homework reading the manual each nite with a few notes before each stage certainly helps to familiarise yourself.
Then just take a few minutes to set the workplace up makes life so much easier.
Having the correct tools for the task makes life so much easier too. Thanks Rod

[brockzila]

looks good

this should not take long you have already done most of the hardwork.

will be good to see any learnings that you have along the way.

im just about to order some plasti gauge and measure up my bearings

[brockzila]

Some info to keep for the records on the std TRX pistons

STD TRX850 piston weight

piston weight 315.1 grams
rings weight 18.5 grams
pin weight 72.1 grams
pin clip weight 0.6 grams

could you also measure the comp height. from the top of the pin to the top of the crown.

thanks

[cobbadiggabuddyblooo]

is this what your chasing???
16.5mm on a std TRX 10.5:1 piston

[cobbadiggabuddyblooo]

Next job is to coat the face of the cases with the loctite 515 and replacing the seal on the drive shaft that lives behind the front sprocket.
Gently locate the opposing case and begin the tightening sequence on the 27 bolts till all is locked into place.

18mths after dismantling the cases I now have the something that is taking shape.

Back into things this arvo and first thing I'm thinking is whats wrong with this picture ????

[Con Rod]

When you get to the lower part of the oil tank be meticulous with making sure the gasket surfaces are clean and use loctite on the bolts to fasten to the top of the gear box. The bolts on mine would vibrate loose and I would get oil weeping. Its a bitch to sort after the fact, engine out job