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October 02, 2014, 12:35:25 AM

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Author Topic: Twin Top End Questions  (Read 476 times)

Bullet Whisperer

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Re: Twin Top End Questions
« Reply #45 on: September 23, 2014, 06:51:29 PM »
Yeah, I'm guessing only 7.5-8:1 compression.  That's why I want to get those base gaskets out of there.
According to the specs, they are probably only 7.25:1.
If you want to liven things up a bit, some Meteor Minor Sports pistons might do the trick - I have used a good number of these in my 'Asbo' 350 Bullets. I don't know if Hitchcocks have any, but Burton Bike Bits, also in the U.K. still had some standard size ones recently  ;)
 B.W.

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Re: Twin Top End Questions
« Reply #46 on: September 24, 2014, 11:50:53 AM »
I got the top end together last night, and there are some goods and bads.  Bad news is that the torque wrench that I bought from Harbor Freight is a POS.  I had it set at 20 ft# and it seemed like I was really cranking on the bolts and the wrench wasn't clicking so I dropped it to 15 ft#.  Go back around the bolts again thinking the whole time "this has got to start clicking any second" when I stripped a head bolt.    >:(   I'm nut sure if the threads on the nut stripped or if the stud pulled out of the case, but something stripped.  Even at only 15 ft#, I only got the wrench to click on maybe half of the head bolts before my internal torque wrench told me not to tighten any further.  Other bad news, I took a peek under the piston and the conrods are stamped with the factory "W41720" stamp.  Which means I need to be very careful of how hard I rev the bike.

Good news is that the pistons only had light scuffing on the skirts and no actual scoring, bore still looks good too, looks like the rings seated nicely.  Also, the alignment dowels were not all the way into the cylinder, so I used a deep socket that fit just over the edge of the dowel and whacked them down further and saw all 4 of them move about a 1/4".  Also removed the base gaskets and fought like hell trying to get the cylinders back on without any extra hands to help, but I got it.  All said and done, once I had the heads torqued, when I went to adjust the valve lash again, I had to back off the rocker adjusters almost 3 full turns.  Then I put about a half ounce of oil in the cylinders and kick her over a bunch of times with the spark plugs out and checked for valve/piston interference, and there isn't any.  Wiped up all the oil that made a mess, put the plugs in and kicked her again, and there is a noticeable amount of compression increase.  I'll put the tank on and fire it up tonight.  Now I guess it's just a waiting game to see how long before the head gasket blows on the left cylinder.     :-\
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High On Octane

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Re: Twin Top End Questions
« Reply #47 on: September 25, 2014, 03:06:34 AM »



Well, the bike is running.  But after 3.5 hours on Sunday, 5 hours on Monday, 4 hours on Tuesday and another 2.5 hours tonight, not to mention 10 hour shifts at work yesterday and today, I am freaking whooped.

I remembered at work today that I had ordered 1 single head nut a while back and never used it because it was a 5/16" nut and I have 3/8" studs.  So I borrowed a tap from a co-worker and drilled out the new nut and retapped it, luckily it worked out good and I was able to torque the head properly.  Threw the tank on and fired up on the 3rd kick.  Let it idle for a while to get the oil flowing then went around the block to get the engine hot.  Once it warmed up it started to ping really bad.  I thought it was the valve at first as it is making a bit of noise too, but then it got kind of loud, so I very carefully and gingerly limped it back home a block.  Pulled the tank and did my hot torque on the head bolts and installed the head stays.  Put the tank back on and pulled the timing back quite a bit and went back out.  The exhaust valve is making a bit of a chirping noise, but I've been hearing that for a few months now.  At least now I know what the noise actually is.  Not sure if the rings need to reseat, if it's the valve is causing an oil leak, or just the oil burning off that I dumped in the cylinders, but I was getting a little bit of smoke out of the exhaust.

Clutch is still slipping when cold, but after she warmed up the bike was pulling pretty hard.  I think I need to put a little bit more timing back into the bike, it was running good, but felt sluggish at the top.  I'll figure that out tomorrow when I have my patience back and more day light, been getting dark at around 7:45p.  Either way, I think I have the bike ready for the DGR ride.  Which ultimately was the only goal for this particular repair.  So despite some head aches, set backs, and a handful of profanity, I was successful with what I wanted to accomplish.
Bulldog Kustoms - Denver, CO
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The Blackhawk
1958 Enfield/Indian 711cc Twin

Building The 1st Ever Ace Performance
Enfield Twin Full Race Heads

DanB

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Re: Twin Top End Questions
« Reply #48 on: September 25, 2014, 03:21:16 AM »
Congrats and nice work Scottie!  Enjoy the DGR now.
Suppose I were an idiot, and suppose I were a member of Congress; but I repeat myself. ... Mark Twain
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High On Octane

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Re: Twin Top End Questions
« Reply #49 on: September 25, 2014, 03:57:28 AM »
Thanks Dan!  I also noticed when I was getting on it, the exhaust seems louder and snappier now with the higher compression.  I'll bring home the compression tester tomorrow and check it out.
Bulldog Kustoms - Denver, CO
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The Blackhawk
1958 Enfield/Indian 711cc Twin

Building The 1st Ever Ace Performance
Enfield Twin Full Race Heads

High On Octane

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Re: Twin Top End Questions
« Reply #50 on: September 27, 2014, 02:07:15 AM »
I finally got a chance to take a good video.  You can hear the chirping out of the right exhaust valve and also hear the difference in the exhaust pipes.  Seems to be running pretty good tho.  Like I mentioned earlier, I had noticed that chirping noise about 6 or 7 months ago and knew it was coming from the head somewhere but I couldn't figure it out.  The timing isn't completely dialed in but it's not pinging and I don't plan on riding too terribly hard until I get that valve replaced.


https://www.youtube.com/watch?v=fxcktM23lro&list=UUOuxT3uDOINbn5OmZ0BwRVA
Bulldog Kustoms - Denver, CO
Specializing In Kustom Paint

The Blackhawk
1958 Enfield/Indian 711cc Twin

Building The 1st Ever Ace Performance
Enfield Twin Full Race Heads

ace.cafe

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Re: Twin Top End Questions
« Reply #51 on: September 27, 2014, 12:40:08 PM »
Sounds stronger in the thumps. Probably the higher compression that you did.
But the chirping and difference in sound of the cylinders is not good.
It's not fixed, but it might limp okay for a while.
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High On Octane

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Re: Twin Top End Questions
« Reply #52 on: September 27, 2014, 12:48:03 PM »
Sounds stronger in the thumps. Probably the higher compression that you did.
But the chirping and difference in sound of the cylinders is not good.
It's not fixed, but it might limp okay for a while.

I agree Tom.  The left exhaust pipe sounds much more aggressive than before.  I assume that "chirping" noise is the flame burning past the valve seat?  It does not do it when just idling after it warms up a little bit and does not do it when cruising at speed, only under load.  I do want to replace that valve ASAP, but being that I've heard that noise for a while now and there wasn't any noticeable damage to the head I think I'll be fine for a few more rides.  Yes?
Bulldog Kustoms - Denver, CO
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The Blackhawk
1958 Enfield/Indian 711cc Twin

Building The 1st Ever Ace Performance
Enfield Twin Full Race Heads

ace.cafe

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Re: Twin Top End Questions
« Reply #53 on: September 27, 2014, 01:24:57 PM »
I agree Tom.  The left exhaust pipe sounds much more aggressive than before.  I assume that "chirping" noise is the flame burning past the valve seat?  It does not do it when just idling after it warms up a little bit and does not do it when cruising at speed, only under load.  I do want to replace that valve ASAP, but being that I've heard that noise for a while now and there wasn't any noticeable damage to the head I think I'll be fine for a few more rides.  Yes?
Probably okay for a while.
Can't say exactly how long.
It is leaking past the valve, and that does do some amount of burn every time it happens. How much damage is done each time is usually related to how much leak it has. The bigger the leak, the more the flame cutting each time. Small leak might last a while.
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ERC

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Re: Twin Top End Questions
« Reply #54 on: September 27, 2014, 09:22:49 PM »
I think before you assume what it is, do a compression and leak down test on each cylinder. Could be the"chirp" isn't what you think it is.  ERC
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Re: Twin Top End Questions
« Reply #55 on: September 27, 2014, 10:04:00 PM »
I know it's the exhaust valve.  The noise only comes from the right exhaust valve cover, plus I did another water test before I put it back together and that valve is still leaking.  It's not as bad as it was but definitely still leaking.
Bulldog Kustoms - Denver, CO
Specializing In Kustom Paint

The Blackhawk
1958 Enfield/Indian 711cc Twin

Building The 1st Ever Ace Performance
Enfield Twin Full Race Heads