potential new bike, help ID aftermarket parts...

[fox23]

I went to look at a potential new bike tonight, right away a few things jumped out at me. Listed as a '78 SE, 36,000kms.

1. oversized fins on cylinders, big bore kit??
2. progressive rear shocks? any good?
3. new mufflers, any idea on quality/brand?

Let me know what you guys think.

 

[tonyc]

1 oversize fins could be 650 also
2 Progresive Shocks are a good brand
3 mufflers look like Dunstall Replicas.

Great looking bike. If the price is right.

 

[5twins]

From the looks of the headpipes, it seems to be running very lean. Probably no re-jetting done for the freer flowing mufflers and possible big bore. Progressive is a good shock but those look very short, probably installed more for the "look" than handling.

 

[fox23]

any way to confirm if its a big bore or not without taking it apart? The seller says that he never re-jetted it and also assumes its running lean. Otherwise its a pretty put together decent bike that hasn't been too effed with (for around here anyway).

 

[gggGary]

Running that way is a holed piston coming up, usually on the first "highway run" of 50 miles or so. It's progressive thing, how much aluminum has been eaten away already??? My collection includes more than few with em'.

Other than that looks like a fairly nice special.

 

[fredintoon]

Hi fox,
Is the price right? Is there room in your garage? Why do you even ask us?
If the pipes are stock double wall with aftermarket mufflers, check the motor.
If the pipes are MikesXS single heavy wall, they do go that colour.

 

[fox23]

The price we've negotiated is pretty fair IMO for what these go for in the area. I always have room in the garage. I ask because I'm not expert in these bikes yet and I value the many lifetimes of experience and opinions of everyone on the forum. I will double check the pipes, they didn't look like the factory double walls but I wasn't looking that closely.

 

[5twins]

Upon further scrutiny, I think that's got the XS1 replica exhaust system from Mike's on it. That's a big ticket item, like $500. It appears to have the special mounting bracket added to the rear passenger peg mount, but the muffler's not attached to it, it looks to be hanging loose. The mufflers also have the "toothed" connector at the headpipe. Here's some mounting instructions for the system that shows all that stuff .....

http://www.mikesxs.net/pdf/manuals/07-0749.pdf

Here's the system .....

http://www.mikesxs.net/product/07-0749.html

I can't believe someone spent all that money (new cylinder too) and then let the bike go to shit like it has, lol. You'd best "rescue" it.

 

[fox23]

You are correct 5twins. Just asked the guy and he replaced the full exhaust last spring with the system from Mikes.

 

[650Skull]

Those aren't the factory Special headers. If they were double walled with that color then i would say the pistons would need to be VERY carefully looked at, Single-walled headers would color very fast, but again it looks like it has been ridden a bit so again i concur with ggGary.

Other than that the bike looks good and these metal side-covered, side-hinged seat 78/79 Specials are a good looking bike. Not to many tanks have the plastic strip left on them these days

 

[fox23]

Well, didn't end up getting the bike. Had some very scary VIN/registration issues that I don't want to be a part of.

 

[fredintoon]

You are correct 5twins. Just asked the guy and he replaced the full exhaust last spring with the system from Mikes.

Hi fox,
my son bought those MikesXS pipes & mufflers mebbe 3 years ago.
The pipes are really heavy gauge single wall and they don't oxidise in the classic blue through straw colour pattern like an old Britbike; they go several shades of brown instead.

 

[XSLeo]

Mike's sells both a big bore and a stock bore with big fins.
One way to get a rough idea of the cc's is with a compression test.
I rebuilt my 75 engine as a 2nd over 650. It had 165 psi compression just after I got it together, full of assembly lube, no carbs, on the engine stand, cranking wit e-start.
I rebuilt it with Mike's 750 big fin kit, same circumstances and got 195 psi.
The stock compression ratio of 8.4-1 or so gives you the 165 psi, Mikes kit is 9.5-1 and gives the 195.
So a compression test if you get around 150-160, good chance the engine is a 650, Get 180 or better and it's probably the 750.
Leo

 

[fox23]

Cool piece of advice Leo, I will keep that in mind for the future.