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Message started by David on 12/09/12 at 16:20:15

Title: Starting without decompressor ?
Post by David on 12/09/12 at 16:20:15

I have just finished building a RYCA kit with the mechanical decompressor conversion. When I had the build finished I had the bike up on blocks so started it standing at the right side without using the mechanical decompressor. Bike started almost immediately no problem. I understand the electric solenoid system kicks out as soon as the bike starts cranking. Not wanting to hold the mechanical decompressor for too long adn do not know how to judge this. If the bike starts OK without the decompressor being used will this cause any damage?
Thanks in advance for any advice

Title: Re: Starting without decompressor ?
Post by Serowbot on 12/09/12 at 17:02:10

No problem,...
If yer' battery is weak,.. or if you catch the engine on the compression stroke, it may need the decomp.. it only needs to engage long enough to get over that compression cycle... Blip!...
:)...

Title: Re: Starting without decompressor ?
Post by Boofer on 12/09/12 at 19:27:23

I don't argue with Serowbot, 'cause he has special powers now. However I scroll through Bike Bandit parts prices occassionally and I wouldn't want to put any extra strain on the starter. I don't know if I'm right but I do want to be safe on this one. What ya' think guys?

Title: Re: Starting without decompressor ?
Post by verslagen1 on 12/09/12 at 19:55:50

on early bikes i think the gears are weak, and some have popped a few teeth off.

probably due to kick back but that's a guess.

Title: Re: Starting without decompressor ?
Post by Serowbot on 12/09/12 at 22:30:37

567B7B727166140 wrote:

I don't argue with Serowbot, 'cause he has special powers now.

Yes,.. I was granted super powers...
Turns out, you don't get to pick...
I can now, see through my eyelids,... understand cats (they're really boring),.. and do origami with my toes....
Not,.. what I expected... :-?...

Title: Re: Starting without decompressor ?
Post by Dave on 12/10/12 at 05:22:41

I am guessing that Suzuki would not be installing a decompressor if it was not needed.......somewhere/sometime.

Based on the fact that severel people have been able to start their bikes without the decompressor on a regular basis.....they must not be exploring the conditions that Suzuki designed it for. Maybe if your bike sits outside in really cold weather, the decompressor is needed when the battery is weak, and the oil is thick, and the piston is on the compression stroke when you hit the button.

It may be that if you only ride in warmish weather and keep your battery in good shape - you can get by without having the decompressor.

Title: Re: Starting without decompressor ?
Post by Cavi Mike on 12/10/12 at 05:30:12

Is it really that difficult to push a little lever every time you start the bike? Seems like a pretty simple thing to do when compared to replacing a burned up starter. I'm also not sure what "holding the decompressor for too long" even means.

Title: Re: Starting without decompressor ?
Post by arteacher on 12/10/12 at 07:09:21

Is there any simple reliable way to determine whether or not the piston is on the compression stroke?

Title: Re: Starting without decompressor ?
Post by verslagen1 on 12/10/12 at 07:13:36

With the only reports of burned up starters coming from newbs or new owners... overheating the starter appears to be more of an issue with holding the button too long rather than strain.

The only other concern I would have is with the older bikes (pre 95)
as there were a few issues of broken teeth that I haven't heard for a long time. But I believe these were more likely from kickback than starting.

Title: Re: Starting without decompressor ?
Post by verslagen1 on 12/10/12 at 07:19:53

545F5F565A55544E4F3B0 wrote:

Is there any simple reliable way to determine whether or not the piston is on the compression stroke?

The only easy way that I know of (ie no wrench involved) w/o out pushing the button... is to flip the decomp lever. If you can do it easily, then you're on the exhaust stroke. Put the bike in a high gear and bump it forward till you can operate the lever, then you're good to go for a bump start. Don't push it backward as you'll engage the starter clutch and on early bike is a recipy for a busted starter mount.

Title: Re: Starting without decompressor ?
Post by Gyrobob on 12/10/12 at 07:37:39

7456415E7A5E5C52370 wrote:

Good point.

Also, if holding the decompressor too long means holding the exhaust valve lifter too long, then that won't hurt anything,.. it just means the motor won't start until you let go.

Another point: The "decompressor" lever is a handy way to shut the motor off when you stop without making a "pow" after the ignition is off.

Title: Re: Starting without decompressor ?
Post by David on 12/10/12 at 16:46:45

Thanks to everyone for the tips. The other reason for the question is the RYCA foot operated system is a bit of a PTA. I am going to make a handlebar mounted cable system. Only problem is finding a 1" bar decompressor lever for a reasonable price is a hassle. 7/8" bar levers are easy to find.

Title: Re: Starting without decompressor ?
Post by Serowbot on 12/10/12 at 17:58:59

Search ebay,.. not just for decomp levers...
Search... magneto, choke, thumb throttle, and bicycle shift, levers... ;)...

I'm thinking of canning mine, too... I might try a lever right at the head...
brass if I can find some...

Title: Re: Starting without decompressor ?
Post by Dave on 12/10/12 at 18:27:01

A Hot Start lever might work - if the bolt holes are spaced properly.

Here is one from Motorcycle Superstore:
http://www.motorcycle-superstore.com/2/9/192/45249/ITEM/Pro-Taper-Hotstart-Assembly.aspx

Here is another one that is more expensive:
http://www.motorcycle-superstore.com/2/10/210/15584/DPITEM/Dirt-Bike-Motocross-Lever-Perch-Sets-Dr--D-Hot-Start-Kit.aspx

Ebay also has some from motocross bikes like the Honda CRF bikes that bolts on top of the clutch lever pivot by using a longer bolt and a spacer - we would just have to figure out a way to mount the cable sheath - you could cut the one of the Honda perch and have it welded onto your perch.
http://www.ebay.com/itm/2006-HONDA-CRF250R-CRF250-CRF-250-CLUTCH-PERCH-LEVER-W-HOT-START-LEVER-/350588914957?pt=Motorcycles_Parts_Accessories&hash=item51a0ba4d0d&vxp=mtr

UPDATE: Last night I measured a CRF 250 Honda front brake lever perch and the bolt spacing was 32mm. Our LS650 brake lever bolt spacing is 35mm. To make the Hot Start levers work, we would have to file each hole out 1mm wider, and then open up the the bracket to fit the 1" diam. bars, as they are built for 7/8" bars. It is doable.....

Title: Re: Starting without decompressor ?
Post by David on 12/11/12 at 15:03:17

Found a reproduction english decompressor on Aust ebay
http://www.ebay.com.au/itm/200541429803?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649
Is 7/8" but supplier says could be made OK for 1" ( no guarantee) Only $23.00 so taking the punt. Will need to grind the saddle on the main body and probably make a new clamp saddle - use a scrap of aluminium and polish or cut up a spare brake / clutch lever. I have some spare cables hanging around but will need to shorten one - will buy a solderless ( screw type ) nipple for the cut end or go to a local rigging shop and have an eye pressed for the head lever connection. Will post pictures if it works out OK

Title: Re: Starting without decompressor ?
Post by Dave on 12/11/12 at 15:20:46

Dave....and David.....and DavidOfMa?

This could get confusing!

"From now On.....I want you all to call me Loretta!"
http://www.youtube.com/watch?v=Dgp9MPLEAqA

Title: Re: Starting without decompressor ?
Post by Serowbot on 12/11/12 at 15:35:31

Loretta..
Here's a classic for 1" bars...
http://www.ebay.com/itm/TRIUMPH-BSA-NORTON-BRITISH-BIKE-1-INCH-LEFT-HAND-AIR-MAGNETO-LEVER-/170794109446?pt=UK_Motorcycle_Parts&hash=item27c41f4a06
http://i.ebayimg.com/t/TRIUMPH-BSA-NORTON-BRITISH-BIKE-1-INCH-LEFT-HAND-AIR-MAGNETO-LEVER-/00/s/NzY4WDEwMjQ=/$(KGrHqR,!rQE88hJMt8iBPe(6duDI!~~60_58.JPG

...or How 'bout a nice brass one?...it's 7/8" though..
http://www.ebay.com.au/itm/NEW-ROYAL-ENFIELD-BRASS-DECOMPRESSOR-LEVER-/221157868360?pt=AU_Motorcycle_Parts_Accessories&hash=item337e094348 :-?...
http://i832.photobucket.com/albums/zz242/ustat13/ROYAL%20ENFIELD%20PARTS/PARVINDER16/SAM_5635.jpg?t=1321610440

Title: Re: Starting without decompressor ?
Post by David on 12/13/12 at 15:31:01

http://pbr1352.photobucket.com/albums/q649/RYCAFAN/FinishedRear_zps506e3fa3.jpg
http://i1352.photobucket.com/albums/q649/RYCAFAN/th_Decompressor_zps02b34531.jpg
Modification of lever went OK just had to grind out the main body a little - the saddle fitted 1" no problem. Think I will use a spare clutch cable as it has the adjustment needed to set this up properly. Shortening the cable will not be a problem I've done this a few times. Picture of my RYCA - just finsihed !

Title: Re: Starting without decompressor ?
Post by Serowbot on 12/13/12 at 21:56:25

Congrats on finishing the Ryca mods...
I'd really like to see a better view of the decomp lever installed...
(I'm probably just gonna' do head mounted lever, but I'd like to see the bar mount)...
:)...

Title: Re: Starting without decompressor ?
Post by Dave on 12/14/12 at 06:12:10

I have been toying around with the handlebar mounted thought. At first I thought the dirt bike "HOT START" levers could be adapted. This is not turning out real promising as the controls on the Savage are really big and get in the way. If you mount the Hot Start lever on the back side of the front brake lever clamp - your thumb is already busy with the starter button - and the large throttle and electrical control box gets in the way of the thumb button and it does not have room to move. The Clutch lever clamping system uses a different type of clamp and the common Hot Start levers would not bolt to the backside of the clamp. Mounting any sort of manual lever will be difficult to work with the clutch safety switch still activated - as you need your right hand to run the starter switch and your left hand to pull in the clutch.....which leaves no extra hands?

My next attempt is going to be to try this sort of Hot Start lever. It mounts by installing a long clutch lever bolt with a spacer beneath the lever. It will be necessary to make a holder for the cable. I believe this one may work as you can pull the lever with your index finger while you pull in the clutch lever with your other fingers.....Maybe!

http://i49.tinypic.com/16jpvmr.jpg

Title: Re: Starting without decompressor ?
Post by Cavi Mike on 12/14/12 at 14:50:57

Man up and get rid of the clutch interlock switch. Now you can use your left hand for the decompressor.

Title: Re: Starting without decompressor ?
Post by Serowbot on 12/14/12 at 15:05:07

That's a cute little lever,... for functionality,.. I'd prefer a left thumb actuation...

Title: Re: Starting without decompressor ?
Post by Dave on 12/14/12 at 18:17:26

496B7C634763616F0A0 wrote:

Man up and get rid of the clutch interlock switch. Now you can use your left hand for the decompressor.

I do plan on getting rid of the clutch and kickstand safety switches when I make the coming change to a Cafe Racer. I was commenting about the "generic" use of a lever to work with as little changes as possible - but in reality the handlebar mounted lever may not be horribly simple.

Title: Re: Starting without decompressor ?
Post by David on 12/16/12 at 15:02:54

I have almost finished the conversion.
Here are a couple of tips to converting a RYCA to handlebar decompression.
A Savage clutch cable is ideal. The hand lever nipple fits the decompressor arm perfectly. may need to open up ever so slightly for the thicker cable.
Using a dremel blade cut off the nipple at the clutch lever end.
The cable outer needs to be removed from the curved tube. Apply a small torch and melt the plastic covering - comes out easy.
I used a 3/16 bracket from your equivalent of Home Depot - you will need a 2" bracket about 4" x 2"
Shorten the 2" length to about 5/8" - this end will mount on the 2 6mm horn mounting holes. These are at 30mm centres.
The 4" leg of the bracket needs to be modified - shortened and twisted to align the cable with decompressor arm
Will send picture if you need it.
Drill a 3/8" hole for the 8mm clutch cable threaded adjuster and join the hole to the edge with a 2.5mm slot for the 2mm cable. This makes fitting the cable easier.
The cable outer should be about 2.5 feet long - It MUST come from the left and cross over behind the headlight to the RIGHT so that the bend into the handlebar decompressor lever is OK.
I made a guide for my decompressor lever to the bowden cable outer using a 6mm x 20mm allen bolt. Drilled through 2.5mm and then drilled the head 6mm.
Making a new nipple on the cable at the lever end was done by getting a 1" block of wood and drilling a 2.5mm hole through about 1/2" from the edge. You will need a small butane torch for this next step
Then drilled 1/2" deep a 6mm hole. Push cable through and then open up using small pliers to make a little brush. Flux the brush and pull into the 6mm hole in the wood. Put solder into the hole and melt with the torch. Wait until cool Push soldered brush out of the hole and cool with water. Cut away the wood and you should have a very strong nipple - may need to be fiiled to suit.