ADVrider

Go Back   ADVrider > Bikes > Old's Cool > Airheads
User Name
Password
Register Inmates Photos Site Rules Search Today's Posts Mark Forums Read

Reply
 
Thread Tools Search this Thread Display Modes
Old 08-08-2011, 04:01 PM   #496
SOLO LOBO
airhead or nothing
 
SOLO LOBO's Avatar
 
Joined: Mar 2004
Location: Shoreline, WA
Oddometer: 8,573
Quote:
Originally Posted by Airhead Wrangler View Post
I have a couple of buddies who are beemer wrenches. Hopefully I can borrow one
I have a nice one you can use.... that actually fits. Those NAPA, and other aftermarket ones sometimes don't fit quite right and tear up the bolts.
__________________
"punkrocks what it's all about" - J. Strummer



Quote:
Originally Posted by Stagehand
your bike is suitably dirty. Well done.
SOLO LOBO is offline   Reply With Quote
Old 08-08-2011, 04:22 PM   #497
Airhead Wrangler OP
Adios Mexico
 
Airhead Wrangler's Avatar
 
Joined: Mar 2008
Location: Back in Seattle, FINALLY
Oddometer: 6,348
Quote:
Originally Posted by SOLO LOBO View Post
I have a nice one you can use.... that actually fits. Those NAPA, and other aftermarket ones sometimes don't fit quite right and tear up the bolts.
Thank you sir. I'll be back up in Seattle for a week in september during which I plan to attack this engine block HARD. I could even give you back that GS muffler of yours that I've had for god only knows how long now.
__________________
R80ST Gets The HPN Treatment
Seattle to TDF on an airhead

Current rides: HPN #834, '93 R100GSPD "red rocket", '73 R75/5 Toaster mongrel, '80 Ducati Pantah 500SL, '92 DR350, '67 Honda SS50, '80 Honda Chaly.
Airhead Wrangler is offline   Reply With Quote
Old 08-08-2011, 04:38 PM   #498
SOLO LOBO
airhead or nothing
 
SOLO LOBO's Avatar
 
Joined: Mar 2004
Location: Shoreline, WA
Oddometer: 8,573
Quote:
Originally Posted by Airhead Wrangler View Post
Thank you sir. I'll be back up in Seattle for a week in september during which I plan to attack this engine block HARD. I could even give you back that GS muffler of yours that I've had for god only knows how long now.
LOL, happy to help...
__________________
"punkrocks what it's all about" - J. Strummer



Quote:
Originally Posted by Stagehand
your bike is suitably dirty. Well done.
SOLO LOBO is offline   Reply With Quote
Old 09-15-2011, 10:06 AM   #499
Airhead Wrangler OP
Adios Mexico
 
Airhead Wrangler's Avatar
 
Joined: Mar 2008
Location: Back in Seattle, FINALLY
Oddometer: 6,348
I got a week off and headed back to Seattle. Here's what I've been up to:

I bought a '83 R80RT short block off of ebay.

Before:





Midway. Evidence of serious grinder violence:



After more grinding and some cleanup with a flap wheel:





Only 1 pound!? Oh well. The increased amount of exposed crankcase will help things stay cooler as well. The timing cover has already lost 1.5 pounds and has a little more to go. The front cover at 1.8 pounds will be ditched altogether. Slow progress. Unfortunately now it's time to head back to Mexico.
__________________
R80ST Gets The HPN Treatment
Seattle to TDF on an airhead

Current rides: HPN #834, '93 R100GSPD "red rocket", '73 R75/5 Toaster mongrel, '80 Ducati Pantah 500SL, '92 DR350, '67 Honda SS50, '80 Honda Chaly.

Airhead Wrangler screwed with this post 09-15-2011 at 10:47 AM
Airhead Wrangler is offline   Reply With Quote
Old 09-15-2011, 10:15 AM   #500
Stagehand
+/- V TDSPP
 
Stagehand's Avatar
 
Joined: Oct 2004
Location: Shawangunks
Oddometer: 25,209
If I recall, the empty case itself is going to be about roughly 18-20 pounds. THe rest is heavy metal
__________________
Unintentional psychokinesis.
Stagehand is offline   Reply With Quote
Old 09-15-2011, 10:15 AM   #501
Airhead Wrangler OP
Adios Mexico
 
Airhead Wrangler's Avatar
 
Joined: Mar 2008
Location: Back in Seattle, FINALLY
Oddometer: 6,348
I got some '83 big valve heads off of ebay and did a little investigative disassembly to see what I actually have here. I pulled the valves out and found the exhaust valves showed basically no wear on them (considering their age). Also, are these valves the OEM ones or are they aftermarket?











Here is the single scribed line around the inside of the seat's circumference indicating these were BMW's first (faulty) attempt at making valve seats for unleaded gas:



Also, in case anybody was wondering, WP 4860 forks weigh 20.5 pounds with oil in them.





EDIT: I just googled the numbers I found on the valve stem and they don't appear to be original. The exhaust valve appears to be a one piece design. Hmmmm. This means the heads got rebuilt, but they didn't replace the bad valve seats. Damn.



Part Number: V94253

69,80 EUR
incl. 19 % Tax, Shipping Info

Contains: 1 item

Shipping time: 2 - 3 days
Average Customer Review
(0 customer reviews)

Criteria
Length: 98.600 mm
Material: Chrome-nickel-magnesium-steel
Supplementary Article/Supplementary Info 2: Chromed valve stem
Valve Head Diameter: 39.900 mm
Valve Seat Angle: 45
Valve stem diameter: 8.000 mm
__________________
R80ST Gets The HPN Treatment
Seattle to TDF on an airhead

Current rides: HPN #834, '93 R100GSPD "red rocket", '73 R75/5 Toaster mongrel, '80 Ducati Pantah 500SL, '92 DR350, '67 Honda SS50, '80 Honda Chaly.

Airhead Wrangler screwed with this post 09-15-2011 at 12:45 PM
Airhead Wrangler is offline   Reply With Quote
Old 10-14-2011, 09:33 AM   #502
Airhead Wrangler OP
Adios Mexico
 
Airhead Wrangler's Avatar
 
Joined: Mar 2008
Location: Back in Seattle, FINALLY
Oddometer: 6,348
More thinking on lightweight exhaust. Maybe one of these coming off a Y-pipe? They're really light.



That'd make for a total head to tail exhaust weight of about 8 pounds rather than about 17. Yes, it'd probably be louder. Maybe a LOT louder.
__________________
R80ST Gets The HPN Treatment
Seattle to TDF on an airhead

Current rides: HPN #834, '93 R100GSPD "red rocket", '73 R75/5 Toaster mongrel, '80 Ducati Pantah 500SL, '92 DR350, '67 Honda SS50, '80 Honda Chaly.
Airhead Wrangler is offline   Reply With Quote
Old 10-14-2011, 09:34 AM   #503
SOLO LOBO
airhead or nothing
 
SOLO LOBO's Avatar
 
Joined: Mar 2004
Location: Shoreline, WA
Oddometer: 8,573
So what's the latest on the HPN frame mods?
__________________
"punkrocks what it's all about" - J. Strummer



Quote:
Originally Posted by Stagehand
your bike is suitably dirty. Well done.
SOLO LOBO is offline   Reply With Quote
Old 10-14-2011, 10:18 AM   #504
Airhead Wrangler OP
Adios Mexico
 
Airhead Wrangler's Avatar
 
Joined: Mar 2008
Location: Back in Seattle, FINALLY
Oddometer: 6,348
Quote:
Originally Posted by SOLO LOBO View Post
So what's the latest on the HPN frame mods?
I was just wondering that the other day, so I called them, but Mr. P wasn't in. Only Mr. H and he doesn't speak english. I'll try giving them another call on Monday. My guess is that they haven't started yet as they probably would've contacted me to talk through what I want done.
__________________
R80ST Gets The HPN Treatment
Seattle to TDF on an airhead

Current rides: HPN #834, '93 R100GSPD "red rocket", '73 R75/5 Toaster mongrel, '80 Ducati Pantah 500SL, '92 DR350, '67 Honda SS50, '80 Honda Chaly.
Airhead Wrangler is offline   Reply With Quote
Old 10-14-2011, 01:16 PM   #505
supershaft
because I can
 
Joined: Sep 2010
Location: San Francisco Bay area
Oddometer: 8,280
Those are not stock valves and it looks like the seat is just starting to get hammered. Close call. But why do you want to run big port heads on a dirt bike? I would stick with small ports! They are plenty for street bikes!
supershaft is offline   Reply With Quote
Old 10-14-2011, 01:30 PM   #506
Airhead Wrangler OP
Adios Mexico
 
Airhead Wrangler's Avatar
 
Joined: Mar 2008
Location: Back in Seattle, FINALLY
Oddometer: 6,348
Quote:
Originally Posted by supershaft View Post
Those are not stock valves and it looks like the seat is just starting to get hammered. Close call. But why do you want to run big port heads on a dirt bike? I would stick with small ports! They are plenty for street bikes!
Well, I'm building a mildly hotted up engine for it as well as keeping my 800 engine on the shelf . It'll have a Siebenrock cylinder kit, possibly a siebenrock assymetrical cam, mikuni VM38s. Let's be clear here - no airhead will ever be a real dirtbike. Though it'll get some tough technical stuff here and there, it's still a fireroad bike at best. I rode a friends GSPD with an early 80s eurospec R100RT engine, 40mm bings and liked it for the mix of riding I do. Any reason I shouldn't?
__________________
R80ST Gets The HPN Treatment
Seattle to TDF on an airhead

Current rides: HPN #834, '93 R100GSPD "red rocket", '73 R75/5 Toaster mongrel, '80 Ducati Pantah 500SL, '92 DR350, '67 Honda SS50, '80 Honda Chaly.
Airhead Wrangler is offline   Reply With Quote
Old 10-14-2011, 02:01 PM   #507
supershaft
because I can
 
Joined: Sep 2010
Location: San Francisco Bay area
Oddometer: 8,280
Cams and hot rodding with 38mm carbs is no reason to jump at big port heads. Late model small port heads work great thusly equipped. I think small port heads with 44mm intakes is the best of two worlds. More flow AND greater velocity for more midrange. I say you shouldn't run big ports because small ports will run better.

I hope the Siebenrock cam has the low end grunt of an advanced 336 and is as easy on the valve train. How much spring pressure do they recommend with that cam?

I don't understand how Seibenrock expects to sell cams without specs?

supershaft screwed with this post 10-14-2011 at 02:11 PM
supershaft is offline   Reply With Quote
Old 10-14-2011, 02:48 PM   #508
Airhead Wrangler OP
Adios Mexico
 
Airhead Wrangler's Avatar
 
Joined: Mar 2008
Location: Back in Seattle, FINALLY
Oddometer: 6,348
Quote:
Originally Posted by supershaft View Post
I don't understand how Seibenrock expects to sell cams without specs?
Without actually emailing them and asking, the most I've been able to find is that it's 320/324 degree duration, stock lift. Nothing about timing really. They say it'll increase torque over the entire rev range, but they don't offer any specifics. Maybe I'll try asking them. I've read a few favorable reviews from some germans who say they like it better than the 336. Nothing specific though. No DATA.

BTW, what makes you say those valve seats are hammered? If you're talking about that ridge, that's just carbon. I couldn't feel any wear with my fingernail on the clean parts.


Quote:
Originally Posted by supershaft View Post
I think small port heads with 44mm intakes is the best of two worlds. More flow AND greater velocity for more midrange. I say you shouldn't run big ports because small ports will run better.
Hmmm. I wasn't aware the small ports were enough to feed a 44mm intake at full tilt. I'm not saying "they aren't" - just that I didn't know. Makes a lot of sense though. Maybe dropping down a carb size would do the same though. The increased turbulence due to the higher velocity through small ports at high revs would be pretty much the same as having a smaller carb. You'd get better mixing at bottom and mid range with slightly less fill at higher revs. Dropping a carb size, maybe to a 36mm, and then having a large and sudden expansion immediately after in the port would create some NICE turbulence if not the continuous velocity through the port that the smaller ports would give you. Hmmmm. I might just have to try it to see. Anyway, I already HAVE big port heads and in my mind that's a good enough reason to try them. We'll see.
__________________
R80ST Gets The HPN Treatment
Seattle to TDF on an airhead

Current rides: HPN #834, '93 R100GSPD "red rocket", '73 R75/5 Toaster mongrel, '80 Ducati Pantah 500SL, '92 DR350, '67 Honda SS50, '80 Honda Chaly.

Airhead Wrangler screwed with this post 10-14-2011 at 03:12 PM
Airhead Wrangler is offline   Reply With Quote
Old 10-14-2011, 03:09 PM   #509
supershaft
because I can
 
Joined: Sep 2010
Location: San Francisco Bay area
Oddometer: 8,280
I was referring to that ridge that is just carbon you say.

What people say? Have have heard so much complete BS on the topic concerning 336's that I have a hard time believing anything on the subject. Some people say the 336 doesn't increase lift and it very clearly does. Cold hard specs is what I would like to compare.
supershaft is offline   Reply With Quote
Old 10-14-2011, 03:45 PM   #510
supershaft
because I can
 
Joined: Sep 2010
Location: San Francisco Bay area
Oddometer: 8,280
Velocity and turbulence? Hopefully the two won't go hand in hand and very often don't. Small ports are very much enough to feed a 44mm at full tilt. Big ports might do it a bit better at full tilt but always remember that you first have to GET to full tilt and that small ports do better than big ports. Are you going to run a close ratio six speed box geared for 100mph top end? That's the only way in hell I would focus on full tilt versus GETTING to full tilt.

I am not sure it all works out like you explained it but I would definitely consider running 36mm carbs with big ports. I like my setup running 38's on my small ports. I was doing it with 42mm intakes but I just switched my own bike over to 44's. I have done it before to customer bikes and so have others that I know and it works real well. Of course, R90S's had small port heads with 38's and 42mm intakes. 44MM intakes with the exact setup except for widening the 90 degree seat face in order to keep the valve seat diameter to seat ID ratio about the same is a great mod! It works across the board.
supershaft is offline   Reply With Quote
Reply

Share

Thread Tools Search this Thread
Search this Thread:

.
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On

Forum Jump


Times are GMT -7.   It's 07:01 AM.


Powered by vBulletin® Version 3.8.5
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Copyright ADVrider 2011-2014