# HS724 conversion to HS924



## RikP (Jan 19, 2021)

Hi,

I am transforming my recently bought HS724 (TA / serial : SZBE-1045594) to HS924 (TA) by replacing the GX200 with a GX270. For fun, for challenge and to change from 15 h/d working remotely with Teams since march 2020.

I've read a lot on the subject. I know it will not be swap only project, but I will try. If it's not working, I will reinstall the GX200.

I bought a used GX270 engine from a old HS928 with original pulleys / pulley stoppers.
Electric starter
Serial : GCAB-2401792

I bought a used HS928 engine bed (upper part only) to keep untouch the original one... Just in case.
I bought new V-Belt cover for HS928 + HS 928 V-Belts (SA29 / SB35)

*I have some questions (see in bold) regarding the used engine / conversion.*

Engine: There is only 1 wire coming out of the blower housing on the right side and was wrapped with blue tape, holding up the wire.

Very strange because I never find this config in parts seller sites, but my Honda dealer told me that it's really a GX270 from a snowblower.
*Anybody already saw this config* ?


My HS724 has 2 wired (white / green) coming out of the blower housing on the right side. My GX270 has only 1.
*I suppose that's the positive wire that exit from the used GX270. Where can connect the negative to plug my lamp. Can I pass a wire in the same file envelope and screw it somewhere in the flywheel compartment to have both wires coming from the same location ?*


Uses GX270 was running fine but, I take the compression (no exhaust / no air filter) and It's about 84-87 psi.
*Is it a problem ?*



Engine bed
Too bad, mine has to holes to connect with the upper handle pipe because, I have a shock for height adjustment. I will do a new hole as the HS724.



Conversion: Except for the engine bed, I take the hypothesis that all pieces (Cables / tension arm / transmissions / anger / wheel pulleys / chuter) will be the same (or fit with minimum handling) from HS727 and HS929. I hope I am right.

I suppose that I will need to move the tension arm bracket (right side engine bed) from lower holes to the higher holes (see_ picture #1_picked from a post in the forum) as the lower holes where for HS624 / HS724
*Can someone confirm ?*


Same for the tension spring stay screwed to the right transmission. Here also, there is many holes. I must use the lower one has tension arm bracket will be higher.
*Can someone confirm ?*


I have a concern for the wire holder (see picture #3) screwed the right bed. If I move the tension arm bracket to the higher holes, I suppose that the wire holder is higher on a HD928 then a HS724.
*Are they the same or I am right ?*


I may have to move the spring pins on the upper chute handle (see picture #4). I do know yet.
*Anyone ?*


Any other hint is welcome.

Thank you very much

Erik
Canada


Picture #1









Picture #2









Picture #3









Picture #4


----------



## 140278 (Aug 27, 2020)

welcome to the SBF

hang tight there are a few VERY knowable honda people in here. 2 are most likely in bed EST the other is PST he might see your post before he hits the sack


----------



## JnC (Feb 21, 2014)

I have done this conversion in the past, in fact it was my first ever Honda snowblower that I did this modification/upgrade to, went from HS624W to HS924TAS.



Here are the answers


The GX270 has 50W/3A coil onboard that one wire coming out is positive for the headlight, ground is usually anywhere on the motor.
The two wire set up on the GX200 means its probably one of the newer motors and has positive/negative coming out for the 15W lamp, oddly I have not seen a HS724 with a 15W lamp as usually they have a 50W/3A coil onboard as well. It could be that your machine has charge coil on board hence one wire might be for the lamp and the other might be to charge the onboard battery, any easy way to take care of this issue and not have to run into any wiring snafus is by just swapping the HS724 coil onto the HS928 motor, the HS928 motor seem to be off of a machine without the electric start, electric chute and onboard battery.
That might be an issue as good compression is suppose to be 85-121PSI, you are on the low end, usually folks don’t change the engine oil on a timely bases, that could be a cause for that and/or the engine might have had a rough life. You can change the rings on the piston and that usually solves the issue, checking the limits within the cylinder might yield a better answer as to if you need to go up in size on the rings.


Engine beds usually have holes punched out in them for the GX240/270 motors, rather than buying a new engine bed I just cut off the old studs and welded new ones in the pre-punched holes from factory to be used with the GX270 motor.

The auger brake apparatus will have to be moved up to the top set of holes on the chassis plate, see picture below, use the holes circled in yellow for the HS928.




The tension spring holder would be mounted to the gearbox using the lowest two holes on the bracket.

The wire hold is different for the HS928 and the HS724, you’d need to get a new one.

The chute rotator will need to be adjusted as well to go around the belt cover, the HS724 chute cover will not fit the bigger HS928 motor.


----------



## RikP (Jan 19, 2021)

JnC said:


> I have done this conversion in the past, in fact it was my first ever Honda snowblower that I did this modification/upgrade to, went from HS624W to HS924TAS.
> 
> 
> 
> ...


----------



## orangputeh (Nov 24, 2016)

I havent done this conversion. a lot of work but may be worth it ..... have done several 1128's which is just a straight switch of bucket/augers.

not sure why Honda went from the 80 ( which is a 824 ) to the 624-724. I put impeller kits on the old 80's and they rival the 928 in blowing power. 

your compression may be okay because of the decompressor on the camshaft. 

look forward to seeing your progress. when done this 924 will be unstoppable.


----------



## RikP (Jan 19, 2021)

orangputeh said:


> I havent done this conversion. a lot of work but may be worth it ..... have done several 1128's which is just a straight switch of bucket/augers.
> 
> not sure why Honda went from the 80 ( which is a 824 ) to the 624-724. I put impeller kits on the old 80's and they rival the 928 in blowing power.
> 
> ...


Thank you very much.
What a great forum full of helpfull members.



> your compression may be okay because of the decompressor on the camshaft.


This is very interesting. Should I understand that I will never get a 85-125 psi with a standard compression mesure as I did ?
I will talk with a small engine mecanic tonight. He rebuild Honda engine everyday. I hope he will give me the same explanation.
If not, we will open the engine together if required. 

For sure, I will post my experience.

Thank you again.

Erik


----------



## Patrick0525 (Dec 24, 2020)

Following this thread.


----------



## AK_Beag (Dec 23, 2020)

Just making sure, but did you check the valve adjustments were in spec before doing the compression test?


----------



## RikP (Jan 19, 2021)

AK_Beag said:


> Just making sure, but did you check the valve adjustments were in spec before doing the compression test?


No, but I will and redo the test. 

However, my investigations lead me to the conclusion that it's impossible to get 85 -125 PSI because of the decompressor on the camshaft.


----------



## drmerdp (Feb 9, 2014)

I’ve been patiently waiting for a hs624wa to pop up for a reasonable price for a couple years now. Same plan, gx270 swap. A HS924 would nicely compliment my HSS1328.


----------



## RikP (Jan 19, 2021)

Hi,
Project is almost finished. Each step is a challenge that I will describe when the project is completed and tested.
My actual challenge is the anger belt.

Gx270 pulleys are 1 inch higher than Gx200 on the bed. 

For wheel drive, HS928 has a sa27 belt and HS724 has a sa27 = ok, perfect fit
For auger, HS928 has a sb35, same thing has HS724. That's impossible because Gx270 is higher than Gx200 and engine pulley and auger pulley are the same size.
My only conclusion is that HS928 auger driven pulley is higher in the auger housing ?

*My only solution is to find a sb37 belt. Do you know if it's available ?*

My plan was also to change the tension arm position (to the upper one) and use the wire holder from a HS928 to use the belt cover from an hs928.

Too bad, as the HS724 auger driven pulley seems lower than a hs928, the auger break arm is too short.
My only solution seems to keep the tension arm in lower position and to modify the belt cover of the HS928 to fit correctly (actually one side is lower than the other. * Any suggestion?*

Thank you

Erik


----------

