Specialized Rockhopper, The Street Stomper.

So I guess this is my second build? The first didn't last long and at some point I changed frames and here I am. Maybe call it build 1.5? Either way, Here is where I am at.

The motor is all apart because its just a place holder, new one is on the way. So nothing around the motor is bolted down, it's just a mock up as I make the cable runs and figure things out. Once I get the new motor in the next big hurdle will be getting the pipe mounted. Its from an RM60 from 1979, it's pretty close to fitting, but might need some massaging. The carb is a mikuni VM18 hooked up to a reed block. Jaguar CDI, sprocket and adapter from MZmiami, saddle is a Cardiff.

I'll be posting more picture and updates as I go along.

Cheers!

 

[SeanPatrick]

Update! 7/27/2015

Today I got a couple of little things done. I came up with a more solid and permanent mount for the ignition coil. Any ideas on mounting the cdi box? I also got some lights up front. The clamps were too big for my bars and needed some rubber backing. I also used epoxy to hold them onto their base as I was worried vibration might make them fall off.

I got my new fuel line, cloth covered VW stuff. Got the Stihl needle bearing and my crank seal retainer today in the mail. There is a pic of the fule hose but I'm waiting for the new filter and clamps to arrive before I cut it.

My cylinder with the 40MM intake came in today as well, Upon first look it appears to be a much better cylinder than the last two I had looked at. All of the ports seems bigger. I broke my dremel a few weeks back so I've been cleaning the casting marks in the port with small hand files. I got the bottoms of the transfers knifed and I'm thinking of lowering the intake 1-3MM.

There was a little discovery I made over the weekend with regards to my head. I made the mistake of not installing a plug and checking the reach before I used it. I was a little underwhelmed with how the "high comp" head did. Felt like LESS compression than my stock slant head. Now I know why. It's this head by the way, from MZMiami http://www.ebay.com/itm/MOTORIZED-BICYCLE-HIGH-PERFORMANCE-RACING-CNC-6-00CC-HEAD-BOLTS-ARE-INLCLUDE-/281729647911?pt=LH_DefaultDomain_0&hash=item4198654527

This is with the stock and stock equivalent plug. I took the picture with an NGK BR6HS installed.
You can't even see it down in there. This would seem to be where my low comp was coming from, and also might have been part of my four stroking problem.


This picture is with an NGK B6ES This is a longer reach plug and looks about perfect.


Here you can see the cloth covered fuel line, and the petcock I taped into the tank to get rid of that uncontrolled fuel leak they called a petcock.


Lights!


These next two are of my revised motor mount. I plan to set them in place with steel epoxy once I have the new motor in and set perfectly square. I would weld them But I do not want to introduce heat to these tubes as they are double butted. I am hoping this will prevent torque twist. I might also incorporate some kind of torque arm to tie the engine into the top tube.








Here are my new gas tank straps as my original ones liked to twist around no matter how tight I got them. That tube is leather wrapped, the straps are rubber and I've got them tripple nutted with a nylock nut in there along with locktite #242


Knifed transfers.


Stock intake on the new jug. I had to remove part of the fin just above the port for clearance with the reed block.

 

[SeanPatrick]

Porting Update.

It was slow going today as I attacked my jug with needle files and got the ports cleaned up for better flow. I didn't want to go to any extremes with the ports. My goal was to match everything as vest I could and remove debris, casting marks, or anything that would hinder good flow and good atomization. In my last post you saw how I knifed the transfers. There are cast mark at the top of the transfers that I am having a hard time getting to, so I may have to leave them.

Its very hard to get a good camera shot of them, but here's what I got.



Pretty hard to get a hand file in here, not sure of any other way to do it right now though.


I also went ahead and decked it. I glued a piece of 1000 grit to a pane of glass, pained the top of the jug and wet sanded it under its own weight until all the paint was gone.


This is what I've got going on with the exhaust port. Don't worry, its not as big as it looks. I actually didn't raise or lower the port any. I widened it as much as was needed to remove casting marks and on the outside I've started opening it up in an effort to match the header of my pipe. I need to wait for the exhaust spigot to get here before I can do much else. Because of stud spacing I think I will need to make some kind of an adapter that will bolt into the jug and allow the spigot to mount onto that. The spigot and pipe are from a 1979 suzuki RM60.
The intake port is not pictured, but I removed very little material and just matched it to the opening of my reed block.


This is the opening of the pipe. my exhaust outlet needs to be just a bit smaller than this and the pipe slips into a collar and is held on with a spring. Currently pretty close. I think having that adapter I mentioned would help in giving me more room to match the flow.


This is a rubbing of the pipe and the stock port before I opened it up at all.


Still a lot to do in the jug. I need to polish the exhaust, chamfer everything and make sure it is burr free. Then get it cleaned. I think I might sneak it into the dishwasher for that part

My engine finally shipped and should be here Friday. When my motor does arrive I'll need to find a way to make a piston window. Not sure which way is best and I'd like some input from folks who have done it. I also ordered some .0216 thick copper for making a head and base gasket. I'll use some new gaskets I have around for templates and anneal them before use.

 

[SeanPatrick]

Things have been at a stand still. My motor is "out for delivery" so it might show up still today. Same story with my exhaust flange. What did arrive was my copper sheet. I picked up a 5x6 inch piece of 16 gauge (.0216'') and was able to get two head and two base gaskets from it. The sheet was $8 and it took me about 45 min to cut the first one. Would be a lot faster with punches but I'm working with a tin snip and files. It's not perfect, but it will get the job done. Still needs annealing before use.

 

[SeanPatrick]

New motor and a small disaster.

Well the motor showed up around 7pm. I got to work tearing into it found the piston was in backwards. Rod says zae50, so it's a half breed motor. I swapped out the head studs for the sick bike parts ones. And this is where it all goes bad. I got it all put together and started to torque the head down. But I never got close to reaching 15ft/lbs. It just spun and spun, and I stopped and looked, I had pulled the studs out of the case halves. I decided to call it a night after that. My plan of attack is to clean the debris from the holes, chase the threads with a tap, and drive the studs in as far as I can with a coat of JB weld on it. If that does not work, I guess I'll get new case halves. I took some pics while building it up, but now you've have to wait until tomorrow to see the motor done.









Edit/update: I chased the threads and was able to get the studs to grab well. Used a very small amount of JB weld on the ends and threads. We'll see tomorrow how it holds.

 

[SeanPatrick]

Because I am confidant that the studs will hold now, I went ahead and got a couple of other things done.


I ordered a "crank seal lock" and here is the install.Not sure if it actually helps or not but it was cheap.

Opening the mag cover


Before


After




Reassembled with new allen bolts and RTV in place of the gasket as well as around the wire outlet.


Went ahead and installed the reed block, some RTV in there as well




Tomorrow I hope to get the motor in and the mounts set in place, finish the top end rebuild, and get my chain line set. I think I need to move my rear sprocket in 1-3MM. I'll need some M10 washers for that. Kinda sucks I have to undo the wire and locktite but that's what I get for doing that before I had my chain line. Still waiting on my filter, spark plug wire, #41 half link, and some other ods and ends. Still need some foam filter oil for the UNI, I'll grab some Klotz this next week to take care of that. My kill switch and 2 wire connectors should be here next week so I can finish the wiring.

Also, guys, feel free to comment or something.

 

[SeanPatrick]

The motor is finished and in! If you look close you can see that I relocated the CDI and coil to the seat tube and put them under and behind the motor.


With the mikuni the clutch stop needed to be moved, so here is what I did.


And I finally got to open up my #41 chain.


Hoping my exhaust flange/spigot arrives today so I can get moving on the exhaust.

 

[SeanPatrick]

It's alive!

I got everything buttoned up this morning and took her for a spin. Damn did the reed and carb make a difference! Smooth and consistent through the revs. A small lag/bog around 1/4-1/2 throttle once in a while. I'm using the Mikuni VM18 with a #25 pilot and a #80 main with the needle in the middle position. Using a gutted stock pipe for now as I still need to make an adapter for my tuned pipe and probably rejet when that's done. For start up I put the choke on and got to a good pace, let the clutch out and she coughed once and popped right to life. Took the choke of and went for a quick ten minute ride. I'm letting it cool down right now and will check it over and go out again in a few minutes.
Here she sat right after I got back.

 

[Devil's Advocate]

Cool thread, so how is it going now?

 

[SeanPatrick]

During break in one of the studs let go while I was checking torque on the head. So it looks like I need another set of bottom end cases. I was able to get a top speed of 42 MPH though. I bought a 1982 Honda nighthawk three weeks ago and all my funds have been going into that currently. Maybe in a couple of weeks I will be able to get this running again.