Build a Bultaco TSS from scratch

[Twin-shocker]

Does the crankcase volume not affect the primary compression ratio then? Not sure whether or not the transfer port velocity might be affected if the ratio was overly high?

[stainlesscycle]

Originally Posted by Twin-shocker

Does the crankcase volume not affect the primary compression ratio then? Not sure whether or not the transfer port velocity might be affected if the ratio was overly high?

not sure if you're referring to it's effect on modern motors or on buls?

on a modern motor with a powervalve, it's not so much an issue. the cranks are stuffed, so the crankcase volume changes become less an issue.. also the gg is shorter stroke...

on the buls, no power valve or reed, i'm sure the primary compression ratio has an effect on the port velocity...

[PSchrauber]

The later Sherpa engine have drilled holes in the piston an "deep vertical grooves" for additional flush, so the crankcase volume is importand.



To determine where to drill, ... was wicked, (old piston left new one right), as the location of the grooves can
vary between the cylinders the holes where made by hand to the specific cylinder. (the shown used piston is the original one with around 1600km, the new one is NOS with first excess). By the way the piston pin is not centered as the ultra short stroke in combination with 85mm bore tends to nod/wobbel to avoid this the pin axis is moved some mm.

[blaine.hale]

I'm loving all of this information guys!
I'm going to check out a guys lot this week to pick up an alpina with a friend. I'm going to ask him about a metralla frame and late pursang motor (he has a few bultacos laying around.)

[blaine.hale]

Someone texted me this pic and is asking $200 for it. Looks like an early model Pursang, I'm thinking MK4? I know that's not the engine I want and I'm not pursuing it, but thought I'd share the whole process.

[PSchrauber]

Originally Posted by blaine.hale

Someone texted me this pic and is asking $200 for it. Looks like an early model Pursang? I know that's not the engine I want and I'm not pursuing it, but thought I'd share the whole process.

...

As there is missing the carb leaving the intake open the bike will have enginewise some corrosion problems.

The bike will be in weight around 90 kg of metal = 10€/kg => 90€ => 110$ would be my offer, if I would live near by. In my opinion too many issues, the thickness of the frametubes will be lowered by corrosion too and certainly there will be micro corrsion between weldings and the tube too, so I would not use this frame for a running bike.

[stainlesscycle]

i'd be all over that - wheels and front end is worth over 200... but as a project....it's some work. and it's not a big port motor.

[blaine.hale]

Originally Posted by stainlesscycle

i'd be all over that - wheels and front end is worth over 200... but as a project....it's some work. and it's not a big port motor.

Maybe it would be good trading material to work towards what I need..

[spo123]

seattle craigslist > tacoma > for sale / wanted > motorcycles/scooters - by owner please flag with care: [?]

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Avoid scams and fraud by dealing locally! Beware any deal involving Western Union, Moneygram, wire transfer, cashier check, money order, shipping, escrow, or any promise of transaction protection/certification/guarantee. More info
Bultaco dirt bike and extra frame - $500 (South Hill Puyallup)

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Date: 2012-03-09, 7:39PM PST
Reply to: v4gpn-2894147133@sale.craigslist.org ^{[Errors when replying to ads?]}

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Bultaco dirt bike. Needs to be restored. Bultaco road bike frame without engine. Asking $500 obo

• Location: South Hill Puyallup
• it's NOT ok to contact this poster with services or other commercial interests

PostingID: 2894147133

[996DL]

Originally Posted by spo123

PostingID: 2894147133

Poor seller probably isn't even out of bed yet, before his phone starts to ring off the hook !



996DL

[PSchrauber]

From the ad's spo123 posted, this looks to be a good basis 800 € or 1,000 $ is OK if the bike is still running:

http://seattle.craigslist.org/oly/mcy/2889537549.html

1977 bultaco 250 pursang - $1000 (rainier)

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Date: 2012-03-07, 9:47AM PST
Reply to: see below ^{[Errors when replying to ads?]}

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its a runner needs to go to a new home so it will get rode call for any questions name is mike 253-310-2340 looking for kx 400 or any kx parts

• Location: rainier
• it's NOT ok to contact this poster with services or other commercial interests

PostingID: 2889537549

[darmst6829]

Originally Posted by 996DL

Poor seller probably isn't even out of bed yet, before his phone starts to ring off the hook !



996DL

The Metralla is the perfect bike for building the TSS replica. Any 5 speed bultaco motor should slide right in. The blue bike is a 4 speed Mercurio with a Sherpa S pipe installed.

[blaine.hale]

Originally Posted by spo123

seattle craigslist > tacoma > for sale / wanted > motorcycles/scooters - by owner please flag with care: [?]

miscategorized
prohibited
spam/overpost
best of craigslist


Avoid scams and fraud by dealing locally! Beware any deal involving Western Union, Moneygram, wire transfer, cashier check, money order, shipping, escrow, or any promise of transaction protection/certification/guarantee. More info
Bultaco dirt bike and extra frame - $500 (South Hill Puyallup)

---

Date: 2012-03-09, 7:39PM PST
Reply to: v4gpn-2894147133@sale.craigslist.org ^{[Errors when replying to ads?]}

---

Bultaco dirt bike. Needs to be restored. Bultaco road bike frame without engine. Asking $500 obo

• Location: South Hill Puyallup
• it's NOT ok to contact this poster with services or other commercial interests

PostingID: 2894147133

Talk about the best case scenario ever for my project...damn you, west coast!

[jcf]

Just in case someone scored that frame;

[/IMG ]

[jcf]