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SMALL DISPLACEMENT FOUR STROKE GLOW TO GAS CONVERSION

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Old 03-25-2012, 12:24 PM
  #651
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Default RE: SMALL DISPLACEMENT FOUR STROKE GLOW TO GAS CONVERSION

Thanks for your replies Adrian and T-man. I always lusted after a VT-240, as I used to own several Enya 4-strokes and really liked them a lot. But I wasn't into large scale models back then.

It's unfortunate that the Walbro WT-456 and the Zama C1Q P8 8YA carbs are both discontinued. I've asked the UK distributor of both makes to see if they can find any, but don't hold any hope of success. After attempting to search through the huge Walbro WT- carb list, and not having a similar Zama list, I gave up and decided to try a different route.

As long as the Laser carbs receive a constant fuel supply they idle, throttle smoothly and give good max revs. The carb throat diameter is 8.34mm, which is significantly larger than that of the WT-456 and is probably why the engine is short of suck on petrol. If anyone can advise me of a Walbro or Zama 4-stroke carb with accelerator pump and around 8.4mm throat dia, and which is still available, I'd be very grateful.

Given that the Laser carbs seem to work on gas, I decided to investigate ways of providing a constant fuel pressure for the existing carbs. First I looked into chicken hopper and uniflow tanks, but they didn't seem to offer what was needed for an R/C aerobatic job.

Next I looked at Cline http://www.billsroom.com/pcfs/ and Iron Bay http://www.ironbaymodelcompany.com/i...es/Page438.htm regulators and the Perry VP40-SG Pump regulator http://www.perrypumps.com/prod02.htm

The Cline and Iron Bay regs need the tank pressurising, and quite honestly I don't want to mess about with muffler pressure. If there is space inside a model, one idea would be to pressurise the tank via a pressure reservoir which could comprise a plastic 10oz fizzy drink bottle pumped to about 10psi. A check valve would stop fuel entering the air reservoir during fuelling.

The Perry gas pump-regulator might be the best thing to try initially, though I don't know if the regulator is a demand-type like the Cline and Iron Bay, or just a needle valve. The Perry website says that it will pump up to a max of 3.5 oz/minute, which is well in excess of what even a 40cc petrol engine needs. I found this page http://saito-engines.info/pumps.html which describes the glow version's use with a large Saito 4-stroke. The same page also describes an interesting Saito system for pressurising a tank from the crankcase, with an extra crankcase vent nipple, and a needle valve and oil vent.

So besides the pumper carb route, there appear to be a number of avenues to investigate which have the advantages of retaining the existing twin carbs and not having to make new intake piping, the configuration of which could be difficult for a Laser vee because of the non-parallel orientation of the intake bores in the head, and the peculiar carb mounting arrangement.
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Old 03-25-2012, 03:15 PM
  #652
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Default RE: SMALL DISPLACEMENT FOUR STROKE GLOW TO GAS CONVERSION

The so called regulator in a Perry pump is just a maximum pressure regulator. It is not a demand regulator like with a Cline or Iron Bay.

You can use the crank case pressure of a two stroke engine to make pressure if you use a check valve in the line.
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Old 03-25-2012, 04:00 PM
  #653
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Default RE: SMALL DISPLACEMENT FOUR STROKE GLOW TO GAS CONVERSION



Here are couple options, Yes means accelerator PUMP.

WT-184-1 7.94 mm yes $ 52.07 http://wem.walbro.com/walbro/product...rtnum=WT-184-1
WT-424-1 7.94 mm yes $ 82.65 http://wem.walbro.com/walbro/product...rtnum=WT-424-1
WT-68-1 7.53 mm yes $ 53.86 http://wem.walbro.com/walbro/product...artnum=WT-68-1


And here is an OS160 Twin GLOWCDI that gave a bit trouble but I got it.

.[youtube]http://www.youtube.com/watch?v=CMq9189ToT8&feature=youtu.be[/youtube]


Thank You
Adrian

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Old 03-25-2012, 04:10 PM
  #654
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Default RE: SMALL DISPLACEMENT FOUR STROKE GLOW TO GAS CONVERSION

Here is a compilation of WT carbs that my wife Cameliadid for CH Ignitions . Hope this will help lot of people.

Thank You
Adrian Ciulei
Walbro WT Series with Acceleration Pump from 6.5mm to13mm
Walbro Part Name Venturi Size Acc Pamp Price Walbro Link
WT-1008-1 11.1 mm Yes $ 117.00 http://wem.walbro.com/walbro/product...=WT%2D1008%2D1
WT-101-1 9.53 mm yes http://wem.walbro.com/walbro/product...m=WT%2D101%2D1
WT-102-1 9.53 mm yes NA http://wem.walbro.com/walbro/product2.asp?Series=WT&partnum=WT%2D102%2D1
WT-103-1 7.94 mm no http://wem.walbro.com/walbro/product2.asp?Series=WT&partnum=WT%2D103%2D1
WT-108-1 11.1 mm yes NA http://wem.walbro.com/walbro/product2.asp?Series=WT&partnum=WT%2D108%2D1
WT-112-1 9.53 mm yes $ 79.00 http://wem.walbro.com/walbro/product2.asp?Series=WT&partnum=WT%2D112%2D1
WT-113-1 9.53 mm yes NA http://wem.walbro.com/walbro/product2.asp?Series=WT&partnum=WT%2D113%2D1
WT-117-1 7.14 mm yes NA http://wem.walbro.com/walbro/product2.asp?Series=WT&partnum=WT%2D117%2D1
WT-125-1 13.49 mm yes http://wem.walbro.com/walbro/product2.asp?Series=WT&partnum=WT%2D125%2D1
WT-126-1 13.49 mm yes http://wem.walbro.com/walbro/product2.asp?Series=WT&partnum=WT%2D126%2D1
WT-130-1 11.1 mm yes NA http://wem.walbro.com/walbro/product...rtnum=WT-130-1
WT-137-1 9.53 mm yes NA http://wem.walbro.com/walbro/product...rtnum=WT-137-1
WT-143-1 12.7 mm yes NA http://wem.walbro.com/walbro/product2.asp?Series=WT&partnum=WT%2D143%2D1
WT-151-1 9.53 mm yes NA http://wem.walbro.com/walbro/product...rtnum=WT-151-1
WT-157-1 7.14 mm no $ 44.68 http://wem.walbro.com/walbro/product...rtnum=WT-157-1
WT-158-1 12.7 mm yes $ 56.28 http://wem.walbro.com/walbro/product2.asp?Series=WT&partnum=WT%2D158%2D1
WT-159-1 12.7 mm yes http://wem.walbro.com/walbro/product2.asp?Series=WT&partnum=WT%2D159%2D1
WT-161-1 9.53 mm yes http://wem.walbro.com/walbro/product...rtnum=WT-161-1
WT-163-1 7.14 mm no $ 50.57 http://wem.walbro.com/walbro/product...rtnum=WT-163-1
WT-166-1 7.94 mm no http://wem.walbro.com/walbro/product...rtnum=WT-166-1
WT-171-1 13.49 mm yes http://wem.walbro.com/walbro/product2.asp?Series=WT&partnum=WT%2D171%2D1
WT-172-1 13.49 mm yes http://wem.walbro.com/walbro/product2.asp?Series=WT&partnum=WT%2D172%2D1
WT-184-1 7.94 mm yes $ 52.07 http://wem.walbro.com/walbro/product...rtnum=WT-184-1
WT-188-1 7.94 mm no $ 51.24 http://wem.walbro.com/walbro/product...rtnum=WT-188-1
WT-189-1 7.94 mm no $ 68.51 http://wem.walbro.com/walbro/product...rtnum=WT-189-1
WT-198-1 7.94 mm no $ 55.67 http://wem.walbro.com/walbro/product...rtnum=WT-198-1
WT-204-1 9.53 mm yes http://wem.walbro.com/walbro/product...rtnum=WT-204-1
WT-210-1 7.94 mm no $ 41.94 http://wem.walbro.com/walbro/product...rtnum=WT-210-1
WT-219-1 9.53 mm yes $ 192.00 http://wem.walbro.com/walbro/product...rtnum=WT-219-1
WT-228-1 13.49 mm yes NA http://wem.walbro.com/walbro/product2.asp?Series=WT&partnum=WT%2D228%2D1
WT-292-1 7.94 mm no $ 52.91 http://wem.walbro.com/walbro/product...rtnum=WT-292-1
WT-298-1 7.14 mm no http://wem.walbro.com/walbro/product...rtnum=WT-298-1
WT-300-1 7.14 mm no http://wem.walbro.com/walbro/product...rtnum=WT-300-1
WT-308-1 7.14 mm no http://wem.walbro.com/walbro/product...rtnum=WT-308-1
WT-311-1 6.50 mm yes NA http://wem.walbro.com/walbro/product...rtnum=WT-311-1
WT-317-1 9.53 mm yes http://wem.walbro.com/walbro/product...rtnum=WT-317-1
WT-323-1 11.1 mm yes NA http://wem.walbro.com/walbro/product...rtnum=WT-323-1
WT-330-1 7.94 mm no $ 56.56 http://wem.walbro.com/walbro/product...rtnum=WT-330-1
WT-332-1 6.50 mm yes NA http://wem.walbro.com/walbro/product...rtnum=WT-332-1
WT-337-1 11.1 mm yes NA http://wem.walbro.com/walbro/product...rtnum=WT-337-1
WT-341-1 7.94 mm no http://wem.walbro.com/walbro/product...rtnum=WT-341-1
WT-346-1 7.94 mm no http://wem.walbro.com/walbro/product...rtnum=WT-346-1
WT-35-1 9.53 mm yes NA http://wem.walbro.com/walbro/product...artnum=WT-35-1
WT-352-1 7.94 mm no
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Old 03-25-2012, 06:37 PM
  #655
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Default RE: SMALL DISPLACEMENT FOUR STROKE GLOW TO GAS CONVERSION

Hey Adrian,

Sure sounds sweet ! ! !

Is it running with a gas carb ?

Mine has been on the conversion "list" for a while, . . .
but it's behind the Saito 150 and 182T

Looks like you are getting settled quick and all is
going you way.

Congrats and best wishes for you, my friend


Mike Brennan
T-man49 in AL
Club Saito 723

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Old 03-26-2012, 04:41 AM
  #656
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Default RE: SMALL DISPLACEMENT FOUR STROKE GLOW TO GAS CONVERSION

I'm pretty sure that he is running it on glow but with his ignition on it. Glow engines run nicely on ignition and you can get lower idle out of them and better fuel economy too.
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Old 03-26-2012, 05:04 AM
  #657
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Default RE: SMALL DISPLACEMENT FOUR STROKE GLOW TO GAS CONVERSION

Hi Mike,

No, the engine is with original Glow old style carb.
I did try it with gas also and it runs. The transition is not as quick as Glow Fuel but it runs fine ,trasition is not as brisk.

Thank you
Adrian
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Old 03-26-2012, 07:58 AM
  #658
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Default RE: SMALL DISPLACEMENT FOUR STROKE GLOW TO GAS CONVERSION

Hello i am new to this forum i went back in the forum to try to find a suitable carb for the saito 125 i have , here i Croatia it is hard to get nitro and very expensive , i want to convert it but can’t find a WT 456-1 anyone have any ideas where i can look. Or what else I can use or just use the stock glow carb. do the o ring seals need to be changed or is it ok for gas in that situation. thank you
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Old 03-26-2012, 08:42 AM
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Default RE: SMALL DISPLACEMENT FOUR STROKE GLOW TO GAS CONVERSION

Hi Elvir,

It is not only the carb, you need also a bracket to support the carb, a pick-up sensor, Ignition. If you will be cloaser I will do it for you.
The WT 456-1 or Zama C1Q P8 8YA , I have the zama carbs.

Thank You
Adrian.
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Old 03-27-2012, 11:56 AM
  #660
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Default RE: SMALL DISPLACEMENT FOUR STROKE GLOW TO GAS CONVERSION


Quote:
ORIGINAL: C&H SparkGuy

Here is a compilation of WT carbs that my wife Camelia did for CH Ignitions . Hope this will help lot of people.

Thank You
Adrian Ciulei


Hi Adrian

A huge thankyou to you and Camelia for sharing your WT lists with us. I'm sure that it was time-consuming and brain-numbing to compile, but it was well-worth doing, resulting in a much more useful list than Walbro's original.

Thanks and best regards

Gordon

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Old 03-27-2012, 01:01 PM
  #661
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Default RE: SMALL DISPLACEMENT FOUR STROKE GLOW TO GAS CONVERSION

Quote:
ORIGINAL: tkg

Oh I'm around for questions.
BTW CH units were potted with a special goo. Worked very well in high vibration environments, but could be easily removed for repairs and then repotted. It just was not poured full of epoxy.
More BTW CH started using the SS (computer timing) unit about 15 years ago. The original MK1 unit was fantastic, the MKII used the same program but was surface mounted. The MKIII and the MKIV were surface mounted but had multiple programs in each chip. The MKIII had 2 programs and the MKIV had 4 programs. We could select the correct program for the engine being used. That selection is why the CH units worked so well on ''difficult'' engines

I bought my C&H units about '97. 1 for a saito FA150, the other for a Saito 300TTDP Twin.

Both run great, Would these be the "Mark I" units you speak of?
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Old 03-28-2012, 01:36 AM
  #662
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Default RE: SMALL DISPLACEMENT FOUR STROKE GLOW TO GAS CONVERSION

Back in 97 Wow that sounds strange! I don't think the CH units came with timing control. I think it was a separate unit. If you have a synchrospark from back then it may be the mark I.
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Old 03-28-2012, 03:07 AM
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Default RE: SMALL DISPLACEMENT FOUR STROKE GLOW TO GAS CONVERSION

Quote:
ORIGINAL: COM

Back in 97 Wow that sounds strange! I don't think the CH units came with timing control. I think it was a separate unit. If you have a synchrospark from back then it may be the mark I.

Yep, it's a "Syncrospark" unit.

I bought the single cylinder sytem in '97 but I think that I bought the twin unit in '98..
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Old 03-28-2012, 03:18 AM
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Default RE: SMALL DISPLACEMENT FOUR STROKE GLOW TO GAS CONVERSION

Quote:
ORIGINAL: triumphman49


Mine has been on the conversion ''list'' for a while, . . .
but it's behind the Saito 150 and 182T


I think you might need 2 separate systems fired by 2 hall sensors for the 182. It's not an even firing twin. W/a "twin" module, 1 cylinder will be firing the "waste spark" near BDC of the intake stroke while the other will be firing the waste spark near BDC of the power stroke.

You will need 2 trigger magnets mounted 180* apart for a "twin" ignition module. For 2 separate "single" modules you only need 1 trigger magnet but you will need to mount 2 hall sensors 180* apart.
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Old 04-07-2012, 06:23 PM
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Default RE: SMALL DISPLACEMENT FOUR STROKE GLOW TO GAS CONVERSION


Quote:
ORIGINAL: COM

Back in 97 Wow that sounds strange! I don't think the CH units came with timing control. I think it was a separate unit. If you have a synchrospark from back then it may be the mark I.

I just picked up an as new Syncro Spark unit for my saito FA 91 on RCG.

Note the date scribed on the back of the unit 12-97.





This unit is about 2/3 the size of the unit I purchsed for my FA 150 back in '97. That unit is scribed W/a date of 5-97.

The unit from RCG was on an engine mounted in an airframe "under construction". It had never been used.

Here is the listing from RCG.

http://www.rcgroups.com/forums/showthread.php?t=1616177

The unit mounted right up to my FA 91 & it made good, hot spark when I passed the magnet over the hall sensor.
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Old 04-08-2012, 04:07 PM
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Default RE: SMALL DISPLACEMENT FOUR STROKE GLOW TO GAS CONVERSION

The size of the coil drove the size of the box.
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Old 04-08-2012, 09:21 PM
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Default RE: SMALL DISPLACEMENT FOUR STROKE GLOW TO GAS CONVERSION

Can I shorten the spark plug leads on a rcxel twin ignition to 5" long?

motorhd

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Old 04-09-2012, 03:18 AM
  #668
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Hi Motorhd,

You can shorten them ...but you will need to use a SPK Cap Kit of the SPK you are using.
Ii You do not feel confortable doing that send it to me and Iwill take care of it.

Thanks
Adrian

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Old 04-13-2012, 12:21 PM
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Default RE: SMALL DISPLACEMENT FOUR STROKE GLOW TO GAS CONVERSION

Hi Guys

I've now got a pair of Zama C1Q P8 8YA carbs and I'd appreciate advice on the items below.

Pic 1 shows the huge plastic needle limiters, which I hope I can do without because they'll get in the way. Is there an easy way to remove them?

Pic 2 shows a tube which I think I saw earlier in the thread is used for priming. Presumably this needs blocking?

Pic 3 shows the throttle butterfly. The spring is far too strong for working with a servo, so is it OK to remove the spring? I remember reading years ago that the spring also stopped the butterfly from chattering, so maybe it needs replacing with a compression spring between the lever and the carb body.

In this pic, have I correctly labelled the pulse pressure hole?

Pic 4 shows the choke and throttle stop screw. I'm thinking of removing the choke, and replacing the the screw with a sharpened grub screw. Any problems?

Thanks

Gordon
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Old 04-13-2012, 12:53 PM
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Default RE: SMALL DISPLACEMENT FOUR STROKE GLOW TO GAS CONVERSION

Hi Gordon,

Pic 1: You can remove the Plastics, just get a pair of pliers and pull them off. I do that 99% of the time.
Pic 2: You must plug that. Get some tygon tubbing, heat it up and one end with a ....lighter and pinch them together when is hot enough...or pinch the brass shut and solder.
Pic 3: Take the spring from curent position and put it on the curve between the 2nd and 3rd hole. look at my pic. Pulse hole is correct.
Pic 4: Yes you can remove it if you like....but why? if is to long...you can cut it. It will make it easier to prime the carb. You can remove also the thootlle adjustment position since you get it on the servo and you will position with that. however
it my get idle sensitive and you will relay on the servo. If the screw is there ...then will hold that position all the times.

This carb can pull gasoline from 1-2 feet away easy. tank can be below ,above center carb.

Hope it helps
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Old 04-13-2012, 03:14 PM
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Default RE: SMALL DISPLACEMENT FOUR STROKE GLOW TO GAS CONVERSION


Hi Gordon,

I've played with a C1Q ZAMA before (a different model by the looks of it) and didn't have a huge amount of success on the engine I used it for (high end lean out at 7000+) but it's still worth a try.

Pic 1: I did it the messy way, just hacking away until it was off. Lucky for you both needles are adjustable, my carb had one adjustable and one pressed/fixed needle.

Pic 2: Just cap it off some how. I wouldn't recommend crimping it closed as you'll never know when you want to use it again.

Pic3: I never removed the spring as the carb never progressed to flight status. Removing it may create some lateral shaft slop so be careful. I'd also suggest removing the butterfly and sealing off any holes in the throttle plate for better idle control. Thin litho plate secured by the centre screw will do fine. Watch which way the plate goes in, it only fits properly one way due to the various bevels/tapers. Yes, that's a pulse hole.

Pic 4: I left the idle screw in place, it will still provide a stop if needed. Removing the choke shaft will cause a detent bearing and spring to come out. I've run mine without this but be aware you could be letting air bleed in from the shaft hole. You could probably plug it with some fuel compatible sealant.

Good luck!

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Old 04-14-2012, 06:30 AM
  #672
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Default RE: SMALL DISPLACEMENT FOUR STROKE GLOW TO GAS CONVERSION

Thankyou for your help guys.

A couple of weeks ago I tried using a Perry regulating pump working from crankcase pulses with the standard glow carbs. I spent an afternoon trying to get pump and carbs to work together, but in the end gave up as I began to lose the settings, couldn't remember what needle settings I'd started with, and couldn't achieve reliability. I wondered about getting a Cline or Iron Bay regulator, but then the Zamas came up on Ebay, and as the pair were cheaper than one Cline or IB, I decided to get the Zamas and give them a go.

With the limiter pulled off and choke shaft shortened, I should be able to fit one per cylinder. Looking at the engine this morning, I spotted what might be an easy way of fitting a single carb. Laser vees aren't just as straightforward as the usual 4-stroke singles or flat twins for fitting gas carbs. It doesn't matter whether I fit one or two carbs, I'll still have to replace the existing radial mount arrangement. A "U" style as used on various flat twins made from alloy plate will suffice. I'll keep you all posted with progress, but please don't hold your breaths as I'm dealing with some other projects right now.

The pulse hole is quite some distance from the intake throat. I'm planning to buy some PTFE sheet to make a heat spacer, so presumably, I can cut a slot in that to link the pulse hole with the intake?

Thanks again

Gordon
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Old 04-19-2012, 04:34 PM
  #673
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Default RE: SMALL DISPLACEMENT FOUR STROKE GLOW TO GAS CONVERSION

Wow, that was quite a read. First off, I want to thank all of the contributers to this thread. I think I'm going to try to do a conversion on my Saito .82. Do you think the Zama (or walbro) mentioned would work with the .82? Assuming I can find either... I'll also be keeping an eye on your CH site, Adrian, for when you start to sell the ignitions again. I may buy one of the other Zama carbs on e-bay that I've seen, even if it won't work for the .82, just to get a better handle on how they work. Maybe I'll try to figure a way to regulate the fuel so that the stock glow carb will work. It sounds like less fuel is needed in the middle. Maybe play with needle taper. The stock needle has a very linear taper which can be changed easily enough, and I have a Cline I can play with. I must admit that I love messing with these small engines. If I get it to run well, I may have to get a plane to fly it in!
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Old 05-27-2012, 01:04 PM
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Default RE: SMALL DISPLACEMENT FOUR STROKE GLOW TO GAS CONVERSION

hello again i just got back to croatia from the states and had my saito 125 converted to gas , Adrian at ch ignitions did it for me while i was in the ststes so i did not have to play around with it . i had him do all the work grate for me and with no fuss, only problem was that i got mixed up on the fule i did like nitro 20 % in stead of 20 to 1 i email to adrian and all was fixed added 3 liters of fuel to the can and what a diffrence smoth idel and grate top end did not finish with the timing i ballparked it for now . here is a small vid on youtube.

http://www.youtube.com/watch?v=p4oxVkKoBi8
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Old 05-27-2012, 01:07 PM
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Default RE: SMALL DISPLACEMENT FOUR STROKE GLOW TO GAS CONVERSION

i almost forgot


thank you again adrian for the grate help you made life much eiser for me to do the conversion


thank you
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