Monster Project (Refresh)

[Yorkie]

The DP pistons look fine, a bit of a clean, polish and maybe a bit of weight removed they will be just right.



Yorkie

[Yorkie]

Both sets of pistons have arrived, so hopefully the engine will be together by the end of the Month!!

Yorkie

[Mr Gazza]

Originally Posted by Yorkie

The DP pistons look fine, a bit of a clean, polish and maybe a bit of weight removed they will be just right.

Yorkie

What's your thinking behind the weight removal? If you don't mind me asking.

Back in the day when I used to rebuild parallel twins of various sorts, I used to sometimes have the crankshaft dynamically balanced to the piston and conrod assys.
Especially if the pistons were a lot different weight to those originally fitted.

I imagine the dynamic balance on an L twin is probably less of an issue than on a parallel twin, but still an issue....My thinking is that lightening the pistons for lightening's sake might not necessarily be a good thing?

Not being familliar with Ducati pistons, I was also wondering if the valve cut-outs are a standard feature, or if the ones in the DP pistons would serve to avoid piston to valve contact if a belt went?

[Dukedesmo]

Originally Posted by Yorkie

What a result. I looked far and wide to try and get some piston rings and most of the prices were £130 and up.

I looked at pistons on eBay for the 1000DS and ST2 and most too far away or really expensive.

I then got a PM from a member from Ducati Up North would was willing to part with a pair of pistons for free.

One was complete with rings and the other without. What a generous bloke and he would not take any payment at all.

On with the project in the next few weeks.

As a side line I have also been offered a set of Ducati Performance pistons for £110 delivered, even better.

Yorkie

I got replacement rings for my Monster (944cc JE pistons) from Total seal in the USA http://www.totalseal.com/ they have most sizes and types, including 'gapless' rings for extra compression (over 220psi in my M900!).

Even with shipping costs etc. they're still cheaper than Ducati.

[Yorkie]

Originally Posted by Dukedesmo

I got replacement rings for my Monster (944cc JE pistons) from Total seal in the USA http://www.totalseal.com/ they have most sizes and types, including 'gapless' rings for extra compression (over 220psi in my M900!).

Even with shipping costs etc. they're still cheaper than Ducati.

I did look at them but free came up, and being Northern and careful with money, it was a no-brainier.

Yorkie

[Dukedesmo]

Originally Posted by Yorkie

I did look at them but free came up, and being Northern and careful with money, it was a no-brainier.

Yorkie

Free is good (especially for a Yorkshireman)...

[Yorkie]

Originally Posted by Mr Gazza

What's your thinking behind the weight removal? If you don't mind me asking.

Back in the day when I used to rebuild parallel twins of various sorts, I used to sometimes have the crankshaft dynamically balanced to the piston and conrod assys.
Especially if the pistons were a lot different weight to those originally fitted.

I imagine the dynamic balance on an L twin is probably less of an issue than on a parallel twin, but still an issue....My thinking is that lightening the pistons for lightening's sake might not necessarily be a good thing?

Not being familliar with Ducati pistons, I was also wondering if the valve cut-outs are a standard feature, or if the ones in the DP pistons would serve to avoid piston to valve contact if a belt went?

The weight removal is purely to get them the same as the originals as they seem slightly heavier:



There is definitely a little more material, the crank has already been balanced.

Yorkie

[Mr Gazza]

Thanks..I see now.
They certainly look a bit chunkier...Hope you can get them down to wieght without making any weak spots...

[Dukedesmo]

Originally Posted by Yorkie

The weight removal is purely to get them the same as the originals as they seem slightly heavier:



There is definitely a little more material, the crank has already been balanced.

Yorkie

Looks like one is the standard flat-top piston and the other a High compression, which are you planning on using? Are they 92mm or 94mm (900 or 944cc)?

Not sure it's a good idea to machine off the high-comp part to get standard compression, or am I reading this wrong?

[Darren69]

I'm sure Yorkie knows what's what. Rather than chop them to save weight I'd be inclined to get them both as close weight wise to each other as possible, so they are well balanced.

I would also hope that they are the correct type for the oil cooling of the engine as a mate did a similar conversion on his 900 SS and melted both pistions within 200 miles since not enough oil was cooling them.

[Yorkie]

The Hi-Comps are 944 will be lightened from underneath just to get it to the same weight as the standard.

They will then slot straight into the ST2 engine as part of the rebuild.

Yorkie

[Dukedesmo]

OK I understand now, I had initially thought you were machining the high domed pistons flat.

[Yorkie]

Back on the project Saturday, its been nearly a month since I did anything. Some tyres arrived today and they seem to be good quality:



At £134 for the pair they had to be worth a try. 190/55/17 rear and a 120/70/17 front.

I all goes well they will be fitted to the rims on Saturday, and the engine should be fully together.

Yorkie

[Darren69]

Yea, they look good especially for that price. I'm with you on the 120/70 front but the rear is oversized I think, does that cause any handling issues in your experience or are you experimenting?

[Yorkie]

I have been using 190's for a while and have had no issues. I like them because they slow the steering down. It is the first time I have used Maxxis tyres though, but they feel really sticky.

Yorkie