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| General MC Message Board Talk about Bikes, Rides or anything motorcycle related. |
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#1 |
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Senior Member
Join Date: May 2009
Location: Greenville, SC
Posts: 1,094
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I bought a cobra tach and it's not accurate. I have an 1800 and the rev limiter kicks in at 5750 rpm. Mine idles perfect @ 800 and tachs 2000 rpm @50mph in 5th. BUT, hitting it hard from 1st to 2nd, tach shows 4,000rpm. 2nd to 3rd=5,000. 3-4 is 5500. Supposed to be 5750 in every gear.
If anyone has a problem like this, please post it or send me a pm. I bought it from a guy on the board and guess I'll have to eat it! I wouldn't sell it to anybody knowing the way it does. Thanks in advance for your help Last edited by X-GUY4HIM; 11-07-2009 at 09:32 AM. |
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#2 |
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Senior Member
Join Date: Nov 2003
Location: Greensburg, PA
Posts: 1,149
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I bought a new one about 5-6 years ago. It never was correct. I contacted Cobra & they told me that they made it that way because some people complained of needle bounce at idle, so they engineered it to respond slowly. I replied 'who cares about needle bounce' and that I bought a tach to see what RPM my motor was doing at full bore.
I returned it & never bought another tach. I shift by sound.
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Tod Hoffmann 2002 VTX1800-C 1990 Chevy 454SS Accel DFI/6 speed 1966 Pontiac GTO hdtp Tri Power/4 Speed 2004 Jeep Grand Cherokee Limited V8 Visit my Website: http://www.akvalley.net/~ss
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#3 | |
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Senior Member
Join Date: May 2009
Location: Greenville, SC
Posts: 1,094
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#4 |
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Senior Member
Join Date: Nov 2003
Location: Greensburg, PA
Posts: 1,149
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I meant that it responded slowly, similar to your complaint about your shifts at 4000 rpm. It is because the needle does not move as fast as the motor spins up.
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Tod Hoffmann 2002 VTX1800-C 1990 Chevy 454SS Accel DFI/6 speed 1966 Pontiac GTO hdtp Tri Power/4 Speed 2004 Jeep Grand Cherokee Limited V8 Visit my Website: http://www.akvalley.net/~ss
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#5 | |
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Senior Member
Join Date: May 2009
Location: Greenville, SC
Posts: 1,094
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#6 |
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Senior Member
Join Date: Nov 2003
Location: Greensburg, PA
Posts: 1,149
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Sorry, I guess we were posting at the same time and you didn't see my first post.
__________________
Tod Hoffmann 2002 VTX1800-C 1990 Chevy 454SS Accel DFI/6 speed 1966 Pontiac GTO hdtp Tri Power/4 Speed 2004 Jeep Grand Cherokee Limited V8 Visit my Website: http://www.akvalley.net/~ss
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#7 |
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Senior Member
Join Date: Aug 2004
Location: Black Hills & Central MN
Posts: 171
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I had a cobra tach on my '03 1800R, & just after the warranty expired, it started acting up. Needle pegged all the way to the right..I had to take a magnet and bring the needle back..it too had the needle bounce..I'd never buy another cobra tach..& would not consider any of there other products because of that..Good Luck..RT
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#8 | |
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Senior Member
Join Date: May 2009
Location: Greenville, SC
Posts: 1,094
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#9 | |
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Senior Member
Join Date: May 2009
Location: Greenville, SC
Posts: 1,094
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#10 |
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Senior Member
Join Date: May 2009
Location: Greenville, SC
Posts: 1,094
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#11 | |
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Senior Member
Join Date: May 2009
Location: Greenville, SC
Posts: 1,094
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#12 |
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Senior Member
Join Date: Aug 2008
Location: Springdale, Arkansas
Posts: 1,090
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I have a Cobra tach on my 07 1300C and have been well pleased with the operation of the tach. I feel comfortable that it is accurately showing the rpm the motor is turning. It looks good on the bike and was easy to install. Sorry to hear that both of you had Cobra problems.
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2007 VTX 1300CCobra Speedster Short, Floorboards, Tach, Mustang seat, Saddlemen Saddlebags w/ EZ Brackets, NC Paladin backrest and luggage rack, Cobra Hwy Bar, Kury LED turns, All Balls Steer Bearings, Progressive front springs, Kury Triple Tree Cover, 2" Headlight Extender, RTB Controller, and Large Silver Bullet Lights. |
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#13 |
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Senior Member
Join Date: Dec 2008
Location: Merritt Island, Florida
Posts: 349
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I have a Cobra tach on my 2003 1300S. It seems reasonably accurate but I have always noticed that it lags the engine speed by a second or so. If I am going at a constant speed the tach reads 2000 at 45MPH in high gear. But if I accelerate quickly from 35 in 5th gear, when I get to 45, the tach still says 1800. By the time I get to 50, the tach is finally getting to to 2000. If I hold the speed constant for a few seconds, the tach catches up and is accurate.
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![]() -Mike- 2003 VTX 1300S Memphis Fats Windshield, Saddleman Bags Cobra:Tachometer, Sissy Bar, Luggage Rack, Back Rest, Freeway Bars; Lotsa Chrome |
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#14 |
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Junior Member
Join Date: Dec 2008
Posts: 15
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Was thinking of buying one. Thank everyone who posted.
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#15 |
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Senior Member
Join Date: Jan 2007
Location: Porterville, CA
Posts: 189
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I'm certainly no expert on tachs, but I think Honda left it off the bike because they had built in a rev limiter. At 5750 rpm it retards the engine to let you know that the engine could break and cause damage to you as a result.
I had once considered putting a tach on the 1800 and researched the forum for one to buy. When I did a minimal amount of research it seemed that Cobra was not the tach of choice for quick response and needle accuracy.The Cobra tach did look nice on the bike and seemed easy to hook up...looks aren't everything tho.I decided against installing a tach after more thought. It's obvious that you are unhappy with your decision to buy this tach. Did you research it fully before purchase? Did you ask all the right questions? Sometimes you really have to get technical in order to make a good decision. Sorry to hear that you got less than you paid for in your dealings. Stu
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2002 1800C Illusion Blue Supertrapp MeanMothers,Dunlop,K&N Forcewinder,Progressive 412's, Kuryakyn Chrome, Ultimate Lowrider/CorbinYoung Guns,Hondaline shield, Aeromach risers, Autometer oil pressure gauge, Leatherneckjims bags w/Easybrackets
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#16 | |
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Senior Member
Join Date: May 2009
Location: Greenville, SC
Posts: 1,094
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Quote:
I do know the rev limiter supposed to kick in @5750rpm. It's way off especially 1st-3rd
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#17 | |
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Senior Member
Join Date: May 2009
Location: Greenville, SC
Posts: 1,094
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#18 | |
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Senior Member
Join Date: May 2009
Location: Greenville, SC
Posts: 1,094
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Quote:
Yes, I understand the rev limiter and that's the very reason I wanted the tach. If I was racing, I would want to shift just shy of the 5750. That way, I wouldn't have a power loss nor lose any time. That was the purpose for the tach! |
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#19 |
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Senior Member
Join Date: May 2009
Location: Greenville, SC
Posts: 1,094
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#20 |
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Senior Member
Join Date: Mar 2005
Location: N/E Ohio
Posts: 695
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Cobra tachs (and many others) react slow. It's not that they're inaccurate, it's that they lag behind what the engine is doing. If U rev the engine in neutral the rev limiter on the engine will probably cut the engine off befor the tach reads 2000 rpm. If U continue to hold the throttle open, the tach will catch up and show the correct rpm reading. It's because of the electronic "shock absorber" that is built in to stop or reduce needle bounce at idle.
They're just not good tachs to use for racing. |
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#21 | |
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Senior Member
Join Date: May 2009
Location: Greenville, SC
Posts: 1,094
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#22 |
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Senior Member
Join Date: Mar 2008
Location: Santa Cruz, Ca
Posts: 166
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X-GUY, I'll take your slash downs for a good price.
In regaurds to the TACH issue. I have a Drag Specialties and it reads correctly but also bounces due to the ignition firing cycle time. I did install a Tach adaptor sold by ********* which helped the bounce some for about $25.00. Rob
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[ Do not forget "Throttle Therapy"
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#23 |
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Senior Member
Join Date: Dec 2008
Location: sun city az
Posts: 1,736
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I have a VDO tach and is dead on with no needle bounce... at least the few times I hit it hard but tough to watch tach and highway at the same time but like i said the couple times I tried it kept up with throttle response no problem.. And in neutrol rev engine right on the money.. Never cared much for Cobra anything...
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#24 |
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Senior Member
Join Date: Dec 2009
Location: mineral point
Posts: 213
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Thanks everyone you just saved me some money.
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![]() 02 1800 C - V&H Pipes - Corbin Seat and a lot more to come. |
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#25 |
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Senior Member
Join Date: Mar 2008
Location: Santa Cruz, Ca
Posts: 166
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Hey Mike N.. What is the O.D. of your VDO tach? Maybe I'll change from my Drag Specialties to rid the bounce.
__________________
[ Do not forget "Throttle Therapy"
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#26 |
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Senior Member
Join Date: Dec 2008
Location: sun city az
Posts: 1,736
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I got mine from Cyclecraft back a few years.. had a choice of VDO.Drag and a couple others and knowing what krap Drag and Cobra were the only choice was VDO... In the old days of big time drag racing VDO gauges were the only way to go.. Today? I have no idea.. Oh and the tach is 2 1/2 inches round... and does lite up with headlite... I still have mine from my 02 X C Model 1800 and when I get copies made for install I will try and sell cuz my 07 X C Model has a factory tach.. hope this helps...
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#27 |
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Senior Member
Join Date: Mar 2008
Location: Santa Cruz, Ca
Posts: 166
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Thanks for responding Mike N. I included a pic of my Drag Specialties. Is this what your tach looks like? Black face chrome bezel but a VDO. If you could get a part # from the tach itself maybe VDO can send me one. VDO is closed today. If you sell yours let me know.
Rob
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[ Do not forget "Throttle Therapy"
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#28 |
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Senior Member
Join Date: Dec 2008
Location: sun city az
Posts: 1,736
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Exactly only mine is the VDO...
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#29 |
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Senior Member
Join Date: Nov 2003
Location: Greensburg, PA
Posts: 1,149
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Anybody have one of those brackets for sale?
__________________
Tod Hoffmann 2002 VTX1800-C 1990 Chevy 454SS Accel DFI/6 speed 1966 Pontiac GTO hdtp Tri Power/4 Speed 2004 Jeep Grand Cherokee Limited V8 Visit my Website: http://www.akvalley.net/~ss
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