hot cam - flat battery!


23 replies to this topic
  • edddie

Posted February 01, 2008 - 06:18 AM

#1

I've had my '93 650l for some time, I'm based in the UK and with a friend a while back decided to go all out and upgrade this bike and supermoto it. I'd seen another one which gave me the idea.

The forks and yokes have been changed to Kayaba upside downs with supermoto springs, I put in a white bros. high comp piston and a hot cam, I'm looking also to do the carb, any suggestions on that would be helpful.

The main problem is , the battery does not seem able to power the start up required with out the decompression system available on the hot cam, so it effectively runs flat. It will start with a booster, but this is impractical. IS this normal...surely it can't be.

I'm looking at either stripping out the cam and getting one that can work with the original decompression gear or some insight hopefully from you guys here at thumper talk. So how should this work??

Also I'm UK based so I'm ordering parts from the US, sometimes its hard to know what to get. Any suggestions on effective carbs to complete the overall upgrades??

The bike needs finishing and I'm going to put it on the bench at a local off road mechanics ....any insight would be great. Thanks

  • jmonay740

Posted February 01, 2008 - 06:20 AM

#2

Why don't you install a manual handle bar mounted decompression lever?

  • absynth01

Posted February 01, 2008 - 08:10 AM

#3

I run into that problem also. I bought a Moose gel battery, and thought it would do the trick. It helped, but if the motor doesn't touch off after 10 sec, you're in trouble. I don't rely on the estart 100%. I just usually park somewhere it will be easier to bump start.

  • resurrection

Posted February 01, 2008 - 08:41 AM

#4

Well this is not good as you'll find in a thread I started back a weeek ago
I Emailed Hot Cams on this very subject and they ashured me there would be no problems.
Now I'm worried allover again.
A TT usser named Schuster PM'd me about being some Hot Cams rep.
We should look to him for answers.

About the carb I installed an R model carb with great results ,only 80$ on Ebay.

  • resurrection

Posted February 01, 2008 - 08:45 AM

#5

Why don't you install a manual handle bar mounted decompression lever?

Where do find this manual device ?the only thing I found was the s/plug style and I sure don't plan on cutting up my head for one of that style.

  • absynth01

Posted February 01, 2008 - 08:46 AM

#6

Maybe not with just the Hotcam, but add high comp piston and that starts to be a problem!!! Mine cranks slow and will fire aggressively at each pass of the piston TDC. I'm going to try a higher octane fuel(over 93) and see if that helps.

  • martinfan30

Posted February 01, 2008 - 09:10 AM

#7

I have JUST the hotcam and it cranks fine.

Another reason to pick the 10.5:1 over the 11:1.

  • resurrection

Posted February 01, 2008 - 10:05 AM

#8

Ok cool you guys had me worried as my daughter rides the L model when we're out riding the pigs.I don't care to listen to her belly ache about starting .
This whole thing boils down to Honda not giving us a kick starter I would never slander Honda .But on this one I may mumble a few nasty words.

  • martinfan30

Posted February 01, 2008 - 10:08 AM

#9

It can be added with a right side case, kicker and shaft, a few others. I beleive the mainshft in the trans has to be replaced with parts from a 600r.

  • resurrection

Posted February 01, 2008 - 10:14 AM

#10

It can be added with a right side case, kicker and shaft, a few others. I beleive the mainshft in the trans has to be replaced with parts from a 600r.

Have you noticed all the engine case talk ?

My 2nd gear is showing it's wheelies so these mods are in my plan.maybe next year

After I finish cam install.this years alotment of funds are used up.

I've got to get that done you guys keep scarring me about it.

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • dldavis_66

Posted February 02, 2008 - 03:34 PM

#11

The main problem is , the battery does not seem able to power the start up required with out the decompression system available on the hot cam, so it effectively runs flat. It will start with a booster, but this is impractical. IS this normal...surely it can't be.


Hello from across the big mud hole:crazy:

Oddly enough, with a high-comp piston and a HotCam, that's pretty normal. I can only speculate that your piston compression ratio is 11:1 or more.

I'm looking at either stripping out the cam and getting one that can work with the original decompression gear or some insight hopefully from you guys here at thumper talk. So how should this work??


If I were you, I would get a stock cam with the decompression mechanism. Then find a place like MegaCycle cam that will take your cam, disassemble the decompression mechanism, hardface/weld it up(the cam), regrind it to your desired profile(they give you 5 different profiles to choose from:mild to extreme), then re-install the Decompression Mechanism.

Also I'm UK based so I'm ordering parts from the US, sometimes its hard to know what to get. Any suggestions on effective carbs to complete the overall upgrades??


There are many people here on TT that really love Edelbrock, Mikuni, or the FCR and they downright HATE the stock Keihin. Well, I'm probably gonna get slapped for this, but I personally wouldn't want to pay out $400 for a new carb or whatever the cost would be for a used one of the eddie,Mikuni, or FCR. Contrary to the negative results many others may have had tweaking the stock carb, desmogging,etc... I have experienced litte if any of these negative results. I tweaked my carb: rejetting, new needle and drilled the slide holes out and I couldn't be more happier with the results. I am very impressed with the overall performance increase that I have obtained with tweaking the stock carb, White Bros Pipe, K&N filter, and desmogged...and still with only a 8.3:1 piston and stock cam. I can't wait till I get the 11:1 piston and a MegaCycle cam. I'm gonna be popping wheelies in 5th gear doing 70 down the freeway.

Hope this helps. Best of luck to you.

  • Frank ZX

Posted February 02, 2008 - 03:53 PM

#12

Just curious,did you install a smalled battery on your bike?My XRL had a big battery.With just the Hotcam and stock piston,I never had a problem starting my XRL even in 20 degree weather.It may be worth a look to see if you have a drain on your electrical system or a load test on your battery.Does the engine start right away with a jump box,or does the engine spin over a few seconds before it lights up?Just a idea.

  • absynth01

Posted February 02, 2008 - 05:02 PM

#13

BTW- another weak spot that came up after building the L is the tranny. 2nd gear especially. That is my next fix. I don't like the way 2nd feels, and don't bang 2nd gear too much. Besides after a cam,piston,rod,valves,carb,and exhaust, 3rd gear is the new 2nd!!:busted:

  • Bibleman

Posted February 03, 2008 - 12:20 PM

#14

So is the bottom line that the Hotcam and HC piston is a no-go for starting?:busted:

  • martinfan30

Posted February 03, 2008 - 12:21 PM

#15

I dont think its going to be a major issue. I'm still going to do it.

  • dldavis_66

Posted February 03, 2008 - 02:50 PM

#16

So is the bottom line that the Hotcam and HC piston is a no-go for starting?


I would not say it is thee "bottom line":thinking: . Much of it depends on how good your battery is. There is no doubt in my mind that a HotCam and a Hi-comp piston WILL make your starter work harder, therefore, lowering it's lifespan, and put more of a drain on your battery, lowering it's lifespan as well. Also depends on: how much risk you want to take just wait and see how things work out; how much time you want to involve yourself in fixing it if things don't work out.

:blah: I believe I have found some much better cam alternatives other than HotCams. One being Megacycle cams and, the other,WebCamshafts.

Megacycle is up near San Francisco,CA. You send them your stock cam, they send you a stock cam that has been hardfaced/welded and reground to one of 5 different profiles. Plus they recommend hardfacing/welding your stock rockers and they have recommendations for Valve Spring Kits (some with mod Guides). Above all that, it's just a modified stock cam with the Decompression re-installed on it.:busted:

WebCamshafts is in Riverside, CA, which just happens to be about 15 miles from my house. I'm not 100% sure, but I believe you send them your stock cam, they hardface/weld your cam, grind it to the profile you want(their 2 mildest profiles are better grinds than HotCam's), re-install the Decompression and then send it back to you. :worthy: They recommend hardening your rockers too, but don't have any recommendations for any Valve Spring Upgrade kits. I'll be calling them tomorrow to get the total scoop. I just discovered their website about an hour ago. www.webcamshafts.com

Hope this clears some things up.:ride:

  • Bibleman

Posted February 03, 2008 - 06:16 PM

#17

Good info. A happy medium might be to just go with the higher compression piston, since with the stock decompression device it wouldn't put any extra strain on all the start-up items. Plus from what I've read it seems like the biggest bang for the buck would be the piston rather than the cam anyway.

  • zodran

Posted February 03, 2008 - 07:23 PM

#18

Bored to the max, 102.4 mm, do the 10.25 or 10.5 to 1 piston, megacycle cam, hardened rockers, bigger headers and a mikuni or fcr and you're good to go. On pump gas!:busted:
Did I miss where he said what grind cam he's got or what battery or what shape his starter is in. The cam I have has a little more lift but lots more overlap than stock which lowers your static compression ratio but still retains the auto decompressor too. :worthy:

  • dldavis_66

Posted February 03, 2008 - 07:40 PM

#19

Hmm...well...I wouldn't just stick with the piston upgrade. Doing that, I feel, would be like getting only half the bang for the buck.

Yeah, maybe revamping the whole valve train like I suggested would be too costly and maybe even pointless for some people. I don't think that at all. Having a "bigger" cam(modified stock or AM replacement) is one thing, but to me is not enough. The upgrades for the Valve Springs and the hardened Rockers play a key role in maintaining, increasing even, the longevity of the whole top end. A good set of beefier Valve Guides wouldn't hurt either (I'm still working on that)

The reply I made prior to this one was just to point out the alternatives to using a HotCam and the added benefit of keeping the Decompression mechanism in tact while having the increased performance with a modded stock cam.

  • dldavis_66

Posted February 03, 2008 - 07:42 PM

#20

Bored to the max, 102.4 mm, do the 10.25 or 10.5 to 1 piston, megacycle cam, hardened rockers, bigger headers and a mikuni or fcr and you're good to go. On pump gas!:busted:
Did I miss where he said what grind cam he's got or what battery or what shape his starter is in. The cam I have has a little more lift but lots more overlap than stock which lowers your static compression ratio but still retains the auto decompressor too. :worthy:



He's just got a HotCam...only one grind, no decomp...that kinda sucks. Why I would never get a HotCam.





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