compression relief valve??

smoothcruiser · Feb 26, 2011

WOWWWWW! You've got some really cool ****! I'm sorry I didn't respond sooner-I didn't know that u sent pics until I realized that we're now on page three of my thread. I really dig that custom stretched frame in pic#3. That's sweet! What kind of ft. susp. is that? Also, where can I get h-bars like that? I want to change my flopped cruiser bars to something like that. They will look bad-*** with my new saddle that came yesterday.(Brooks B-190,black). I put 15 mi. of seat time on her today. Now I Know why they cost so much....I don't even get a ride that smooth in my GMC Suburban.Anyway, the Rat's doin fine .I went out ridin' today with Injun A and managed to squeeze 37 mph out of her on the flat but confident she'll do more after Andy gets done tweakin' my carb. Anyway , thanks for takin the time to chat with the newbie and I really appreciate the pics. The hook is now pretty-well set on this mtrzd. bike thing and m looking forward to my next build.
Build on brother and give my regards to that operation in Worcester..... dance1

flybytaco · Feb 27, 2011

smooth, thank you for the kind words. The bars are stock shwinn occ choppa bars and the forks are tripple tree rigid forks from pirate

smoothcruiser · Feb 27, 2011

Thanks,but it was my buddy's brainstorm and talent that made it happen.I was more just a willing participant in an experiment. Fortunately for me, it worked out fine and life is good. Others have suggested to try adding an additional base gasket or head gasket to relieve some compression.I'm not saying that's good or bad. I just did what made the most sense to me. This forum is loaded with fine people that are willing to jump in and offer their help. I've got about 80 miles on this set-up now and so far it still hasn't " loosened-up" enough to make it any easier to start without using the compression relief. Have you noticed any measurable improvement in starting yours over time?
p.s.(you'd better install that chain guard that SBP included in your kit before the sprocket monster grabs ahold of your pant leg and throws you a** over tea-kettle....no joke!!) If you need some inspiration to do this,just take a look at "KC takes a spill" under General discussion topic on this forum. :-||

flybytaco · Mar 2, 2011

so you had bad luck with that rat head huh ? the heads i have are pretty mint

smoothcruiser · Mar 2, 2011

yeah, not so good. it was loaded with pits and pores.Combustion gases burned right through from the new relief valve threads right to the spark plug compression washer. It's junk. I'd be willing to lay a coat of wax on all your china girls and maybe sweep the shop floor for a line on a suitable replacement?

lmao,
smooth :-||

Goat Herder · Mar 2, 2011

That did not last long. Are you sure the crush washers were sitting flush? It should have stood had a chance. I had one china head that the spark plug leaked a bit until I worked the plug tight. After that it was fine but that was one china head outta 10.

flybytaco · Mar 2, 2011

his head was junk goat right from the factory

smoothcruiser · Mar 2, 2011

yeah, the seat was milled with a new carbide bit on a Bridgeport. Even the three copper washers backing up the compression washer on the valve were wet sanded (both sides) with #400 to ensure good seal. When tapping new threads though,I encountered a couple of bad spots (slag pockets) in the casting. The finished threads were a little less than perfect, if you know what I mean. What do you do at this point? I gobbed them up with some 263 Loctite and hoped for the best. It lasted for about a hundred miles or so before it went south.Oh well.
Hey, thanks for the lead on the stage 6 Extra wide sm. end bearing (10mm).I spend an awful lot of time snooping around and i caught one of your posts.I thought that I had already found the perfect replacement bearing.It was a German made one with 11 rollers in the cage. Too bad the cage was made out of PLASTIC! Can you imagine!

smooth

dmb · Mar 2, 2011

maybe a heli-coil? i was thinking about using a 2 stroke compression release like we put in the second plug hole in the 70's worked good on them, might be to big two plug holes 14mm

smoothcruiser · Mar 2, 2011

no go. using a magnifying glass I found a hairline crack that's visible almost to the spark plug hole. Nice thought though.
smooth

flybytaco · Mar 10, 2011

your heads should be there tomorrow or sat they said at post office smooth

Black_Moons · Mar 16, 2011

Considered just changing how you start it?

On my shift kit bike, I just pedal up to speed (10kph?) then put the crank at 30 degrees off vertical, release the clutch and stand on the pedal.
It takes just about a quarter to half second for the compression of the first cycle to bleed off, then once you get one revolution in, getting over that next compression hump is easy because of the momentium.

I also have non stock sprockets on my shift kit to make the gearing to the pedals much higher, IE, more torque required to start it (But pedal assist is better matched for engine RPM)

smoothcruiser · Mar 16, 2011

Black Moons,
That is the exact procedure that I was using before the cylinder head failure. It wasn't until after replacing the head (THANKS TACO) that I discovered the reason for the difficulty with starting. After replacing the head,the Rat motor was still kickin' my butt trying to get it to turn over. That's when I started thinking more about what jaguar had suggested earlier in this thread. LOWER YOUR COMPRESSION.
I borrowed a friends compression gauge and checked it.Holy crap. I was at 195lbs. I guess I'm lucky the head wasn't launched into outer space. I removed the head,doubled up on the head gasket and checked it again.150lbs. Much better. Now I can start it like a gentleman and the motor runs terrific.
Thank-you for your interest in this thread and your reply.

p.s. Ok Jaguar, you can say it now.....I TOLD YOU SO,YOU DOPE laff

Goat Herder · Mar 16, 2011

150 psi is about as high as I would go with these motors any way.

smoothcruiser · Mar 16, 2011

Is 150 a good number to be at? I'm still using the original base gasket because I had to re-torque the original head three times before the thing finally stopped squishing.

smoothcruiser · Mar 16, 2011

Thanks,I guess I should have listened to you a month ago.

flybytaco · Mar 16, 2011

i run around 190psi single head gasket and thin base gasket and run race fuel they run so good i love my bikes

smoothcruiser · Mar 16, 2011

wow.I figured I was way out of the ballpark at 195.I just didn't want to grenade a fairly fresh motor.I'm trying to get a feel for what others are running.I appreciate and value your input. Thanks and keep me updated on that sweet full suspension ride your building. That is so cooool.

flybytaco · Mar 16, 2011

Ya i finally found all the stuff I need for the fastening part of the swinger. all i need now is a disk rear wheel and a tophat and sprkt from kings and a brake kit from pirates and some serious hrs to finish it.. It will def be done for the august rally. I plan on having the coolest bike there lol. wish me luck

smoothcruiser · Mar 16, 2011

Right on brother. There's no doubt it's gonna be an eye-catcher.I think I'm as excited as you to see the finished product.
Hey, is that Aug. rally in Lebanon a private deal by invitation only? I'm just chompin' at the bit to load my bike in the back of the dually and get together with some people and ride. It's been a long,cold winter and I can't wait to ride.

compression relief valve??

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