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Discussion Starter · #1 ·
Great site!! I sure wish I had spent more time digging in here would have saved me some time!!
To many purists dismay, I have purchased a 1970 custom chopper. It was sold to me as a "Bonnie"... however, I've been duped!! With a VIN of JD26605 TR6R I have learned it to be a Tiger fitted with twin 32mm Mikuni's with a 750 big bore kit. :mad:
Full yet short story, I was deployed to Iraq, found it on the internet, drove to FL, started it, looked good, sounded good, bought it, put it in the garage then deployed to Afghanistan only two weeks after being back from Iraq.
I now see why he sold it... It idled great!! but I only have awesome top end power (struggling to get there) or mediocre bottom end power. I have learned much about the internals of Miki's in the last two weeks! I've set the idle/air mixture, synched slides, and adjusted needles up and down one notch at a time... Arg!

So, on with my question... Are there internal head/cam differences between Tiger and Bonnie engines? A Tiger normally having a single carb and this one having twin 32 Miki's am I trying to push way too much fuel to it? Any thoughts?:confused:
 

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Welcome to the Group...No difference between Tiger, & Bonneville other than single carb. I'm only guessing, but it could be the gearing???

Cheers, MM
 

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I posted a similiar question elsewhere.
Im finding TR6s are cheaper to buy and probably easier for the first-time restorer due to only having one carb to fiddle with.
I was only going to buy a Bonnie but now have opened my search up to TR6s since it seems to be 95% the same thing (and will be a bit easier to restore and cheaper on the pocket--initially).
 

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Kev, go to http://www.jaxed.com/cgi-bin/mash.cgi?cat=cpmoto

Find Triumphs in the first box, and than click on go, unless you have a certain year you want.....

Posted yesterday=
1971 Triumph - $2000 (Ypsilanti)

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Reply to: [email protected] [Errors when replying to ads?]
Date: 2009-03-15, 4:50PM EDT



1971 Triumph 650cc Tiger. This motorcycle has the original tires, battery kit, has been in storage, and has not been driven for 25 years. It needs brakes and speedometer. Thank you for looking. Call 734-717-4487 / Dave


Good luck with your search!!

Cheers, MM
 

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Kev, go to http://www.jaxed.com/cgi-bin/mash.cgi?cat=cpmoto

Find Triumphs in the first box, and than click on go, unless you have a certain year you want.....

Posted yesterday=
1971 Triumph - $2000 (Ypsilanti)

--------------------------------------------------------------------------------
Reply to: [email protected] [Errors when replying to ads?]
Date: 2009-03-15, 4:50PM EDT



1971 Triumph 650cc Tiger. This motorcycle has the original tires, battery kit, has been in storage, and has not been driven for 25 years. It needs brakes and speedometer. Thank you for looking. Call 734-717-4487 / Dave


Good luck with your search!!

Cheers, MM
Great search engine MM, appreciate it!
I was using CraigsHelper but that one you sent me is much easier!
Cheers, Kevin
 

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It sure is a nice looking chopper. I don't know what you paid for it, but you done good. Other chopping might depreciate the value, but I think yours doesn't, so much, because it's so nice looking.

I would think that the more important value quality for you is whether the numbers match. You can always go back to a single carb.

I don't know how much you paid for that chopper, though. If you paid more than $25,000, you paid too much.
 

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That is one sharp bike! Are you sure they're 32mm? Maybe it needs something a bit smaller... When you crank on the throttle at a low speed, does the engine bog, or does it "pink"? Is the exhaust black? Do the carbs have a choke (that may be stuck "on")?
 

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Discussion Starter · #8 ·
Bonnie vs Tiger

Thanks for the input. I ride with the Patriot Guard Riders. The PGR is dedicated to the US Soldiers and their families. Attending funerals as invited guests to honor fallen soldiers. So with the POW/MIA motif it was the perfect bike for such missions. The engine casing has signatures of Vets from WWII to present. Find the PGR at www.patriotguard.org PGR is not a Motorcycle Club.

Anywho, I know I paid too much at $9500 but I was in Iraq and HAD to have it. My wife hates it so it makes it that much more attractive to me! lol

My symptom now is as follows.. roll on the throttle (clutch in or in neutrel) and it boggs out... let off and it fires flames out the pipes (shorties with no baffles) If you work up the RPMs by lightly feathering it more and more you can get past the bog and crank it.

Drivability is nil... no take off power to get out of my own way from a stop.

What was the original Amal PN on a Tiger? Yes, the Miki's are 32's! Choke is fully operational, no issues there.

Thanks again
 

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If it idles ok and runs clean wide open, it sounds like you're too lean in the midrange. Try raising the needles. You might have to go to bigger needle jets if rasing them doesn't cure the prob. Before you do that though, check for maniflod air leaks. I'm not familiar with Mikuni set up for Triumphs but the slide cutaway might be wrong also. Can you ask the previous owner if it ran right with them before?Any of you Gurus set up Mikunis?
 

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Discussion Starter · #11 ·
Bonnie vs Tiger

I'm torn... finally 80*!! Sure I ride in the cold... no worries there... but Man what an awesome day!!! So... go tear up some roads on the Victory Jackpot.... or tinker on the Trumpet????? Decisions, Decisions :cool: hmmm

OK... undecided as of yet...

However, I will...
-- check the plugs and annotate.
-- better document engine response with each change so that I can determine what makes it better/worse.
-- research local shops to find someone who carries Mikuni Jets and needles.

I have...
-- replaced fuel filters
-- ensured fresh fuel, free from fuel stabilizers (put in while in Afghanistan)
-- purchased several sets of N3C Champion plugs for testing

Anything else?
 

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Discussion Starter · #13 ·
Bonnie vs Tiger

Well... finally able to spend some quality time with the Trumpet.

Jamo... hate to say... numbers do not match. :mad:

I've checked the timing... I'm running a Boyer Mk III ignition. Lined up the timing mark with the pin on the left side of the engine to verify the magnets for the ignition were horizontal. Started the bike with many kicks and allowed it to warm up. Then hooked up the timing gun. The ignition plate is rotated all the way CW, the timing mark is closer to center but only half in the hole. She definately runs better now that it's closer to center. Mikuni carbs are leaned out with the needle clips in position 1. It's ridable now,:) but still not quite right. Ran out of time today but next weekend I'll put the needle clips in position 2 to see if it improves ridability.

Thoughts on the timing?
 

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Discussion Starter · #14 ·
Bonnie vs Tiger

Well Gents, I finally located and downloaded the documentation for timing the Mk III... I now see where I need to loosen and adjust the magnetic bar, centering it in the timing hole with the stator plate centered on it's slots. Hopefully this will fix 95% of the tuning problems.
 

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Discussion Starter · #15 ·
Bonnie vs Tiger

Well... I adjusted the magnetic rotor for the Boyer Mk III. I still was unable to get the timing spot to center in the timing hole. I adjusted by ear... based on throttle response. The Trumpet is now ridable! I rode about 10 miles yesterday with only minor hiccups towards top end.
 

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This is dangerous territory.

Because the bike is "rideable", you are tempted to ride it. If you don't verify that the timing is not too advanced, you risk burning a hole in a piston.

Put a timing light on it, and fine-tune it once and for all time.
 

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Discussion Starter · #17 ·
Bonnie vs Tiger

Duly noted!!!

I'll double check timing and get it as close as I can.

With the Boyer Mk III is it possible to have wires crossed to where the auto-advance won't work?
 

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Discussion Starter · #19 ·
Bonnie vs Tiger

Rgr, Thanks

I verified the wiring to make sure they were not crossed. They were correct. Again, I set the timing with the light and the white dot is left of the hole and I can't get it to center. I got it as close as possible.
 
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