hammer ss 250 low gear grinding noise - BuggyMasters.Com - An On Line Mini Buggy Forum and Go Kart Forum

tigen22 · #1 11-08-2010, 02:27 PM

just recently purchased hammerhead ss 250 with some aftermarket parts already installed, i had to put on a new kevlar belt... i believe it is set up for high speed, when i put in low gear it goes in too gear and when you push the accelerator it takes off, but the more gas you give it makes a clanking/grinding noise. it almost seems to be coming from clutch area... could it be the clutch spring?

EJ Mac · #2 11-09-2010, 01:58 PM

Did you check to insure the rollers were installed in the variator properly and what size belt did you install? The proper one is 868x24.2x30

tigen22 · #3 11-09-2010, 02:11 PM

yea rollers are in properly and belt fits fine spent a little extra and got kevlar as well! runs superb in high and reverse clocked it yesterday with a radar at 62mph!

Turf · #4 03-03-2011, 07:18 AM

I am having the same issue. Ran great until yesterday. When in low gear it sounds as if the chain is jumping. Checked belt tension and it was about 1/2 inch. Seems to be fine in high and reverse. Buggy is less than 3 months old. Only modification is AMS Swamp Fox 22x10-10 tires on rear.

bige · #5 03-05-2011, 06:16 AM

check the chain tension and the idle to make sure it is fully in gear

Turf · #6 03-07-2011, 04:48 AM

Thanks for the response. The chain tension is fine. I am not sure what you mean by checking the idle. It seems like goes into gear. The buggy will move on flat ground, it is when I start to climb a hill that it feels as if the chain is jumping.

bige · #7 03-07-2011, 05:00 AM

have you adjusted the shift cable? also how much slack is in the chain? dosent need to be more than 1/4-3/8 inch of play

Turf · #8 03-07-2011, 06:38 AM

Have not adjusted the shift cable. There is about 1/2 inch slack in the chain.

KID4LIFE · #9 03-12-2011, 02:26 PM

so what you are saying is that it goes into gear fine.....runs in high gear fine....but under a load in low gear, it's jumping?

i would think that your issue is either with the chain being too loose or you have a bad sprocket.??
hopefully, it's nothing to do with low gear inside the case.

Turf · #10 03-14-2011, 04:42 AM

That is correct. No issue in high gear. In low gear, as soon as I put it under any load, it acts as if the chain is jumping. I have adjusted the chain tension, and I checked the sprocket to see if a tooth was missing or something else. I thought if there was a problem with the sprocket it would also jump in high gear.

bige · #11 03-14-2011, 05:36 AM

if the shifter adjustment is good then there could be a problem with the shift fork. I have a hh250 in the shop now that just grinds in low gear and the shift fork was bent slightly and has worn the teeth of the main shaft

Turf · #12 03-14-2011, 06:09 AM

I also checked the shifter adjustment and it seems to be fine. It should still be under warranty, so I am going to call the dealer I bought the buggy from.

KID4LIFE · #13 03-14-2011, 11:11 AM

i would assume that if the buggy goes into low gear without an issue that your problem may be internal with gearing. if when you shift it into low gear and you hear it "click" into gear, the linkage and fork is doing it's job.

Turf · #14 03-14-2011, 12:13 PM

It does go into low with no problem, just starts slipping when any load is applied.

jwags55 · #15 03-23-2011, 09:34 AM

It is very possible the low gear (part # 172MM-B-062004) and drive gear (part # 172MM-B-062005) are bad. The teeth are probably OK, but the dogs that engage are likely rounded. I just purchased a used 250 SS with this exact problem. If you can hold it in low gear by using the shifter, then this is good indication that the dogs are rounded. I carefully ground the rounded edges square with a hand grinder as a temporary solution, but I have ordered new gears. Check several websites for prices, they range from $20 to $75 for the same part. I have to say up front, that getting to the gearbox is a real pain.

Turf · #16 03-23-2011, 10:22 AM

Thanks for your response. Sounds like you are correct. I talked to the dealer who I bought the buggy from, and you just reitterated his diagnosis. Fortunately mine is still under warranty. I will be dropping it off on Saturday for repair. Do you have any idea what would cause the the dogs to become rounded? I have only had mine for three months.

jwags55 · #17 03-23-2011, 11:28 AM

This happens when the gears are changed while buggy is in motion or the engine is at a relatively high rpm. Make sure the shifter lock is working properly (cable that goes from the brake pedal to the shifter). You should have to depress the brake before the shifter can be moved. That was not working on mine. I traced the cause back to a ill-fitting brake stop (the washer-shaped gizmo welded to the brake pedal with a bolt though it). It was not accurately welded and it limited the travel of the brake pedal. Because there wasn't enough travel, the shifter lock mechanism would not work, so the original seller just adjusted it enough so it never locked. The buggy didn't need the brake depressed to shift gears. That works OK if you never shift if while moving, but that's a bit risky.

There a ball and detent mechanism inside the gearbox that hold the shifting forks in position, but it is not designed to securely lock the gear shifter.

Turf · #18 03-23-2011, 11:52 AM

Thanks for the explanation. You really know these buggies. I will definitely check the shifter lock. What is your overall impression of the buggy?

jwags55 · #19 03-23-2011, 02:28 PM

I hope it helps. I just purchased my 250 SS recently. I haven't even hit the trails with it yet. I also have a Carter 150 that I have significantly modified over the last year, but I finally threw in the towel with the 150 - just not enough horsepower for my hill climbing needs. I was seriously considering a 232 cc GY6 motor for the Carter when I saw the Hammerhead on craigslist and got it for $2500 (low miles with bad low gear). The high / low gearbox was the main reason for buying the 250 SS. Just from driving it around the yard, I can't wait to hit the trails soon.

Turf · #20 03-23-2011, 02:39 PM

I have only had mine for three months, but so far I really like it. I was very hesitant to pay almost $ 4,000.00 for a chinese made buggy. The high/low gearing does come in handy for steeper hills.

Turf · #21 04-11-2011, 02:28 PM

Got the buggy back from the dealer two weeks ago, took it home and when I went to back off the trailer I could not move the shifter. Took it back to the dealer and they said the shaft that goes through the casing was stuck. Picked it up Saturday and it now shifts fine. The grooves on the side of the low range gear were stripped.